Multidimensional factors associated with the loss of independence: A population-based longitudinal study.

Aim: To clarify the factors associated with loss of independence multidimensionally over a 3-year period among community-dwelling older adults.

Methods: The survey was exclusively carried out by the local government for people aged >65 years who were independent at baseline living in H-City, a mid-sized urban city in Japan. The participants completed a self-administered postal questionnaire, and we obtained data regarding their loss of independence from administrative records 3 years later.

Results: A total of 22 328 participants completed the follow up (baseline mean age 71.6 years). At follow up, 998 (4.3%) participants were categorized as dependent, with 606 requiring partial support in toileting, bathing and so on (mild loss of independence), and 392 requiring complete support (severe loss). Factors independently associated with mild loss of independence after 3 years for both men and women were advanced age, low physical function, low nutritional status, low cognitive function and high depression risk. In contrast, factors independently associated with severe loss of independence were advanced age, low physical function and high depression risk in men, and advanced age, and low physical and cognitive function in women.

Conclusions: We clarified the variety of factors associated with loss of independence according to its severity, and the strength of those independent associations was different in the whole city longitudinal study. The present study's findings have important clinical implications for the development of better preventive medicine to establish a society of healthy longevity. Geriatr Gerontol Int 2018; 18: 448-455.