Familial Obesity, Sympathetic Activation and Blood Pressure Level

Abstract

This study was conducted to evaluate the relative contributions of existing obesity and a family history of obesity (FHOB) to blood pressure (BP) level, sympathetic activity, plasma leptin and insulin levels in young men without a family history of hypertension. The study was of "four-corner" design according to body mass index (BMI). A positive FHOB (FHOB+) was defined as both parents being obese (BMI>26.0 kg/m 2 ), and a negative FHOB (FHOB–) was defined as both parents being lean (BMI<22.0 kg/ m 2 ). The cutoff limits of BP for the subjects and their parents enrolled in present study was defined as a supine reading of <140/90 mmHg. In 12 lean young subjects with FHOB–, 9 obese young subjects with FHOB–, 8 lean young subjects with FHOB+ and 16 obese young subjects with FHOB+, BMI, BP, plasma norepinephrine (NE), insulin and leptin were measured. All subjects were men and non-diabetic. Obese subjects, irrespective of FHOB, had higher levels of BMI, BP, plasma NE, leptin and insulin compared to lean subjects. In subjects with FHOB+, regardless of their current degree of adiposity, there was a higher level of BP and plasma NE than in subjects with FHOB–. In lean subjects, FHOB+ was associated with a higher plasma NE level and BP, but similar levels of plasma leptin and insulin were found when compared with FHOB– subjects. These results suggest that existing obesity and a positive family history of obesity appear to have an association with sympathetic overactivity and BP elevation.