Abdominal Obesity, Body Mass Index, and Hypertension in US Adults: NHANES 2007–2010

BACKGROUND: Both abdominal obesity, defined as waist circumference (WC) ≥ 102 cm for men and WC ≥ 88 cm for women and increased body mass index (BMI; kg/m²) are known to be associated with hypertension. The aim of this study was to examine the independent and the combined relationship between abdominal obesity and increased BMI and hypertension by age, race, and gender in a national sample. METHODS: This report is based on national level cross-sectional data for adults aged 18 years and older (11,145 participants) from the US National Health and Nutrition Examination Survey (NHANES) 2007-2010. RESULTS: Abdominal obesity, after adjusting for BMI categories and other covariables, was independently associated with hypertension. That is, survey participants classified as abdominally obese had almost 50% increased odds of being hypertensive (odds ratio (OR) 1.51, 95% confidence interval (CI) 1.27-1.81) after controlling for BMI. After adjusting for covariables, the groups of individuals classified as abdominally obese and normal BMI; as abdominally obese and overweight; and abdominally obese and obese each had a progressive increase in the odds of hypertension when compared with individuals who had a normal BMI and no abdominal obesity (OR 1.81, 95% CI 1.28-2.57, OR 1.87, 95% CI 1.55-2.25, and OR 3.23, 95% CI 2.63-3.96, respectively). CONCLUSIONS: Abdominal obesity is independently associated with hypertension after adjusting for BMI. After adjusting for covariables and parameterizing BMI categories and abdominal obesity the new variable showed a progressive increase in the odds of hypertension. Both BMI and WC should be included in models assessing hypertension risks.