Psychological distress and mortality among US adults: prospective cohort study of 330 367 individuals

Background: Previous studies have shown inconsistent findings on the association between psychological distress and risk of mortality. This study aimed to address this inconsistent association using a large US population-based cohort.

Methods: This study used data from 1997 to 2009 US National Health Interview Survey, which were linked with National Death Index through 31 December 2011. Psychological distress was measured using Kessler-6 scale and was categorised into six groups based on scores as 0, 1-3, 4-6, 7-9, 10-12 and ≥13. Main outcomes were all-cause, cancer-specific and cardiovascular disease (CVD)-specific mortality. Analyses were completed in 2019. Cox proportional hazards models were used to determine the association between psychological distress and mortality.

Results: A total of 330 367 participants aged ≥18 years were included. During a mean follow-up of 8.2 years, 34 074 deaths occurred, including 8320 cancer-related and 8762 CVD-related deaths. There was a dose-response association between psychological distress and all-cause mortality. Compared with the 0 score category, adjusted HRs (95% CIs) for other categorical psychological distress scores, that is, 1-3, 4-6, 7-9, 10-12 and ≥13, were 1.09 (1.05 to 1.12), 1.22 (1.17 to 1.27), 1.38 (1.31 to 1.46), 1.49 (1.40 to 1.59) and 1.57 (1.47 to 1.68), respectively. Corresponding values for cancer-specific mortality were 1.06 (0.99 to 1.12), 1.13 (1.04 to 1.23), 1.27 (1.14 to 1.42), 1.38 (1.22 to 1.57) and 1.32 (1.15 to 1.51), respectively; those for CVD-specific mortality were 1.11 (1.05 to 1.18), 1.22 (1.12 to 1.32), 1.30 (1.17 to 1.45), 1.38 (1.20 to 1.58), and 1.46 (1.27 to 1.68), respectively.

Conclusions: We found a dose-response relationship between psychological distress and all-cause and cause-specific mortality, emphasising the need for early prevention strategies among individuals with potential psychological distress.