The water balance questionnaire: design, reliability and validity of a questionnaire to evaluate water balance in the general population

Development and assessment of relative validity and reliability of the Workplace Beverage Intake Questionnaire in UK office workers

BACKGROUND

There are no beverage measurement tools evaluated for use in UK working-age adults. This study aimed to develop and evaluate a novel beverage intake questionnaire.

METHODS

A 57-item online tool (Workplace Beverage Intake Questionnaire [WBIQ]) was developed through stakeholder consensus. Relative validity was measured against 7-day food records, and reliability was tested across three time points. Evaluation outcomes of interest were total beverage intake and beverage intake during working hours, intake from seven beverage categories (plain water, sugar sweetened, low/zero calorie, tea, coffee, milk based and 100% fruit based) and energy, caffeine and free sugar intake from beverages. Reliability was determined by intraclass correlation coefficients (ICC) and validity via correlation analyses and visual assessment of Bland-Altman plots.

RESULTS

The evaluation study population comprised office workers (n = 71, 74.6% women, mean age: 32, standard deviation: 8.5 years). The WBIQ had moderate reliability (ICC: 0.50-0.75) across total fluid intake and all beverage categories except milk-based drinks and 100% fruit-based drinks where it was rated poor. Caffeine, free sugar and energy from beverages had poor-to-moderate reliability. Correlation coefficients were large (r > 0.50, p < 0.001) comparing diet records and WBIQ across all categories of beverage except low-/zero-calorie soft drinks (r = 0.34, p < 0.01). Bland-Altman plots showed a similar trend across all variables, with better agreements at lower intake and the absolute difference increasing proportionally at higher intakes. Over 90% of respondents agreed/strongly agreed that the tool was easy to navigate and understand.

CONCLUSIONS

The WBIQ is the first stage in the development of a tool for UK-specific beverage intake measurement in working-age adults. Further refinement and testing are required to improve reliability.

Online Arabic Beverage Frequency Questionnaire (ABFQ): evaluation of validity and reliability

BACKGROUND

Obesity and chronic diseases are significant public health issues in the Middle East and North Africa region. A robust body of evidence demonstrated the association between beverage consumption, obesity, and chronic diseases. Therefore, the assessment of beverage consumption is gaining more interest in health policy development, food industry partnerships, research expansion and community involvement. Although beverage-consumption assessment tools have been developed for various populations, none were developed for the Arabic population. In this study, we developed and validated an online Arabic Beverage Frequency Questionnaire (ABFQ) to assess the total beverage intake among Arabic speaking population.

METHODS

A cross-sectional validation study was conducted among healthy adults aged between 18 and 55 years. Participants (n = 49) completed a 24-item ABFQ on two occasions and provided one 24-h urine sample. For validity, total beverage consumption (ABFQ1) was assessed against a 24-h urine sample using an osmolality test and correlation analysis. Reliability was assessed by comparing the participants' consumption in total and for every 24 individual items from ABFQ1 with the total and individual items in ABFQ2 using correlation and paired sample t-test.

RESULTS

The average daily consumption of beverages was 1504 ml/day, while the average urine osmolality/kg was 614. The validity assessment between ABFQ and urine osmolality indicates a negative correlation. However, the correlation was week and not statistically significant (r_s = -0.2, p = 0.12). In reliability test, correlation analysis was positive and acceptable in all beverage categories (r_s = 0.4 - 0.9; all p < 0.05) except flavored milk (r_s = 0.2; p < 0.181) and sweetened coffee (r_s = 0.3; p < 0.022). Furthermore, no significant differences were found between the means of total consumption in both ABFQ1 and ABFQ2.

CONCLUSIONS

The finding of this study suggest that the ABFQ is a reliable reproducible tool for assessing beverage consumption among Arabic-speaking consumers. However, the survey could not be validated using 24-h urine osmolality only and other methods such as multi dietary records may use in future re-assessment.

