4.8 Fracture represents a substantial burden to public health and health care costs in the United States. Although vitamin D supplementation is widely recommended for bone health, studies of its effectiveness in preventing fracture have shown inconsistent results.? 骨折給美國公共衛(wèi)生和醫(yī)療費用帶來沉重負擔。盡管補充維生素D被廣泛推薦用于促進骨骼健康，但關于其骨折預防效果的研究結果并不一致。 ??注釋：? ??fracture /?fr?kt??/ 骨折 ??represent /?r?pr??z?nt/ 構成；代表；相當于 ??substantial? /s?b?st?n??l/ 大量的；價值巨大的；重大的 ??vitamin /?v?t?m?n; ?va?t?m?n/ 維生素；維他命 ??effectiveness /??f?kt?vn?s/ 有效性；效果 ??inconsistent /??nk?n?s?st?nt/ 不一致的；相矛盾的 4.9 文獻把長難句啃了就行， In this ancillary study of a 2x2 factorial, randomized, controlled trial, 25,871 U.S. men 50 years of age or older and women 55 years of age or older, who were not recruited on the basis of vitamin D deficiency, osteoporosis, or low bone mass, were assigned to receive daily vitamin D3, at a dose of 2000 International Units, or placebo, and were followed for a median of approximately 5 years. Frequencies of the three primary end points were similar among the assigned groups. 這是一項2x2析因設計、隨機對照試驗的補充研究，該研究納入美國25,871名年齡≥50歲男性或≥55歲女性，而且并非基于維生素D缺乏、骨質(zhì)疏松或骨量低被納入研究，該人群被分配接受每日2000 IU的維生素D3或安慰劑，并接受中位約5年隨訪。兩組的三項主要終點發(fā)生率相似。 ??注釋：? ??ancillary /?n?s?l?r?/ 輔助的；補充的；附屬的；附加的 ??factorial /f?k?t??r??l/ 因子的；階乘的；析因的 ??randomized /?r?nd??ma?zd/ 隨機化的；隨機的 ??controlled trial /k?n?tr??ld ?tra??l/ 對照試驗；對照實驗 ??vitamin /?v?t?m?n; ?va?t?m?n/ 維生素；維他命 ??deficiency? /d??f???ns?/ 缺乏；不足 ??osteoporosis /??st???p??r??s?s/? 骨質(zhì)疏松癥 ??bone mass /?b??n m?s/ 骨量 ??assign /??sa?n/ 分配；分派；布置 ??dose? /d??s/ 劑量；一劑，一服 ??median? /?mi?d??n/ 中位數(shù)；中間值的；中位數(shù)的 ??approximately? /??pr?ks?m?tl?/? 大概；大約 ??end point 終點