Concentrations of Follicle-Stimulating Hormone Correlate with Alkaline Phosphatase and a Marker for

Serum alkaline phosphatase (ALP), a gross marker of bone turnover, has been reported to be elevated after menopause, a period characterized by hallmark increases in follicle-stimulat-ing hormone (FSH). Whether the ALP rise coincides with the perimenopausal transition when changes in FSH, estrogen levels, and menstrual cycles are first apparent is not known. The purpose of this cross-sectional study was twofold: (1) to characterize the influence of the peri-menopausal transition on ALP activity and (2) to correlate ALP activity with more precise markers for bone, osteocalcin (OC), and vitamin K status assessed with undercarboxylated osteocalcin (ucOC). Thirty-eight studies of hourly FSH were conducted on cycle day 6 of the follicular phase in perimenopausal women volunteers, aged 40–54 years (mean body mass in-dex [BMI] 5 24.2 6 0.5). Mean FSH was used to define the perimenopausal stage (early peri-menopausal, mean FSH # 15 IU/L, n 5 27; late perimenopausal, mean FSH. 15 IU/L, n 5 11). As expected, late perimenopausal women had irregular and longer menstrual cycles, lower estradiol (E2) and estrone (E1) levels, and a lower frequency of ovulations vs. the early group. ALP was higher (76.5 6 8.3 vs. 58.3 6 2.7 IU/L, p 5 0.045) compared with the early peri-menopausal group. In a subsample (n 5 10), OC was associated with ALP (r 5 0.69, p, 0.03), FSH was positively related to ucOC concentrations (r 5 0.7, p, 0.03), and women with E1 con-centrations, 40 pg/ml had double the percentage of ucOC compared with those where E1 was. 40 pg/ml (46.3 % 6 6.6 % vs. 22.0 % 6 3.1%, p, 0.006). Clinical markers of the peri-menopause are associated with a nonspecific but inexpensive marker of enhanced bone turnover (i.e., higher ALP) and correlate well with more precise markers of bone activity. These findings suggest that health-promotion strategies for preserving bone should be insti-tuted well before the last menstrual period. 73