Association between Vitamin D Status and Premenstrual Symptoms

Background Premenstrual symptoms are experienced by up to 95% of women, and few treatments are available. Previous studies suggest that 25-hydroxyvitamin D (25(OH)D) may be associated with the severity of premenstrual symptoms, but the findings have been inconclusive. Objective The objective of this study was to determine whether vitamin D status is associated with the severity of individual premenstrual symptoms. Design/participants Cross-sectional analysis of 998 women aged 20 to 29 years recruited at the University of Toronto campus from 2004 through 2010. Main outcome measures Participants provided data on their premenstrual symptoms in a premenstrual symptom questionnaire. Fasting overnight blood samples were collected, and plasma 25(OH)D was measured. Participants with plasma 25(OH)D concentrations <20 ng/mL were considered to have inadequate vitamin D status, and those with >= 20 ng/mL, adequate vitamin D status. Statistical analyses performed Multinomial logistic regressions were used to calculate the odds ratio (OR) and 95% confidence interval for the associations between vitamin D status and the severity of 15 premenstrual symptoms. Adjustments were made for age, body mass index, ethnicity/race, physical activity, hormonal contraceptive use, season of blood draw, use of analgesics, and calcium intake. Results Compared with participants with adequate vitamin D status, those with inadequate vitamin D status had an increased risk (odds ratio [OR]; 95% CI) of experiencing the following mild symptoms: confusion (OR=1.72; 95% CI, 1.14 to 2.59) and desire to be alone (OR=1.47; 95% CI; 1.03 to 2.10), as well as the following moderate/severe symptoms: cramps (OR=1.50; 95% CI, 1.02 to 2.21), fatigue (OR=1.51; 95% CI, 1.04 to 2.21), anxiety (OR=1.63; 95% CI, 1.02 to 2.63), confusion (OR=2.23; 95% CI, 1.18 to 4.21), and sexual desire (OR=1.65; 95% CI, 1.09 to 2.51). Vitamin D status was not associated with other premenstrual symptoms (acne, bloating, mood swings, increased appetite, headache, clumsiness, insomnia, depression, or nausea). Conclusion Findings suggest that inadequate vitamin D status may be associated with increased severity of some, but not all, premenstrual symptoms.