Obesity and Hypertension

Abstract

The link between obesity and hypertension is well known, but there are still many questions to be answered: Is abdominal adiposity rather than overall obesity more closely associated with high blood pressure? Is obesity an independent cardiovascular risk factor even if not combined with hypertension? Can obesity be metabolically benign? To what extent weight reduction is expected to contribute to the management or the primary prevention of hypertension? Are there compelling indications and/or contraindications to the use of specific classes of antihypertensive drugs for the pharmacological treatment of obesity hypertension? Consequently, the present editorial seeks to answer these questions by briefly reviewing the current state of knowledge of the association of obesity with hypertension. Several tools are used to estimate obesity. The body mass index (BMI), or Quetelet index, is a statistical measurement which compares a person’s weight and height. BMI is body weight in kilograms divided by the height in meters squared, expressed as weight (in kg)/height (m). Overweight is defined as a BMI >25, obesity as a BMI >30, and morbid obesity is a BMI >35. Abdominal obesity is the accumulation of visceral fat resulting in an increase in waist size. It is often referred to as central, visceral, male-type or android obesity vs. female-type or gynoid obesity with a preferential gluteofemoral distribution. Abdominal obesity is diagnosed by a waist circumference >102 cm in men, and >88 cm in women or by a waist-to-hip ratio >0.95 in men and >0.85 in women. As early as in 1980, in the second National Health and Nutrition Examination Survey (NHANES II), it was noted that the prevalence of hypertension was 2.9 times higher in obese than in non-obese adult Americans. The Third National Health and Nutrition Examination Survey (NHANES III) conducted from 1988 to 1994 revealed a similar linear relationship despite a lower prevalence of hypertension. BMI was recently found to be positively associated with blood pressure even in active, American veteran football players. In a cross-sectional analysis of adults enrolled in NHANES 1999-2004, the odds ratio for hypertension for every 5-unit increase in BMI was 1.45 (95% CI 1.39-1.52). Although obesity was associated with hypertension in all age groups and both sexes, the odds for hypertension associated with obesity were relatively higher in younger people. With regard to hypertension subtypes, increasing BMI was a significant predictor of isolated diastolic hypertension or systodiastolic hypertension as opposed to isolated systolic hypertension. Isolated systolic hypertension represented a minority of hypertension cases in obese men, but remained the most prevalent type in obese women. There is substantial evidence that in addition to BMI, both waist circumference and waist-to-hip ratio are correlated with blood pressure, even after adjustment for BMI. The associations of BMI and waist circumference with systolic and diastolic blood pressure and their possible interactions with gender and age were assessed in a cohort of 10,928 non-smoking and never treated for hypertension adults, recruited from all regions of Greece during 1994–1999, within the context of the European From the Center for the Prevention of Cardiovascular Disease, “Hygieias Melathron,” Athens, Greece