The relative contributions of hostility and depressive symptoms to the income gradient in hospital-based incidence of ischaemic heart disease: 12-Year follow-up findings from the GLOBE study

There is evidence to support the view that both hostility and depressive symptoms are psychological risk factors for ischaemic heart disease (IHD), additional to the effects of lifestyle and biomedical risk factors. Both are also more common in lower socioeconomic groups. Studies to find out how socioeconomic status (SES) gets under the skin have not yet determined the relative contributions of hostility and depression to the income gradient in IHD. This has been examined in a Dutch prospective population-based cohort study (GLOBE study), with participants aged 15-74 years (n = 2374). Self-reported data at baseline (1991) and in 1997 provided detailed information on income and on psychological, lifestyle and biomedical factors, which were linked to hospital admissions due to incident IHD over a period of 12 years since baseline. Cox proportional hazard models were used to study the contributions of hostility and depressive symptoms to the association between income and time to incident IHD. The relative risk of incident IHD was highest in the lowest income group, with a hazard ratio of 2.71. Men on the lowest incomes reported more adverse lifestyles and biomedical factors, which contributed to their higher risk of incident IHD. An unhealthy psychological profile, particularly hostility, contributed to the income differences in incident IHD among women. The low number of IHD incidents in the women however, warrants additional research in larger samples.