Minimum income for healthy living and frailty in adults over 65 years old in the English Longitudinal Study of Ageing: A population-based cohort study

Abstract

Objective To test whether minimum income for healthy living of a person aged 65 years or older (MIHL 65) is associated with frailty in older adults. Design and setting Secondary analysis of the English Longitudinal Study of Ageing, a multiwave prospective cohort study in England, UK. Participants A subset (n=1342) of English Longitudinal Study of Ageing participants, who at wave 1 in 2002 were aged 65 years or older, without any limiting long-standing illnesses, and who had the information required to calculate MIHL 65 in 2002, 2004 and 2006 and two measures of frailty in 2008. Main outcome measures Frailty defined using Fried's phenotype criteria and Rockwood's Index of deficits. Results The odds of frailty in 2008 were significantly higher for participants living below MIHL 65 in 2002, both on Fried's phenotype criteria (OR 2.56, 95% CI 1.57 to 4.19) and Rockwood's Index (OR 2.83, 95% CI 1.74 to 4.60). These associations remained after adjustment for age and gender for both Fried's phenotype (OR 1.85, 95% CI 1.18 to 2.90) and Rockwood's Index (OR 2.15, 95% CI 1.38 to 3.35). Compared with those whose income during 2002-2006 was always above MIHL 65, the odds of frailty in 2008 for those below MIHL 65 were two-to-three times higher, with a tendency for the ORs to increase in line with the length of time spent below MIHL 65 (ORs (95% CIs) were: Fried's phenotype, below MIHL 65 once: 2.02 (1.23 to 3.34); twice: 2.52 (1.37 to 4.62); thrice: 3.53 (1.65 to 7.55). Rockwood's Index: Once: 2.34 (1.41 to 3.86); twice: 3.06 (1.64 to 5.71); thrice: 2.56 (1.22 to 5.34)). These associations remained after adjustment for age and gender on Rockwood's Index, but not Fried's phenotype. Conclusions These results provide some support for the idea that frailty at older ages is associated with not having sufficient income to lead a healthy life.