A systematic review of measurement methods used to estimate fluid and beverage intake in free-living, working-age adults

BACKGROUND

Beverage intake in employees is important to quantify due to the potential of dehydration to increase the risk of errors and reduced work performance. This systematic review aimed to (1) characterise existing fluid intake measurement tools used in the workplace setting or among free-living, healthy adults of working age and (2) report the current validation status of available assessment tools for use in a UK setting.

METHODS

Three electronic databases were searched for publications measuring beverage intake using a defined tool or method. Additional studies were identified by hand from trial registers, grey literature and reference lists. Eligibility was determined using predefined inclusion/exclusion criteria. Study quality was assessed using a modified Strengthening the Reporting of Observational Studies in Epidemiology framework. Narrative synthesis was performed.

RESULTS

The review identified 105 studies. The most frequently reported beverage assessment methods were total diet diaries/records (n = 22), fluid specific diaries/records (n = 18), food and fluid frequency questionnaires (n = 17), beverage-specific frequency questionnaires (n = 23) and diet recalls (n = 11). General dietary measurement tools (measuring beverages as part of total diet) were used in 60 studies, and 45 studies used a beverage-specific tool. This review identified 18 distinct dietary assessment tools, of which 6 were fluid/beverage specific. Twelve tools published relative validity for a beverage-related variable and seven tools for total daily fluid intake (from whole diet or from beverages only).

CONCLUSIONS

Several fluid intake assessment tools were identified; however, few have been fully evaluated for total beverage intake, and none in a UK working population.

A questionnaire for physical findings of malnutrition when physical exams are not possible

BACKGROUND

When nutrition assessments must be performed virtually, such as during the coronavirus pandemic, it is difficult to fully assess patients for malnutrition without the ability to perform a nutrition-focused physical exam. Practitioners may ask patients about their physical appearance, but there is currently no validated set of questions whose answers correlate with nutrition-focused physical findings for the diagnosis of malnutrition in such situations. The aim of this study was to evaluate correlations between patients' responses to verbalized questions and physical signs of malnutrition.

METHODS

Questions related to the physical findings of malnutrition were developed and evaluated for content validity. Thirty patients receiving nutrition assessments at an acute care veterans' hospital were asked the questions prior to a nutrition-focused physical exam. Patients' responses were compared with a diagnosis of malnutrition and physical findings of muscle, fat, fluid accumulation, and handgrip strength.

RESULTS

Four questions significantly correlated with malnutrition: "Does the area around your eyes appear sunken in?" (P = 0.03), "Are you able to see your ribs?" (P = 0.05), "Do you feel you are unusually skinny for you?" (P = 0.001), and "Do you find yourself eating less due to swelling in your belly?" (P = 0.008).

CONCLUSION

There are relationships between patients' responses to certain verbalized questions and their physical status. Such questions can be used to identify physical signs of malnutrition when nutrition-focused physical exams cannot be performed. Further research is needed to validate these questions in other populations.

[Quality of diet is associated with water intake among residents in São Paulo, Brazil]

The scope of the study was to evaluate the probability of the adequacy of water intake among residents of São Paulo, and to investigate if the quality of diet differs according to the adequacy of water intake. Data were extracted from the Health Survey of São Paulo, a cross-sectional, population-based study. Water intake (drinking water beverages and food) was evaluated using two 24-hours dietary recalls and a supplementary dietary intake questionnaire. Adequacy and classification of water intake was assessed using the corresponding Adequate Intake for sex and age of the individual. Dietary quality was evaluated using the revised Brazilian Healthy Eating Index (BHEI). The associations were tested using the Theil-Sen median test and logistic regression models. A low probability of adequate water intake was observed, and this decreased with advancing age. Except among the elderly, among whom no association was observed, a positive association between water intake and the BHEI was observed, and for the total and integral fruit components, which was maintained after confusion adjustments. Among adults, it was observed that those who ingested less water had even lower scores for saturated fats. The residents of São Paulo have low water intake, and the quality of diet is worse among those who drink less water.

