The association between adherence to cancer screening programs and health literacy. A systematic review and meta-analysis

The effectiveness of a cancer screening program relies on its adherence rate. Health literacy (HL) has been investigated among the factors that could influence such participation, but the findings are not always consistent. The aim of this meta-analysis was to summarize the evidence between having an adequate level of HL (AHL) and adherence to cancer screening programs. PubMed, Scopus, and Web of Science were searched. Cross-sectional studies, conducted in any country, that provided raw data, unadjusted or adjusted odds ratio (OR) on the associations of interest were included. The quality of the studies was assessed with the Newcastle-Ottawa Scale. Inverse-variance random effects methods were used to produce pooled ORs and their associated confidence interval (CI) stratified by time interval (e.g., undergoing screening in the last period, or at least once during lifetime) for each cancer type, considering unadjusted and adjusted estimates separately. A sensitivity analysis was performed for those studies providing more estimates. Overall, 15 articles of average-to-good quality were pooled. We found a significant association between AHL and higher screening participation for breast, cervical and colorectal cancer, independently of other factors, both overall (N = 7, aOR = 1.73; 95% CI: 1.27–2.36; N = 3, aOR = 1.64; 95% CI: 1.30–2.09; and N = 5, aOR = 1.25, 95% CI: 1.12–1.39, respectively) and in most time-stratified analyses. The sensitivity analyses confirmed these results. Health literacy seems to be critical for an effective cancer prevention. Given the high prevalence of illiterate people across the world, a long-term action plan is needed.