Mind the uncertainties – a cross-sectional study on perceptions of cancer risks for factors with inconclusive or limited evidence among the Swedish general public

Background Identifying environmental and lifestyle factors that increase the risk of cancer is a complex scientific endeavour, with the degree of certainty regarding carcinogenicity existing along a continuum. To make informed health decisions, the general public must be well informed, both about factors that increase and decrease cancer risk. However, misconceptions can easily gain a foothold in the public consciousness. This study aimed to examine perceptions of carcinogenicity in Sweden regarding factors where the scientific evidence is inconclusive or limited, in relation to demographic strata. Methods This cross-sectional study used a pre-existing data set with a randomly selected sample of 1520 participants (18–84 years old) recruited from a Swedish online panel. Statistical analyses utilized post-stratification weights to make the results representative for the general Swedish population. Weighted univariate tests and logistic regression models were used for examining associations between demographic groups and perceptions of carcinogenicity for twelve factors with inconclusive or limited evidence. Results Most participants perceived snus (76%), E-cigarettes (67.1%), food additives (63.0%), stress (50.7%), and burnt food (50.4%) as carcinogenic. Whilst no significant differences were observed regarding E-cigarettes, snus was more likely to be perceived as carcinogenic by older (adjusted odds ratio [AOR] 1.01; 95% confidence interval [CI] 1.00–1.02 per year older) and college/university educated (1.47; 1.09–2.00) participants, while it was less likely to be perceived as carcinogenic by males (0.66; 0.48–0.90) and high-income earners (0.62; 0.40–0.95 compared to low-income earners). Food additives were more often perceived as carcinogenic by older participants (AOR 1.02; 95% CI 1.01–1.03 per year older) and middle-income earners (1.47; 1.03–2.08 compared to low-income earners), while stress and burnt food were more likely to be perceived as carcinogenic by college/university educated (1.49; 1.15–1.91 and 1.54; 1.20–1.98, respectively) participants. Conclusions A large proportion of the Swedish general public endorses several unestablished cancer risk factors as carcinogenic. The heterogeneous awareness regarding different factors observed in this study illustrates how challenging it is for individuals to navigate the complex and nuanced scientific evidence regarding cancer risk factors. This highlights the importance of clear and transparent public health messaging.