Purpose: To determine whether higher rates of mortality are observed in people reporting psychological distress, to establish the nature of any excess, and to examine the possible existence of a dose response relationship.
Methods: We conducted a prospective follow-up study of mortality over an eight-year period in the North West of England. A total of 4,501 adults were recruited from two general practices during a population-based survey conducted at the start of 1992. At baseline psychological distress was assessed using the General Health Questionnaire (12-item version, GHQ-12). The relationship between levels of distress and subsequent mortality was examined using Cox proportional hazard models.
Results: Risk of all-cause mortality was greatest in subjects reporting the highest levels of distress (hazard ratio (HR) 1.71, 95% CI 1.32-2.23) but was also raised in subjects reporting intermediate distress (HR 1.38 95% CI 1.06-1.79) when compared to those reporting no distress. Increased risk of mortality in subjects reporting distress appeared to be due largely to an excess of deaths from ischaemic heart disease (high distress, HR 1.90, 95% CI 1.08-3.35; intermediate distress, HR 1.58, 95% CI 0.90-2.76) and respiratory diseases (high distress, HR 5.39, 95% CI 2.70-10.78; intermediate distress, HR 2.33, 95% CI 1.12-4.22).
Conclusions: The association between mortality and psychological distress observed in this study seems to arise largely because of premature deaths from ischaemic heart disease and respiratory diseases. The existence of a dose-response effect between distress and mortality provides further evidence to support the existence of a casual relationship.