Is Seasonal Affective Disorder a Symptom of a Larger Collection of Sedentary and Obesity-Related Disorders?

Document Type

Conference Presentation

Department

Health, Exercise, and Sport Sciences Department

Conference Title

American College of Sports Medicine - Medicine & Science in Sports & Exercise conference

Organization

American College of Sports Medicine

Location

Orlando, FL

Date of Presentation

5-29-2019

Journal Publication

Medicine & Science in Sports & Exercise

ISSN

0195-9131

DOI

10.1249/01.mss.0000561190.19326.27

Volume

51

Issue

6S

First Page

227

Abstract

Seasonal affective disorder (SAD) is a subtype of major depressive disorder (MDD) that occurs during cold and overcast months. Physical activity (PA) is known to counteract depressive symptoms; however, the relationship between seasonal changes in PA and MDD is largely unexplored. Physical inactivity and consequent weight gain may contribute to a host of cardiometabolic and cerebral complications, with SAD being one diagnostic feature. PURPOSE: To evaluate seasonal differences in MDD among obese and non-obese patients in conjunction with cardiovascular, metabolic, and cerebral diagnoses. METHODS: We analyzed 2,306 consecutively-admitted patients at a Midwestern hospital over 3 years. Mean environmental temperature of the hospital’s city during each of the 36 months was computed. Patients were assessed for obesity, MDD, diabetes, hypertension, peripheral vascular disease, congestive heart failure, cerebrovascular accidents, and dementia. Logistic regressions tested the effects of season and temperature on all diagnoses. RESULTS: Patients were 52.1±22.4 years old, 16.3% were obese, 1.1% had MDD, 14.3% had diabetes, 36.8% had hypertension, 0.7% had peripheral vascular disease, 4.4% had congestive heart failure, 3.6% had a cerebrovascular accident, and 4.6% had dementia. Between March 1 and June 30, MDD incidence was 532.8% higher than it was during all other months (p<0.001). These were not the coldest months (mean temperature was 5.9°F higher during this period; p<0.001), but it was the period of greatest obesity (33.3% higher incidence; p=0.003). Likewise, colder temperature was a poor predictor of MDD (p=0.465), but predicted elevated rates of obesity (p<0.001), diabetes (p=0.034), hypertension (p<0.001), congestive heart failure (p=0.013), peripheral vascular disease (p=0.058), cerebrovascular accidents (p=0.003), and dementia (p=0.001). CONCLUSION: MDD diagnosis was highest at the end of the cold season, when obesity was at its peak; in turn, the likelihood of numerous obesity-related diagnoses was increased. This suggests a possibility that seasonal incidence of depression is not exclusively caused by diminished exposure to sunlight. Perhaps a colder environment limits engagement in PA; in turn, SAD is one component of a larger picture, which includes dysfunction of numerous systems.

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