Research Studies & Publications


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Inadequate Hydration, BMI, and Obesity Among US Adults: NHANES 2009-2012.

Chang, T., Ravi, N., Plegue, M.A., Sonneville, K.R., Davis, M.M., Annals of Family Medicine, July 2016

PURPOSE: Improving hydration is a strategy commonly used by clinicians to prevent overeating with the goal of promoting a healthy weight among patients. The relationship between weight status and hydration, however, is unclear. Our objective was to assess the relationship between inadequate hydration and BMI and inadequate hydration and obesity among adults in the United States. METHODS: Our study used a nationally representative sample from the National Health and Nutrition Examination Survey (NHANES) 2009 to 2012, and included adults aged 18 to 64 years. The primary outcome of interest was body mass index (BMI), measured in continuous values and also categorized as obese (BMI ≥30) or not (BMI <30). Individuals with urine osmolality values of 800 mOsm/kg or greater were considered to be inadequately hydrated. Linear and logistic regressions were performed with continuous BMI and obesity status as the outcomes, respectively. Models were adjusted for known confounders including age, race/ethnicity, sex, and income-to-poverty ratio. RESULTS: In this nationally representative sample (n = 9,528; weighted n = 193.7 million), 50.8% were women, 64.5% were non-Hispanic white, and the mean age was 41 years. Mean urine osmolality was 631.4 mOsm/kg (SD = 236.2 mOsm/kg); 32.6% of the sample was inadequately hydrated. In adjusted models, adults who were inadequately hydrated had higher BMIs (1.32 kg/m(2); 95% CI, 0.85-1.79; P <.001) and higher odds of being obese (OR = 1.59; 95% CI, 1.35-1.88; P <.001) compared with hydrated adults. CONCLUSION: We found a significant association between inadequate hydration and elevated BMI and inadequate hydration and obesity, even after controlling for confounders. This relationship has not previously been shown on a population level and suggests that water, an essential nutrient, may deserve greater focus in weight management research and clinical strategies.

Prevention of Childhood Lead Toxicity

Council on Environmental Health, Pediatrics, June 2016

Blood lead concentrations have decreased dramatically in US children over the past 4 decades, but too many children still live in housing with deteriorated lead-based paint and are at risk for lead exposure with resulting lead-associated cognitive impairment and behavioral problems. Evidence continues to accrue that commonly encountered blood lead concentrations, even those below 5 µg/dL (50 ppb), impair cognition; there is no identified threshold or safe level of lead in blood. From 2007 to 2010, approximately 2.6% of preschool children in the United States had a blood lead concentration ≥5 µg/dL (≥50 ppb), which represents about 535 000 US children 1 to 5 years of age. Evidence-based guidance is available for managing increased lead exposure in children, and reducing sources of lead in the environment, including lead in housing, soil, water, and consumer products, has been shown to be cost-beneficial. Primary prevention should be the focus of policy on childhood lead toxicity.

Hydration and Chronic Kidney Disease Progression: A Critical Review of the Evidence

Clark W.F., Sontrop J.M., Huang S.-H., Moist L., Bouby N., Bankir L., American Journal of Nephrology, 2016;43:281-292, June 2016

We performed a comprehensive literature review to examine evidence on the effects of hydration on the kidney. By reducing vasopressin secretion, increasing water intake may have a beneficial effect on renal function in patients with all forms of chronic kidney disease (CKD) and in those at risk of CKD. This potential benefit may be greater when the kidney is still able to concentrate urine (high fluid intake is contraindicated in dialysis-dependent patients). Increasing water intake is a well-accepted method for preventing renal calculi, and current evidence suggests that recurrent dehydration and heat stress from extreme occupational conditions is the most probable cause of an ongoing CKD epidemic in Mesoamerica. In polycystic kidney disease (PKD), increased water intake has been shown to slow renal cyst growth in animals via direct vasopressin suppression, and pharmacologic blockade of renal vasopressin-V2 receptors has been shown to slow cyst growth in patients. However, larger clinical trials are needed to determine if supplemental water can safely slow the loss of kidney function in PKD patients.

Multimedia exposures to arsenic and lead for children near an inactive mine tailings and smelter site

Loh, M.M.,, Environmental Research, Volume 146, Pages 331–339, April 1, 2016

Children living near contaminated mining waste areas may have high exposures to metals from the environment. This study investigates whether exposure to arsenic and lead is higher in children in a community near a legacy mine and smelter site in Arizona compared to children in other parts of the United States and the relationship of that exposure to the site. Arsenic and lead were measured in residential soil, house dust, tap water, urine, and toenail samples from 70 children in 34 households up to 7 miles from the site. Soil and house dust were sieved, digested, and analyzed via ICP-MS. Tap water and urine were analyzed without digestion, while toenails were washed, digested and analyzed. Blood lead was analyzed by an independent, certified laboratory. Spearman correlation coefficients were calculated between each environmental media and urine and toenails for arsenic and lead. Geometric mean arsenic (standard deviation) concentrations for each matrix were: 22.1 (2.59) ppm and 12.4 (2.27) ppm for soil and house dust (<63 μm), 5.71 (6.55) ppb for tap water, 14.0 (2.01) μg/L for specific gravity-corrected total urinary arsenic, 0.543 (3.22) ppm for toenails. Soil and vacuumed dust lead concentrations were 16.9 (2.03) ppm and 21.6 (1.90) ppm. The majority of blood lead levels were below the limit of quantification. Arsenic and lead concentrations in soil and house dust decreased with distance from the site. Concentrations in soil, house dust, tap water, along with floor dust loading were significantly associated with toenail and urinary arsenic but not lead. Mixed models showed that soil and tap water best predicted urinary arsenic. In our study, despite being present in mine tailings at similar levels, internal lead exposure was not high, but arsenic exposure was of concern, particularly from soil and tap water. Naturally occurring sources may be an additional important contributor to exposures in certain legacy mining areas.

