- Japan Epidemiological Association
- Journal of Epidemiology (ISSN:09175040)
- pp.JE20200260, (Released:2020-12-26)
Background: Both weight loss and cognitive impairment are common in late-life, but it remains unknown whether weight change is associated with risk of incident dementia among elderly Japanese. Our study aimed to investigate the association between long-term weight change since midlife and risk of incident disabling dementia using a community-based cohort study of elderly Japanese.Methods: In 2006, we conducted a cohort study of 6,672 disability-free Japanese adults aged ≥65 years. In both 1994 and 2006, the participants reported their weight using a self-reported questionnaire. Based on weight obtained at these two time points, participants were classified into: stable weight (-1.4 – +1.4kg), weight gain (≥ +1.5kg), and weight loss of -2.4 – -1.5kg, -3.4 – -2.5 kg, -4.4 – -3.5kg, -5.4 – -4.5kg, and ≤-5.5kg. Incident disabling dementia was retrieved from the public Long-term Care Insurance database. Participants were followed-up for 5.7 years (between April 2007 and November 2012). Cox proportional hazards model was used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for incident disabling dementia.Results: During 32,865 person-years of follow-up, 564 participants were ascertained as having incident disabling dementia. Compared with stable weight, the multivariable-adjusted HRs (95%CIs) were 0.97 (0.70, 1.34) for weight loss of -2.4 – -1.5kg, 0.98 (0.70, 1.38) for -3.4 – -2.5kg, 1.28 (0.91, 1.81) for -4.4 – -3.5kg,1.27 (0.92, 1.77) for -5.4 – -4.5kg, and 1.64 (1.29, 2.09) for ≤-5.5kg.Conclusion: Our study suggested that a ≤-3.5kg weight loss over 12 years might be associated with higher risk of incident disabling dementia among elderly Japanese.