摘要：Objectives. To evaluate whether differences in tap water and other beverage intake explain differences in inadequate hydration among US adults by race/ethnicity and income. Methods. We estimated the prevalence of inadequate hydration (urine osmolality ≥ 800 mOsm/kg) by race/ethnicity and income of 8258 participants aged 20 to 74 years in the 2009 to 2012 National Health and Nutrition Examination Survey. Using multivariable regression models, we estimated associations between demographic variables, tap water intake, and inadequate hydration. Results. The prevalence of inadequate hydration among US adults was 29.5%. Non-Hispanic Blacks (adjusted odds ratio [AOR] = 1.44; 95% confidence interval [CI] = 1.17, 1.76) and Hispanics (AOR = 1.42; 95% CI = 1.21, 1.67) had a higher risk of inadequate hydration than did non-Hispanic Whites. Lower-income adults had a higher risk of inadequate hydration than did higher-income adults (AOR = 1.23; 95% CI = 1.04, 1.45). Differences in tap water intake partially attenuated racial/ethnic differences in hydration status. Differences in total beverage and other fluid intake further attenuated sociodemographic disparities. Conclusions. Racial/ethnic and socioeconomic disparities in inadequate hydration among US adults are related to differences in tap water and other beverage intake. Policy action is needed to ensure equitable access to healthy beverages. Access to safe, clean drinking water is defined as a human right by the United Nations. 1 Consuming adequate water, whether in the form of plain water, other beverages, or food, is essential for maintaining hydration status, which is in turn critical for proper physiological functioning. Drinking water instead of sugary drinks could help reduce the risk of obesity, 2,3 and fluoridated water can promote dental health. 4 Although severe dehydration can be life threatening and often requires urgent medical intervention, an emerging body of evidence suggests that mild dehydration or inadequate hydration (i.e., when one is beginning to feel thirsty) may increase the risk of (1) disruptions in cognitive function, (2) fatigue, and (3) lower endurance. 5 Inadequate hydration has also been associated with worse mood and overall subjective feelings of poor health, such as headaches 6 ; conversely, interventions to rehydrate via water intake can improve mood and fatigue. 7,8 As the recent catastrophe with Flint, Michigan’s municipal water system has made plain, access to safe, clean drinking water is by no means universal in the United States and may be negatively affecting both perceptions of water quality and water intake (total water intake and water as a beverage). A national study of US adults found that non-Hispanic Black and Hispanic adults were substantially more likely to report that their local tap water was not safe to drink and that this was associated with drinking less water (either tap or bottled) and more sugar-sweetened beverages. 9 Total water intake, that is, water from all food and beverage sources, is lower among non-Hispanic Black and Hispanic adults than among non-Hispanic White adults, 10 and non-Hispanic White adults are more likely to specifically consume tap water. 11 Despite growing research on inadequate hydration and health, 12–16 disparities in hydration status have not yet been directly assessed in US adults. One recent study found significant disparities among US youths, with boys and non-Hispanic Black youths more likely to be inadequately hydrated. 17 Two recent evaluations of urine osmolality 18 and inadequate hydration as related to body mass index (BMI; defined as weight in kilograms divided by the square of height in meters) 15 in the US population found it to vary by race/ethnicity; however, these studies’ aims did not include quantifying these disparities or exploring why these disparities exist. Understanding population disparities in hydration status among adults, and identifying whether differential consumption of tap water and other beverages influences disparities, may help inform public health efforts to promote well-being. We sought to provide an assessment of disparities in hydration status among US adults by income and race/ethnicity using nationally representative cross-sectional data. We also sought to evaluate the extent to which racial/ethnic or socioeconomic differences in intake of tap water as well as other beverages could explain disparities in hydration status, adjusting for relevant confounders.