Plain water consumption in relation to energy intake and diet quality among US adults, 2005–2012

An, R.,, Journal of Human Nutrition and Dietetics - February 22, 2016

Objective: The present study examined plain water consumption in relation to energy intake and diet quality among US adults. Methods: A nationally representative sample of 18,311 adults aged ≥18 years, from the National Health and Nutrition Examination Survey 2005–2012, was analysed. The first-difference estimator approach addressed confounding bias from time-invariant unobservables (e.g. eating habits, taste preferences) by using within-individual variations in diet and plain water consumption between two nonconsecutive 24-h dietary recalls. Results: One percentage point increase in the proportion of daily plain water in total dietary water consumption was associated with a reduction in mean (95% confidence interval) daily total energy intake of 8.58 (7.87–9.29) kcal, energy intake from sugar-sweetened beverages of 1.43 (1.27–1.59) kcal, energy intake from discretionary foods of 0.88 (0.44–1.32) kcal, total fat intake of 0.21 (0.17–0.25) g, saturated fat intake of 0.07 (0.06–0.09) g, sugar intake of 0.74 (0.67–0.82) g, sodium intake of 9.80 (8.20–11.39) mg and cholesterol intake of 0.88 (0.64–1.13) g. The effects of plain water intake on diet were similar across race/ethnicity, education attainment, income level and body weight status, whereas they were larger among males and young/middle-aged adults than among females and older adults, respectively. Daily overall diet quality measured by the Healthy Eating Index-2010 was not found to be associated with the proportion of daily plain water in total dietary water consumption. Conclusions: Promoting plain water intake could be a useful public health strategy for reducing energy and targeted nutrient consumption in US adults, which warrants confirmation in future controlled interventions.

Effect of a School-Based Water Intervention on Child Body Mass Index and Obesity

Schwartz, A.E.,, JAMA - January 19, 2016

Importance: Decreasing the amount of caloric beverages consumed and simultaneously increasing water consumption is important to promoting child health and decreasing the prevalence of childhood obesity. Objective: To estimate the impact of water jets (electrically cooled, large clear jugs with a push lever for fast dispensing) on standardized body mass index, overweight, and obesity in elementary school and middle school students. Milk purchases were explored as a potential mechanism for weight outcomes. Design, Setting, and Participants This quasi-experimental study used a school-level database of cafeteria equipment deliveries between the 2008-2009 and 2012-2013 and included a sample of 1227 New York, New York, public elementary schools and middle schools and the 1 065 562 students within those schools. Intervention Installation of water jets in schools. Main Outcomes and Measures: Individual body mass index (BMI) was calculated for all students in the sample using annual student-level height and weight measurements collected as part of New York’s FITNESSGRAM initiative. Age- and sex-specific growth charts produced by the Centers for Disease Control and Prevention were used to categorize students as overweight and obese. The hypothesis that water jets would be associated with decreased standardized BMI, overweight, and obesity was tested using a difference-in-difference strategy, comparing outcomes for treated and nontreated students before and after the introduction of a water jet. Results This study included 1 065 562 students within New York City public elementary schools and middle schools. There was a significant effect of water jets on standardized BMI, such that the adoption of water jets was associated with a 0.025 (95% CI, −0.038 to −0.011) reduction of standardized BMI for boys and a 0.022 (95% CI, −0.035 to −0.008) reduction of standardized BMI for girls (P < .01). There was also a significant effect on being overweight. Water jets were associated with a 0.9 percentage point reduction (95% CI, 0.015-0.003) in the likelihood of being overweight for boys and a 0.6 percentage reduction (95% CI, 0.011-0.000) in the likelihood of being overweight for girls (P < .05). We also found a 12.3 decrease (95% CI, −19.371 to −5.204) in the number of all types of milk half-pints purchased per student per year (P < .01). Conclusions and Relevance: Results from this study show an association between a relatively low-cost water availability intervention and decreased student weight. Milk purchases were explored as a potential mechanism. Additional research is needed to examine potential mechanisms for decreased student weight, including reduced milk taking, as well as assessing impacts on longer-term outcomes.

Sugar-Sweetened Beverage Consumption Among Adults — 18 States, 2012

Prenatal drinking-water exposure to tetrachloroethylene and ischemic placental disease: a retrospective cohort study

Carwile, J.L.,, Environmental Health - 13:72, September 2014

Prenatal drinking water exposure to tetrachloroethylene (PCE) has been previously related to intrauterine growth restriction and stillbirth. Pathophysiologic and epidemiologic evidence linking these outcomes to certain other pregnancy complications, including placental abruption, preeclampsia, and small-for-gestational-age (SGA) (i.e., ischemic placental diseases), suggests that PCE exposure may also be associated with these events. We examined whether prenatal exposure to PCE-contaminated drinking water was associated with overall or individual ischemic placental diseases. Methods: Using a retrospective cohort design, we compared 1,091 PCE-exposed and 1,019 unexposed pregnancies from 1,766 Cape Cod, Massachusetts women. Exposure between 1969 and 1990 was estimated using water distribution system modeling software. Data on birth weight and gestational age were obtained from birth certificates; mothers self-reported pregnancy complications. Results: Of 2,110 eligible pregnancies, 9% (N = 196) were complicated by ≥1 ischemic placental disease. PCE exposure was not associated with overall ischemic placental disease (for PCE ≥ sample median vs. no exposure, risk ratio (RR): 0.90; 95% confidence interval (CI): 0.65, 1.24), preeclampsia (RR: 0.36; 95% CI: 0.12-1.07), or SGA (RR: 0.98; 95% CI: 0.66-1.45). However, pregnancies with PCE exposure ≥ the sample median had 2.38-times the risk of stillbirth ≥27 weeks gestation (95% CI: 1.01, 5.59), and 1.35-times of the risk of placental abruption (95% CI: 0.68, 2.67) relative to unexposed pregnancies. Conclusions: Prenatal PCE exposure was not associated with overall ischemic placental disease, but may increase risk of stillbirth. Keywords: Drinking-water; Ischemic placental disease; Placental abruption; Preeclampsia; Small for gestational age; Stillbirth; Tetrachloroethylene

Sugar-Sweetened Beverage Consumption Among Adults — 18 States, 2012

Kumar, G.S.,, CDC Morbidity and Mortality Weekly Report, August 15, 2014

Reducing consumption of calories from added sugars is a recommendation of the 2010 Dietary Guidelines for Americans* and an objective of Healthy People 2020.† Sugar-sweetened beverages (SSB) are major sources of added sugars in the diets of U.S. residents (1). Daily SSB consumption is associated with obesity and other chronic health conditions, including diabetes and cardiovascular disease (2). U.S. adults consumed an estimated average of 151 kcal/day of SSB during 2009–2010, with regular (i.e., nondiet) soda and fruit drinks representing the leading sources of SSB energy intake (3,4). However, there is limited information on state-specific prevalence of SSB consumption. To assess regular soda and fruit drink consumption among adults in 18 states, CDC analyzed data from the 2012 Behavioral Risk Factor Surveillance System (BRFSS). Among the 18 states surveyed, 26.3% of adults consumed regular soda or fruit drinks or both ≥1 times daily. By state, the prevalence ranged from 20.4% to 41.4%. Overall, consumption of regular soda or fruit drinks was most common among persons aged 18‒34 years (24.5% for regular soda and 16.6% for fruit drinks), men (21.0% and 12.3%), non-Hispanic blacks (20.9% and 21.9%), and Hispanics (22.6% and 18.5%). Persons who want to reduce added sugars in their diets can decrease their consumption of foods high in added sugars such as candy, certain dairy and grain desserts, sweetened cereals, regular soda, fruit drinks, sweetened tea and coffee drinks, and other SSBs. States and health departments can collaborate with worksites and other community venues to increase access to water and other healthful beverages.

