Determinants of vitamin D status in older women living in a subtropical climate
Determinants of vitamin D status in older women living in a subtropical climate
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DOI：
10.1007/s00198-005-1888-2
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发表时间：
2005-12-01
影响因子：
4
通讯作者：
Reid, IR
中科院分区：
文献类型：
--
作者：
Lucas, JA;Bolland, MJ;Reid, IR
在北方半球和远离赤道的地区进行的研究表明，25-羟基维生素D（25 OHD）水平存在显著的季节性变化。这种变异是否发生在亚热带地区，如澳大拉西亚，尚不清楚。我们对1,606名健康的绝经后妇女进行了为期33个月的横断面研究。这项研究有三个目标：确定生活在新西兰奥克兰的健康绝经后妇女的25 OHD的正常水平;确定25 OHD在该纬度是否发生季节性变化;评估25 OHD、生化指标、人体测量变量和骨矿物质密度（BMD）之间的关系。我们发现显着的季节变化，在25 OHD水平，每月紫外线剂量从夏季到冬季的变化，随后6-8周后，相应的变化在25 OHD水平。维生素D不足（25 OHD < 50 nmol/l）常见。在夏季，28-58%的参与者维生素D状况不佳，而在冬季，频率增加到56- 74%。25 OHD水平与年龄（r=-0.15）、体重（r=-0.11）、体重指数（r=-0.13）、脂肪量（r=-0.14）、体脂百分比（r=-0.16）、体力活动（r=0.10）和采血月份相关（均P < 0.0001）。总的来说，年龄、脂肪量、体力活动和采样月份解释了25 OHD方差的21%。任何部位的25 OHD和BMD之间均无显著相关性。其他显示出显著月变化的变量是葡萄糖（P=0.002）、血清磷酸盐、碱性磷酸酶和白蛋白（均P < 0.0001）。腰椎或股骨近端的BMD无月变化。总之，即使在亚热带气候中，25 OHD水平也存在显著的季节性变化。此外，尽管阳光充足，但相当多的女性即使在夏天也没有达到最佳的维生素D状态。我们的研究结果支持这样的建议，即维生素D补充剂应该成为这一人群的标准做法，特别是在冬季。
Studies performed in the Northern Hemisphere and in areas distant from the equator have demonstrated significant seasonal variation in 25-hydroxyvitamin D (25OHD) levels. Whether such variation occurs in a subtropical area such as Australasia is not clear. We performed a cross-sectional study of 1,606 healthy, postmenopausal women recruited over a 33-month period. The study had three goals: to determine the normal levels of 25OHD in healthy postmenopausal women living in Auckland, New Zealand; to determine whether seasonal variation of 25OHD occurs at this latitude; to assess the relationship between 25OHD, biochemical indices, anthropometric variables and bone mineral density (BMD). We found significant seasonal variation in 25OHD levels, with the change in monthly ultraviolet dose from summer to winter being followed 6-8 weeks later by a corresponding change in 25OHD levels. Vitamin D insufficiency (25OHD < 50 nmol/l) was common. During summer, 28-58% of participants had suboptimal vitamin D status, while in winter, the frequency increased to 56-74%. 25OHD levels correlated with participants' age (r=-0.15), weight (r=-0.11), body mass index (r=-0.13), fat mass (r=-0.14), percentage body fat (r=-0.16), physical activity (r=0.10) and the month of blood sampling (all P < 0.0001). Collectively, age, fat mass, physical activity, and month of sampling explained 21% of the variance in 25OHD. No significant relationships were noted between 25OHD and BMD at any site. Other variables that showed significant monthly variation were glucose (P=0.002), serum phosphate, alkaline phosphatase, and albumin (all P < 0.0001). There was no monthly variation in BMD at the lumbar spine or proximal femur. In conclusion, there is significant seasonal variation in 25OHD levels, even in a subtropical climate. Furthermore, despite generous amounts of sunlight, considerable numbers of women have suboptimal vitamin D status, even in summer. Our findings support the suggestion that vitamin D supplementation should become standard practice in this population of women, particularly during winter.