Amount of bone loss in relation to time around the final menstrual period and follicle-stimulating hormone staging of the transmenopause.

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.