Rouen, Patricia, Nancy Reame, and Jane Lukacs
To distinguish the effects of menopause versus aging on adipokine concentrations and IR in healthy women.
Midlife women are at risk for increased central fat distribution and insulin resistance (IR), but the role of aging or menopause as contributors to these conditions has been inconclusive. Adiponectin (AD), an adipocyte-secreted peptide may be a biomarker and early signal of IR, a central feature in the metabolic syndrome and type 2 diabetes. AD concentrations are sexually dimorphic, implying a role for the sex steroids in its secretion. The few studies of AD in women report increased, decreased or unchanged levels with menopause.
Using parent study data, a cross-sectional comparative group design was employed to analyze new data from archived blood samples of three groups of BMI-matched volunteers: 21 young cycling (CY), 19 older cycling (CO) and 19 postmenopausal (PM; 2.8±0.5 years postmenopause) women. CO women had similar estradiol levels as CY women and were age-matched to PM women. By ANOVA, measures of AD, leptin, insulin and IR (calculated by HOMA-IR) were compared.
IR and leptin values were similar in all three groups. AD was higher in PM women (p = 0.05). When stratified by BMI and menopause status, AD was highest in normal weight PM women and lowest in overweight premenopausal women. High BMI had opposing effects on AD and leptin regardless of reproductive status.
Estrogen in the reproductive years may act to suppress AD. In early postmenopause, a rise in AD may deter IR in nonobese women. Further research with larger samples and adiposity measures are needed to clarify how reproductive status influences IR and AD concentrations in normal weight and obese women.