Evaluation of hydration status during the COVID-19 pandemic: a study of Turkish young adults

Adequate hydration is an essential component of health at every stage of life. Although many factors such as age, gender, physical activity, drug use, and illness affect hydration status, it is vital to maintain water balance, especially in infectious diseases. This study was conducted to estimate the hydration status of young adults living in Turkey during the COVID-19 pandemic. The total water intake (TWI) and total water loss of the individuals were determined using the Water Balance Questionnaire (WBQ), which consists of questions about physical activity status, frequency of food and beverage consumption, water consumption, and water loss with urine and feces. The TWI of men and women was found to be 4,776.1 and 4,777.3 mL/day, respectively (p > 0.05). It was determined that 29% of the total water was obtained from drinking water, 49% from other beverages, and 22% from food. A positive net water balance was found in all body mass index (BMI) groups, men, and women. The net water balance was statistically lower in men (2,230.6 mL) than women (2,783.8 mL) (p < 0.05). As the COVID-19 pandemic continues, studies should be done on hydration status in the more balanced populations in terms of BMI and age groups.

Validity and Reliability of a Water Frequency Questionnaire to Estimate Daily Total Water Intake in Adults

The purpose of this investigation was to assess the validity and reliability of a seven-day water frequency questionnaire (TWI-FQ) to estimate daily total water intake (TWI) in comparison to a water turnover objective reference value via deuterium oxide (D₂O). Data collection occurred over 3 weeks, with a wash-out period during week two. Healthy adults (n = 98; 52% female; 41 ± 14 y; BMI, 26.4 ± 5.5 kg·m^-2) retrospectively self-reported consumption frequencies of 17 liquids and 35 foods with specified volumes/amounts for weeks one and three via TWI-FQ. Standard water content values were utilized to determine the volume of water consumed from each liquid and food for calculation of mean daily TWI for each week. Diet records were completed daily during week two to estimate metabolic water production. To assess validity of the TWI-FQ, participants consumed D₂O at the start of each week and provided urine samples immediately before ingestion, the following day, and at the end of the week to calculate water turnover. Metabolic water was subtracted from water turnover to estimate TWI. TWI-FQ validity was assessed via Bland-Altman plot for multiple observations. Reliability was assessed via intraclass correlation and Pearson's correlation between weeks. TWI-FQ significantly underestimated D₂O TWI by -350 ± 1,431 mL·d^-1 (95% confidence interval (CI): -551, -149 mL·d^-1). TWI-FQ TWI was significantly correlated (r = 0.707, P <0.01) and not different (198 ± 1,180 mL·d^-1, 95% CI: -38, 435 mL·d^-1) between weeks. TWI-FQ intraclass correlation = 0.706 was significant [95% CI: 0.591, 0.793; F _{(97, 98)} = 5.799], indicating moderate test-retest reliability. While this tool would not be suitable for individual TWI assessment, the magnitude of bias may be acceptable for assessment at the sample-level.

Investigation of the Association between Drinking Water Habits and the Occurrence of Women Breast Cancer

Risk and protective factors for breast cancer (BC) include lifestyle, diet, reproduction, and others. Increased risk for colon cancer was linked with low water intake. The link between water consumption and BC was scarcely studied. We investigated the association between water and fluid consumption and the occurrence of BC in a retrospective case-control study in the Shaare Zedek Medical Center, Jerusalem, in 206 women aged 25-65 years (106 with newly diagnosed BC, and 100 controls). A food frequency questionnaire (FFQ), consumption of water, foods, and beverages, lifestyle, and other risk and protective factors were recorded. The age of women in both groups was comparable ((M ± SD) 52.7 ± 9.8 and 50.6 ± 11.4 years, respectively (p = 0.29)). Women with BC consumed 20.2% less water (M ± SD = 5.28 ± 4.2 and 6.62 ± 4.5 cups/day, respectively, p = 0.02) and 14% less total fluids than controls (M ± SD = 2095 ± 937 mL/day and 2431 ± 1087 mL/day, respectively, p = 0.018). Multiple stepwise logistic regression showed that the differences remained significant both for daily water consumption (p = 0.031, CI = 0.462-0.964) and for total daily liquid intake (p = 0.029, CI = 0.938-0.997). Low water and liquids intake as a risk factor for BC may be related to the younger age of our subjects. The effect of age on the potential role of water intake in decreasing BC risk should be investigated.