Large Outbreak of Cryptosporidium hominis Infection Transmitted through the Public Water Supply, Sweden

Widerström, M.,, Emerging Infectious Diseases - Vol 20, No 4, April 2014

In November 2010, ≈27,000 (≈45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Cryptosporidium hominis subtype IbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.

Added Sugar Intake and Cardiovascular Diseases Mortality Among US Adults

Quanhe Yang,, JAMA Internal Medicine - February 3, 2014.

Importance: Epidemiologic studies have suggested that higher intake of added sugar is associated with cardiovascular disease (CVD) risk factors. Few prospective studies have examined the association of added sugar intake with CVD mortality. Objective: To examine time trends of added sugar consumption as percentage of daily calories in the United States and investigate the association of this consumption with CVD mortality. Design, Setting, and Participants: National Health and Nutrition Examination Survey (NHANES, 1988-1994 [III], 1999-2004, and 2005-2010 [n = 31 147]) for the time trend analysis and NHANES III Linked Mortality cohort (1988-2006 [n = 11 733]), a prospective cohort of a nationally representative sample of US adults for the association study. Main Outcomes and Measures: Cardiovascular disease mortality. Results: Among US adults, the adjusted mean percentage of daily calories from added sugar increased from 15.7% (95% CI, 15.0%-16.4%) in 1988-1994 to 16.8% (16.0%-17.7%; P = .02) in 1999-2004 and decreased to 14.9% (14.2%-15.5%; P < .001) in 2005-2010. Most adults consumed 10% or more of calories from added sugar (71.4%) and approximately 10% consumed 25% or more in 2005-2010. During a median follow-up period of 14.6 years, we documented 831 CVD deaths during 163 039 person-years. Age-, sex-, and race/ethnicity–adjusted hazard ratios (HRs) of CVD mortality across quintiles of the percentage of daily calories consumed from added sugar were 1.00 (reference), 1.09 (95% CI, 1.05-1.13), 1.23 (1.12-1.34), 1.49 (1.24-1.78), and 2.43 (1.63-3.62; P < .001), respectively. After additional adjustment for sociodemographic, behavioral, and clinical characteristics, HRs were 1.00 (reference), 1.07 (1.02-1.12), 1.18 (1.06-1.31), 1.38 (1.11-1.70), and 2.03 (1.26-3.27; P = .004), respectively. Adjusted HRs were 1.30 (95% CI, 1.09-1.55) and 2.75 (1.40-5.42; P = .004), respectively, comparing participants who consumed 10.0% to 24.9% or 25.0% or more calories from added sugar with those who consumed less than 10.0% of calories from added sugar. These findings were largely consistent across age group, sex, race/ethnicity (except among non-Hispanic blacks), educational attainment, physical activity, health eating index, and body mass index. Conclusions and Relevance: Most US adults consume more added sugar than is recommended for a healthy diet. We observed a significant relationship between added sugar consumption and increased risk for CVD mortality.

Water and beverage consumption among adults in the United States: cross-sectional study using data from NHANES 2005–2010

Drewnowski A, et. al., BMC Public Health - November 12, 2013.

Background: Few studies have examined plain water consumption among US adults. This study evaluated the consumption of plain water (tap and bottled) and total water among US adults by age group (20-50y, 51-70y, and ≥71y), gender, income-to-poverty ratio, and race/ethnicity. Methods: Data from up to two non-consecutive 24-hour recalls from the 2005–2006, 2007–2008 and 2009–2010 National Health and Nutrition Examination Survey (NHANES) was used to evaluate usual intake of water and water as a beverage among 15,702 US adults. The contribution of different beverage types (e.g., water as a beverage [tap or bottled], milk [including flavored], 100% fruit juice, soda/soft drinks [regular and diet], fruit drinks, sports/energy drinks, coffee, tea, and alcoholic beverages) to total water and energy intakes was examined. Total water intakes from plain water, beverages, and food were compared to the Adequate Intake (AI) values from the US Dietary Reference Intakes (DRI). Total water volume per 1,000 kcal was also examined. Results: Water and other beverages contributed 75-84% of dietary water, with 17-25% provided by water in foods, depending on age. Plain water, from tap or bottled sources, contributed 30-37% of total dietary water. Overall, 56% of drinking water volume was from tap water while bottled water provided 44%. Older adults (≥71y) consumed much less bottled water than younger adults. Non-Hispanic whites consumed the most tap water, whereas Mexican-Americans consumed the most bottled water. Plain water consumption (bottled and tap) tended to be associated with higher incomes. On average, younger adults exceeded or came close to satisfying the DRIs for water. Older men and women failed to meet the Institute of Medicine (IOM) AI values, with a shortfall in daily water intakes of 1218 mL and 603 mL respectively. Eighty-three percent of women and 95% of men ≥71y failed to meet the IOM AI values for water. However, average water volume per 1,000 kcal was 1.2-1.4 L/1,000 kcal for most population sub-groups, higher than suggested levels of 1.0 L/1.000 kcal. Conclusions: Water intakes below IOM-recommended levels may be a cause for concern, especially for older adults.

Resolved: there is sufficient scientific evidence that decreasing sugar-sweetened beverage consumption will reduce the prevalence of obesity and obesity-related diseases

Hu FB, Obesity Reviews - June 13, 2013.

