Gretchen Mach’13

Vitamin D and Seasonal Affective Disorder in Collegiate Females during the Winter  

Seasonal affective disorder (SAD) is characterized by an increase in anxiety and depression during the winter months. There is an inverse relationship between solar ultraviolet (UVB) ray exposure in the winter and SAD occurrence in young adults (Groh, C., Kwasky, A., J Am Psychiatr Nurses Assoc. 18(4): 236-243, 2012). The major source of vitamin D in humans is endogenous synthesis from UVB exposure. It is unclear if low vitamin D status contributes to the onset of SAD.

Purpose: To compare serum vitamin D (25[OH]D) status with depressive symptoms using Beck Depression Inventory (BDI)-II scores in collegiate females.

Methods: Institutional Review Board approval was received and informed consent was obtained by 136 college-aged women. Subjects were recruited via email and participants completed the BDI-II online in early March to assess depressive symptoms. Participants were screened for current antidepressant medications and vitamin D supplement use was noted. Caucasian women with the highest and the lowest BDI-II scores were asked to provide a serum for vitamin D analysis, measured using a 25(OH)D ELISA Assay.

Results: BDI-II scores obtained from the 136 participants had an average of 13 ± 12. Forty two women were invited to provide serum samples. Twenty subjects had a BDI-II survey score range from 0-3 (minimal depression), average score of 2 ± 1; 22 subjects had a BDI-II survey score from 19-36 (moderate to severe depression), average score of 24 ± 6. Vitamin D deficiency was identified as <50 nmol/L; optimal vitamin D was identified as >75 nmol/L. Subjects scoring in the minimally depressed range (0-3) had average vitamin D values of 54.6 ± 24.1 nmol/L; participants scoring in the moderate to severe depression range (19-36) had an average vitamin D value of 61.8 ± 25.7 nmol/L. Thirteen subjects were either currently taking a vitamin D supplement or multivitamin or had tanned recently. There was no significant correlation between BDI-II scores and serum vitamin D values.

Conclusion: There was no relationship between vitamin D values and BDI-II scores in this population of young adult females in March. Vitamin D levels ranged from a minimum of 14 nmol/L to a maximum of 154 nmol/L. The average serum level of vitamin D was 58.4 ± 25.8 nmol/L. Vitamin D levels were inadequate in 38% of the 42 subjects; 6 out of the 8 subjects that had optimal levels were either taking supplements or tanned. More research is needed to identify the relationship between vitamin D storage capacity and chronic deficiency with depressive symptoms attributed to SAD in the young adult population.

 Gretchen Mach presented her research at the Minnesota Academy of Nutrition and Dietetics April 25, 2013.

Vitamin D and Seasonal Affective Disorder in Collegiate Females during the Winter

Research Advisors: Amy Olson, PhD, RDN, LD and Manuel Campos, PhD. Biology