Study to Test and Operationalize Preventive Approaches for CKD of Undetermined Etiology in Andhra Pradesh, India

INTRODUCTION

High prevalence of chronic kidney disease (CKD) not associated with known risk factors has been reported from coastal districts of Andhra Pradesh. The Study to Test and Operationalize Preventive Approaches for Chronic Kidney Disease of Undetermined Etiology in Andhra Pradesh (STOP CKDu AP) aims to ascertain the burden (prevalence and incidence) of CKD, the risk factor profile, and the community perceptions about the disease in the Uddanam area of Andhra Pradesh.

METHODS

Study participants will be sampled from the Uddanam area using multistage cluster random sampling. Information will be collected on the demographic profile, occupational history, and presence of conventional as well as nonconventional risk factors. Glomerular filtration rate (GFR) will be estimated using the Chronic Kidney Disease Epidemiology Collaboration equation, and proteinuria will be measured. All abnormal values will be confirmed by repeat testing after 3 months. Cases of CKD not associated with identified etiologies will be identified. Biospecimens will be stored to explore future hypotheses. The entire cohort will be followed up every 6 months to determine the incidence of CKD and to identify risk factors for decline in kidney function. Qualitative studies will be performed to understand the community perceptions and expectations with respect to the interventions.

IMPLICATIONS

CKD is an important public health challenge in low- and middle-income countries. This study will establish the prevalence and determine the incidence of CKD not associated with known risk factors in a reported high-burden region, and will provide insights to help design targeted health systems responses. The findings will contribute to the policy development to tackle CKD in the region and will permit international comparisons with other regions with similar high prevalence.

Influence of Water Intake and Balance on Body Composition in Healthy Young Adults from Spain

The increasing prevalence of overweight and obesity has become an epidemic public health problem worldwide. In the last years, several investigations have suggested that water intake and retention could have important implications for both weight management and body composition. However, there is a lack of information about this issue globally, and mainly specifically in Spain. Thus, the aim of this study was to analyze the association between hydration status and body composition in a sample of healthy Spanish adults. The study involved 358 subjects, aged 18–39 years. The recently validated “hydration status questionnaire” was used to assess their water intake, elimination, and balance. Anthropometric measurements were performed according to the recommendations of the International Standards for Anthropometric Assessment (ISAK). Body composition variables were acquired by bioelectrical impedance analysis. Differences in anthropometric and body composition variables were assessed through the ANOVA test and considered significant at p < 0.05. Fluid intake was correlated with body water content. Inverse associations between water consumption, normalized by weight, with body weight, body fat mass, and waist circumference were found. Moreover, according to water balance, significant differences in body water content in females were observed. In conclusion, higher fluid intake seems to be related with a healthier body composition. Therefore, the improvement of water intake and water balance could be useful for overweight and obesity prevention, although further studies are needed to confirm the present findings.

Adaptation and Validation of the Hydration Status Questionnaire in a Spanish Adolescent-Young Population: A Cross Sectional Study

The achievement of adequate hydration status is essential for mental and physical performance and for health in general, especially in children and adolescents. Nevertheless, little is known about hydration status of this population, mainly due to the limited availability of research tools; thus, the objective of the current study was to adapt and validate our hydration status questionnaire in a Spanish adolescent-young population. The questionnaire was validated against important hydration markers: urine colour, urine specific gravity, haemoglobin, haematocrit and total body water and involved 128 subjects aged between 12⁻17 years. Water intake was also estimated through a three-day dietary record and physical activity was assessed through accelerometers. Participants completed the questionnaire twice. Water balance and water intake were correlated with urine specific gravity and with total body water content. Water intake obtained by the questionnaire was correlated with results from the three-day dietary record. The intraclass correlation coefficient indicated moderate concordance between both recordings and the Cronbach's alpha revealed high consistency. The Bland and Altman method indicated that the limits of agreement were acceptable to reveal the reliability of the estimated measures. In conclusion, this is the first time that a questionnaire is valid and reliable to estimate hydration status of adolescent-young populations.

