Vitamin D Status, Sleep Patterns and the Risk of Type 2 Diabetes

Takeaway

• Higher serum 25-hydroxyvitamin D (25[OH]D) levels were associated with a lower risk of incident type 2 diabetes (T2D).
• This association was influenced by overall sleep patterns, with daytime sleepiness being the major contributor.

Why this matters

• Findings may have implications for the development of T2D prevention strategies targeting improvement of vitamin D supplementation in people with sleep disorders, particularly daytime sleepiness.

Study design

• This prospective study of 350,211 participants without T2D from the UK Biobank evaluated the association between 25(OH)D and incident T2D and particularly examined the potential modification effect of overall sleep patterns, which incorporated sleep duration, chronotype, insomnia, snoring and excessive daytime sleepiness.
• Funding: National Heart, Lung, and Blood Institute and others.

Key results

• 6940 case participants with incident T2D were documented during a median follow-up of 8.1 years.
• 25(OH)D levels were inversely associated with the risk of incident T2D in a dose-response fashion, and the multivariate-adjusted HR of T2D was 0.88 (95% CI, 0.87-0.90) for a 10 nmol/L increase of 25(OH)D.
• A significant interaction was observed between 25(OH)D and overall sleep patterns on the risk of incident T2D (P_interaction=.002).
• The inverse link between high 25(OH)D levels and T2D was more prominent in participants with healthy sleep patterns (HR, 0.87; 95% CI, 0.84-0.89).
• Among the individual sleep behaviours, daytime sleepiness showed the strongest modification effect (P_interaction=.0006).
• Reduced risk of T2D associated with high 25(OH)D level was more evident in participants with no frequent daytime sleepiness (HR, 0.88; 95% CI, 0.87-0.89) vs those with excessive daytime sleepiness (HR, 0.92; 95% CI, 0.87-0.97).
• Genetic variations in sleep patterns did not alter the association between 25(OH)D and T2D.

Limitations

• Some cases with incident T2D were based on the secondary diagnosis.
• Single measurement of serum 25(OH)D at baseline was used.

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.