Effect of Vitamin D3 Supplementation on Sleep Quality in Deficient Adults: A Randomized Controlled Trial

Emerging evidence suggests a link between serum vitamin D3 deficiency and poor sleep quality, but the optimal dosing frequency to improve sleep quality remains unclear. This study investigates the impact of daily versus weekly vitamin D3 supplementation on sleep quality in adults with vitamin D3 deficiency.

This single-center, prospective, single-blinded, randomized controlled trial randomized vitamin D3-deficient adults in a 1:1 ratio to receive either daily supplementation (6000 IU/day for 8 weeks) or weekly supplementation (60,000 IU/week for 8 weeks). Subjective sleep quality was evaluated with the Pittsburg Sleep Quality Index (PSQI) questionnaire at baseline and after 8 weeks. The Wilcoxon signed-rank test and Mann-Whitney U test were used to compare both groups.

This study enrolled 87 patients, with 45 in the weekly arm and 42 in the daily arm. The mean age was 39.26 [11.03] years, and 71% (n = 62) were female. On follow-up, the daily arm showed significant improvements in "duration of sleep" (0.93 [0.65] vs 1.55 [0.75], P = 0.002) and "daytime dysfunction due to sleep" (0.67 [0.57] vs 1.11 [1.15], P = 0.007). In contrast, the weekly arm performed better in the "need medication to sleep" parameter (0.13 [0.50] vs 0.37 [0.54], P = 0.034). However, the daily supplementation arm showed a favorable trend in the PSQI total score (8.46 [3.14] vs 9.93 [2.68], P = 0.024).

Daily vitamin D3 supplementation is more effective than weekly supplementation in improving overall sleep quality, sleep duration, and daytime dysfunction in vitamin D3-deficient adults.

Clinical Trial Registry of India (CTRI/2024/01/061970) on 29.1.2024.