Intrinsic capacity and ageing well for Aboriginal people in remote Western Australia: a longitudinal cohort study

To assess intrinsic capacity, an important component of ageing well, in older Aboriginal people living in remote Western Australia.

Longitudinal cohort study; secondary analysis of survey and clinical assessment data.

Kimberley region of Western Australia (six remote communities, and the town of Derby).

Aboriginal people aged 45 years or older, initially recruited 15 July 2004 - 17 November 2006.

Intrinsic capacity (assessed in each participant by questionnaire and review by a consultant specialist), overall and by domain, and presence of core activity limitations, at baseline and follow-up (8 February 2011 - 6 June 2013); risk of death by follow-up; preservation of intrinsic capacity at follow-up.

The mean age of the 345 participants at baseline was 60.2 years (standard deviation [SD], 11.6 years; range, 45-96 years); 152 were men (44.1%) and 193 were women (55.9%). Intrinsic capacity was unimpaired in all five domains for 55 participants (15.9%; 95% confidence interval [CI], 12.4-20.2%). Capacity in the vitality domain was unimpaired in 325 respondents (94.2%), in the psychological/mood domain in 318 (92.2%), and in the cognition domain in 289 people (83.8%); the locomotion domain was unimpaired in 174 people (50.4%), and the sensory domain in 117 people (33.9%). The proportion of men with full capacity in all five domains (32 of 152, 21.1%) was larger than for women (23 of 193, 11.9%). Of the 274 people included in follow-up analyses, intrinsic capacity was lower than at baseline for 66 people (24.1%), it was unchanged or improved in 111 participants (40.5%; 95% CI, 34.8-46.5%), and 97 people had died (35.4%). Thirty-seven of the 177 surviving participants for whom complete data were available had full capacity in all domains (20.9%; 95% CI, 15.5-27.6%). After adjustment for age, the number of unimpaired intrinsic capacity domains at baseline was inversely associated with having a core activity limitation at baseline (per domain: adjusted prevalence ratio, 0.43; 95% CI, 0.34-0.55) and follow-up (adjusted risk ratio, 0.62; 95% CI, 0.44-0.88), and with risk of death by follow-up (adjusted risk ratio, 0.83; 95% CI, 0.71-0.96).

Impaired intrinsic capacity in older Aboriginal people living in the Kimberley was most frequent in the sensory and locomotion domains. Reduced capacity in these domains could be highly amenable to treatment that would ensure that Elders can continue to take part in activities important for quality of life.