Relationship between vitamin D in obstructive sleep apnea syndrome and psoriasis patients

INTRODUCTION: Although psoriasis and obstructive sleep apnea syndrome (OSAS) are associated with systemic inflammation, studies on their potential bilateral relationship are not sufficient. AIM: To investigate vitamin D levels and receptor gene polymorphisms in patients with OSAS and psoriasis and the associations with these diseases. MATERIAL AND METHODS: One hundred thirty-seven patients included in the study consisted of 4 different groups: group 1, those with both diseases; group 2, those with OSAS only; group 3, patients with psoriasis only; and group 4, healthy controls. The patients’ serum calcium, phosphorus, AHI, Epworth Sleepiness Scale, Psoriasis Area Severity Index, and VDR TagI, ApaI, BsmI polymorphisms were compared. RESULTS: Vitamin D levels of groups 1, 2 and 3 were found to be lower than in controls. There was no statistically significant correlation between VDR TagI, ApaI, BsmI gene polymorphisms of the groups. Vitamin D levels were significantly higher in patients with heterozygous ApaI genotype (A/C) compared to patients with normal (A/A) or homozygous mutant (C/C) genotype (p < 0.05). No relationship was determined between VDR TagI, ApaI, BsmI, and the other parameters. CONCLUSIONS: In our study, 1,25(OH)(2)-vitamin D(3) levels were significantly lower in all disease groups compared to the control group. Although there is no difference between the groups in terms of VDR gene polymorphism, we think that there may be a bidirectional relationship between these diseases based on the low vitamin D levels.