Abstract
INTRODUCTION: Tobacco industry studies on consumers' perceptions of modified risk claims (MRCs) often had important omissions (eg, no control group, not investigating whether consumers understand what 'switching completely' means). This study examined the effects of IQOS MRCs on risk perceptions and behavioural intentions. METHOD: Based on tobacco companies' MRCs, we manipulated three MRC language features: explanation about 'switching completely' (absent vs present), number of diseases (single vs multiple) and language certainty (hypothetical vs certain). In an online experiment, we randomised 1523 US adult current smokers and 1391 young adult non-smokers to 1 of 9 conditions following a 2×2×2+1 control design. People reported their comprehension of 'switching completely', IQOS risk perceptions and behavioural intentions after message exposure. RESULTS: More smokers exposed to MRCs that included an explanation about 'switching completely' (22.2%) (vs explanation absent (11.2%) and control (10.7%)) mentioned that 'switching completely' meant smoking 0 cigarettes. Compared with the control, several MRCs (eg, certain language) produced lower perceived risk of IQOS, including for diseases not mentioned in the MRCs. MRCs using certain and hypothetical language did not differ on any outcomes. MRCs highlighting reduced risk for a single disease and multiple diseases did not differ on any outcomes. MRCs did not influence behavioural intentions. CONCLUSION: The Food and Drug Administration should ensure that consumers understand what 'switching completely' means in an MRC and recognize that some language features may mislead consumers into believing that a product reduces the risk of diseases not mentioned in an MRC.