Sugar-sweetened beverages (SSBs) are the single largest source of added sugar and the top source of energy intake in the U.S. diet. In this review, we evaluate whether there is sufficient scientific evidence that decreasing SSB consumption will reduce the prevalence of obesity and its related diseases. Because prospective cohort studies address dietary determinants of long-term weight gain and chronic diseases, whereas randomized clinical trials (RCTs) typically evaluate short-term effects of specific interventions on weight change, both types of evidence are critical in evaluating causality. Findings from well-powered prospective cohorts have consistently shown a significant association, established temporality and demonstrated a direct dose–response relationship between SSB consumption and long-term weight gain and risk of type 2 diabetes (T2D). A recently published meta-analysis of RCTs commissioned by the World Health Organization found that decreased intake of added sugars significantly reduced body weight (0.80 kg, 95% confidence interval [CI] 0.39–1.21; P < 0.001), whereas increased sugar intake led to a comparable weight increase (0.75 kg, 0.30–1.19; P = 0.001). A parallel meta-analysis of cohort studies also found that higher intake of SSBs among children was associated with 55% (95% CI 32–82%) higher risk of being overweight or obese compared with those with lower intake. Another meta-analysis of eight prospective cohort studies found that one to two servings per day of SSB intake was associated with a 26% (95% CI 12–41%) greater risk of developing T2D compared with occasional intake (less than one serving per month). Recently, two large RCTs with a high degree of compliance provided convincing data that reducing consumption of SSBs significantly decreases weight gain and adiposity in children and adolescents. Taken together, the evidence that decreasing SSBs will decrease the risk of obesity and related diseases such as T2D is compelling. Several additional issues warrant further discussion. First, prevention of long-term weight gain through dietary changes such as limiting consumption of SSBs is more important than short-term weight loss in reducing the prevalence of obesity in the population. This is due to the fact that once an individual becomes obese, it is difficult to lose weight and keep it off. Second, we should consider the totality of evidence rather than selective pieces of evidence (e.g. from short-term RCTs only). Finally, while recognizing that the evidence of harm on health against SSBs is strong, we should avoid the trap of waiting for absolute proof before allowing public health action to be taken.

Water and beverage consumption among children age 4-13y in the United States: analyses of 2005–2010 NHANES data

Drewnowski A, Rehm C and Constant F, Nutrition Journal - June 19, 2013.

Few studies have examined water consumption patterns among US children. Additionally, recent data on total water consumption as it relates to the Dietary Reference Intakes (DRI) are lacking. This study evaluated the consumption of plain water (tap and bottled) and other beverages among US children by age group, gender, income-to-poverty ratio, and race/ethnicity. Comparisons were made to DRI values for water consumption from all sources. Data from two non-consecutive 24-hour recalls from 3 cycles of NHANES (2005–2006, 2007–2008 and 2009–2010) were used to assess water and beverage consumption among 4,766 children age 4-13y. Beverages were classified into 9 groups: water (tap and bottled), plain and flavored milk, 100% fruit juice, soda/soft drinks (regular and diet), fruit drinks, sports drinks, coffee, tea, and energy drinks. Total water intakes from plain water, beverages, and food were compared to DRIs for the US. Total water volume per 1,000 kcal was also examined. Results: Water and other beverages contributed 70-75% of dietary water, with 25-30% provided by moisture in foods, depending on age. Plain water, tap and bottled, contributed 25-30% of total dietary water. In general, tap water represented 60% of drinking water volume whereas bottled water represented 40%. Non-Hispanic white children consumed the most tap water, whereas Mexican-American children consumed the most bottled water. Plain water consumption (bottled and tap) tended to be associated with higher incomes. No group of US children came close to satisfying the DRIs for water. At least 75% of children 4-8y, 87% of girls 9-13y, and 85% of boys 9-13y did not meet DRIs for total water intake. Water volume per 1,000 kcal, another criterion of adequate hydration, was 0.85-0.95 L/1,000 kcal, short of the desirable levels of 1.0-1.5 L/1,000 kcal. Conclusions: Water intakes at below-recommended levels may be a cause for concern. Data on water and beverage intake for the population and by socio-demographic group provides useful information to target interventions for increasing water intake among children.

Relation between urinary hydration biomarkers and total fluid intake in healthy adults

Perrier E, Rondeau P, Poupin M, Le Bellego L, Armstrong LE, Lang F, Stookey J, Tack I, Vergne S and Klein A, European Journal of Clinical Nutrition - May 22, 2013.

In sedentary adults, hydration is mostly influenced by total fluid intake and not by sweat losses; moreover, low daily fluid intake is associated with adverse health outcomes. This study aimed to model the relation between total fluid intake and urinary hydration biomarkers. During 4 consecutive weekdays, 82 adults (age, 31.6±4.3 years; body mass index, 23.2±2.7 kg/m2; 52% female) recorded food and fluid consumed, collected one first morning urine (FMU) void and three 24-h (24hU) samples. The strength of linear association between urinary hydration biomarkers and fluid intake volume was evaluated using simple linear regression and Pearson’s correlation. Multivariate partial least squares (PLS) modeled the association between fluid intake and 24hU hydration biomarkers. Results: Strong associations (|r|greater than or equal to0.6; P<0.001) were found between total fluid intake volume and 24hU osmolality, color, specific gravity (USG), volume and solute concentrations. Many 24hU biomarkers were collinear (osmolality versus color: r=0.49–0.76; USG versus color: r=0.46–0.78; osmolality versus USG: 0.86–0.97; P<0.001). Measures in FMU were not strongly correlated to intake. Multivariate PLS and simple linear regression using urine volume explained >50% of the variance in fluid intake volume (r2=0.59 and 0.52, respectively); however the error in both models was high and the limits of agreement very large. Conclusions: Hydration biomarkers in 24hU are strongly correlated with daily total fluid intake volume in sedentary adults in free-living conditions; however, the margin of error in the present models limits the applicability of estimating fluid intake from urinary biomarkers.

Impact of fluid intake in the prevention of urinary system diseases: a brief review

Lotan et al., Current Opinions in Nephrology and Hypertension - Vol. 22, sup. 1, May 2013.

