Association Between Long-term Weight Change Since Midlife and Risk of Incident Disabling Dementia Among Elderly Japanese: The Ohsaki Cohort 2006 Study

Abstract

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 to +1.4 kg), weight gain (≥+1.5 kg), and weight loss of −2.4 to −1.5 kg, −3.4 to −2.5 kg, −4.4 to −3.5 kg, −5.4 to −4.5 kg, and ≥−5.5 kg. 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 (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 were 0.97 (95% CI, 0.70–1.34) for weight loss of −2.4 to −1.5 kg, 0.98 (95% CI, 0.70–1.38) for −3.4 to −2.5 kg, 1.28 (95% CI, 0.91–1.81) for −4.4 to −3.5 kg, 1.27 (95% CI, 0.92–1.77) for −5.4 to −4.5 kg, and 1.64 (95% CI, 1.29–2.09) for ≥−5.5 kg. Conclusion Our study suggested that a ≥−3.5 kg weight loss over 12 years might be associated with higher risk of incident disabling dementia among elderly Japanese.

Weight Loss Is a Strong Predictor of Memory Disorder Independent of Genetic Influences

“…Therefore, it is unlikely that the observation of pre-dementia weight loss is an artifact of one-year accelerated weight loss due to preclinical cognitive decline [ 30 ]. This also suggests that our finding aligns with previously conducted research that suggests that a higher degree of weight loss can be observed in patients several years before a diagnosis of dementia [ 7 , 8 , 9 , 11 , 30 ]. Our results are also in agreement with two recent publications using different analytical approaches that identified pre-diagnosis weight changes as a predictor of dementia [ 31 , 32 ].…”

“…Another study conducted by LeBlanc et al (2017) observed a greater rate of weight loss (on average additional −0.11 kg/year) over 20 years in women before a diagnosis of mild cognitive impairment (MCI) and dementia [ 8 ]. A recent study conducted in 2020 by Lu et al also suggested that long-term weight loss (≥1.5 kg) can be detected 12 years prior to a diagnosis of disabling dementia in a Japanese population [ 9 ]. These studies suggest that weight loss during middle adulthood may serve as a prognostic factor of future cognitive decline.…”

“…For instance, Barrett-Connor et al considered only a weight change of ≥5 kg meaningful [ 6 ]. Lu et al set the weight change threshold to 1.5 kg [ 9 ]. Besser et al considered yearly weight change of >4% meaningful [ 15 ].…”

Association Between Late-Life Weight Change and Dementia: A Population-based Cohort Study

“…Previous studies that have explored the association between weight change in late life and dementia mostly observed an increased dementia risk linked to weight loss ( 14–16 , 19 , 27 , 33 , 34 ). Conversely, in some studies, weight gain has been either not significantly related to dementia or seemed to be with reduced dementia risk ( 15 , 19 , 35 ). A recent meta-analysis pooling data from 19 prospective cohorts and 4 clinical trials showed that older adults (aged ≥60 and older) with ≥0.5% annual weight loss had approximately one-third greater risk of all-cause dementia than those with a relatively stable weight.…”

Utilization of Japanese long-term care-related data including Kaigo-DB: An analysis of current trends and future directions

“…The typical study was a cohort of healthy older adults, with information from unique questionnaires, interviews, health check-up data, other measurement data measurements and medical claims as the exposure and LTC certification or care needs level data as the outcome . Additionally, several similar studies with the independent degree of daily living for older adults with dementia as an outcome were conducted (43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). Easily applicable research like this is expected to continue to be widely conducted.…”