Bikle D D, Ettinger B, Sidney S, Tekawa I S, Tolan K
Department of Medicine, Division of Endocrinology, University of California and Veterans Administration Medical Center, San Francisco, Calif. 94121, USA.
Miner Electrolyte Metab. 1999 May-Jun;25(3):178-84. doi: 10.1159/000057442.
To determine whether environmental factors influence racial differences in calcium metabolism, the authors evaluated the influence of three factors (season, length of sunlight exposure, and diet) on calciotropic hormones, renal calcium excretion, and markers of bone turnover in an ambulatory population aged 25-36 years. Included were 109 black men, 114 white men, 95 black women, and 84 white women. Compared with white subjects, black subjects of both genders showed lower levels of serum 25-hydroxyvitamin D (25-OHD) and higher levels of serum 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. The mean winter levels of 25-OHD were 19 to 29% lower than the summer levels in all groups. The urinary calcium excretion was 26% lower in black men than in white men and was 36% lower in black women than in white women. The parathyroid hormone levels were 29% higher in black women than in white women, but no statistically significant racial differences in parathyroid hormone levels were seen in men. Bone turnover markers (serum osteocalcin, bone-specific alkaline phosphatase, urinary pyridinoline cross-link excretion) did not show consistent racial differences. Racial and gender differences in calcium excretion did not significantly correlate with differences in lifestyle or with levels of the calciotropic hormones. Environmental factors such as diet and sunlight exposure do not appear to influence racial differences in the levels of the calciotropic hormones or renal calcium excretion.
为了确定环境因素是否会影响钙代谢的种族差异，作者评估了三个因素（季节、日照时长和饮食）对25至36岁非卧床人群中钙调节激素、肾钙排泄以及骨转换标志物的影响。研究对象包括109名黑人男性、114名白人男性、95名黑人女性和84名白人女性。与白人受试者相比，两个性别的黑人受试者血清25-羟维生素D（25-OHD）水平较低，而血清1,25-二羟维生素D [1,25(OH)(2)D]水平较高。所有组中，25-OHD的冬季平均水平比夏季水平低19%至29%。黑人男性的尿钙排泄比白人男性低26%，黑人女性的尿钙排泄比白人女性低36%。黑人女性的甲状旁腺激素水平比白人女性高29%，但男性甲状旁腺激素水平未显示出统计学上的显著种族差异。骨转换标志物（血清骨钙素、骨特异性碱性磷酸酶、尿吡啶啉交联物排泄）未显示出一致的种族差异。钙排泄的种族和性别差异与生活方式差异或钙调节激素水平无显著相关性。饮食和日照等环境因素似乎不会影响钙调节激素水平或肾钙排泄的种族差异。
