摘要：Objectives. We assessed the contributions of the prevalence and disabling impact of specific diseases to educational disparities in the prevalence of disability. Methods. We examined a large representative survey of the Dutch population, the Dutch Permanent Survey of Living Conditions (2001–2007; n = 24 883; ages 40–97 years). We attributed the prevalence of disability to chronic diseases by using their empirical associations and assuming independent competing causes of disability. We estimated contributions of prevalence and the disabling impact of diseases to disparities in disability using counterfactuals. Results. We found that the prevalence of disability in individuals with only an elementary education was 19 to 20 percentage points higher than that in individuals with tertiary education. Sixty-five percent of this difference could be attributed to specific chronic diseases, but more so to their disabling impact (49%–51%) than to their prevalence (20%–29%). Back pain, neck or arm conditions, and peripheral vascular disease contributed most to the disparity in men, and arthritis, back pain, and chronic nonspecific lung disease contributed most to the disparity in women. Conclusions. Educational disparities in the burden of disability were primarily caused by high disabling impacts of chronic diseases among low educated groups. Tackling disparities might require more effective treatment or rehabilitation of disability in lower socioeconomic groups. Worldwide, health is strongly patterned along socioeconomic lines. 1,2 Those with the lowest income or with the lowest level of education are consistently less healthy on numerous health indicators. 1–3 For example, a recent study using data from the World Health Survey showed significant and substantial pro-rich inequality in the prevalence of disability in 43 of 49 countries worldwide. 3 The disparities, also in disability, have not declined, but appear to have a strongly persistent nature. 4–6 Reducing health disparities is a top priority of health policy agendas, and there is an urgent need to develop interventions that effectively reduce socioeconomic disparities in health. 7 This requires that we know which diseases and determinants contribute most to health disparities, but studies assessing contributions of specific diseases to disparities in fatal and nonfatal health outcomes are limited in number. With respect to fatal outcomes, several studies show that various diseases contribute to socioeconomic disparities in total mortality, but that a few conditions contribute most. 1,8–13 For example, Huisman et al. 8 found that among European men, cardiovascular diseases accounted for 39% of the difference between low and high educational groups in total mortality, cancer accounted for 24%, other diseases accounted for 32%, and external causes accounted for 5%. Among women, contributions were 60%, 11%, 30%, and 0%, respectively. 8 A relative stagnation of cardiovascular mortality declines among low socioeconomic groups has contributed to the persistence and even widening of disparities in total mortality over the past few decades. 5 With respect to nonfatal health outcomes, substantial disparities exist in terms of the occurrence of many chronic diseases and in generic health outcomes, such as disability. 3,14 Only a handful of studies has investigated which diseases contribute most to the socioeconomic disparity in the burden of disability. In a study by Sainio et al., 15 diabetes contributed most to educational disparities in stair climbing limitations among men, and osteoarthritis of the knee and angina pectoris contributed most among women. In a study by Koster et al., 16 knee pain contributed most to an excess hazard for mobility limitations among low educated persons. In another study, Nusselder et al. 17 found that in the Belgian population, back complaints and arthritis contributed most to educational disparities in years lived with functional mobility limitations among men, and that arthritis and chronic nonspecific lung disease contributed most among women. The latter study clearly showed that substantial differences exist in the prevalence of and in the disabling impact of chronic diseases, and suggested that both contribute to the total disparity in disability. Because these 2 aspects may require an entirely different intervention approach, knowing their relative contribution to disparities in disability is crucial for policy development. To our knowledge, no study has investigated to what extent the total inequality in the burden of disability is explained by differences in the prevalence of diseases and by differences in the disabling impact. Our aim in this study was to assess contributions of differences in the prevalence and the disabling impact of specific diseases to educational disparities in the prevalence of disability.
