School of Population Health, The University of Western Australia, Perth, WA, Australia.
Osteoporos Int. 2013 Apr;24(4):1285-93. doi: 10.1007/s00198-012-2131-6. Epub 2012 Sep 18.
Uncertainty remains over whether or not high intakes of retinol or vitamin A consumed through food or supplements may increase fracture risk. This intervention study found no increase in fracture risk among 2,322 adults who took a controlled, high-dose retinol supplement (25,000 IU retinyl palmitate/day) for as long as 16 years. There was some evidence that beta-carotene supplementation decreased fracture risk in men.
There is conflicting epidemiological evidence regarding high intakes of dietary or supplemental retinol and an increased risk for bone fracture. We examined fracture risk in a study administering high doses of retinol and beta-carotene (BC) between 1990 and 2007.
The Vitamin A Program was designed to test the efficacy of retinol and BC supplements in preventing malignancies in persons previously exposed to blue asbestos. Participants were initially randomised to 7.5 mg retinol equivalents (RE)/day as retinyl palmitate, 30 mg/day BC or 0.75 mg/day BC from 1990 to 1996; after which, all participants received 7.5 mg RE/day. Fractures were identified by questionnaire and hospital admission data up until 2006. Risk of any fracture or osteoporotic fracture according to cumulative dose of retinol and BC supplementation was examined using conditional logistic regression models adjusting for age, sex, smoking, body mass index, medication use and previous fracture.
Supplementation periods ranged from 1 to 16 years. Of the 2,322 (664 females and 1,658 males) participants, 187 experienced 237 fractures. No associations were observed between cumulative dose of retinol and risk for any fracture (OR per 10 g RE=0.83; 95% CI, 0.63-1.08) or osteoporotic fracture (OR per 10 g RE=0.95; 95% CI 0.64-1.40). Among men, cumulative dose of BC was associated with a slightly reduced risk of any fracture (OR per 10 g=0.89; 95% CI 0.81-0.98) and osteoporotic fracture (OR per 10 g=0.84; 95% CI 0.72-0.97).
This study observed no increases in fracture risk after long-term supplementation with high doses of retinol and/or beta-carotene.
通过食物或补充剂摄入高剂量视黄醇或维生素 A 是否会增加骨折风险，目前仍存在不确定性。这项干预研究发现，2322 名成年人长期（长达 16 年）服用控制剂量的高剂量视黄醇补充剂（25,000IU 棕榈酸视黄酯/天），并未增加骨折风险。有证据表明β-胡萝卜素补充剂可降低男性骨折风险。
关于高剂量饮食或补充视黄醇与骨骨折风险增加之间的关系，存在相互矛盾的流行病学证据。我们在 1990 年至 2007 年期间进行了一项研究，检测了高剂量视黄醇和β-胡萝卜素（BC）的补充对预防先前接触过蓝石棉的人发生恶性肿瘤的效果，以此来检查骨折风险。最初，参与者根据随机分配，每天服用 7.5 毫克视黄醇当量（RE）作为棕榈酸视黄酯、30 毫克/天 BC 或 0.75 毫克/天 BC，时间为 1990 年至 1996 年；此后，所有参与者每天都服用 7.5 毫克 RE。通过问卷调查和住院数据来确定骨折情况，直到 2006 年。使用条件逻辑回归模型，根据视黄醇和 BC 补充剂的累积剂量，调整年龄、性别、吸烟、体重指数、用药情况和既往骨折情况，检查骨折的风险。
补充期从 1 年到 16 年不等。在 2322 名参与者（664 名女性和 1658 名男性）中，187 人发生了 237 次骨折。未观察到视黄醇累积剂量与任何骨折（每 10 克 RE 的比值比[OR]为 0.83；95%置信区间[CI]，0.63-1.08）或骨质疏松性骨折（每 10 克 RE 的 OR 为 0.95；95%CI 0.64-1.40）风险之间存在关联。在男性中，BC 的累积剂量与任何骨折（OR 每 10 克=0.89；95%CI 0.81-0.98）和骨质疏松性骨折（OR 每 10 克=0.84；95%CI 0.72-0.97）的风险降低有关。
本研究观察到长期补充高剂量视黄醇和/或β-胡萝卜素后，骨折风险并未增加。
