Clare J Wotton1, Michael J Goldacre1. 1. Unit of Health-Care Epidemiology, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
Abstract
OBJECTIVE: Obesity in mid-life may increase the risk of subsequent dementia. Our objective was to study this risk, focusing on differences by age at the time of recording of obesity, in a large defined population. METHODS: A record linkage cohort study was undertaken using national administrative statistical data on hospital care and mortality in England, 1999-2011. A cohort of 451 232 people with obesity and a control cohort was constructed. Results were expressed as age-specific risk ratios comparing the two cohorts. RESULTS: The risk ratio for dementia in people admitted to hospital with obesity aged 30-39 years was significantly increased at 3.5 (95% CI 2.1 to 5.6). Risk ratios for dementia then gradually reduced with increasing age at obesity from 1.7 (95% CI 1.3 to 2.2) in people aged 40-49 years when obesity was first recorded to 1.4 (95% CI 1.3 to 1.5) in those aged 60-69 years. People in their 70s when obesity was recorded had neither an increased nor a reduced risk of subsequent dementia at 0.97 (95% CI 0.93 to 1.01), and those aged ≥80 years had a reduced risk of subsequent dementia at 0.78 (95% CI 0.74 to 0.82). CONCLUSIONS: Obesity is associated with a risk of dementia in a way that appears to vary with age. Investigation of the mechanisms mediating this association might give insights into the biology of both conditions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
OBJECTIVE:Obesity in mid-life may increase the risk of subsequent dementia. Our objective was to study this risk, focusing on differences by age at the time of recording of obesity, in a large defined population. METHODS: A record linkage cohort study was undertaken using national administrative statistical data on hospital care and mortality in England, 1999-2011. A cohort of 451 232 people with obesity and a control cohort was constructed. Results were expressed as age-specific risk ratios comparing the two cohorts. RESULTS: The risk ratio for dementia in people admitted to hospital with obesity aged 30-39 years was significantly increased at 3.5 (95% CI 2.1 to 5.6). Risk ratios for dementia then gradually reduced with increasing age at obesity from 1.7 (95% CI 1.3 to 2.2) in people aged 40-49 years when obesity was first recorded to 1.4 (95% CI 1.3 to 1.5) in those aged 60-69 years. People in their 70s when obesity was recorded had neither an increased nor a reduced risk of subsequent dementia at 0.97 (95% CI 0.93 to 1.01), and those aged ≥80 years had a reduced risk of subsequent dementia at 0.78 (95% CI 0.74 to 0.82). CONCLUSIONS:Obesity is associated with a risk of dementia in a way that appears to vary with age. Investigation of the mechanisms mediating this association might give insights into the biology of both conditions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.