Obesity and central obesity as risk factors for incident dementia and its subtypes: a systematic review and meta-analysis

Obes Rev. 2008 May;9(3):204-18. doi: 10.1111/j.1467-789X.2008.00473.x. Epub 2008 Mar 6.


While dementia affects 6-10% of persons 65 years or older, industrialized countries have witnessed an alarming rise in obesity. However, obesity's influence on dementia remains poorly understood. We conducted a systematic review and meta-analysis. PUBMED search (1995-2007) resulted in 10 relevant prospective cohort studies of older adults (40-80 years at baseline) with end points being dementia and predictors including adiposity measures, such as body mass index (BMI) and waist circumference (WC). There was a significant U-shaped association between BMI and dementia (P = 0.034), with dementia risk increased for obesity and underweight. Pooled odds ratios (OR) and 95% confidence intervals (CI) for underweight, overweight and obesity compared with normal weight in relation to incident dementia were: 1.36 (1.07, 1.73), 0.88 (0.60, 1.27) and 1.42 (0.93, 2.18) respectively. Pooled ORs and 95% CI for obesity and incident Alzheimer's disease (AD) and vascular dementia were 1.80 (1.00, 3.29) vs. 1.73 (0.47, 6.31) and were stronger in studies with long follow-up (>10 years) and young baseline age (<60 years). Weight gain and high WC or skin-fold thickness increased risks of dementia in all included studies. The meta-analysis shows a moderate association between obesity and the risks for dementia and AD. Future studies are needed to understand optimal weight and biological mechanisms.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adipose Tissue
  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / epidemiology
  • Body Mass Index
  • Cohort Studies
  • Comorbidity
  • Dementia / epidemiology*
  • Humans
  • Incidence
  • Middle Aged
  • Obesity / epidemiology*
  • Odds Ratio
  • Prospective Studies
  • Risk Factors
  • Skinfold Thickness