[Functional difficulty among elderly Brazilians: a study based on the National Health Survey (PNS - 2013)].

The objective of this study was to study the factors that present a high degree of association with functional difficulties among the elderly. A cross-sectional, quantitative study was conducted among individuals aged 60 years or older (n = 23,815). Two dependent variables were considered: Basic Activity of Daily Living and Instrumental Activity of Daily Living, and 42 independent variables related to sociodemographic issues, general health, oral health and the use of health services. For the analysis, the Waikato Environment for Knowledge Analysis software was used. Data set balancing and the dimensionality reduction test were performed through 10-fold cross-validation and lastly, the variables related to the dependent variables were evaluated through logistic regression. Eight variables had a strong association with functional difficulties among the elderly, related to physical aspects, intrinsic factors, social relations, literacy and the use of health services. The results obtained enable the bolstering of planning and execution of strategies in public health, directed to the elderly population, avoiding or minimizing situations of functional difficulty.