Effective Message Elements for Disclosures About Chemicals in Cigarette Smoke

Identifying promising themes and messages for youth vaping prevention: A national study

Use of e-cigarettes and vapes among adolescents continues to be a major public health concern. Health communication efforts can discourage e-cigarette use among adolescents by influencing beliefs and behavior. However, to do so, studies need to identify the most promising themes and messages based on the latest evidence about the harms of e-cigarettes and vaping. Participants were a nationally representative sample of 1,603 US adolescents aged 13-17 years, recruited in the summer of 2022. Adolescents were randomly assigned to view 7 vaping prevention statements (one from each theme: nicotine addiction, chemical harms, health symptoms, mental health, organ effects, cosmetic effects, and monetary cost) and 1 control statement (vape litter theme) from a pool of 46 statements that were developed through a systematic process. Participants rated each statement on perceived message effectiveness (PME), awareness, and believability. Results of linear mixed models indicated that all vaping prevention themes out-performed control messages on PME, with chemical harms and organ effects having the largest effects, followed by nicotine addiction and then other themes. For most message themes, PME effects were stronger for youth susceptible to vaping compared to non-susceptible youth and users. Both awareness and believability predicted higher levels of PME. In secondary analyses, we found that statements specifying the target ("you") and longer statements were also rated higher on PME. Results suggests that the most potent vaping prevention messages for adolescents are those that focus on vape chemicals and the potential of vaping to damage organs and increase disease risk.

Effects of Modified Risk Tobacco Product Claims on Consumer Responses

INTRODUCTION

US tobacco manufacturers can seek authorization from the US Food and Drug Administration (FDA) to market products using modified risk tobacco product (MRTP) claims. To inform regulatory decisions, we examined the impact of MRTP claim specificity and content, including whether the claims produced halo effects (ie, inferring health benefits beyond what is stated).

AIMS AND METHODS

Participants were 3161 US adult cigarette smokers. Using a two (general vs. specific) × 2 (risk vs. exposure) plus independent control design, we randomized participants to view one message from these conditions: general risk claim (eg, "smoking-related diseases"), general exposure claim (eg, "chemicals in smoke"), specific risk claim (eg, "lung cancer"), specific exposure claim (eg, "arsenic"), or control. Claims described the benefits of completely switching from cigarettes to the heated tobacco product IQOS.

RESULTS

MRTP claims of any sort elicited a higher willingness to try IQOS relative to control (d = 0.09, p = .043). Claims also elicited lower perceived risk of disease and exposure to harmful chemicals for completely switching from cigarettes to IQOS (d = -0.32 and -0.31) and partially switching (d = -0.25 and d = -0.26; all p < .05). Relative to specific MRTP claims, general MRTP claims led to lower perceived risk and exposure for complete switching (d = -0.13 and d = -0.16) and partial switching (d = -0.14 and d = -0.12; all p < .05). Risk and exposure MRTP claims had similar effects (all p > .05).

DISCUSSION

MRTP claims led to lower perceived risk and exposure, and higher willingness to try IQOS. General claims elicited larger effects than specific claims. MRTP claims also promoted unintended halo effects (eg, lower perceived risk of disease and chemical exposure for partial switching).

IMPLICATIONS

We found evidence that MRTP claims promoted health halo effects. In light of these findings, the FDA should require research on halo effects prior to authorization. Further, if an MRTP claim is authorized, FDA should require tobacco manufacturers to conduct post-market surveillance of how the claim affects consumer understanding, including partial switching perceived risk and exposure beliefs, as well as monitoring of dual-use behaviors.

The Effect of Repetition on the Perceived Truth of Tobacco-Related Health Misinformation Among U.S. Adults

As concerns about the effects of health misinformation rise, understanding why misbeliefs are accepted is increasingly important. People believe repeated statements more than novel statements, an effect known as truth by repetition, however this has not been examined in the context of tobacco information. Misbeliefs about tobacco are rampant and novel facts about tobacco are viewed as less believable. This paper examines how repetition of true and false tobacco statements affects truth perceptions. We recruited an online sample of 1,436 U.S. adults in May 2021. In an exposure phase, each participant rated their interest in 30 randomly selected statements about tobacco products and general knowledge trivia, half of them true and half false. The study had a two (tobacco product) by two (familiarity of statement claim) between-subjects design and a two (statement truth) by two (statement repetition) within-subjects design. During the testing phase participants rated the truthfulness of 24 repeated statements and 24 unseen statements. Repetition of true and false tobacco statements increased their subjective truth (diff=.20, p < .001), and the effect was larger for false claims compared to true claims. This underscores the importance of strategies to inoculate people against misinformation and calls for interventions that can stop the repetition of newly generated false claims.

