Tracking FSH levels each year from premenopause on can help predict bone loss during menopause, reported MaryFran R. Sowers, Ph.D., of the University of Michigan, Ann Arbor, and her associates.
They conducted what they called the first study to longitudinally characterize bone mineral density (BMD) loss at the spine and hip in conjunction with changes in reproductive hormone concentrations. The interaction between baseline FSH level before menopause and serial FSH levels measured every year thereafter predicted bone loss. However, this interaction “is complex, requires at least two FSH values, and may be challenging to apply in a busy clinical setting,” they cautioned.
The study comprised 2,311 women aged 42–52 at baseline who were assessed at several medical centers across the United States for 5 years. Half the women were white, 28% were African American, and 22% were Asian American.
The women underwent annual spine, femoral neck, and total hip BMD assessments with densitometers. Blood samples obtained annually in the early follicular phase of the menstrual cycle were analyzed for estradiol, FSH, testosterone, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS) content.
At baseline, 53% were classified as premenopausal due to no reported drop in menstrual regularity in the preceding year; 47% were grouped in the “early perimenopausal” period, having reported less menstrual regularity in the last 3 months (J. Clin. Endocrin. Metab. doi:10.1210/jc.2005–1836; Jan. 10, 2006).
The interaction between baseline FSH levels and subsequent levels predicted bone loss. Estradiol levels measured throughout this transitional period “were poor predictors of incremental BMD change.”