Fig. 2
From: Mendelian randomization studies of depression: evidence, opportunities, and challenges
Cigarette smoking, excessive alcohol consumption, marijuana use, elevated circulating TG, C-reactive protein(CRP) and IL-6 levels, decreased DHA and increased omega-6: omega-3 fatty acid ratios, BMI, AAM, shorter telomere lengths, intestinal flora, type 2 diabetes mellitus, and breast cancer were associated with increased risk of major depressive disorder (MDD). In contrast, higher carbohydrate and beef intake, physical activity, higher education, early circadian preference, and living with a spouse or partner were associated with a lower risk of MDD. MR analyses have not yet established a causal relationship between genetic prediction of the prevalence of CAD, MS, types of cancer other than breast cancer, AD, JIAU, or periodontitis