We are often told that we should drink more water, but the rationale for this remains unclear and no recommendations based on scientific evidence are available today. Meanwhile, the prevalence of urinary tract pathologies continues to increase. It becomes necessary to identify new risk factors for these pathologies. Danone Research decided to organize a multidisciplinary experts meeting to review the scientific research assessing the role of water to prevent four diseases of the urinary system: urolithiasis, urinary tract infection, chronic kidney disease and bladder cancer. The panel of experts discussed a narrative review of the epidemiology, pathophysiology and clinical evidence for each pathology. Key findings: Urolithiasis is a high prevalent condition worldwide ranging from 7-13% in the US. Increased fluid intake may reduce the risk of recurrence of kidney stones by avoiding supersaturation of the urine. Borghi et al showed a 50% reduction of recurrence by achieving a diuresis of 2L /day (level Ib of evidence). However, data on primary prevention is still limited. More than half of woman population will present at least one UTI during their lives. Increasing diuresis may have a diluting effect on bacteria, washing the epithelium and decreasing the adhesion area. Increased urine volume also decreases urine osmolality and acidity, which may difficult adhesion. However, experimental and clinical data supporting this hypothesis is still inconsistent. CKD affects 14% of the adult population in the US. Main causes of the pathology are diabetes (44%) and hypertension (28%). Low drinkers have high vasopressin plasma concentration. This hormone chronically increased may causes glomerular hyperfiltration and kidney hypertrophia. However, clinical evidence for a beneficial role of water in CKD is scarce. Two recent observational studies (Strippoli et al and Clark et al 2011) support this hypothesis. Bladder cancer: Bladder cancer is the fifth most common cancer. Main risk factors are exposure to cigarette smoking and occupational exposure to chemicals. Increasing fluid intake may result in rapid dilution and flushing of carcinogens from the bladder through increasing voiding. However, available literature on the topic is contradictory. It could be related to the presence of pollutants in water.

Influence of progressive fluid restriction on mood and physiological markers of dehydration in women

Pross, N., et al., British Journal of Nutrition - 2013, 109, 313-321.

The present study evaluated, using a well-controlled dehydration protocol, the effects of 24 h fluid deprivation (FD) on selected mood and physiological parameters. In the present cross-over study, twenty healthy women (age 25 (SE 0·78) years) participated in two randomised sessions: FD-induced dehydration v. a fully hydrated control condition. In the FD period, the last water intake was between 18.00 and 19.00 hours and no beverages were allowed until 18.00 hours on the next day (23–24 h). Water intake was only permitted at fixed periods during the control condition. Physiological parameters in the urine, blood and saliva (osmolality) as well as mood and sensations (headache and thirst) were compared across the experimental conditions. Safety was monitored throughout the study. The FD protocol was effective as indicated by a significant reduction in urine output. No clinical abnormalities of biological parameters or vital signs were observed, although heart rate was increased by FD. Increased urine specific gravity, darker urine colour and increased thirst were early markers of dehydration. Interestingly, dehydration also induced a significant increase in saliva osmolality at the end of the 24 h FD period but plasma osmolality remained unchanged. The significant effects of FD on mood included decreased alertness and increased sleepiness, fatigue and confusion. The most consistent effects of mild dehydration on mood are on sleep/wake parameters. Urine specific gravity appears to be the best physiological measure of hydration status in subjects with a normal level of activity; saliva osmolality is another reliable and noninvasive method for assessing hydration status.

Association between Water Intake, CKD, and Cardiovascular Disease: A Cross-Sectional Analysis of NHANES Data

Sontrop et al., American Journal of Nephrology 2013; 37:434-442, April 17 2013.

Recent evidence from animal and human studies suggests that a higher water intake may have a protective effect on kidney function and cardiovascular disease. We wish to examine the association between water intake, chronic kidney disease and cardiovascular disease in a cross-sectional analysis of the 2005-2006 National Health and Nutrition Examination Survey Population. Total water intake from food and beverages was categorized as low - that is less than 2 litres per day, moderate – 2 to 4.3 litres per day and high – greater than 4.3 litres per day. We examined the associations between the low total water intake and chronic kidney disease and self-reported cardiovascular disease. Key Findings: Of the 3427 adults, whose mean age was 46, with a mean eGFR of 95ml/min/1.73m2, 13% had chronic kidney disease and 18% suffered cardiovascular disease. Chronic kidney disease was higher among those with the lowest (less than 2 litres of fluid per day) versus the highest total water intake (greater than 4.3 litres per day), (odds ratio 2.52, 95% confidence interval, 0.91-6.96). Once stratified by the intake of plain water and other beverages, CKD was associated with a low intake of plain water with an odds ratio of 2.36 at 95% confidence intervals of 1.1-5.06 but not other beverages. There was no association between low water intake and cardiovascular disease.

Blood pressure hyperreactivity: an early cardiovascular risk in normotensive men exposed to low-to-moderate inorganic arsenic in drinking water

Kunrath, J., et al., Journal of Hypertension - February 2013

Background: Essential hypertension is associated with chronic exposure to high levels of inorganic arsenic in drinking water. However, early signs of risk for developing hypertension remain unclear in people exposed to chronic low-to-moderate inorganic arsenic. OBJECTIVE: We evaluated cardiovascular stress reactivity and recovery in healthy, normotensive, middle-aged men living in an arsenic-endemic region of Romania. METHODS: Unexposed (n = 16) and exposed (n = 19) participants were sampled from communities based on WHO limits for inorganic arsenic in drinking water (<10 μg/l). Water sources and urine samples were collected and analyzed for inorganic arsenic and its metabolites. Functional evaluation of blood pressure included clinical, anticipatory, cold pressor test, and recovery measurements. Blood pressure hyperreactivity was defined as a combined stress-induced change in SBP (>20 mmHg) and DBP (>15 mmHg). RESULTS: Drinking water inorganic arsenic averaged 40.2 ± 30.4 and 1.0 ± 0.2 μg/l for the exposed and unexposed groups, respectively (P < 0.001). Compared to the unexposed group, the exposed group expressed a greater probability of blood pressure hyperreactivity to both anticipatory stress (47.4 vs. 12.5%; P = 0.035) and cold stress (73.7 vs. 37.5%; P = 0.044). Moreover, the exposed group exhibited attenuated blood pressure recovery from stress and a greater probability of persistent hypertensive responses (47.4 vs. 12.5%; P = 0.035). CONCLUSIONS: Inorganic arsenic exposure increased stress-induced blood pressure hyperreactivity and poor blood pressure recovery, including persistent hypertensive responses in otherwise healthy, clinically normotensive men. Drinking water containing even low-to-moderate inorganic arsenic may act as a sympathetic nervous system trigger for hypertension risk.