Relative Validity of a Beverage Frequency Questionnaire Used to Assess Fluid Intake in the Autosomal Dominant Polycystic Kidney Disease Population

Maintaining hydration sufficient to reduce levels of arginine vasopressin has been hypothesised to slow kidney cyst growth in autosomal dominant polycystic kidney disease (ADPKD). The semi-quantitative beverage frequency questionnaire (BFQ) was designed to measure usual fluid intake over the past month. The aim of this study was to assess the validity and reliability of the BFQ compared with the 24-h urine biomarkers. Participants with ADPKD (18–67 years; estimated glomerular filtration rate (eGFR) ≥ 30 mL/min1.73 m²) completed the BFQ. Serum creatinine, eGFR, 24-h urine volume, and osmolality were measured. Pearson correlation coefficients, paired t test, and Bland–Altman plots were used to evaluate agreement between the methods. A subset repeated the BFQ to assess reliability. A total of 121 participants (54% male, 43 ± 11 years; mean ± SD) completed the BFQ and at least one 24-h urine collection. The correlation between the BFQ and the 24-h urine volume was moderate (r = 0.580) and weaker with the 24-h urine osmolality (r = −0.276). The Bland–Altman plots revealed good agreement between the BFQ and the 24-h urine volume with no obvious bias; however, the limits of agreement were wide (−1517–1943 mL). The BFQ1 and BFQ2 were strongly correlated (r = 0.799, p < 0.001) and were not significantly different (p = 0.598). The BFQ is a valid and reliable tool to assess the usual fluid intake of the ADPKD population.

Evaluation of water balance in a population of older adults. A case control study

Older adults are at risk for dehydration and its' potentially life-threatening consequences. Unrecognized dehydration can complicate chronic medical problems and increase morbidity. The objective of the study was to estimate water balance, intake and loss in elderly people living in Greece using the Water Balance Questionnaire (WBQ). WBQ was administered in winter to 108 independents (65-81yrs) (Group A), 94 independents (82-92yrs) (Group B) and 51 hospitalized (65-92yrs) (Group C). A database from previous study of 335 adults (18-65yrs) (Control Group) used for comparison. Mean estimates of water balance, intake and loss were, respectively, for Group A -749 ± 1386 mL/day, 2571 ± 739 mL/day and 3320 ± 1216 mL/day, for Group B -38 ± 933 mL/day, 2571 ± 739 mL/day and 3320 ± 1216 mL/day, for Group C 64 ± 1399 mL/day, 2586 ± 1071 mL/day and 2522 ± 1048 mL/day and for Control Group -253 ± 1495 mL/day, 2912 ± 1025 mL/day and 3492 ± 2099 mL/day. Significant differences were detected in water balance, intake and loss (p < 0.01). Water balance and water intake in Group A was the lowest. For Groups A, B, C and Control, contribution of solid foods to water intake was 36%, 29%, 32%, 25%, of drinking water was 32%, 48%, 45%, 47%, of beverages was 32%, 23%, 23% and 28% respectively. Significant differences observed in the contribution of drinking water and beverages (p < 0.01). Group A had lower water balance and water intake. Groups B and C had lower water intake from beverages.

