Changes in Menopause Stage, Body Mass, and Fat Mass as Drivers of Midlife Changes in C-reactive Protein Levels: A Prospective Cohort Study.

Background: Serum levels of C-reactive protein (CRP), a marker of chronic inflammation, increase in many, but not all, women going through the menopause transition (MT). It is not known whether this is driven entirely by changes in body mass and fat mass in midlife or by other physiological changes during the MT. Methods: We use individual fixed effects analysis of repeated measurements across the MT, in a multi-ethnic cohort of 1681 women followed for over two decades (1996-2018), to address this knowledge gap; we also test whether associations between body mass increase (likewise fat mass increase) and CRP increase differ by race/ethnicity. Results: Adjusted for changes in body mass index (BMI), change in menopause stage was not associated with change in CRP. Every kg/m Conclusions: Midlife increases in CRP levels in women are not directly related to menopause stage but appear to be driven by increases in body mass, particularly fat mass. While changes in body mass have different implications for CRP changes in Black vs. White women, increases in fat mass have similar associations with CRP increases in Black and White women. However, changes in fat mass have modestly smaller associations with CRP changes in postmenopause than before the MT.