HealthDay News — Objectively assessed physical activity is associated with a protective relationship with major depressive disorder (MDD), according to a study published online January 23 in JAMA Psychiatry.
Karmel W. Choi, PhD, from Massachusetts General Hospital in Boston, and colleagues examined bidirectional correlations between physical activity and depression using a genetically informed method for assessing potential causal inference. Independent top genetic variants associated with 2 physical activity phenotypes (self-reported [377,234 participants] and objective accelerometer-based [91,084 participants]) and with MDD (143,265 participants) were used as genetic instruments from the largest available non-overlapping genome-wide association studies (GWAS) in 2-sample Mendelian randomization.
GWAS summary data were available for 611,583 adult participants. Based on evidence from Mendelian randomization, the researchers observed a protective relationship between accelerometer-based activity and MDD (odds ratio, 0.74 for MDD per one-standard deviation increase in mean acceleration; 95% confidence interval, 0.59 to 0.92; P=.006). No statistically significant correlation was seen between MDD and accelerometer-based activity (β=−0.08 in mean acceleration per MDD vs control status; 95% confidence interval, −0.47 to 0.32; P=.70). No significant relationship was seen between self-reported activity and MDD or between MDD and self-reported activity.
“Our findings validate a potential protective relationship between physical activity and depression and point to the importance of objective measurement of physical activity in epidemiologic studies of mental health,” the authors write.
Several authors disclosed financial ties to the biopharmaceutical industry.