AIM: The purpose of the present study was to investigate the relationship between knee-extension (KE) strength and instrumental activities of daily living (IADL), and to examine the risk of IADL disability in relation to KE strength in community-dwelling older adults. METHODS: The participants were 1235 community-dwelling older adults (261 men and 974 women) in Tokyo who underwent a comprehensive health survey in 2009. The health survey included measurement of KE strength and a questionnaire on the Tokyo Metropolitan Institute of Gerontology (TMIG)-IADL. Pearson product-moment correlation coefficients and partial correlation coefficients were calculated separately for each sex for four parameters representing quadriceps muscle strength and TMIG-IADL. Pearson's χ(2)-test of independence and the Cochran-Armitage test of trend were also carried out to determine the relationship between KE strength and IADL disability. RESULTS: In women, all correlations between the quadriceps muscle strength parameters and the TMIG-IADL score were statistically significant (P < 0.0005). The significance persisted remained even after factors regarding cognition or depression were taken into consideration. Furthermore, the percentage of female participants with IADL disability was dependent on KE strength; there was an inverse trend between KE strength and the percentage of people with IADL disability. In men, no significant relationship was found between KE strength and IADL. CONCLUSIONS: KE strength and IADL correlated positively, and the percentage of people with IADL disability decreased with increasing KE strength in women.
AIM: The purpose of the present study was to investigate the relationship between knee-extension (KE) strength and instrumental activities of daily living (IADL), and to examine the risk of IADL disability in relation to KE strength in community-dwelling older adults. METHODS: The participants were 1235 community-dwelling older adults (261 men and 974 women) in Tokyo who underwent a comprehensive health survey in 2009. The health survey included measurement of KE strength and a questionnaire on the Tokyo Metropolitan Institute of Gerontology (TMIG)-IADL. Pearson product-moment correlation coefficients and partial correlation coefficients were calculated separately for each sex for four parameters representing quadriceps muscle strength and TMIG-IADL. Pearson's χ(2)-test of independence and the Cochran-Armitage test of trend were also carried out to determine the relationship between KE strength and IADL disability. RESULTS: In women, all correlations between the quadriceps muscle strength parameters and the TMIG-IADL score were statistically significant (P < 0.0005). The significance persisted remained even after factors regarding cognition or depression were taken into consideration. Furthermore, the percentage of female participants with IADL disability was dependent on KE strength; there was an inverse trend between KE strength and the percentage of people with IADL disability. In men, no significant relationship was found between KE strength and IADL. CONCLUSIONS: KE strength and IADL correlated positively, and the percentage of people with IADL disability decreased with increasing KE strength in women.