The effect of vitamin D supplementation on the severity of dysmenorrhea: a systematic review and meta-analysis

The effectiveness of nutritional supplements to relieve dysmenorrhea pain has been investigated in some studies. The present study aimed to review and summarize the available evidence on the effect of vitamin D supplementation on the severity of dysmenorrhea.

In the present systematic review and meta-analysis, clinical trial studies were eligible to be included in the study if they examined the effect of vitamin D supplementation on the severity of dysmenorrhea. Academic databases including Scopus, PubMed, ISI and international clinical trial registration systems as well as Google Scholar were searched from the beginning of the establishment of the above databases until July 2022.

In five studies with 368 people (185 intervention / 183 control), the effect of vitamin D on primary dysmenorrhea was investigated. The standardized mean difference of primary dysmenorrhea for the intervention group with vitamin D supplement compared to the control group was -1.57 with a 95% confidence interval of -0.67 to -2.47. In two studies with 107 people (46 intervention / 61 control) the effect of vitamin D on secondary dysmenorrhea was investigated. The standardized mean difference, the severity of secondary dysmenorrhea for the intervention group with vitamin D supplement compared to the control was 0.66 with a 95% confidence interval of -1.12 to 2.45.

Considering the small number of studies and the risk of methodological bias in the selected studies and considering the wide confidence interval and inconclusive results, there is a need to design stronger methodological studies with a larger sample size.