A Longitudinal Study of the Menopause and Fat Patterning

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DESCRIPTION (provided by applicant): It was once believed that menopause-related coronary risk was associated with a gain in total body fat, but recent research has suggested that it is not total fat per se, but the location of that fat, that is a key risk factor. Indices of central adiposity, particularly intra-abdominal fat (IAF), have: (1) predicted coronary events better than indices of total fat; (2) been associated with altered glucose and lipid metabolism and elevated blood pressure; and (3) been associated with changes in menopausal status. This gives rise to the hypothesis that menopause-related changes in sex hormones accelerate the accumulation of IAF, which in turn is associated with adverse cardiovascular risk. Existing studies of this hypothesis share major limitations in that they are small, cross-sectional and primarily Caucasian, focus only on comparisons of pre-and post-menopausal status, and have minimal controls for the important covariates of age and total fat. This is a study of the natural history of the accumulation of IAF as women transverse the menopause. It will be conducted on an intact biracial cohort of 868 women (419 African Americans; 449 Caucasians) who are participating in a larger study of women undergoing the menopausal transition. This is a population-based cohort that was randomly selected from an existing census with a 72 percent participation rate, approximately equal distribution of socioeconomic status within the African American and Caucasian subgroups, and a dropout rate of only 1 percent/year. As part of the larger study, this cohort undergoes annual exams in which a variety of cardiovascular, hormonal, and lifestyle factors are tracked. For this study, 2 clinical tests will be added to the battery at the 4th or 5th annual exam for the 536 women who are expected to be eligible by virtue of not having had a hysterectomy or begun taking hormone therapy. The 2 tests will be a CT scan for the assessment of IAF, and a DEXA scan for the assessment of total body fat. These tests will be repeated on an annual basis for the next 3 years. By the end of the study, it is projected that 462 transitions in menopausal status will have taken place. Random effects models will be used to estimate longitudinal changes in level and rate of IAF as one moves from one menopausal status to another.