Low Health Literacy and Health Information Avoidance but Not Satisficing Help Explain "Don't Know" Responses to Questions Assessing Perceived Risk.

Background: People who say they don't know (DK) their disease risk are less likely to engage in protective behavior.

Purpose: This study examined possible mechanisms underlying not knowing one's risk for common diseases.

Methods: Participants were a nationally representative sample of 1005 members of a standing probability-based survey panel who answered questions about their comparative and absolute perceived risk for diabetes and colon cancer, health literacy, risk factor knowledge and health information avoidance, and beliefs about illness unpredictability. Survey satisficing was a composite assessment of not following survey instructions, nondifferentiation of responses, haphazard responding, and speeding. The primary outcomes were whether a person selected DK when asked absolute and comparative risk perception questions about diabetes or colon cancer. Base structural equation modeling path models with pathways from information avoidance and health literacy/knowledge to DK responding for each DK outcome were compared to models that also included pathways from satisficing or unpredictability beliefs.

Results: Base models contained significant indirect effects of health literacy (odds ratios [ORs] = 0.94 to 0.97, all P < 0.02) and avoidance (ORs = 1.05 to 1.15, all P < 0.01) on DK responding through risk factor knowledge and a direct effect of avoidance (ORs = 1.21 to 1.28, all P < 0.02). Adding the direct effect for satisficing to models resulted in poor fit (for all outcomes, residual mean square error estimates >0.17, all weighted root mean square residuals >3.2, all Comparative Fit Index <0.47, all Tucker-Lewis Index <0.49), indicating that satisficing was not associated with DK responding. Unpredictability was associated with not knowing one's diabetes risk (OR = 1.01, P < 0.01).

Limitations: The data were cross-sectional; therefore, directionality of the pathways cannot be assumed.

Conclusions: DK responders may need more health information, but it needs to be delivered differently. Interventions might include targeting messages for lower health literacy audiences and disrupting defensive avoidance of threatening health information.