Amount of Bone Loss in Relation to Time around the Final Menstrual Period and Follicle-Stimulating Hormone Staging of the Transmenopause

Abstract

Background and Objective: The objective of the study was to describe bone loss rates across the transmenopause related to FSH staging and the final menstrual period (FMP). Design and Setting: This was a population-based cohort of 629 women (baseline age 24–44 yr) with annual data points over 15 yr. Measurements: Measures were bone mineral density (BMD), FSH to define four FSH stages, and menstrual bleeding cessation to define the FMP. Bone loss rates were reported by obesity status. Results: Annualized rates of lumbar spine bone loss began in FSH stage 3, which occurs approximately 2 yr prior to the FMP (1.67%/yr); bone loss continued into FSH stage 4 (1.21%/yr). Mean spine BMD in FSH stage 4 was 6.4% less than spine BMD value in FSH stage 1. Annualized rates of femoral neck (FN) bone loss began in FSH stage 3 (0.55%/yr) and continued into FSH stage 4 (0.72%/yr). The FN difference between mean values in FSH stage 1 and FSH stage 4 was 5%. Annualized rates of spine bone loss in the 2 yr prior to the FMP were 1.7%/yr, 3.3%/yr in the 2 yr after the FMP, and 1.1%/yr in the 2- to 7-yr period after the FMP. Nonobese women had lower BMD levels and greater bone loss rates. Conclusions: Spine and FN bone loss accelerates in FSH stage 3. Bone loss also began to accelerate 2 yr before the FMP with the greatest loss occurring in the 2 yr after the FMP. Bone loss rates in both spine and FN BMD were greater in nonobese women than obese women.