Factors associated with health-related quality of life (HRQoL): differential patterns depending on age

The aims of this study were: (1) to analyze age differences in health-related quality of life (HRQoL) between the young old (aged 65-84) and the oldest old (aged 85 and over), and (2) to investigate three types of predictors: (a) physical health [Basic Activities of Daily Living (BADL), Instrumental Activities of Daily Living, comorbidity, use of medication], (b) global cognitive ability and (c) psychosocial factors, specifically personality traits, social support and emotional functioning (positive and negative affect and life satisfaction), which may influence the HRQoL of both the young old and the oldest old.

A cross-sectional study was conducted with 257 healthy community-dwelling elderly people. HRQoL was assessed using the SF-36 Health Survey. Functional and health status, global cognitive ability and psychosocial variables were also assessed.

Age differences were found in HRQoL, with the oldest old scoring lower for this variable. Multiple stepwise hierarchical linear regression analyses revealed that, in relation to the physical health component, use of medication, BADL and positive affect had the greatest influence among the young old (65-84), whereas among the oldest old, neuroticism and the BADL were the most influential factors. As regards the mental health component, neuroticism, use of medication and positive affect were the main predictor variables among the young old, while neuroticism and negative affect had the greatest influence among the oldest old group.

The oldest old had a poorer HRQoL in both dimensions measured (physical and mental). There appear to be differences between the determinants of HRQoL for young old and oldest old adults, suggesting that these associations change with age.