Risk factors for late-onset Alzheimer's disease: a population-based, case-control study

Our current knowledge of risk factors for Alzheimer's disease is limited and primarily addresses early-onset disease. This study aimed to determine the risk factors for late-onset Alzheimer's disease using a case-control approach. Ninety-eight cases and 216 controls were gathered from an ongoing population survey on aging and dementia in Stockholm (the Kungsholmen Project). We found a high relative risk (3.2; 95% confidence interval, 1.8-5.7) with the presence of at least one first-degree relative affected by dementia. Among all the other risk factors, alcohol abuse (relative risk, 4.4; 95% confidence interval, 1.4-13.8) and manual work (relative risk for men of 5.3; 95% confidence interval, 1.1-25.5) emerged as positively associated. No clear association was found with a family history of Parkinson disease, advanced parental age at index delivery, season of birth, or previous head trauma. In conclusion, our data suggest that the main risk factor for late-onset Alzheimer's disease is a family history of dementia, as has been previously reported for early-onset disease. Moreover, alcohol abuse and occupational exposure might play a specific role for this form of the disease.