Validation Testing Demonstrates Efficacy of a 7-Day Fluid Record to Estimate Daily Water Intake in Adult Men and Women When Compared with Total Body Water Turnover Measurement

Background: Mean daily water intake from fluids (WATER-FL) has proven to be difficult to measure because of a range of nonvalidated data collection techniques. Few questionnaires have been validated to estimate WATER-FL against self-reported diaries or urinary hydration markers, which may limit their objectivity.Objectives: The goals of this investigation were 1) to assess the validity of a 7-d fluid record (7dFLR) to measure WATER-FL (WATER-FL-7dFLR) through comparison with WATER-FL as calculated by measuring deuterium oxide (D₂O) disappearance (WATER-FL-D₂O), and 2) to evaluate the reliability of the 7dFLR in measuring WATER-FL.Methods: Participants [n = 96; 51% female; mean ± SD age: 41 ± 14 y; mean ± SD body mass index (in kg/m²): 26.2 ± 5.1] completed body water turnover analysis over 3 consecutive weeks. They completed the 7dFLR and food diaries during weeks 2 and 4 of the observation. The records were entered into nutritional software to determine the water content of all foods and fluids consumed. WATER-FL-D₂O was calculated from water turnover (via the D₂O dilution method), minus water from food and metabolic water. The agreement between the 2 methods of determining WATER-FL were compared according to a Bland-Altman plot at week 2. The test-retest reliability of 7dFLR between weeks 2 and 4 was assessed via intraclass correlation (ICC).Results: The mean ± SD difference between WATER-FL-7dFLR and WATER-FL-D₂O was -131 ± 845 mL/d. In addition, no bias was observed (F_[1,94] = 0.484; R² = 0.006; P = 0.488). When comparing WATER-FL-7dFLR from weeks 2 and 4, no significant difference (mean ± SD difference: 71 ± 75 mL/d; t_[79] = 0.954; P = 0.343) and an ICC of 0.85 (95% CI: 0.77, 0.90) was observed.Conclusions: The main findings of this study were that the use of the 7dFLR is an effective and reliable method to estimate WATER-FL in adults. This style of questionnaire may be extremely helpful for collecting water intake data for large-scale epidemiologic studies.

Hydration status, drug interactions, and determinants in a Spanish elderly population: a pilot study

Proper hydration is essential to maintain optimal health and well-being at all stages of life, especially for the elderly. Side effects of certain drugs that affect hydration status may compromise the health of the ancients, who also constitute the most vulnerable group. No studies have been carried out, to our knowledge, at the intersection of drugs and hydration status. Our study aimed to evaluate the effects of chronic use of certain drugs (diuretics, corticoids and metformin) in the hydration status of the elderly. Results were obtained from a cross-sectional study with 96 volunteers (65-93 years) selected based on their pharmacological treatment. It included a validated food and drink frequency questionnaire and water removal, dehydration signs and symptoms assessment and urine analysis. All data were analysed by age and sex. Water balance decreased with advanced age, especially in men's group. Results were confirmed by means of the evaluation of dehydration signs and symptoms and colorimetric and chemical analysis of urine. Correlations between consumption of corticoids and hydration status were found, with different signs depending on the administration route (Rho = 0.522 and Rho = - 0,522 for oral and pulmonary corticoids, respectively). Furthermore, correlations between diuretics (Rho = - 0.343, p < 0.05) and metformin (Rho = - 0.802, p < 0.01) consumption and different urine markers were determined. In conclusion, the predominant dehydration state of the volunteers of the study is affected by drugs consumption and their route of administration. Hence, there is an urgent need for monitorization of hydration status based on drugs consumption.

Water Intake in a Sample of Greek Adults Evaluated with the Water Balance Questionnaire (WBQ) and a Seven-Day Diary

