Distinction of hypertriglyceridemic waist phenotype from simple abdominal obesity: interaction with sex hormone-binding globulin levels to confer high coronary risk.

OBJECTIVE

The associations of total testosterone (TT) and sex hormone-binding globulin (SHBG) with the hypertriglyceridemic waist (HtgW) phenotype and coronary heart disease (CHD) risk have scarcely been examined. We explored such cardiometabolic risk mediations in middle-aged adults.

METHODS

Participants (n = 1924) in a population-based study were studied by forming categories consisting of abdominal obesity, hypertriglyceridemia, both (HtgW), or none ('healthy'). Cardiometabolic risk was prospectively analyzed (mean follow-up 5.7 years).

RESULTS

With reference to the healthy group, SHBG values in HtgW were significantly lower, alike serum HDL-cholesterol. ApolipoproteinB-containing lipoproteins, fasting glucose and complement C3 levels, inverse to lipoprotein[Lp](a) especially in female participants with HtgW phenotype compared with those in the 'healthy' category, suggested the operation of aggregation to Lp(a). Multivariable Cox regression analysis in a model comprising age, waist circumference and systolic blood pressure showed significant protection by SHBG against incident diabetes which tended to be so with TT in men. Sex hormones were not associated with risk of incident CHD or MetS. In another multivariable model, compared to the 'healthy' and the hypertriglyceridemia categories, dichotomized high and, in females, low SHBG values within the HtgW category, positively predicted CHD at significant over 2-fold relative risks.

CONCLUSIONS

HtgW phenotype distinguishes itself from the (virtually neutral) simple abdominal obesity in independently conferring high CHD risk when elevated or reduced SHBG levels interact. Underlying operation of Lp(a) aggregation is suggested.