Table 2

Summary of studies investigating the effect of CPAP treatment on serum levels of vitamin D in OSAS

First author [ref.]Comparison groupsFollow-up periodComments
Liguori [75]Non-OSAS controls versus severe OSAS responders versus severe OSAS non-responders7 nightsMale, 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 OSAS1 yearSerum 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 CPAP24 weeksAfter 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.