Stookey JD, Barclay D, Arieff A, Popkin BM. The altered fluid distribution in obesity may reflect plasma hypertonicity.
Eur J Clin Nutr 2006;
61:190-9. [PMID:
17021599 DOI:
10.1038/sj.ejcn.1602521]
[Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE
This study explored whether the increased extracellular relative to intracellular fluid (ECF/ICF) ratio in obesity might reflect osmotic effects of elevated plasma solute concentrations.
DESIGN
Cross-sectional, epidemiological survey.
SETTING AND SUBJECTS
The present analysis used nationally representative data from the Third National Health and Nutrition Examination Survey on community-dwelling adults (aged 40-59 years) in the US without evidence of glucose dysregulation or chronic disease (n=1285).
INTERVENTION
Body mass index (BMI) was estimated from measured height and weight. Total body reactance, an index of body fluid distribution, was determined by bioelectrical impedance analysis. Plasma tonicity (the cumulative index of osmotically effective plasma solute) was estimated from plasma glucose, sodium and potassium. Sex-specific relative odds of lower reactance (<or=50 Omega/m for women, <or=40 Omega/m for men) and plasma hypertonicity (tonicity >or=295 mmol/l) associated with overweight (25<or=BMI <30) and obesity (BMI>or=30) were estimated using logistic regression models that controlled for sociodemographic variables, smoking, leisure-time physical activity, total energy intake, serum creatinine, plasma insulin and glucose. Multinomial logistic regression models tested for associations between weight status and specific serum solute.
RESULTS
Independent of covariates, in men and women, overweight and obesity were associated with increased odds of lower reactance and hypertonicity. Overweight and obese individuals with lower reactance had significantly higher serum sodium than normal weight individuals.
CONCLUSIONS
Elevated plasma solute concentrations are associated with obesity in free-living adults. Physicians and researchers should be alert to a possible link between hypertonicity and obesity.
SPONSORSHIP
Grants from the NIH, Nestle Waters.
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