Summary of studies investigating the effect of CPAP treatment on serum levels of vitamin D in OSAS
| First author [ref.] | Comparison groups | Follow-up period | Comments |
| Liguori [75] | Non-OSAS controls versus severe OSAS responders versus severe OSAS non-responders | 7 nights | Male, but not female, OSAS responders showed a significant increase in 25(OH)D levels. OSAS non-responders did not show modifications of serum 25(OH)D concentrations. |
| Liguori [78] | OSAS compliant versus OSAS non-compliant and obese compliant OSAS versus non-obese compliant OSAS | 1 year | Serum 25(OH)D levels increased in OSAS compliant, but not in OSAS non-compliant patients. Obese compliant OSAS patients shifted from insufficient to sufficient vitamin D status more than the non-obese compliant OSAS patients. BMI at baseline positively correlated with serum 25(OH)D variation levels. |
| Theorell-Haglöw [79] | OSAS real CPAP versus OSAS sham CPAP | 24 weeks | After 12 weeks there were no between-group differences in 25(OH)D serum levels. After 24 weeks 25(OH)D increased in patients with severe OSAS and in sleepy patients. |