ビタミンD不足高齢女性に対するビタミンD投与のRCT

今日は、ビタミンD不足高齢女性に対してビタミンD投与を行った場合の筋力と移動能力に関するRCTの論文を紹介します。

Kun Zhu, Nicole Austin, Amanda Devine, David Bruce, Richard L. Prince: A Randomized Controlled Trial of the Effects of Vitamin D on Muscle Strength and Mobility in Older Women with Vitamin D Insufficiency. Journal of the American Geriatrics Society Volume 58, Issue 11, pages 2063–2068, November 2010 DOI: 10.1111/j.1532-5415.2010.03142.x

血中ビタミンDが24ng/mL以下で、在宅生活で歩行可能な70～90歳の女性302人を対象としたRCTです。介入群はVitamin D2 1,000 IU/dを内服、対象群は1 g calcium/dを1年間内服します。

1年後にビタミンD投与群では当然、血中ビタミンDが上昇しますが、コントロール群では不変でした。サブグループ解析なので微妙ですが、血中ビタミンDが最も低い1/4群では、股関節の伸展筋力、内転筋力とTimed Up and Go TestがビタミンD投与群で有意に改善しました。

弱い結論として、ビタミンD不足高齢女性に対するビタミンD投与で、筋肉量と移動能力が改善する可能性があります。筋肉量と移動能力が改善するかどうかは明確ではありませんが、ビタミンDが欠乏もしくは不足している高齢女性では、ビタミンDを投与することが望ましいといえます。

Abstract

OBJECTIVES: To evaluate the effects of vitamin D treatment on muscle strength and mobility in older women with vitamin D insufficiency.

DESIGN: One-year population-based, double-blind, randomized, controlled trial.

SETTING: Perth, Australia (latitude 32°S).

PARTICIPANTS: Three hundred two community-dwelling ambulant elderly women aged 70 to 90 with a serum 25-hydroxyvitamin D (25(OH)D) concentration less than 24 ng/mL.

INTERVENTION: Vitamin D2 1,000 IU/d or identical placebo; calcium citrate (1 g calcium/d) in both groups.

MEASUREMENTS: Lower limb muscle strength and mobility as assessed using the Timed Up and Go Test (TUAG).

RESULTS: At baseline, mean±standard deviation serum 25(OH)D was 17.7±4.2 ng/mL; this increased to 24.0±5.6 ng/mL in the vitamin D group after 1 year but remained the same in the placebo group. For hip extensor and adductor strength and TUAG, but not for other muscle groups, a significant interaction between treatment group and baseline values was noted. In those with baseline values in the lowest tertile, vitamin D improved muscle strength and TUAG more than calcium alone (mean (standard error): hip extensors 22.6% (9.5%); hip adductors 13.5% (6.7%), TUAG 17.5% (7.6%), P<.05). Baseline 25(OH)D levels did not influence patient response to supplementation.

CONCLUSION: Vitamin D therapy was observed to increase muscle function in those who were the weakest and slowest at baseline. Vitamin D should be given to people with insufficiency or deficiency to improve muscle strength and mobility.