Vitamin D and vitamin D receptor polymorphism in Asian adolescents with primary dysmenorrhea.

Background: The expression of vitamin D receptor in the normal endometrium and ovaries supports the role of vitamin D in local immunity and inflammatory cytokines regulation.

Objective: This study aimed to detect the relation between serum 25(OH)D and primary dysmenorrhea in Asian Adolescents.

Methods: Two hundred and five (205) adolescents complaining of primary dysmenorrhea (study group) were compared in this prospective study to matched controls (210 controls) after informed consent following the Helsinki Declaration. After thorough evaluation, including a thorough history and pelvic ultrasound examination, blood samples were collected from the studied adolescents to measure serum 25(OH)D and for vitamin D receptor TaqI (rs731236) genotyping. The studied adolescents' data were analyzed using the Pearson's correlation to detect the relation between serum 25(OH)D and primary dysmenorrhea (primary outcome). The secondary outcome measures the odds of primary dysmenorrhea in Asian adolescents with vitamin D receptor TaqI (rs731236) polymorphism.

Results: The serum 25(OH)D was significantly lower in the studied-dysmenorrhea group compared to controls (16.17 ± 7.36 versus 17.65 ± 6.36 ng/ml, respectively), (P = 0.01). The correlation analysis showed a significant negative correlation between the serum 25(OH)D and visual analogue scale of dysmenorrhea (r = -0.9003, P < 0.0001). The studied-dysmenorrhea cases with vitamin D receptor T/t and t/t genotypes had significantly lower serum 25(OH)D (16.7 ± 8.05 and 14.4 ± 4.1 ng/ml, respectively) compared to controls (18.97 ± 6.7 and 21.4 ± 2.45 ng/ml, respectively), (P = 0.02 and 0.004, respectively). The VDR T/t and t/t polymorphisms significantly increase the odds of primary dysmenorrhea (OR 1367.2, P < 0.0001 and OR 106.2, P = 0.001, respectively).

Conclusion: The serum 25(OH)D was significantly lower in the studied-dysmenorrhea group compared to controls. The studied-dysmenorrhea cases with VDR T/t and t/t TaqI genotypes had significantly lower serum 25(OH)D compared to controls. The VDR T/t and t/t polymorphisms significantly increase the odds of primary dysmenorrhea.