Contribution of chronic conditions to functional limitations using a multinomial outcome: results for the older population in Belgium and Brazil

BACKGROUND: The global phenomenon of population ageing is creating new challenges in both high and middle income countries, as functional limitations are expected to increase with age. The attribution method has been proposed to identify which conditions contribute most to disability using cross-sectional data. Although the original method was based on binary outcomes, we recently proposed an extension to multinomial responses, since different disability levels are often investigated in surveys. This is the first application of the extended method to evaluate differences in the contribution of chronic conditions to functional limitations in the older population of Brazil and Belgium. METHODS: Representative data from individuals aged ≥65 years who participated in the 2008 or 2013 Health Interview Surveys in Belgium (N = 4521) or in the 2008 National Household Sample Survey in Brazil (N = 28,437) were analysed. Individuals were classified as without, moderate or severe functional limitations, based on three activities of daily living: eating, showering, and toileting. Six chronic conditions common to the surveys – diabetes, heart diseases, musculoskeletal conditions, depression, chronic respiratory diseases, and cancer – were included in the analysis. Separate multinomial additive hazards models by gender for each country were fitted. RESULTS: The prevalence of moderate functional limitations was larger in men in Brazil (8.4%) compared to Belgium (6.0%) and similar in women (approximately 12.0%). Conversely, the severe prevalence in men was similar in the two countries (around 8.0%) and higher in women from Belgium (16.6%) than from Brazil (9.1%). Musculoskeletal conditions were the main contributors to the prevalence of functional limitations in men and women in Belgium but only in men and women with moderate functional limitations in Brazil. Depression and heart diseases contributed most to the severe prevalence of functional limitations in men and women in Brazil, respectively. CONCLUSIONS: Our findings provide a better understanding of differences in the prevalence of different levels of functional limitations in Brazil and Belgium. These differences can be related to differences in socioeconomic conditions, health care access and quality, disease diagnosis, stage of epidemiology transition, life expectancy, and the prevalence of lifestyle risk factors in the two countries. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13690-017-0235-3) contains supplementary material, which is available to authorized users.