Discussion
This integrative review of the literature reveals the limited number of peer-reviewed publications addressing mood disorders and serum 25(OH)D. Of the six studies reviewed, four reported significant results showing an association between decreased serum 25(OH)D and symptoms of a mood disorder,[53] SAD,[3] major depressive disorder (using DSM-IV criteria),[51] or PMS.[50] However, neither the study addressing major depression (using DSM-III-R criteria)[52] nor the one on seasonal mood changes[49] reported an association between these disorders and serum 25(OH)D levels. Yet both of these studies had limitations, such as using 3-year-old data to compare to newly drawn serum 25(OH)D levels[49] and a failure to report any statistical comparison between 25(OH)D levels and incidence of major depression.[52] Of the four studies with positive results,[3,50,51,53] only one was a RCT[3]; the other three were descriptive studies.[50,51,53] Each of the four studies showing an association with 25(OH)D and a mood disorder had flaws within their sampling, methodology, or analysis.
The studies varied with their sample sizes and demographic makeup. Each of these studies had samples composed of white females; only two included African American females, and they composed less than 13% of the total sample, limiting the generalizability to other populations.[50,53] The age groups ranged from 15 to 61 years, 21 to 45 years, 28 to 46 years, and 60 years of age and older; unfortunately, the largest range of ages composed the smallest sample size (15 subjects).[3] Two of the four studies[3,51] included both males and females as participants.
The studies did not report validity or reliability for the psychological instruments used or the measurement assay used to determine serum 25(OH)D levels, except for Thys-Jacobs et al.,[50] who did report intra- and interassays for serum 25(OH)D. Each study used different psychological testing instruments. While all studies reported using a radioimmunoassay method to measure 25(OH)D, only Eskandari et al.[51] disclosed which assay was used. According to Hollis,[55] the Vitamin D External Quality Assessment Scheme (DEQAS, an international monitoring program that evaluates the accuracy of 25[OH]D assays in the United Kingdom), states that only the DiaSorin RIA (DiaSorin, S.p.A., Vercelli, Italy) is effective at detecting 25(OH)D levels accurately at this time. When other methods are used, validation of the method is highly important. If the validation of methods used to detect 25(OH)D are not reported, findings of the studies may be debatable because the technique used may be flawed and produce inaccurate results.
Guidelines for classification of vitamin D status varied in each study, if they were reported at all.[3,49,51,52] Classification becomes an integral part of analysis when evaluating for vitamin D deficiency in relation to mood disorders because the results can be misrepresented if each participant is actually vitamin D–deficient, but only serum 25(OH)D values are presented and analyzed. Using the definition of vitamin D deficiency and insufficiency set forth in this article, all four studies (although each used different parameters to define deficiency and insufficiency) note that participants who were vitamin D–deficient (25[OH]D <20 ng/mL) were more likely to experience a mood disorder of varying types compared to participants who were insufficient or sufficient in vitamin D status.
J Midwifery Womens Health. 2008;53(5):440-446. © 2008 Elsevier Science, Inc.
Cite this: Vitamin D and Mood Disorders Among Women: An Integrative Review - Medscape - Sep 01, 2008.
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