Obesity is associated with a higher risk of dementia up to 15 years later, finds a new UK study suggesting that weight management could play a significant role in reducing risk.
The findings, published in the International Journal of Epidemiology, found that people who are obese (body mass index [BMI] ≥30 kg/m2) in late adulthood face a 31 per cent increased risk of dementia than those whose BMI is within the 'normal' (BMI, 18.5-24.9 kg/m2) range. The risk may be particularly high for women.
Researchers studied 6582 participants from the English Longitudinal Study of Ageing who were aged ≥50 years and were dementia free.
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. Three different sources were used to ascertain dementia: doctor diagnosis, informant reports and hospital episode statistics.
From the overall sample, 6.9 per cent (n=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 (HR, 1.34; 95% CI, 1.07-1.61) independent of sex, baseline age, apolipoprotein E-ε4, education, physical activity, smoking and marital status. The relationship was slightly accentuated after additionally controlling for hypertension and diabetes (HR, 1.31; 95% CI, 1.03-1.59).
Women with central obesity had a 39 per cent greater risk of dementia compared with non-central obese women (HR, 1.39; 95% CI, 1.12-1.66). When compared with a normal BMI and waist circumference group, the obese and high waist circumference group had 28 per cent (HR, 1.28; 95% CI, 1.03–1.53) higher risk of dementia.
The findings have significant implications for dementia prevention and overall public health, said the study authors.