The study, among the findings presented last week at the first Alzheimer’s Assn. International Conference on Prevention of Dementia, examined lifestyle factors of more than 100 pairs of identical twins. All of the pairs included one twin who had developed dementia and one who hadn’t. Because identical twins are genetically indistinguishable, the study involved only risk factors that could be modified to help protect against dementia.
Twins who had severe periodontal disease before they were 35 years old had a fivefold increase in risk of developing Alzheimer’s disease, the researchers found.