Sex-related differences in the relations of insulin resistance and obesity to left ventricular hypertrophy in Japanese hypertensive patients

Echocardiographically determined left ventricular (LV) hypertrophy is a powerful, independent predictor of cardiovascular morbidity and mortality. Both insulin resistance and obesity have a well-known association with LV hypertrophy. However, whether or not there are sex-related differences in the relations of insulin resistance and obesity to LV hypertrophy has never been systematically explored in Japan. We enrolled 91 never-treated hypertensive patients (49 men and 42 women) to assess the possible relations of insulin resistance and obesity to LV geometry. Insulin resistance was estimated using the homeostasis model assessment (HOMA) formula. Echocardiographically determined LV mass and relative wall thickness were measured as markers of LV geometry. In addition, body mass index (BMI) was calculated as weight (kg) divided by height (m)(2) as a marker of obesity. Independent determinants of LV mass in male hypertensive patients were HOMA value (p<0.0001) and age (p=0.034). BMI did not bear a significant relation to LV mass. In comparison, in female hypertensive patients BMI was an independent determinant of LV mass (p=0.011). The HOMA value did not bear a significant relation to LV mass in the female hypertensive patients. In conclusion, these findings indicate the presence of sex-related differences in the relations of insulin resistance and obesity to LV hypertrophy in Japanese hypertensive patients. The effect of obesity on LV geometry was greater in female hypertensive patients than in male hypertensive patients.