Duke 2008 | ASHE | Equity and Efficiency in Health and Healthcare

Background: The prevalence of Alzheimer's disease (AD) is drastically increasing as the population ages, affecting 5% of people over age 65 and 50% of people over age 85. At present, there is no known effective treatment for dementia but the progression to AD can be slowed by addressing modifiable lifestyle factors in the early or pre-clinical stage of the disease. Understanding how older adults perceive their risk and how the risk perception shapes their health care decisions regarding AD is necessary for designing and implementing intervention or policy aimed to promote preventive behavior or early assessment. Objectives: We examined whether objective risk factors of AD explain perceived risk of AD, and whether preference for prevention of AD reflect objective risk factors in addition to perceived risk of AD. Method: Data came from a random subsample of Health and Retirement Study participants who were 50 years or older in 2002 (N=740). Perceived risk is the probability that a respondent would develop AD in the next 10 years. Preference for AD prevention was measured with five questions asking willingness to pay (WTP) for a hypothetical drug 100% effective preventing AD; based on these questions, we created a six-category ordinal variable which represents levels of preference for AD prevention (>$1000, >$250, >$100, >$25, and >$5 per month). We used linear regressions for the perceived risk and ordered probit regressions for the prevention preference. Based on literature, we identified established risk factors of AD, including age, memory functioning, cardiovascular disease, and physical activity. Variables indicating ability to pay, general health status, and relevant demographic factors were also controlled for. Findings: The average perceived risk was 31 (percent chance of developing AD) and the most frequent WTP category was $100-$250 per month. Better memory, either objective or self-rated, and physical activity predicted decreased perceived risk. However, age and cardiovascular diseases were not significant. Strikingly, Blacks had 10 points lower perceived risk than whites. For the prevention preference, perceived risk was significant predictor, but none of objective risk factors was. Paradoxically, the better mental status or functional status the higher the prevention preference was, and similarly, the wealthier the higher preference for prevention was.

Implications: Individuals do not appear to formulate their own risk of AD based on objective risk factors of AD. Similarly, perceived risk, but not objective needs, may influence decisions on AD prevention. These altogether suggest a potential discrepancy between need and demand for AD preventive care, and thus, public resources for AD may be consumed largely by those who are at low risk. Sources of the discrepancy should be better understood to help educate people who are at higher risk of AD. Differences in risk perception by race/ethnicity should be appropriately addressed in policy and practice.