Osei-Hyiaman D, Satoshi T, Ueji M, Hideto T, Kano K
Graduate School of Medical Sciences, University of Tsukuba, Japan.
Am J Epidemiol. 1998 Dec 1;148(11):1055-61. doi: 10.1093/oxfordjournals.aje.a009582.
Age at menopause has been found to be associated positively with bone mineral density, and age at menarche has been found to be associated negatively with bone mineral density. However, there have been few studies on the relations of timing of menopause and length of the reproductive period with bone mineral density. The purpose of this study was to examine the relations of timing of menopause and reproductive years (calculated as age at menopause minus age at menarche) with mineral density of the second metacarpal bone in postmenopausal Japanese women. The study population consisted of 1,035 naturally menopausal women aged 40-70 years who were screened in 1996-1997. Using computed x-ray densitometry, the authors measured bone mineral density by analyzing radiographic films of the right second metacarpal bone. Using the women with early menopause (age < 49 years) as the reference group and adjusting for age, subjects with late menopause were at decreased risk for low bone mineral density (odds ratio (OR) = 0.69, 95% confidence interval (CI) 0.49-0.97). After adjustment for additional covariates (grip strength, physical activity, body mass index, smoking, and calcium intake), the association was unchanged (OR = 0.70, 95% CI 0.50-0.99). Postmenopausal women with more reproductive years (> or = 40 years) were at decreased risk for low bone mineral density compared with those with fewer reproductive years, after adjustment for age (OR = 0.73, 95% CI 0.40-1.30) and potentially confounding factors (OR = 0.76, 95% CI 0.41-1.37); the p-value for trend was not statistically significant. In multiple linear regression analysis, early menopause and fewer reproductive years were independent predictors of low bone mineral density. In this study, postmenopausal Japanese women who had a late menopause and more reproductive years were at decreased risk for low bone mineral density, and may therefore be less prone to osteoporosis.
研究发现，绝经年龄与骨矿物质密度呈正相关，而初潮年龄与骨矿物质密度呈负相关。然而，关于绝经时间和生育期长短与骨矿物质密度之间关系的研究较少。本研究的目的是探讨绝经时间和生育年限（以绝经年龄减去初潮年龄计算）与绝经后日本女性第二掌骨矿物质密度之间的关系。研究人群包括1996 - 1997年筛查的1035名年龄在40 - 70岁的自然绝经女性。作者使用计算机X线骨密度仪，通过分析右侧第二掌骨的X线片来测量骨矿物质密度。以早绝经（年龄<49岁）女性为参照组，并对年龄进行校正后，晚绝经女性骨矿物质密度低的风险降低（优势比（OR）=0.69，95%置信区间（CI）0.49 - 0.97）。在对其他协变量（握力、体力活动、体重指数、吸烟和钙摄入量）进行校正后，这种关联没有改变（OR = 0.70，95% CI 0.50 - 0.99）。在对年龄（OR = 0.73，95% CI 0.40 - 1.30）和潜在混杂因素（OR = 0.76，95% CI 0.41 - 1.37）进行校正后，生育年限较多（≥40年）的绝经后女性与生育年限较少的女性相比，骨矿物质密度低的风险降低；趋势的p值无统计学意义。在多元线性回归分析中，早绝经和生育年限少是骨矿物质密度低的独立预测因素。在本研究中，绝经晚且生育年限多的绝经后日本女性骨矿物质密度低的风险降低，因此可能不易患骨质疏松症。