Awareness on the importance of hydration in health has created an unequivocal need to enrich knowledge on water intake of the general population and on the contribution of beverages to total water intake. We evaluated in the past water intake in a sample of Greek adults using two approaches. In study A, volunteers completed the Water Balance Questionnaire (WBQ), a food frequency questionnaire, designed to evaluate water intake (n = 1092; 48.1% males; 43 ± 18 years). In study B, a different population of volunteers recorded water, beverage, and food intake in seven-day diaries (n = 178; 51.1% males; 37 ± 12 years). Herein, data were reanalyzed with the objective to reveal the contribution of beverages in total water intake with these different methodologies. Beverage recording was grouped in the following categories: Hot beverages; milk; fruit and vegetable juices; caloric soft drinks; diet soft drinks; alcoholic drinks; other beverages; and water. Total water intake and water intake from beverages was 3254 (SE 43) mL/day and 2551 (SE 39) mL/day in study A; and 2349 (SE 59) mL/day and 1832 (SE 56) mL/day in study B. In both studies water had the highest contribution to total water intake, approximately 50% of total water intake, followed by hot beverages (10% of total water intake) and milk (5% of total water intake). These two approaches contribute information on water intake in Greece and highlight the contribution of different beverages; moreover, they point out differences in results obtained from different methodologies attributed to limitations in their use.

Beverage Intake Assessment Questionnaire: Relative Validity and Repeatability in a Spanish Population with Metabolic Syndrome from the PREDIMED-PLUS Study

We assess the repeatability and relative validity of a Spanish beverage intake questionnaire for assessing water intake from beverages. The present analysis was performed within the framework of the PREDIMED-PLUS trial. The study participants were adults (aged 55–75) with a BMI ≥27 and <40 kg/m², and at least three components of Metabolic Syndrome (MetS). A trained dietitian completed the questionnaire. Participants provided 24-h urine samples, and the volume and urine osmolality were recorded. The repeatability of the baseline measurement at 6 and 1 year was examined by paired Student’s t-test comparisons. A total of 160 participants were included in the analysis. The Bland–Altman analysis showed relatively good agreement between total daily fluid intake assessed using the fluid-specific questionnaire, and urine osmolality and 24-h volume with parameter estimates of −0.65 and 0.22, respectively (R² = 0.20; p < 0.001). In the repeatability test, no significant differences were found between neither type of beverage nor total daily fluid intake at 6 months and 1-year assessment, compared to baseline. The proposed fluid-specific assessment questionnaire designed to assess the consumption of water and other beverages in Spanish adult individuals was found to be relatively valid with good repeatability.

Water Intake and Hydration Indices in Healthy European Adults: The European Hydration Research Study (EHRS)

Hydration status is linked with health, wellness, and performance. We evaluated hydration status, water intake, and urine output for seven consecutive days in healthy adults. Volunteers living in Spain, Germany, or Greece (n = 573, 39 ± 12 years (51.1% males), 25.0 ± 4.6 kg/m² BMI) participated in an eight-day study protocol. Total water intake was estimated from seven-day food and drink diaries. Hydration status was measured in urine samples collected over 24 h for seven days and in blood samples collected in fasting state on the mornings of days 1 and 8. Total daily water intake was 2.75 ± 1.01 L, water from beverages 2.10 ± 0.91 L, water from foods 0.66 ± 0.29 L. Urine parameters were: 24 h volume 1.65 ± 0.70 L, 24 h osmolality 631 ± 221 mOsmol/kg Η₂Ο, 24 h specific gravity 1.017 ± 0.005, 24 h excretion of sodium 166.9 ± 54.7 mEq, 24 h excretion of potassium 72.4 ± 24.6 mEq, color chart 4.2 ± 1.4. Predictors for urine osmolality were age, country, gender, and BMI. Blood indices were: haemoglobin concentration 14.7 ± 1.7 g/dL, hematocrit 43% ± 4% and serum osmolality 294 ± 9 mOsmol/kg Η₂Ο. Daily water intake was higher in summer (2.8 ± 1.02 L) than in winter (2.6 ± 0.98 L) (p = 0.019). Water intake was associated negatively with urine specific gravity, urine color, and urine sodium and potassium concentrations (p < 0.01). Applying urine osmolality cut-offs, approximately 60% of participants were euhydrated and 20% hyperhydrated or dehydrated. Most participants were euhydrated, but a substantial number of people (40%) deviated from a normal hydration level.