Changes in water and beverage intake and long-term weight changes: results from three prospective cohort studies

Pan, A., et al., International Journal of Obesity - January 2013

OBJECTIVE: To examine the long-term relationship between changes in water and beverage intake and weight change. SUBJECTS: Prospective cohort studies of 50 013 women aged 40–64 years in the Nurses’ Health Study (NHS, 1986–2006), 52 987 women aged 27–44 years in the NHS II (1991–2007) and 21 988 men aged 40–64 years in the Health Professionals Follow-up Study (1986–2006) without obesity and chronic diseases at baseline. MEASURES: We assessed the association of weight change within each 4-year interval, with changes in beverage intakes and other lifestyle behaviors during the same period. Multivariate linear regression with robust variance and accounting for within-person repeated measures were used to evaluate the association. Results across the three cohorts were pooled by an inverse-variance-weighted meta-analysis. RESULTS: Participants gained an average of 1.45 kg (5th to 95th percentile: −1.87 to 5.46) within each 4-year period. After controlling for age, baseline body mass index and changes in other lifestyle behaviors (diet, smoking habits, exercise, alcohol, sleep duration, TV watching), each 1 cup per day increment of water intake was inversely associated with weight gain within each 4-year period (−0.13 kg; 95% confidence interval (CI): −0.17 to −0.08). The associations for other beverages were: sugar-sweetened beverages (SSBs) (0.36 kg; 95% CI: 0.24–0.48), fruit juice (0.22 kg; 95% CI: 0.15–0.28), coffee (−0.14 kg; 95% CI: −0.19 to −0.09), tea (−0.03 kg; 95% CI: −0.05 to −0.01), diet beverages (−0.10 kg; 95% CI: −0.14 to −0.06), low-fat milk (0.02 kg; 95% CI: −0.04 to 0.09) and whole milk (0.02 kg; 95% CI: −0.06 to 0.10). We estimated that replacement of 1 serving per day of SSBs by 1 cup per day of water was associated with 0.49 kg (95% CI: 0.32–0.65) less weight gain over each 4-year period, and the replacement estimate of fruit juices by water was 0.35 kg (95% CI: 0.23–0.46). Substitution of SSBs or fruit juices by other beverages (coffee, tea, diet beverages, low-fat and whole milk) were all significantly and inversely associated with weight gain. CONCLUSION: Our results suggest that increasing water intake in place of SSBs or fruit juices is associated with lower long-term weight gain.

Water consumption, not expectancies about water consumption, affects cognitive performance in adults

Edmonds, C.J., et al., Appetite - January 2013

Research has shown that water supplementation positively affects cognitive performance in children and adults. The present study considered whether this could be a result of expectancies that individuals have about the effects of water on cognition. Forty-seven participants were recruited and told the study was examining the effects of repeated testing on cognitive performance. They were assigned either to a condition in which positive expectancies about the effects of drinking water were induced, or a control condition in which no expectancies were induced. Within these groups, approximately half were given a drink of water, while the remainder were not. Performance on a thirst scale, letter cancellation, digit span forwards and backwards and a simple reaction time task was assessed at baseline (before the drink) and 20 min and 40 min after water consumption. Effects of water, but not expectancy, were found on subjective thirst ratings and letter cancellation task performance, but not on digit span or reaction time. This suggests that water consumption effects on letter cancellation are due to the physiological effects of water, rather than expectancies about the effects of drinking water.

Observations of drinking water access in school food service areas before implementation of federal and state school water policy, California, 2011

Al Patel, et al., Preventing Chronic Disease - September 2012

Recent legislation requires schools to provide free drinking water in food service areas (FSAs). Our objective was to describe access to water at baseline and student water intake in school FSAs and to examine barriers to and strategies for implementation of drinking water requirements. METHODS: We randomly sampled 24 California Bay Area public schools. We interviewed 1 administrator per school to assess knowledge of water legislation and barriers to and ideas for policy implementation. We observed water access and students' intake of free water in school FSAs. Wellness policies were examined for language about water in FSAs. RESULTS: Fourteen of 24 schools offered free water in FSAs; 10 offered water via fountains, and 4 provided water through a nonfountain source. Four percent of students drank free water at lunch; intake at elementary schools (11%) was higher than at middle or junior high schools (6%) and high schools (1%). In secondary schools when water was provided by a nonfountain source, the percentage of students who drank free water doubled. Barriers to implementation of water requirements included lack of knowledge of legislation, cost, and other pressing academic concerns. No wellness policies included language about water in FSAs. CONCLUSION: Approximately half of schools offered free water in FSAs before implementation of drinking water requirements, and most met requirements through a fountain. Only 1 in 25 students drank free water in FSAs. Although schools can meet regulations through installation of fountains, more appealing water delivery systems may be necessary to increase students' water intake at mealtimes.

Sugar-Sweetened Beverages and Genetic Risk of Obesity

Qibin Qi, Ph.D., et al., The New England Journal of Medicine - September 21, 2012

Temporal increases in the consumption of sugar-sweetened beverages have paralleled the rise in obesity prevalence, but whether the intake of such beverages interacts with the genetic predisposition to adiposity is unknown. We analyzed the interaction between genetic predisposition and the intake of sugar-sweetened beverages in relation to body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) and obesity risk in 6934 women from the Nurses' Health Study (NHS) and in 4423 men from the Health Professionals Follow-up Study (HPFS) and also in a replication cohort of 21,740 women from the Women's Genome Health Study (WGHS). The genetic-predisposition score was calculated on the basis of 32 BMI-associated loci. The intake of sugar-sweetened beverages was examined prospectively in relation to BMI. In the NHS and HPFS cohorts, the genetic association with BMI was stronger among participants with higher intake of sugar-sweetened beverages than among those with lower intake. In the combined cohorts, the increases in BMI per increment of 10 risk alleles were 1.00 for an intake of less than one serving per month, 1.12 for one to four servings per month, 1.38 for two to six servings per week, and 1.78 for one or more servings per day (P<0.001 for interaction). For the same categories of intake, the relative risks of incident obesity per increment of 10 risk alleles were 1.19 (95% confidence interval [CI], 0.90 to 1.59), 1.67 (95% CI, 1.28 to 2.16), 1.58 (95% CI, 1.01 to 2.47), and 5.06 (95% CI, 1.66 to 15.5) (P=0.02 for interaction). In the WGHS cohort, the increases in BMI per increment of 10 risk alleles were 1.39, 1.64, 1.90, and 2.53 across the four categories of intake (P=0.001 for interaction); the relative risks for incident obesity were 1.40 (95% CI, 1.19 to 1.64), 1.50 (95% CI, 1.16 to 1.93), 1.54 (95% CI, 1.21 to 1.94), and 3.16 (95% CI, 2.03 to 4.92), respectively (P=0.007 for interaction).

