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.
Methods: Two hundred and five (205) adolescents complaining of primary dysmenorrhea (study group) were compared with matched controls (210 controls), after informed consent following the Helsinki Declaration.
After thorough evaluation, and pelvic ultrasound examination, blood samples were collected from the studied adolescents for measuring the serum 25(OH)D and for vitamin D receptor TaqI (rs731236) genotyping.
Collected 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 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 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 odds of primary dysmenorrhea were significantly higher in T/t and t/t genotypes (OR 1367.2, P<0.0001, and 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 T/t and t/t TaqI genotypes had significantly lower serum 25(OH)D compared to controls. The odds of primary dysmenorrhea were significantly higher in T/t and t/t TaqI genotypes.