Associations between hypertension and body mass index and waist circumference in U.S. adults: A comparative analysis by gender

Generalized obesity (body mass index (BMI)) and abdominal obesity (waist circumference (WC)) are a risk of hypertension, but their potentially multiplicative effect on hypertension is underexplored particularly by gender.  The objective of this research is to examine the association between hypertension and these two obesity measures and modifying effects using a nationally representative sample of U.S. adults.  Data were derived from the 2009-2010 National Health and Nutrition Examination Survey (n=5,886).  Overweight and obesity were based on BMI of 25.0-29.9kg/m² and ≥30kg/m², respectively. High-risk WC was based on ≥102.0cm and ≥88.0cm for males and females, respectively. Hypertension was determined by systolic/diastolic blood pressure (BP) of ≥140mmHg/≥90mmHg, or taking prescribed medications for high BP.  Logistic regression was used to examine the association between hypertension and BMI and WC for all subjects and by gender.  Interaction terms were added in each model to examine if BMI modified the effect of WC on hypertension. Results indicated that both BMI and WC were associated with hypertension in overall population. Gender-specific models indicated that BMI played an important role in males, but WC in females.  The interaction effects were present among males implying that the association of WC with hypertension was stronger if subjects were overweight or obese.  This effect, however, was not present in overall population and females.  BMI and WC may influence hypertension differently among males and females.  Various measures of obesity and gender-specific approaches to reducing the risk of hypertension should be encouraged.