BACKGROUND Calcium and vitamin D play important roles in bone health as essential nutrients. We explored whether serum calcium, 25(OH)D were associated with bone mineral density (BMD) in older adults. METHODS This cross-sectional study was conducted on a sample of 4595 participants (2281 men and 2314 women) aged ≥ 50 years (from 50 to 85 years, 60.1 ± 8.7 years for men and 62.0 ± 9.7 years for women) from the National Health and Nutrition Examination Survey (NHANES) 2001-2006. The independent variables were serum calcium and 25(OH)D. The dependent variable was lumbar BMD. The other variables were considered potential effect modifiers. We performed weighted multivariate linear regression models and smooth curve fittings to evaluate the associations between them. Subgroup analyses were also performed. RESULTS We observed a negative association between serum calcium and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association was no longer significant among males and other race/ethnicity. On the other hand, there was a positive association between serum 25(OH)D and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association did not differ in different age groups, between men and women. However, the association between serum 25(OH)D and lumbar BMD followed a U-shaped curve in Mexican Americans. CONCLUSIONS This cross-sectional study indicated that serum calcium negatively correlated with lumbar BMD, and serum 25(OH)D positively correlated with lumbar BMD in older adults. However, the association between serum calcium and lumbar BMD in males followed a U-shaped curve.

中文翻译：

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老年人血清钙，25（OH）D水平与骨矿物质密度之间的关联。

背景技术钙和维生素D作为必需营养素在骨骼健康中起着重要作用。我们探讨了老年人血清钙，25（OH）D是否与骨矿物质密度（BMD）相关。方法这项横断面研究是对来自国家卫生局的4595名年龄≥50岁（50至85岁，男性为60.1±8.7岁，女性为62.0±9.7岁）的参与者（2281名男性和2314名女性）进行的和营养检查调查（NHANES），2001-2006年。自变量为血清钙和25（OH）D。因变量是腰椎BMD。其他变量被认为是潜在影响修饰符。我们执行了加权多元线性回归模型和平滑曲线拟合，以评估它们之间的关联。还进行了亚组分析。结果我们在完全调整的模型中观察到血清钙与腰椎骨密度之间呈负相关。在亚组分析中，这种关联在男性和其他种族/族裔中不再重要。另一方面，在完全调整的模型中，血清25（OH）D与腰椎BMD之间存在正相关。在亚组分析中，男女之间的这种关联在不同年龄组中没有差异。但是，在墨西哥裔美国人中，血清25（OH）D与腰椎BMD之间的关系遵循U形曲线。结论这项横断面研究表明，老年人的血清钙与腰椎BMD呈负相关，血清25（OH）D与腰椎BMD呈正相关。然而，男性血清钙和腰椎骨密度之间的关系遵循U形曲线。