Arcobacter in Lake Erie Beach Waters: an Emerging Gastrointestinal Pathogen Linked with Human-Associated Fecal Contamination

Cheonghoon Lee, et al., Applied and Environmental Microbiology - September 2012

The genus Arcobacter has been associated with human illness and fecal contamination by humans and animals. To better characterize the health risk posed by this emerging waterborne pathogen, we investigated the occurrence of Arcobacter spp. in Lake Erie beach waters. During the summer of 2010, water samples were collected 35 times from the Euclid, Villa Angela, and Headlands (East and West) beaches, located along Ohio's Lake Erie coast. After sample concentration, Arcobacter was quantified by real-time PCR targeting the Arcobacter 23S rRNA gene. Other fecal genetic markers (Bacteroides 16S rRNA gene [HuBac], Escherichia coli uidA gene, Enterococcus 23S rRNA gene, and tetracycline resistance genes) were also assessed. Arcobacter was detected frequently at all beaches, and both the occurrence and densities of Arcobacter spp. were higher at the Euclid and Villa Angela beaches (with higher levels of fecal contamination) than at the East and West Headlands beaches. The Arcobacter density in Lake Erie beach water was significantly correlated with the human-specific fecal marker HuBac according to Spearman's correlation analysis (r = 0.592; P < 0.001). Phylogenetic analysis demonstrated that most of the identified Arcobacter sequences were closely related to Arcobacter cryaerophilus, which is known to cause gastrointestinal diseases in humans. Since human-pathogenic Arcobacter spp. are linked to human-associated fecal sources, it is important to identify and manage the human-associated contamination sources for the prevention of Arcobacter-associated public health risks at Lake Erie beaches.

Hydration biomarkers and dietary fluid consumption of women.

Armstrong, L., et. al. Journal of the Academy of Nutrition and Dietetics - July 2012

Normative values and confidence intervals for the hydration indices of women do not exist. Also, few publications have precisely described the fluid types and volumes that women consume. This investigation computed seven numerical reference categories for widely used hydration biomarkers (eg, serum and urine osmolality) and the dietary fluid preferences of self-reported healthy, active women. Participants (n=32; age 20±1 years; body mass 59.6±8.5 kg; body mass index [calculated as kg/m(2)] 21.1±2.4) were counseled in the methods to record daily food and fluid intake on 2 consecutive days. To reduce day-to-day body water fluctuations, participants were tested only during the placebo phase of the oral contraceptive pill pack. Euhydration was represented by the following ranges: serum osmolality=293 to 294 mOsm/kg; mean 24-hour total fluid intake=2,109 to 2,506 mL/24 hours; mean 24-hour total beverage intake=1,300 to 1,831 mL/24 hours; urine volume=951 to 1,239 mL/24 hours; urine specific gravity=1.016 to 1.020; urine osmolality=549 to 705 mOsm/kg; and urine color=5. However, only 3% of women experienced a urine specific gravity <1.005, and only 6% exhibited a urine color of 1 or 2. Water (representing 45.3% and 47.9% of 24-hour total fluid intake), tea, milk, coffee, and fruit juice were consumed in largest volumes. In conclusion, these data provide objective normative values for hyperhydration, euhydration, and dehydration that can be used by registered dietitians and clinicians to counsel women about their hydration status

Lead (Pb) in Tap Water and in Blood: Implications for Lead Exposure in the United States

Triantafyllidou, S., Edwards, M., Critical Reviews in Environmental Science and Technology - July 2012

Lead is widely recognized as one of the most pervasive environmental health threats in the United States, and there is increased concern over adverse health impacts at levels of exposure once considered safe. Lead contamination of tap water was once a major cause of lead exposure in the United States and, as other sources have been addressed, the relative contribution of lead in water to lead in blood is expected to become increasingly important. Moreover, prior research suggests that lead in water may be more important as a source than is presently believed. The authors describe sources of lead in tap water, chemical forms of the lead, and relevant U.S. regulations/guidelines, while considering their implications for human exposure. Research that examined associations between water lead levels and blood lead levels is critically reviewed, and some of the challenges in making such associations, even if lead in water is the dominant source of lead in blood, are highlighted. Better protecting populations at risk from this and from other lead sources is necessary, if the United States is to achieve its goal of eliminating elevated blood lead levels in children by 2020.

French children start their school day with a hydration deficit

Bonnet, F., et al., Annals of Nutrition & Metabolism - June 1, 2012

Background and Aims: Fluid requirements of children vary as a function of gender and age. To our knowledge, there is very little literature on the hydration status of French chil- dren. We assessed the morning hydration status in a large sample of 529 French schoolchildren aged 9–11 years. Methods: Recruited children completed a questionnaire on fluid and food intake at breakfast and collected a urine sample the very same day after breakfast. Breakfast food and fluid nutritional composition was analyzed and urine osmolality was measured using a cryoscopic osmometer. Results: More than a third of the children had a urine osmolality between 801 and 1,000 mosm/kg while 22.7% had a urine osmolality over 1,000 mosm/kg. This was more frequent in boys than in girls (p ! 0.001). A majority of children (73.5%) drank less than 400 ml at breakfast. Total water intake at breakfast was significantly and inversely correlated with high osmolality values. Conclusions: Almost two thirds of the children in this large cohort had evidence of a hydration deficit when they went to school in the morning, despite breakfast intake. Children’s fluid intake at breakfast does not suffice to maintain an adequate hydration status for the whole morning.

Mild Dehydration Affects Mood in Healthy Young Women

Lawrence Armstrong, et al., The Journal of Nutrition - February 2012

Limited information is available regarding the effects of mild dehydration on cognitive function. Therefore, mild dehydration was produced by intermittent moderate exercise without hyperthermia and its effects on cognitive function of women were investigated. Twenty-five females (age 23.0 ± 0.6 y) participated in three 8-h, placebo-controlled experiments involving a different hydration state each day: exercise-induced dehydration with no diuretic (DN), exercise-induced dehydration plus diuretic (DD; furosemide, 40 mg), and euhydration (EU). Cognitive performance, mood, and symptoms of dehydration were assessed during each experiment, 3 times at rest and during each of 3 exercise sessions. The DN and DD trials in which a volunteer attained a ≥1% level of dehydration were pooled and compared to that volunteer’s equivalent EU trials. Mean dehydration achieved during these DN and DD trials was −1.36 ± 0.16% of body mass. Significant adverse effects of dehydration were present at rest and during exercise for vigor-activity, fatigue-inertia, and total mood disturbance scores of the Profile of Mood States and for task difficulty, concentration, and headache as assessed by questionnaire. Most aspects of cognitive performance were not affected by dehydration. Serum osmolality, a marker of hydration, was greater in the mean of the dehydrated trials in which a ≥1% level of dehydration was achieved (P = 0.006) compared to EU. In conclusion, degraded mood, increased perception of task difficulty, lower concentration, and headache symptoms resulted from 1.36% dehydration in females. Increased emphasis on optimal hydration is warranted, especially during and after moderate exercise.