Awareness of and reactions to health and environmental harms of red meat among parents in the United States

OBJECTIVE

Evidence of the health and environmental harms of red meat is growing, yet little is known about which harms may be most impactful to include in meat reduction messages. This study examined which harms consumers are most aware of and which most discourage them from wanting to eat red meat.

DESIGN

Within-subjects randomised experiment. Participants responded to questions about their awareness of, and perceived discouragement in response to, eight health and eight environmental harms of red meat presented in random order. Discouragement was assessed on a 1-to-5 Likert-type scale.

SETTING

Online survey.

PARTICIPANTS

544 US parents.

RESULTS

A minority of participants reported awareness that red meat contributes to health harms (ranging from 8 % awareness for prostate cancer to 28 % for heart disease) or environmental harms (ranging from 13 % for water shortages and deforestation to 22 % for climate change). Among specific harms, heart disease elicited the most discouragement (mean = 2·82 out of 5), followed by early death (mean = 2·79) and plants and animals going extinct (mean = 2·75), though most harms elicited similar discouragement (range of means, 2·60-2·82). In multivariable analyses, participants who were younger, identified as Black, identified as politically liberal, had higher general perceptions that red meat is bad for health and had higher usual red meat consumption reported being more discouraged from wanting to eat red meat in response to health and environmental harms (all P < 0·05).

CONCLUSIONS

Messages about a variety of health and environmental harms of red meat could inform consumers and motivate reductions in red meat consumption.

Designing more effective cigar warnings: an experiment among adult cigar smokers

INTRODUCTION

Little systematic evidence exists about the effectiveness of cigar warnings. This study examined the perceived message effectiveness (PME) of warning statements about different health consequences caused by cigars. PME is a validated self-report scale of how effectively a health message discourages smoking.

METHODS

We conducted an online study from April-May 2020 with adults in the United States who used cigars in the past 30 days (n=777). Participants were randomly assigned to view and rate PME (3 items, range 1 to 5) for 7 out of 37 text warning statements about different health consequences from cigar use. Linear mixed effects models evaluated the most effective warning characteristics (e.g., type of health consequence), controlling for repeated measures and participant demographics.

RESULTS

Analyses showed that health consequences about the cardiovascular system (B=0.38), mouth (B=0.40), other digestive (B=0.45), respiratory system (B=0.36), and early death (B=0.36) were associated with higher PME scores than reproductive health consequences (all p-values <0.001). Similar results were found for these health consequences compared to addiction (all p-values p<0.001). We also observed that awareness of the health consequence was associated with higher PME scores (B=0.19, p<0.001) and length of the warning message (number of characters) was associated with lower PME scores (B=-0.007, p=0.03). No differences were observed between cancer and non-cancer health consequences (p=0.27) or health consequences that used plain language vs. medical jargon (p=0.94).

CONCLUSIONS

Our study provides new evidence about the perceived effectiveness of different cigar health warning statements and identifies features that may strengthen statements.

IMPLICATIONS

Our study with cigar smokers from across the United States provides much-needed evidence concerning the perceived effectiveness of different cigar health warning statements and features that may strengthen such statements. Mandated cigar warnings in the United States could be strengthened by including health consequences that were perceived as more effective in our study (e.g., early death), using health consequences that participants were aware of, and using short warning statements.

Awareness of and reactions to the health harms of sugary drinks: An online study of U.S. parents

Evidence about the health problems associated with sugary drink consumption is well-established. However, little is known about which sugary drink health harms are most effective at changing consumers' behavior. We aimed to identify which harms people were aware of and most discouraged them from wanting to buy sugary drinks. Participants were a national convenience sample of diverse parents (n = 1,058), oversampled for Latino parents (48%). Participants rated a list of sugary drink-related health harms occurring in children (7 harms) and in adults (15 harms). Outcomes were awareness of each harm and how much each harm discouraged parents from wanting to purchase sugary drinks. Most participants were aware that sugary drinks contribute to tooth decay in children (75%) and weight gain in both children (73%) and adults (69%). Few participants were aware that sugary drinks contribute to adult infertility (16%), arthritis (18%), and gout (18%). All health harms were rated highly in terms of discouraging parents from wanting to buy sugary drinks (range: 3.59-4.11 on a 1-5 scale), with obesity, pre-diabetes, and tooth decay eliciting the highest discouragement ratings. Harm-induced discouragement was higher for participants who were aware of more health harms (B = 0.05, p < 0.0001), identified as female (B = 0.15 compared to male, p = 0.02), or had an annual household income of $50,000 or more (B = 0.16 compared to less than $50,000, p = 0.03). These findings suggest health messages focused on a variety of health harms could raise awareness and discourage sugary drink purchases.

