Incidence of AD may decline in the early 90s for men, later for women: The Cache County study.

OBJECTIVES: To characterize the incidence of AD among the elderly population of Cache County, UT, noted for its longevity and high response rates; to explore sex differences; and to examine whether AD incidence plateaus or declines in extreme old age. METHODS: Using a multistage screening process in 1998 and 1999, and re-examining 122 individuals who had been identified 3 years earlier as cognitively compromised but not demented, the authors found 185 individuals with incident dementia (123 with AD) among 3,308 participants who contributed 10,541 person-years of observation. Adjusting for nonresponse and screening sensitivity, the authors estimated the incidence of dementia and of AD for men and women in 3-year age intervals. Multivariate discrete time survival analysis was used to examine influences of age, sex, education, and genotype at APOE, as well as interactions of these factors. RESULTS: The incidence of both dementia and AD increased almost exponentially until ages 85 to 90, but appeared to decline after age 93 for men and 97 for women. A statistical interaction between age and the presence of two APOE-epsilon 4 alleles indicated acceleration in onset of AD with this genotype; the interaction of age and one epsilon 4 suggested more modest acceleration. A statistical interaction of sex and age indicated greater incidence of AD in women than in men after age 85. CONCLUSIONS: The incidence of AD in the Cache County population increased with advancing age, but then peaked and declined among the extremely old. The presence of APOE-epsilon 4 alleles accelerated onset of AD, but did not appreciably alter lifetime incidence apparent over a span of 100 years.

Socioeconomic status and health at midlife. A comparison of educational attainment with occupation-based indicators.

PURPOSE: Educational attainment is a widely used indicator of socioeconomic status (SES) in health studies. However, little is known about its relationship to health relative to measures of occupational standing. This study directly compared education with an array of occupational measures-including social class-in relation to health. METHODS: The Wisconsin Longitudinal Study collected self-reported health data from a sample of 6875 Wisconsin high school graduates aged 53-54 in 1992-1993. The analysis regressed overall health, physical symptoms, and medical conditions on socioeconomic indicators, using logistic regression. RESULTS: Associations of health outcomes with occupational standing net of educational attainment are mainly weak or non-existent. "Occupational education" is the only indicator to have a strong association with health net of education in analyses of both men and women. CONCLUSIONS: While occupation is sometimes an important mechanism linking education and health, control for the overall relation between SES and health may not require measures of occupational standing when educational attainment is measured well. However, the present findings are limited to non-Hispanic white high school graduates from Wisconsin at ages 53-54.