Traumatic life events as predictors for depression in middle-aged men and women: A Finnish twin study

Background: We examined exposure to adulthood traumatic life events (TLEs) and their associations with depression in women and men. Then we examined whether those associations are independent of exposure loading and vulnerability including familial confounding.

Methods: The fourth survey in 2011 of the population-based Finnish Twin Cohort had 8410 participants (45 % men, mean age 60 years). Using the Center for Epidemiologic Studies Depression (CES-D) scale, depression was defined using a cut-off value ≥20. Participants reported exposure to TLEs during adulthood. Logistic regression adjusted for multiple covariates was used as the individual-based analyses. Familial confounding was tested using conditional logistic regression in 399 twin pairs discordant for depression.

Results: More women (15 %) than men (11 %) were depressed. Men reported more traffic accidents (men: 11.8 %, women: 7.4 %), other serious accidents (11.8 %, 5.8 %), and violent crime (3.1 %, 2.0 %) whereas women reported more sexual assault (0.7 %, 10.6 %). Violent crime (Odds Ratio 3.86; 95 % Confidence Intervals 2.59, 5.73), sexual assault (3.49; 2.67, 4.55), physical assault (3.10; 2.45, 3.93), and other serious accidents (1.36; 1.01, 1.85) were associated with depression. These associations, except other serious accidents, remained significant after adjusting for multiple covariates including shared familial factors. The associations did not differ by sex.

Limitations: A relatively small set of relevant TLEs was reported retrospectively and the order of TLEs was not assessed.

Conclusions: Women and men differ in exposure to TLEs but, if exposed, they are equally vulnerable for depression. Because traumatic life events are robustly associated with depression, they should be considered in treatment.