The study has revealed that the prevalence of metabolic syndrome, which has been linked to the development of cardiovascular disease and diabetes, increases when testosterone progressively dominates the hormonal milieu during the menopausal transition
The longitudinal, 9-year-study of 949 participants in the Study of Women's Health Across the Nation (SWAN) shows that the incidence of metabolic syndrome increased progressively from six years before to six years after the final menstrual period, independent of aging and other known cardiovascular disease risk factors.
Writing about their observations in the Archives of Internal Medicine, one of the JAMA/Archives journals, the researchers said that the increase was steeper during the menopausal transition compared to the post menopausal years.
"Menopause-related testosterone predominance appears to be implicated as a key hormonal change that is associated with the incidence of metabolic syndrome," said lead investigator Dr. Imke Janssen, assistant professor, Department of Preventive Medicine at Rush University Medical Center.
It was previously thought that oestrogen exerted a direct positive effect on cardiovascular disease risk in women, a benefit that was lost as women transitioned from a pre-menopausal to a postmenopausal state and experienced a loss of oestrogen.
"Our study data shows that the change in estrogen level is, at best, a weak and nonsignificant predictor of metabolic syndrome risk. A more likely story is that the progressive testosterone predominance exerts a direct negative effect on cardiovascular risk," said Janssen.
The SWAN study is a multiethnic, community-based, longitudinal cohort study of the natural history of the menopausal transition in over 3300 women enrolled in seven sites throughout the United States.