Relationship between 5-year decline in instrumental activity of daily living and accumulation of cardiovascular risk factors: NIPPON DATA90

Aim: To clarify the relationship between the accumulation of cardiovascular risk factors and the 5-year decline in instrumental activity of daily living (IADL) among a cohort representative of the Japanese population aged 65 years and over. Methods: An IADL survey was performed by public health centers throughout Japan. Study subjects were elderly men and women living in districts under the jurisdiction of collaborating health centers. Subjects were invited to participate in the IADL survey assessed by the Tokyo Metropolitan Institute of Gerontology (TMIG) Index of Competence twice in 1995 and in 2000; 1222 participants were eligible for the analysis. The relationship between the number of cardiovascular risk factors, such as hypertension, hypercholesterolemia, hypertriglycemia, low serum high-density lipoprotein cholesterol, diabetes, obesity and smoking, at baseline and the 5-year difference in IADL scores was examined by linear regression analysis and logistic regression analysis. Results: Decrease in IADL scores was larger in those with cardiovascular risk factors than in those without. The multivariable odds ratio (OR) for decreased IADL after adding one CVD risk factor was 1.16 (95% confidence interval (CI), 1.04-1.29) after adjusting for age, sex, alcohol consumption and TMIG score at baseline. Among participants who were regarded as physically independent with respect to basic ADL in the baseline survey, the odds ratio was also similar and significant. Conclusion: Preventive interventions directed against cardiovascular risk factors, especially against their accumulation, may contribute to maintaining IADL in the Japanese elderly.