Article Figures & Data
Tables
Characteristic Unweighted Weighted Age, ya 18–24, No (%) 1,653 (17.4) 14.9 25–30, No (%) 1,136 (11.9) 12.8 31–40, No (%) 1,942 (20.4) 20.4 41–50, No (%) 1,951 (20.5) 22.3 51–64, No (%) 2,846 (29.9) 29.6 Mean (SD), y 40.8 (14.1) 41.1 (11.7) Race/ethnicitya Mexican American, No (%) 1,541 (16.2) 9.2 Other Hispanic, No (%) 1,019 (10.7) 6.2 Non-Hispanic white, No (%) 3,645 (38.3) 64.5 Non-Hispanic black, No (%) 2,201 (23.1) 12.2 Other, No (%)b 1,122 (11.8) 7.9 Sexa Male, No (%) 4,656 (48.9) 49.2 Female, No (%) 4,872 (51.1) 50.8 Income-to-poverty ratioc <1 (<100% federal poverty level) 2,308 (26.6) 17.9 Mean (SD) ratio 2.4 (1.7) 2.9 (1.4) - Table 2
Bivariate Relationships Between Hydration Status and Participants’ Characteristics
Characteristic Adequately Hydrateda (67.4%, Weighted) Inadequately Hydratedb (32.6%, Weighted) Age, mean (SD), yc 43 (12) 37 (12) Race/ethnicityd Mexican American, % 7.8 12.0 Other Hispanic, % 5.4 7.8 Non-Hispanic white, % 68.4 57.8 Non-Hispanic black, % 10.4 15.0 Other, %e 8.1 7.5 Sexd Male, % 46.0 59.1 Female, % 54.0 40.9 Income-to-poverty ratio, mean (SD)c 3.0 (1.5) 2.8 (1.5) BMI, mean (SE)c,d 28.3 (0.15) 29.2 (0.20) Obese, %f 67.7 59.7 Not obese, %g 32.3 40.3 BMI = body mass index; SE = standard error.
↵a Urine osmolality <800 mOsm/kg.
↵b Urine osmolality ≥800 mOsm/kg.
↵c Compared using independent samples t test, all P <.001.
↵d Compared using Pearson χ2 test, all P <.001.
↵e Includes Asian, Native American, multiracial, and all other populations.
↵F BMI ≥30.
↵g BMI <30.
Variable Linear Regression: Continuous BMI β (95% CI) Logistic Regression: BMI ≥30 OR (95% CI) Inadequate hydration 1.32 (0.85 to 1.79)a 1.59 (1.35 to 1.88)a Sex Female Reference Reference Male 0.21 (–0.12 to 0.53) 1.09 (0.96 to 1.25) Race/ethnicity Non-Hispanic white Reference Reference Mexican American 1.02 (0.42 to 1.62)b 1.40 (1.17 to 1.66)a Other Hispanic 0.39 (–0.17 to 0.95) 1.15 (0.94 to 1.42) Non-Hispanic black 2.32 (1.76 to 2.88)a 1.76 (1.48 to 2.09)a Other –2.11 (–2.73 to –1.49)a 0.49 (0.38 to 0.62)a Income-to-poverty ratio –0.28 (–0.44 to –0.13)b 0.93 (0.89 to 0.97)b Age 0.09 (0.07 to 0.11)a 1.02 (1.01 to 1.03)a
Additional Files
The Article in Brief
Inadequate Hydration, BMI, and Obesity Among US Adults: NHANES 2009-2012
Tammy Chang , and colleagues
Background People who want to lose weight are often counseled to first drink water when they have the urge to eat, as they may actually be thirsty rather than hungry. However, studies of water intake as a weight loss tool have shown mixed results. This study assesses the relationship between adequate hydration, as measured by urine concentration (also called urine osmolality) and obesity (measured by body mass index).
What This Study Found The findings suggest that inadequate hydration is associated with higher body mass index and obesity. In a nationally representative sample, 33 percent of adults were inadequately hydrated and had a higher average body mass index than hydrated individuals. The odds of being obese were 1.59 times higher for inadequately hydrated individuals compared with hydrated individuals.
Implications
- Although causality and directionality cannot be established with the study design, these findings raise the possibility that drinking more water could be part of a solution to the obesity problem. The authors call for additional investigation to examine the relationship between inadequate hydration and weight status.
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