Bone mineral density changes during the menopause transition in a multiethnic cohort of women

Abstract

Context: Rates of bone loss across the menopause transition and factors associated with variation in menopausal bone loss are poorly understood.

Objective: Our objective was to assess rates of bone loss at each stage of the transition and examine major factors that modify those rates.

Design, setting, and participants: We conducted a longitudinal cohort study of 1902 African-American, Caucasian, Chinese, or Japanese women participating in The Study of Women's Health Across the Nation. Women were pre- or early perimenopausal at baseline.

Outcome measure: We assessed bone mineral density (BMD) of the lumbar spine and total hip across a maximum of six annual visits.

Results: There was little change in BMD during the pre- or early perimenopause. BMD declined substantially in the late perimenopause, with an average loss of 0.018 and 0.010 g/cm2.yr from the spine and hip, respectively (P<0.001 for both). In the postmenopause, rates of loss from the spine and hip were 0.022 and 0.013 g/cm2.yr, respectively (P<0.001 for both). During the late peri- and postmenopause, bone loss was approximately 35-55% slower in women in the top vs. the bottom tertile of body weight. Apparent ethnic differences in rates of spine bone loss were largely explained by differences in body weight.

Conclusions: Bone loss accelerates substantially in the late perimenopause and continues at a similar pace in the first postmenopausal years. Body weight is a major determinant of the rate of menopausal BMD loss, whereas ethnicity, per se, is not. Healthcare providers should consider this information when deciding when to screen women for osteoporosis.

Figure 1

Annual rate of change in BMD of the lumbar spine and total hip in premenopausal (red bars), early perimenopausal (blue bars), late perimenopausal (yellow bars), and postmenopausal (green bars) women (n = 1902). Rates of change were estimated from multivariable linear mixed models and adjusted for multiple covariates. Error bars represent 95% confidence limits. Comparisons were made across status categories: early peri- vs. premenopausal, P < 0.001 (spine) and P = 0.002 (hip); late peri- vs. early perimenopausal, P < 0.001 (spine) and P < 0.001 (hip); and post- vs. late perimenopausal, P = 0.002 (spine) and P < 0.001 (hip).

Figure 2

Top panel, Annual rate of change in BMD of the lumbar spine in premenopausal (red bars), early perimenopausal (blue bars), late perimenopausal (yellow bars), and postmenopausal (green bars) African-American (n = 494), Caucasian (n = 944), Chinese (n = 221), and Japanese (n = 243) women from the full cohort. Rates of change were estimated from multivariable linear mixed models and adjusted for multiple covariates. Error bars represent 95% confidence limits. Comparisons were made between ethnic groups (P values for lumbar spine in pre-, early peri-, late peri-, and postmenopausal women, respectively): African-American vs. Caucasian, 0.65, 0.11, 0.10, and <0.001; African-American vs. Chinese, 0.031, <0.001, 0.006, and <0.001; African-American vs. Japanese, 0.87, <0.001, <0.001, and <0.001; Caucasian vs. Chinese, 0.004, 0.014, 0.06, and 0.003; Caucasian vs. Japanese, 0.58, <0.001, 0.009, and <0.001; Chinese vs. Japanese, 0.09, 0.43, 0.81, and 0.51. Bottom panel, Annual rate of change in BMD of the lumbar spine in premenopausal (red bars), early perimenopausal (blue bars), late perimenopausal (yellow bars), and postmenopausal (green bars) African-American (n = 198), Caucasian (n = 587), Chinese (n = 167), and Japanese (n = 181) women weighing between 50 and 78 kg. Rates of change were estimated from multivariable linear mixed models and adjusted for multiple covariates. Error bars represent 95% confidence limits. Comparisons were made between ethnic groups, with P values for lumbar spine in pre-, early peri-, late peri-, and postmenopausal women, respectively, as follows: African-American vs. Caucasian, 0.13, 0.24, 0.43, and 0.07; African-American vs. Chinese, 0.80, 0.007, 0.56, and 0.31; African-American vs. Japanese, 0.10, 0.010, 0.24, and 0.02; Caucasian vs. Chinese, 0.22, 0.041, 0.18, and 0.52; Caucasian vs. Japanese, 0.59, 0.06, 0.52, and 0.34; Chinese vs. Japanese, 0.16, 0.87, 0.11, and 0.17.

