Behavioural change, weight loss and risk of dementia: A longitudinal study

Patterns of Aging Changes in Bodyweight May Predict Alzheimer's Disease

Relationships between patterns of aging-changes in bodyweight and AD are not fully understood. We compared mean age-trajectories of weight between those who did and did not develop late-onset-AD, and evaluated impact of age at maximum weight (AgeMax), and slope of decline in weight, on AD risk. Women with late-onset-AD had lower weight three or more decades before AD onset, and ∼10 years younger AgeMax, compared to AD-free women. APOE4 carriers had younger AgeMax and steeper slope. Older AgeMax and flatter slope predicted lower AD risk. Premature decline in weight could be a sign of accelerated physical aging contributing to AD.

Long-term Weight Change and its Temporal Relation to Later-life Dementia in the Health and Retirement Study

CONTEXT

Weight loss among middle-aged and older adults has been associated with a higher risk of subsequent dementia. However, most studies have limited follow-up durations or suboptimal control for the potential influence of physical frailty (PF).

OBJECTIVE

Our study aimed to investigate the long-term and temporal relations of weight change to risk of dementia among middle-aged and older adults in the United States.

METHODS

A total of 5985 participants aged 65 years and older were included from the Health and Retirement Study. History of long-term weight change was calculated using 9 repeated body mass index measurements during 1992-2008. We then followed participants' dementia status from 2008 to 2018. Multivariable Cox proportional hazard models were used.

RESULTS

During the study follow-up period (mean = 7.54 years), a total of 682 (11.40%) dementia cases were documented. After adjustment for basic demographic and lifestyle factors, participants with weight loss (median: -0.23 kg/m2 per year) were at a significantly higher risk of dementia (HR = 1.60; 95% CI, 1.33, 1.92), compared with the stable weight group (median: 0.11 kg/m2 per year). This association was attenuated but remained strong and significant after further adjustment for PF (HR = 1.57; 95% CI, 1.30, 1.89). Significant association was observed for weight loss assessed approximately 14 to 18 years preceding dementia diagnosis (HR = 1.30; 95% CI, 1.07, 1.58), and was consistent closer to diagnosis.

CONCLUSION

Both recent and remote weight loss were associated with a higher risk of later-life dementia among middle-aged and older adults independent of PF status.

Urban-Rural Disparities in the Association Between Body Mass Index and Cognitive Impairment in Older Adults: A Cross-Sectional Study in Central China

BACKGROUND

Some studies have demonstrated an association between low and high body mass index (BMI) and an increased risk of dementia. However, only a few of these studies were performed in rural areas.

OBJECTIVE

This cross-sectional study investigated the associations between BMI and cognitive impairment among community-dwelling older adults from rural and urban areas.

METHODS

8,221 older persons enrolled in the Hubei Memory & Ageing Cohort Study (HMACS) were recruited. Sociodemographic and lifestyle data, comorbidities, physical measurements, and clinical diagnoses of cognitive impairment were analyzed. Logistic regression was performed to assess the associations of BMI categories with cognitive impairment. A series of sensitivity analyses were conducted to test whether reverse causality could influence our results.

RESULTS

Being underweight in the rural-dwelling participants increased the risk of cognitive impairment. Being overweight was a protective factor in rural-dwelling participants aged 65-69 years and 75-79 years, whereas being underweight was significantly associated with cognitive impairment (OR, 1.37; 95% CI: 1.03-1.83; p < 0.05). Sensitivity analyses support that underweight had an additive effect on the odds of cognitive impairment and was related to risk of dementia. Interaction test revealed that the differences between urban/rural in the relationship between BMI and cognitive impairment are statistically significant.

CONCLUSION

Associations between BMI and cognitive impairment differ among urban/rural groups. Older people with low BMI living in rural China are at a higher risk for dementia than those living in urban areas.