摘要：Objectives. Data from the Netherlands indicate a recent increase in prevalence of chronic diseases and a stable prevalence of disability, suggesting that diseases have become less disabling. We studied the association between chronic diseases and activity limitations in the Netherlands from 1990 to 2008. Methods. Five surveys among noninstitutionalized persons aged 55 to 84 years (n = 54 847) obtained self-reported data on chronic diseases (diabetes, heart disease, peripheral arterial disease, stroke, lung disease, joint disease, back problems, and cancer) and activity limitations (Organisation for Economic Co-operation and Development [OECD] long-term disability questionnaire or 36-item Short Form Health Survey [SF-36]). Results. Prevalence rates of chronic diseases increased over time, whereas prevalence rates of activity limitations were stable (OECD) or slightly decreased (SF-36). Associations between chronic diseases and activity limitations were also stable (OECD) or slightly decreased (SF-36). Surveys varied widely with regard to disease and limitation prevalence rates and the associations between them. Conclusions. The hypothesis that diseases became less disabling from 1990 to 2008 was only supported by results based on activity limitation data as assessed with the SF-36. Further research on how diseases and disability are associated over time is needed. As populations in many Western countries grow older, changes in population health constitute a major public health issue. Insight into health-status trends in older populations may help with estimating future health care needs and setting priorities for improving population health. Important indicators for health in old age are prevalence of chronic diseases and prevalence of disability. Previous studies in the Netherlands showed that the prevalence of chronic diseases increased over the past 20 to 25 years. 1,2 This increase was not only attributable to aging of the population; age-group-specific prevalence rates also increased. 3 In contrast, the age-adjusted prevalences of activity limitations and disabilities have shown varying trends in the Netherlands: rates have remained constant, increased, or even decreased, depending on the study. 4–7 Decreasing disability trends have also been observed in several other Western countries, suggesting a postponement of limitations and disabilities despite increases in chronic diseases in many countries. 8 Because diseases are important causes of activity limitations and disabilities, 9,10 these opposing trends warrant further study. Several possible explanations for these contradictory trends have been suggested. First, trends in disability rates do not necessarily follow trends in chronic diseases, because increasing use of aids and devices facilitates greater independence in people with or without diseases. 11,12 Also, changes in the environment can mitigate disabilities for people with a disease. 13 Safer and better sidewalks, for example, can make it easier for people with joint disease to move around. Another explanation is that improved medical knowledge and health services utilization lead to more detection of disease even though the actual disease prevalence remains the same. For some diseases, such as type 2 diabetes, hypertension, and some cancers, people are now being diagnosed earlier and are receiving better treatment than before. 11 These advancements in detection and treatment lead to longer periods of known morbidity—and thus to higher estimates of disease prevalence—but with improved functional status. These trends would result in stable or decreasing prevalence of activity limitations and disabilities. 8,13,14 In that case, the conclusion would be that diseases have become less disabling over time. For different diseases, different underlying developments are possible, resulting in different trends in the disabling impact of diseases. 6 We sought to investigate time trends in the disabling impact of chronic diseases in the Netherlands. We examined time trends in disease prevalence, activity limitations, and the strength of the associations between diseases and activity limitations. To ensure the best estimates of these trends, we combined all available data sources.
