SAN FRANCISCO — Angina pectoris was associated with an approximately 50% increased risk for Alzheimer's disease or dementia within 15 years in a longitudinal study of 20,146 Swedish twins.
Ulrika K. Eriksson and her associates analyzed data from the Swedish Twin Registry and found a 56% increased risk for hospitalization or death resulting from Alzheimer's disease in people with a history of angina pectoris, compared with those without angina pectoris, they reported in a poster presentation at the annual meeting of the Gerontological Society of America. The risk for hospitalization or death from dementia was 53% higher in those with angina pectoris, compared with the controls, said Ms. Eriksson, a doctoral student in medical epidemiology and biostatistics at Karolinska Institutet, Stockholm.
The increased risk was more prominent in women. Women with angina pectoris had a significant 64% increased risk for Alzheimer's disease, compared with women without angina pectoris, but an increased risk for dementia was not significant. Increased risks for Alzheimer's disease and dementia in men with angina pectoris also were not statistically significant.
In previous studies, some risk factors for coronary artery disease have been associated with increased risk for future dementia, she noted.
The Swedish Twin Registry is an ongoing database of twins born in 1903, 1925, and 1936. Questionnaires mailed to the twins in 1963, 1967, and 1973 identified 8% as having a history of angina. The investigators linked two population-based registries to identify hospitalizations or deaths primarily caused by dementia from 1974 to 2001. In all, 5% of the cohort was diagnosed with dementia, 68% of which was Alzheimer's disease.
The increased risk for Alzheimer's disease or dementia in people with angina was significant in the first 15 years (1974–1989) but not for the entire 28-year follow-up period. The increased risk in women with angina also occurred in the first 15 years of follow-up only. These differences over time may be a result of survival bias, the investigators said.
The results were adjusted for age, smoking, education, and BMI. By matching twin pairs in co-twin controls, the investigators adjusted for early life factors and genetic confounding.