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.