High adiponectin levels fail to protect against the risk of hypertension and, in women, against coronary disease: involvement in autoimmunity?

AIM

To investigate whether serum adiponectin protects against cardiometabolic risk in a population sample with prevailing metabolic syndrome.

METHODS

Middle-aged adults representative of a general population with baseline circulating adiponectin measurements (n = 1224) were analyzed prospectively at a mean of 3.8 years' follow-up, using continuous values or sex-specific tertiles. Total adiponectin was assayed by an ELISA kit. Type-2 diabetes was identified by criteria of the American Diabetes Association. Hypertension was defined as a blood pressure ≥ 140 mmHg and/or ≥ 90 mmHg and/or use of antihypertensive medication. Outcomes were predicted using Cox proportional hazards regression analysis in models that were controlled for potential confounders.

RESULTS

In models of multiple linear regression, sex hormone-binding globulin, fasting insulin (inverse) and, in men, age were significant independent covariates of serum adiponectin which further tended in women to be positively associated with serum creatinine. Cox regression analyses for incident coronary heart disease (CHD), adjusted for sex, age, non-HDL cholesterol, waist circumference and C-reactive protein, revealed significant inverse association with adiponectin tertiles in men but not women (HR = 0.66; 95%CI: 0.32-1.38 for highest tertile). Cox regression for type-2 diabetes in a similar model (wherein glucose replaced non-HDL cholesterol), adiponectin tertiles appeared to protect in each gender. HR for incident hypertension roughly displayed unity in each of the adiponectin tertiles (P-trend = 0.67).

CONCLUSION

High adiponectin levels failed to protect against the development of hypertension and, in women, against CHD, presumably paralleling impairment in renal function as well. Involvement of adiponectin in autoimmune complex with loss of antioxidative-antiatherogenic properties may be underlying.