Ma,Y., Ajnakina, A, Steptoe, A. & Cadar, D. | 2021 | Higher risk of dementia in English older individuals who are overweight or obese| International Journal of Epidemiology | Volume 49|z Issue 4 P 1353–1365| https://doi.org/10.1093/ije/dyaa099
Researchers involved in The English Longitudinal Study of Ageing (ELSA) investigated whether increased body weight or central obesity were associated with a higher risk of developing dementia; to facilitate this they tracked more than 6 500 people aged over 50 for more than a decade. For those with obesity at the outset of the study, their risk of developing the syndrome increased by a third ( 34 per cent). None of the participants had dementia at baseline.
Almost 7 per cent of participants (n equal to 453) developed dementia. When compared with a normal BMI and waist circumference ( WC ) group, the obese and high WC group had 28% higher risk of dementia.
Nearly three quarters (74 per cent) of the participants who developed dementia were overweight or obese at baseline, in comparison with 72 per cent of those who were not diagnosed with dementia by the end of the study period.
Obesity and larger waist circumference were associated with increased dementia incidence. These findings have significant implications for dementia prevention and overall public health associated with a higher dementia risk across a decade follow-up period, independent of demographics, lifestyle behaviours, apolipoprotein E-ε4, hypertension and diabetes
From the various modifiable risk factors, obesity could represent a target for intervention, and these findings have significant implications for public health and dementia prevention.
Several risk factors contribute to dementia, but the role of obesity remains unclear. This study investigated whether increased body weight or central obesity were associated with a higher risk of developing dementia in a representative sample of older English adults.
We studied 6582 participants from the English Longitudinal Study of Ageing (ELSA) who were aged more than or equal to 50 years and were dementia-free at baseline, that being either wave 1 (2002–2003) for study members who started at wave 1, or at either wave 2 (2004–2005) or 4 (2008–2009) for those who began the study as refreshment samples. Body mass index (BMI) was measured at baseline and categorized into normal weight (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2) and obese (more than or equal to 30 kg/m2). Central obesity was defined as a waist circumference (WC) more than 88 cm for women and over 102 cm for men. Cumulative incidence of dementia was ascertained based on physician-diagnosed dementia, an overall score more than 3.38 on the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) and Hospital Episodes Statistics (HES) data at every ELSA wave from baseline until wave 8 (2016–2017). Cox proportional hazards models were used to assess the association between baseline BMI levels or abdominal obesity in relation to dementia incidence during the mean follow-up period of 11 years.
From the overall sample, 6.9% (n equal to 453) of participants developed dementia during the follow-up period of maximum 15 years (2002–2017). Compared with participants with normal weight, those who were obese at baseline had an elevated risk of dementia incidence independent of sex, baseline age, apolipoprotein E-ε4 (APOE-ε4), education, physical activity, smoking and marital status. The relationship was slightly accentuated after additionally controlling for hypertension and diabetes. Women with central obesity had a 39% greater risk of dementia compared with non-central obese women . When compared with a normal BMI and WC group, the obese and high WC group had 28 per cent higher risk of dementia.
Our results suggest that having an increased body weight or abdominal obesity are associated with increased dementia incidence. These findings have significant implications for dementia prevention and overall public health.
Primary paper is available in the International Journal of Epidemiology
The findings of this study are highlighted in a recent NIHR Signal Being overweight is linked with an increased risk of dementia in new research