Insulin sensitivity in obese normotensive adults: influence of family history of hypertension.

OBJECTIVE

To evaluate the influence of family history of hypertension on insulin sensitivity in obese normotensive adults, comparing them with lean subjects.

SUBJECTS

136 normotensives (N)(mean 24 h blood pressure < 130/80 mmHg; age range 35-45 y): 32 lean (body mass index, BMI < or = 25 kg/m2) N with normotensive parents (F-), 37 lean N with one or two parents hypertensive (F+), 32 obese (BMI > or = 30 kg/m2) NF- and, 35 obese NF+.

METHODS

24 h ambulatory blood pressure monitoring; glucose, insulin and C-peptide before and 30, 60, 90 and 120 min after an oral glucose load; index of insulin peripheral activity (Ia: 10(4)/insulin x glucose values at glucose peak); fasting insulin/C-peptide ratio (I/Cp).

RESULTS

The four groups were comparable for age, gender and blood pressure values throughout the 24 h. Glucose, fasting and during test, and I/Cp were similar among the four groups; insulin and C-peptide, fasting and stimulated, were significantly higher and Ia lower in obese N than in lean N; at similar BMI, insulin and C-peptide were significantly higher and Ia lower, in F+ than in F-. The correlation between insulin and BMI was significantly closer in F- than in F+.

CONCLUSIONS

Family history of hypertension appears to be significantly associated with insulin sensitivity in both lean and obese normotensive adults; moreover, overweight and a genetic predisposition to hypertension may have additive adverse effects on insulin sensitivity in normotensive adult subjects.