Background: the identification of modifiable risk factors for preventing disability in older individuals is essential for planning preventive strategies.
Purpose: to identify cross-sectional correlates of disability and risk factors for the development activities of daily living (ADL) and instrumental ADL (IADL) disability in community-dwelling older adults.
Methods: the study population consisted of 897 subjects aged 65-102 years from the InCHIANTI study, a population-based cohort in Tuscany (Italy). Factors potentially associated with high risk of disability were measured at baseline (1998-2000), and disability in ADLs and IADLs were assessed both at baseline and at the 3-year follow-up (2001-03).
Results: the baseline prevalence of ADL disability and IADL disability were, respectively, 5.5% (49/897) and 22.2% (199/897). Of 848 participants free of ADL disability at baseline, 72 developed ADL disability and 25 of the 49 who were already disabled had a worsening in ADL disability over a 3-year follow-up. Of 698 participants without IADL disability at baseline, 100 developed IADL disability and 104 of the 199 who already had IADL disability had a worsening disability in IADL over 3 years. In a fully adjusted model, high level of physical activity compared to sedentary state was significantly associated with lower incidence rates of both ADL and IADL disability at the 3-year follow-up visit (odds ratio (OR): 0.30; 95% confidence intervals (CI) 0.12-0.76 for ADL disability and OR: 0.18; 95% CI 0.09-0.36 for IADL disability). After adjusting for multiple confounders, higher energy intake (OR for difference in 100 kcal/day: 1.09; 95% CI 1.02-1.15) and hypertension (OR: 1.91; 95% CI 1.06-3.43) were significant risk factors for incident or worsening ADL disability.
Conclusions: higher level of physical activity and lower energy intake may be protective against the development in ADL and IADL disability in older persons.