Evaluation of drinks contribution to energy intake in summer and winter

All drinks hydrate and most also provide nutrients and energy. Our objective was to evaluate the contribution of drinks to total energy intake in summer and winter. Data were obtained using the Water Balance Questionnaire (WBQ) from a sample of the general population in Athens, Greece (n = 984), 473 individuals (42 ± 18 years) in summer and 511 individuals (38 ± 20 years) in winter stratified by sex and age. The WBQ embeds a semi-quantitative food frequency questionnaire of 58 foods and the Short International Physical Activity Questionnaire. Data were analyzed for the contribution of drinks to total energy intake. In winter, total energy intake was 2082 ± 892 kcal/day; energy intake from drinks was 479 ± 286 kcal/day and energy expenditure 1860 ± 390 kcal/day. In summer, total energy intake was 1890 ± 894 kcal/day, energy intake from drinks 492 ± 499 kcal/day and energy expenditure 1830 ± 491 kcal/day. Energy intake from drinks in summer was higher than in winter (p < 0.001) and in men higher than in women in both seasons (p < 0.001 in summer, p = 0.02 in winter). Coffee, coffee drinks, milk, chocolate milk and alcoholic drinks contributed approximately 75% of energy from drinks. Fruit juice and sugar-sweetened drinks, including soft drinks and fruit juice based drinks, were consumed less frequently contributing up to 25% of drink energy intake. Drinks contribute approximately 1/4 of total energy intake depending on the energy content of the drink and frequency of consumption. Coffee, dairy and alcoholic drinks were the main energy contributors.

Sensory attributes of soft drinks and their influence on consumers' preferences

Soft drinks are beverages composed of water and other ingredients that provide specific sensorial attributes. Soft drink consumption patterns have recently been changed partially influenced by an increased availability of different types of beverages during the last few years. Consumers' preferences to choose one drink over another are influenced, not only by genetic, psychological and environmental factors, but also by the beverage's specific attributes. In fact, beverage consumption is driven by the sensations it gives. Because the main component of soft drinks is water, an increase in the intake of soft drinks might improve fluid intake and the levels of water in the body if it is regarded as an "essential nutrient".

The development of the predisposition to dehydration questionnaire

The role played by hydration in general health and well-being is an emerging public health issue, yet there are few tools available to monitor its status in large populations. The aim was therefore to develop a questionnaire that assesses individual differences in the tendency to lose body fluid in a warm environment and hence become dehydrated. Fifty-three subjects sat in a room at 30°C for four hours and changes in mood and measures of hydration were monitored. There were marked individual differences in the loss of body mass that differed from 0.24% to 2.39%. Females who reported habitually drinking a lot had more water in their diet and at baseline the osmolality of urine was lower. After being subject to heat, those who reported habitually drinking more produced more urine, had a lower urine osmolality at the end of the study, and overall more body mass was lost. Females who reported that they responded badly to heat were more confused, unsure and depressed after four hours at 30°C. In males those reporting that they habitually drank to a greater extent had more water in the diet, and also those who dealt badly with heat habitually drank more. It was concluded that particularly in females, questionnaire measures were able to predict changes in hydration that result from a warm environment.

Estimations of water balance after validating and administering the water balance questionnaire in pregnant women

Dehydration during pregnancy may be harmful for the mother and fetus; thus our objective was to understand whether pregnant women balance water intake and loss. The Water Balance Questionnaire (WBQ) was modified to reflect pregnancy (WBQ-P). Validation was performed using 3-day diaries (n = 60) and hydration indices in urine (osmolality, specific gravity, pH and color, n = 40). The WBQ-P was found valid according to Kedhal τ-b coefficient agreement. The WBQ-P was administered to 95, 100 and 97 women per trimester, in Greece. Median (IQR) water balance, intake and loss were, respectively, 203 (-577, 971), 2917 (2187, 3544) and 2658 (2078, 3391) ml/day; these did not differ among the trimesters or between pregnant and non-pregnant women. However, more pregnant women were falling in the higher quartiles of water balance distribution. No differences in sources of water intake were identified except that women in the third trimester had lower water intake from beverages.