Body mass index and hypertension hemodynamic subtypes in the adult US population

Obesity produces various hemodynamic abnormalities that may impact hypertension subtypes. Similarly, the study of hypertension subtypes provides important information regarding the relative importance of hemodynamic abnormalities contributing to obesity-related hypertension.

Cross-sectional analysis of adults enrolled in the Third National Health and Nutrition Examination Survey (NHANES III) (n = 16 545) and NHANES 1999-2004 (n = 12 137). We examined the relationship between body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) and the risk of hypertension and hemodynamic subtypes: isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systodiastolic hypertension (SDH).

In NHANES 1999-2004, the odds ratio (OR) for hypertension for every 5-unit increase in BMI was 1.45 (95% confidence interval [CI], 1.39-1.52) (P < .001). However, the magnitude of the relative increase in the odds of hypertension was higher among younger adults. Among patients with hypertension, increasing BMI was a significant predictor of IDH or SDH (OR for IDH or SDH, 1.04; 95% CI, 1.02-1.06) (P < .001), as opposed to ISH. Isolated systolic hypertension represented a minority of hypertension cases in obese men (38.9%; 95% CI, 30.9-47.6) but remained the most prevalent type in obese women (62.1%; 95% CI, 52.4%-71.0%) (P < .001), despite a significant relative decrease in the frequency of ISH with increasing BMI in both sexes. Findings in NHANES III were very similar.

Isolated diastolic hypertension and SDH account for most cases of obesity-related hypertension, suggesting that determinants of mean arterial pressure account for the major burden of obesity-related hypertension in US adult men. These findings should be considered in the design of clinical trials and therapeutic strategies for obesity-related hypertension. Further studies should assess determinants of mean arterial pressure in obesity and the role of sex in the pathogenesis of obesity-related hypertension.