Education-based disparities in knowledge of novel health risks: The case of knowledge gaps in HIV risk perceptions.

OBJECTIVE: Risk perception is a key determinant of preventive health behaviour, but when asked, some individuals indicate they do not know their health risk. Low education is associated with both lack of knowledge about health risk and with the persistence and exacerbation of gaps in knowledge about health issues. This study uses the context of an emerging infectious disease threat to explore the hypothesis that the education-don't know risk relation results from differences in knowledge about the health issue of interest. Specifically, we examine whether patterns of change over time follow theoretical predictions that disparities in risk knowledge would increase over time in less educated sectors of the population (knowledge gap hypothesis).

DESIGN: Secondary analysis of population-representative behavioural surveillance survey.

METHOD: We analysed data from the 1993 to 2000 Behavior Risk Factor Surveillance System surveys, which measured education and perceived HIV/AIDS risk in a population sample collected separately in each survey year; don't know responses were coded.

RESULTS: In each year, individuals with higher education were less likely to respond don't know. The absolute prevalence of don't know responding dropped over time; nonetheless, there was an increase over time in the magnitude of the pattern of lower education being associated with greater don't know responding.

CONCLUSIONS: We found support for the knowledge gap hypothesis. Over time, populations with greater education gained more knowledge about their HIV risk than populations with lower education. Results highlight the need to carefully consider health communication strategies to reach and address those individuals with low education and health knowledge. Statement of contribution What is already known on this subject? A meaningful potion of the population answers 'don't know' when asked to report their risk for health problems, indicating a lack of risk perception in the domain. Previous studies have shown that level of education is associated with don't know responding - those with lower educational attainment are more likely to respond don't know. The education-don't know responding relation suggests that lack of health information and health domain knowledge might be a factor in lacking risk perception, but this mechanism has not been previously tested. What does this study add? Patterns of changes in don't know responding over time as population-level knowledge of a health risk increase are consistent with the health information/health knowledge hypothesis outlined above. As population knowledge of HIV/AIDS risk in the United States increased over time (indicated by declining overall rates of don't know responses), the relation of education level to don't know responding actually became stronger. The pattern of change over time is the classic 'knowledge gap hypothesis' pattern, which has not been previously demonstrated for knowledge of personal health risk. The knowledge gap response pattern supports the health information/health knowledge hypothesis.