APOE genotype and the risk of dementia in the oldest-old: The Monzino 80-plus study

Abstract

Background: The risks, prevention and epidemiology of Alzheimer’s disease continue to remain uncertain despite extensive research. A few modifiable risk and preventive factors, such as low education, obesity, smoking, physical inactivity, and certain hormone therapies, have been reported from epidemiological studies. However, many studies have been limited by methodological quality and relatively small sample sizes, typically involving up to a few hundred Alzheimer’s disease cases and a few thousand participants. Studies from large-scale population-based cohorts with extensive exposure assessment and sufficiently long followup are critically needed. We describe the California Teachers Study cohort, established in 1995 primarily for breast cancer research, as a developing resource for large-scale etiologic Alzheimer’s disease research. Methods: The California Teachers Study consists of 133,479 women who have provided extensive exposure data over their life course including most putative risk factors for Alzheimer’s disease. Four waves of questionnaires have been sent since 1995. In the year 2000, we included neuropsychological test items that focused on visuospatial and language function. Results: Active and retired California public school professionals provided information on environmental and lifestyle factors that may be important for Alzheimer’s disease risk, including obesity, physical and social activity, medical history, medications, hormone use, diet, and demographic factors. In 2000-2001, w78,000 participants completeda clock drawing, cube drawing, and picture description task. Of these, w35,000 were 70 years or older in 2010. Assessment of Alzheimer’s disease in the cohort can be done by database linkage to California statewide hos pitalization data, which includes diagnoses after hospitalization, emergency department visits, and outpatient surgery. Conclusions:Large cohorts are needed in order to pursue risk and prevention research in Alzheimer’s disease, as recommended by the 2010 NIH State-ofthe-Science expert consensus conference. The California Teachers Study provides extensive high quality information on mostpotential environmental and lifestyle risk and protective factors, and represents a robust cohort for epidemiologic research, as a resource to conduct timely analyses using accrued cases, and for prospective outcomes research in Alzheimer’s disease.