The effects of age, sex, education, family status, obesity and smoking on disability: a systematic literature review

Elena Muth, Max Planck Institute for Demograhic Research
Anne Kruse, Max Planck Institute for Demograhic Research
Christina Westphal, Max Planck Institute for Demograhic Research
Gabriele Doblhammer, Max Planck Institute for Demographic Research

A large and complex body of literature exists about the effects of various demographic and socio-demographic dimensions as well as of particular risk factors on disability. In a systematic literature review we focus on the effects of age, sex, education, family status, smoking and obesity on various indicators of disability and mortality. Our review is based on a search of the databases Medline, PsychINFO and SOCA under the surfaces OVID and CSA, on references provided by experts and on references derived from citations. Only articles that describe the outcome of longitudinal studies in industrialized countries (USA, European countries, Australia, New Zealand, and Japan) are considered. The search is restricted to the years 1985 to 2005. In a first step we review about 5000 references that are derived from a logical combination of key words. The search is restricted to titles, abstracts and key-words. Special emphasis is put on details of the study design as well as on odds ratios, relative risks and hazard ratios reported in the studies. Performing a meta-analysis of existing studies we take into account the different study designs and the different definitions of disability. Many of the studies are based on private households only and exclude the institutionalized populations. A large range of indicators of disability is used ranging from “Activities of Daily Living” to composite indicators such as the Katz, Nagi or Rosow-Breslau Indicator. We focus solely on the incidence of and recovery from disability as well as death and explore the effect of the risk factors on these transitions.