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Water intake may be overlooked factor in weight management

There is a significant association between inadequate hydration and elevated BMI and obesity, even after controlling for confounders, according to data published in the Annals of Family Medicine.

The researchers further concluded that their findings suggest that water consumption may deserve a greater focus in weight management research and clinical strategies.

“The drivers of obesity are multifactorial and represent a major clinical challenge

in both prevention and management,” Tammy Chang, MD, MPH, MS, of the department of Family Medicine, at the University of Michigan, Ann Arbor, and colleagues wrote. “In addition to replacing sugar-sweetened beverages with water, improving overall hydration is a

strategy commonly used to prevent overeating, with the goal of promoting a healthy weight among patients…. To date, no population-level studies have investigated the relationship between adequate hydration, as measured by urine osmolality, and obesity.”

To determine the association between inadequate hydration and BMI and obesity, among adults in the United States, the researchers used data from a nationally representative sample of 9,528 participants aged 18 to 64 years, obtained from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2012. The primary outcome was BMI, measured in continuous values and categorized as obese, defined as a BMI of 30 or greater, or not obese. Participants with urine osmolality values of 800 mOsm/kg or greater were considered to be inadequately hydrated.

The researchers used linear and logistic regressions 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.

According to the researchers, 32.6% of those in the sample were inadequately hydrated, with a mean osmolality of 631.4 mOsm/kg. In adjusted models, adults who were inadequately hydrated had higher BMIs (1.32 kg/m²; 95% CI, 0.85-1.79; P < .001) compared with adequately hydrated adults. They also had higher odds of being obese (OR = 1.59; 95% CI, 1.35-1.88; P < .001) compared with hydrated adults.

“Our study highlights a novel relationship between hydration and BMI that may have important clinical implications,” Chang and colleagues wrote. “Although causality and directionality cannot be established in our cross-sectional study, our findings suggest that additional investigation is warranted to examine the relationship between inadequate hydration

and weight status…. Our findings also suggest that individuals with higher BMIs may behave in ways that lead them to be inadequately hydrated.” – by Jason Laday

Disclosure: The researchers report no relevant financial disclosures.