Menopause: clustering of metabolic syndrome components and population changes in insulin resistance

Aim The incidence of the metabolic syndrome (MS) in women rises rapidly during the menopause, substantially increasing their cardiovascular risk and mortality. The aim of the study was to analyze menopausal changes in individual MS components and the parameter of insulin resistance (HOMA-IR). Methods A random population sample of 909 women aged 45-54 years, resident in Prague 4, was examined in an epidemiological study. After excluding women with gynecological hormone therapy or surgical therapy, the two groups of women were compared: women of reproductive age (REPRO, n = 245) vs. naturally postmenopausal women (POSTm, n = 149). Results The incidence of MS rose significantly in menopause (REPRO/POSTm 22.9 +/- 2.6%/38.3 +/- 4.0%; p < 0.001). However, a detailed analysis among the five components defining MS showed that increases were only seen in waist circumference (p < 0.0001) and triglycerides (p < 0.001). There was no increase in the other components or HOMA-IR. A detailed analysis showed an increase in HOMA-IR at levels above the median (REPRO/POSTm: low HOMA-IR 0.9/0.9, not significant; high HOMA-IR 1.8/2.1, p < 0.001) and an increase in the incidence of MS just in these high levels of HOMA-IR and those rising during menopause (REPRO/POSTm: low HOMA-IR 13.8%/18.7%, not significant; high HOMA-IR 30.9%/57.3%, p < 0.0001). In menopause, there was an increase in the clustered incidence (accompanying MS) of each of the five MS components at the expense of isolated incidence (not accompanying MS). Conclusion The acceleration of MS incidence at the onset of menopause may be accompanied by an increase in insulin resistance only in the population at highest risk. Reproductive women entering the menopause with an isolated MS component are at high risk for developing additional risk factors during menopause.