Figure 3

Annual rate of change in BMD of the lumbar spine (top panel) and total hip (bottom panel) in premenopausal (red bars), early perimenopausal (blue bars), late perimenopausal (yellow bars), and postmenopausal (green bars) women divided by tertiles of baseline body weight (tertile 1, < 60.7 kg; tertile 2, 60.7–77.3 kg; tertile 3, >77.3 kg) in the entire cohort. Rates of change were estimated from multivariable linear mixed models and adjusted for multiple covariates. Error bars represent 95% confidence limits. Comparisons were made between tertile groups, with P values for lumbar spine in pre-, early peri-, late peri-, and postmenopausal women, respectively, as follows: tertile 1 vs. 3, <0.001, <0.001, <0.001, and <0.001; tertile 2 vs. 3, 0.033, <0.001, <0.001, and <0.001; tertile 1 vs. 2, 0.13, 0.002, 0.39, and 0.044; and with P values for total hip in pre-, early peri-, late peri-, and postmenopausal women, respectively: tertile 1 vs. 3, 0.15, <0.001, 0.027, and <0.001; tertile 2 vs. 3, 0.51, 0.08, 0.09, and <0.001; tertile 1 vs. 2, 0.032, 0.017, 0.68, and 0.17.

Figure 4

Annual rate of change in BMD of the lumbar spine in premenopausal (red bars), early perimenopausal (blue bars), late perimenopausal (yellow bars), and postmenopausal (green bars) women divided by tertiles of body weight in African-American (tertile 1, <73.4 kg; tertile 2, 73.4–91.5 kg; tertile 3, >91.5 kg), Caucasian (tertile 1, <64.0 kg; tertile 2, 64.0–78.1 kg; tertile 3, >78.1 kg), Chinese (tertile 1, <52.9 kg; tertile 2, 52.9–59.8 kg; tertile 3, >59.8 kg), and Japanese (tertile 1, <52.4 kg; tertile 2, 52.4–58.6 kg; tertile 3, >58.6 kg) women. Rates of change were estimated from multivariable linear mixed models and adjusted for multiple covariates. Error bars represent 95% confidence limits. Note that a relatively small number of Chinese and Japanese women in each weight tertile transitioned to late perimenopause or beyond (Chinese: tertile 1, n = 24; tertile 2, n = 24; tertile 3, n = 30; Japanese: tertile 1, n = 31; tertile 2, n = 31; tertile 3, n = 25) or became postmenopausal (Chinese: tertile 1, n = 22; tertile 2, n = 23; tertile 3, n = 24; Japanese: tertile 1, n = 24; tertile 2, n = 25; tertile 3, n = 22) during the follow-up period. Comparisons were made between tertile groups, with P values for African-Americans in pre-, early peri-, late peri-, and postmenopausal women, respectively, as follows: tertile 1 vs. 3, 0.008, 0.039, 0.30, and <0.001; tertile 2 vs. 3, 0.18, 0.88, 0.08, and <0.001; tertile 1 vs. 2, 0.31, 0.028, 0.57, and 0.78; with P values for Caucasians in pre-, early peri-, late peri-, and postmenopausal women, respectively: tertile 1 vs. 3, 0.012, <0.001, <0.001, and <0.001; tertile 2 vs. 3, 0.25, <0.001, <0.001, and <0.001; tertile 1 vs. 2, 0.21, 0.11, 0.95, and 0.29; with P values for Chinese in pre-, early peri-, late peri-, and postmenopausal women, respectively: tertile 1 vs. 3, 0.21, 0.015, 0.038, and <0.001; tertile 2 vs. 3, 0.56, 0.002, 0.020, and <0.001; tertile 1 vs. 2, 0.44, 0.57, <0.001, and 0.24; and with P values for Japanese in pre-, early peri-, late peri-, and postmenopausal women, respectively: tertile 1 vs. 3, 0.08, <0.001, 0.001, and 0.002; tertile 2 vs. 3, 0.18, 0.028, 0.002, and 0.003; tertile 1 vs. 2, 0.42, 0.14, 0.89, and 0.79.