Screening and diagnostic criteria also differ. Although ageing is by no means a causative factor in Alzheimer's disease, the disorder is clearly age-related. According to Alzheimer Europe, about one person in 20 over the age of 65 has the disease compared to the below-65 population, where the incidence is less than one person in 1,000. Despite a small percentage of apparently familial cases, heredity seems to play a minor role at best. The field of genomic research is one that holds great hope for unraveling the mysteries of the disease.
Gender appears to be a factor.
The risk is greater for men up to age 75, but rises for women in older age groups, in part because of women's greater longevity. A new study shows that women have a higher relative risk for dementia, particularly for Alzheimer's disease. Educational levels may play a role, although the reasons for this are not certain. According to the data, this may be particularly true for women. This finding may be related to socio-economic factors, diagnostic bias in neurological tests or may be a biological marker in some cases.