Tartu University Hospital, Sports Medicine and Rehabilitation Clinic, Tartu, Estonia.
University of Tartu, Department of Sports Medicine and Rehabilitation, Institute of Clinical Medicine, Faculty of Medicine, Tartu, Estonia.
J Int Soc Sports Nutr. 2022 Jul 19;19(1):437-454. doi: 10.1080/15502783.2022.2100718. eCollection 2022.
There has been a growing interest in the role of vitamin D for the well-being and physical performance of humans under heavy training such as conscripts in military service; however, there is a lack of long-term supplementation studies performed on members of this type of young, physically active, male population. The hypothesis of the study was that vitamin D supplementation during wintertime will decrease the prevalence of critically low vitamin D blood serum levels and increase hand grip strength during the winter season among young male conscripts.
Longitudinal, triple-blinded, randomized, placebo-controlled trial.
Fifty-three male conscripts from the Estonian Army were randomized into two groups: 27 to an intervention group and 26 to a placebo group. The groups were comparable in terms of their demographics. The intervention group received 1200 IU (30 µg) capsules of vitamin D3, and the control group received placebo oil capsules once per day. The length of the follow-up was 7 months, from October 2016 until April 2017. Blood serum vitamin D (25(OH)D), parathyroid hormone (PTH), calcium (Ca), ionized calcium (Ca-i), testosterone and cortisol values, and hand grip strength were measured four times during the study period.
The mean 25(OH)D level decreased significantly in the control group to a critically low level during the study, with the lowest mean value of 22 nmol/l found in March 2017. At that time point, 65% in the control group vs 15% in the intervention group had 25(OH)D values of less than 25 nmol/l (p < 0.001). In the intervention group, the levels of 25(OH)D did not change significantly during the study period. All other blood tests revealed no significant differences at any time point. The corresponding result was found for hand grip strength at all time points.
Long-term vitamin D supplementation during wintertime results in fewer conscripts in the Estonian Army with critically low serum vitamin D (25(OH)D) levels during the winter season. However, this did not influence their physical performance in the form of the hand grip strength test.
人们对维生素 D 在高强度训练下对人类健康和身体表现的作用越来越感兴趣，例如在兵役中的新兵；然而，对于这种年轻、活跃的男性人群，缺乏长期补充研究。本研究的假设是，在冬季补充维生素 D 将降低新兵血清维生素 D 水平极低的发生率，并在冬季增加新兵的握力。
纵向、三盲、随机、安慰剂对照试验。
53 名爱沙尼亚军队的男性新兵被随机分为两组：27 名干预组和 26 名安慰剂组。两组在人口统计学方面具有可比性。干预组每天服用 1200IU（30μg）维生素 D3 胶囊，对照组服用安慰剂油胶囊。随访时间为 7 个月，从 2016 年 10 月至 2017 年 4 月。在研究期间，四次测量血清维生素 D（25（OH）D）、甲状旁腺激素（PTH）、钙（Ca）、离子钙（Ca-i）、睾酮和皮质醇值以及握力。
对照组的平均 25（OH）D 水平在研究期间显著下降至临界低值，2017 年 3 月的最低平均值为 22nmol/L。此时，对照组中有 65%的人 25（OH）D 值低于 25nmol/L，而干预组中只有 15%（p<0.001）。在干预组中，25（OH）D 水平在研究期间没有显著变化。在任何时间点，所有其他血液检查均未显示出显著差异。在所有时间点，握力也得到了相应的结果。
在冬季长期补充维生素 D 可使爱沙尼亚军队中在冬季血清维生素 D（25（OH）D）水平极低的新兵人数减少。然而，这并没有影响他们的握力测试等身体表现。