Health Risks of Limited-Contact Water Recreation

Samuel Dorevitch, et al., Environmental Health Perspectives - February 2012

Wastewater-impacted waters that do not support swimming are often used for boating, canoeing, fishing, kayaking, and rowing. Little is known about the health risks of these limited-contact water recreation activities. We evaluated the incidence of illness, severity of illness, associations between water exposure and illness, and risk of illness attributable to limited-contact water recreation on waters dominated by wastewater effluent and on waters approved for general use recreation (such as swimming). The Chicago Health, Environmental Exposure, and Recreation Study was a prospective cohort study that evaluated five health outcomes among three groups of people: those who engaged in limited-contact water recreation on effluent-dominated waters, those who engaged in limited-contact recreation on general-use waters, and those who engaged in non–water recreation. Data analysis included survival analysis, logistic regression, and estimates of risk for counterfactual exposure scenarios using G-computation. Results: Telephone follow-up data were available for 11,297 participants. With non–water recreation as the reference group, we found that limited-contact water recreation was associated with the development of acute gastrointestinal illness in the first 3 days after water recreation at both effluent-dominated waters [adjusted odds ratio (AOR) 1.46; 95% confidence interval (CI): 1.08, 1.96] and general-use waters (1.50; 95% CI: 1.09, 2.07). For every 1,000 recreators, 13.7 (95% CI: 3.1, 24.9) and 15.1 (95% CI: 2.6, 25.7) cases of gastrointestinal illness were attributable to limited-contact recreation at effluent-dominated waters and general-use waters, respectively. Eye symptoms were associated with use of effluent-dominated waters only (AOR 1.50; 95% CI: 1.10, 2.06). Among water recreators, our results indicate that illness was associated with the amount of water exposure. Conclusions: Limited-contact recreation, both on effluent-dominated waters and on waters designated for general use, was associated with an elevated risk of gastrointestinal illness.

Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial

Deborah F Tate, et al., The American Journal of Clinical Nutrition - February 2012

Replacement of caloric beverages with noncaloric beverages may be a simple strategy for promoting modest weight reduction; however, the effectiveness of this strategy is not known. We compared the replacement of caloric beverages with water or diet beverages (DBs) as a method of weight loss over 6 mo in adults and attention controls (ACs). Results: In an intent-to-treat analysis, a significant reduction in weight and waist circumference and an improvement in systolic blood pressure were observed from 0 to 6 mo. Mean (±SEM) weight losses at 6 mo were −2.5 ± 0.45% in the DB group, −2.03 ± 0.40% in the Water group, and −1.76 ± 0.35% in the AC group; there were no significant differences between groups. The chance of achieving a 5% weight loss at 6 mo was greater in the DB group than in the AC group (OR: 2.29; 95% CI: 1.05, 5.01; P = 0.04). A significant reduction in fasting glucose at 6 mo (P = 0.019) and improved hydration at 3 (P = 0.0017) and 6 (P = 0.049) mo was observed in the Water group relative to the AC group. In a combined analysis, participants assigned to beverage replacement were 2 times as likely to have achieved a 5% weight loss (OR: 2.07; 95% CI: 1.02, 4.22; P = 0.04) than were the AC participants. Conclusions: Replacement of caloric beverages with noncaloric beverages as a weight-loss strategy resulted in average weight losses of 2% to 2.5%. This strategy could have public health significance and is a simple, straightforward message. This trial was registered at as NCT01017783

Atrazine Exposure in Public Drinking Water and Preterm Birth

Rinsky, Jessica L., et al., Public Health Reports - January/February 2012

Approximately 13% of all births occur prior to 37 weeks gestation in the U.S. Some established risk factors exist for preterm birth, but the etiology remains largely unknown. Recent studies have suggested an association with environmental exposures. We examined the relationship between preterm birth and exposure to a commonly used herbicide, atrazine, in drinking water. RESULTS: An increase in the odds of preterm birth was found for women residing in the counties included in the highest atrazine exposure group compared with women residing in counties in the lowest exposure group, while controlling for covariates. Analyses using the three exposure assessment approaches produced odds ratios ranging from 1.20 (95% confidence interval [CI] 1.14, 1.27) to 1.26 (95% CI 1.19, 1.32), for the highest compared with the lowest exposure group.

What is the cell hydration status of healthy children in the USA? Preliminary data on urine osmolality and water intake

Stookey JD, Brass B, Holliday A, Arieff A, Public Health Nutrition - January 27, 2012

Hyperosmotic stress on cells limits many aspects of cell function, metabolism and health. International data suggest that schoolchildren may be at risk of hyperosmotic stress on cells because of suboptimal water intake. The present study explored the cell hydration status of two samples of children in the USA. RESULTS: Elevated urine osmolality (>800 mmol/kg) was observed in 63 % and 66 % of participants in LA and NYC, respectively. In multivariable-adjusted logistic regression models, elevated urine osmolality was associated with not reporting intake of drinking water in the morning (LA: OR = 2·1, 95 % CI 1·2, 3·5; NYC: OR = 1·8, 95 % CI 1·0, 3·5). Although over 90 % of both samples had breakfast before giving the urine sample, 75 % did not drink water. CONCLUSIONS: Research is warranted to confirm these results and pursue their potential health implications.

Hydration, morbidity, and mortality in vulnerable populations

Maughan, RJ, Nutrition Reviews - January 2012

Both acute and chronic fluid deficits have been shown to be associated with a number of adverse health outcomes. At the extreme, deprivation of water for more than a few days inevitably leads to death, but even modest fluid deficits may precipitate adverse events, especially in young children, in the frail elderly and in those with poor health. Epidemiological studies have shown an association, although not necessarily a causal one, between a low habitual fluid intake and some chronic diseases, including urolithiasis, constipation, asthma, cardiovascular disease, diabetic hyperglycemia, and some cancers. Acute hypohydration may be a precipitating factor in a number of acute medical conditions in elderly persons. Increased mortality, especially in vulnerable populations, is commonly observed during periods of abnormally warm weather, with at least part of this effect due to failure to increase water intake, and this may have some important implications for those responsible for forward planning in healthcare facilities.