Is the association between posttraumatic stress disorder symptoms and poor health due to a common familial or genetic factor?

Abstract

Objective: The objective of this study was to identify genetic, familial and environmental contributions to the association between posttraumatic stress disorder (PTSD) symptoms and poor health.

Methods: A community sample of 1852 twin pairs was assessed for symptoms of PTSD [with the Impact of Events Scale (IES)] and self-reported global health status using a single five-level question. An ordinal logistic regression model estimated odds ratio/s (OR) for the association between PTSD and health status. Within-pair analysis assessed confounding by familial and genetic factors and adjusted for the possible confounding influence of age, sex, race, education and self-reported physician diagnosis of depression.

Results: The IES was strongly and significantly associated with self-reported health [OR=1.8; 95% confidence interval (95% CI)=1.5-2.2; highest quartile vs. lowest quartile]. This association remained significant in within-pair analysis (OR=1.3; 95% CI=1.0-1.7), but after further adjustment for sociodemographics and depression, it was no longer significant (P(trend)=.17). Separate analysis by zygosity did not show differential effect in monozygotic or dizygotic pairs.

Conclusion: These findings suggest that the association between PTSD symptoms and poor health is, in part, due to familial confounding and sociodemographic factors. Little evidence of confounding by genetic factors was found. These findings suggest that early prevention efforts would have the greatest potential for improving poor health in PTSD-prone patients, whereas later intervention efforts directed at treating PTSD may have a more limited impact on improving poor health.