Quality of life in older age: evidence from an Irish cohort study

To compare the role of different life domains in determining quality of life (QoL) in Ireland with international results.

Cross-sectional study of responses to The Irish Longitudinal Study of Ageing.

Individuals aged 50 and older living in private residential addresses in the Republic of Ireland.

Eight thousand five hundred four individuals living in 6,279 households in the Republic of Ireland (response rate 62%) were interviewed and completed a self-completion questionnaire.

Quality of life was measured using the Control, Autonomy, Self-realization and Pleasure measure (CASP-19). The domains of physical and mental health, social participation, economic resources, and sociodemographic status were measured using a large number of indicators. Ordinary least squares regression models were used to estimate the effect of factors on CASP-19, with the relative contribution of different domains to total explanation measured using a measure of statistical fit.

The mean CASP-19 score for the sample was 43.8 (95% confidence interval = 43.6-44.1), significantly higher than the mean score for the English Longitudinal Study of Ageing (mean 42.5: 42.3-42.7). In unadjusted analyses, CASP-19 was curvilinear with age, peaking at 67 and falling thereafter. Controlling for predictors of QoL, CASP-19 continued to rise, at a decreasing rate, with age. Mental health independently explained the largest proportion of variance in CASP-19 (7.6%), but no single domain of life dominated in terms of explanation.

Increasing longevity can be associated with increasing QoL as long as it is accompanied by reasonable levels of mental and physical health, high-quality relationships, and social participation. Even if physical health becomes poor, evidence suggests that QoL can often remain high as individuals find value and enjoyment in other dimensions of life.