Effect of Cigarette Constituent Messages With Engagement Text on Intention to Quit Smoking Among Adults Who Smoke Cigarettes: A Randomized Clinical Trial

IMPORTANCE

The US Food and Drug Administration (FDA) is required to communicate the risks of tobacco constituents to the public. Few studies have addressed how FDA media campaigns can effectively communicate about cigarette smoke constituents.

OBJECTIVE

To examine whether messages about cigarette smoke constituents are effective in reducing smoking intentions and behaviors among adults who smoke.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial enrolled participants who were aged between 18 and 65 years, were English speakers, were living in the United States, and who smoked at least 100 cigarettes during their lifetime and now smoked every day or some days. Participants received daily messages via email for 15 days. Participants were randomized to 1 of 2 message conditions or a control group and reported their previous-day smoking behaviors daily. Follow-up surveys were conducted on days 16 and 32. Data were collected from June 2017 to April 2018 and analyzed from April to September 2018.

INTERVENTIONS

The 3 groups were (1) constituent plus engagement messages (eg, "Cigarette smoke contains arsenic. This causes heart damage.") that included the FDA as the source and engagement text (eg, "Within 3 months of quitting, your heart and lungs work better. Ready to be tobacco free? You can quit. For free nicotine replacement, call 1-800-QUIT-NOW"); (2) constituent-only messages that did not list the FDA as the source or include engagement text; and (3) a control condition with messages about littering cigarette butts.

MAIN OUTCOMES AND MEASURES

The primary outcome was the change in quit intentions (range, 1-4, with higher scores indicating stronger intentions) from pretest to day 16. Secondary outcome measures included daily smoking behaviors and quit attempts.

RESULTS

A total of 789 participants (mean [SD] age, 43.4 [12.9] years; 483 [61.2%] women; 578 [73.3%] White; 717 [90.9%] non-Hispanic) were included in the study. The mean (SD) quit intention score was 2.5 (0.9) at pretest. Mean (SE) change in quit intention score from pretest to day 16 was 0.19 (0.07) points higher in the constituent plus engagement condition than in the control condition (P = .005) and 0.23 (0.07) points higher in the constituent-only condition compared with the control condition (P = .001). Participant reports of cigarettes smoked, forgone, and butted out were similar across study conditions at baseline and did not differ significantly at days 16 and 32 across study conditions. Viewing more messages was associated with an estimated decrease of 0.15 (SE, 0.01) cigarettes smoked per day per message viewed overall across conditions.

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the first longitudinal test of cigarette constituent campaign messages in a national sample of adults who currently smoke. Messages about cigarette smoke constituents, with or without engagement text and source information, increased participants' intentions to quit, lending support to FDA efforts to educate consumers about such constituents.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03339206.

Reactions to messages about smoking, vaping and COVID-19: two national experiments

Introduction

The pace and scale of the COVID-19 pandemic, coupled with ongoing efforts by health agencies to communicate harms, have created a pressing need for data to inform messaging about smoking, vaping, and COVID-19. We examined reactions to COVID-19 and traditional health harms messages discouraging smoking and vaping.

Methods

Participants were a national convenience sample of 810 US adults recruited online in May 2020. All participated in a smoking message experiment and a vaping message experiment, presented in a random order. In each experiment, participants viewed one message formatted as a Twitter post. The experiments adopted a 3 (traditional health harms of smoking or vaping: three harms, one harm, absent) × 2 (COVID-19 harms: one harm, absent) between-subjects design. Outcomes included perceived message effectiveness (primary) and constructs from the Tobacco Warnings Model (secondary: attention, negative affect, cognitive elaboration, social interactions).

Results

Smoking messages with traditional or COVID-19 harms elicited higher perceived effectiveness for discouraging smoking than control messages without these harms (all p <0.001). However, including both traditional and COVID-19 harms in smoking messages had no benefit beyond including either alone. Smoking messages affected Tobacco Warnings Model constructs and did not elicit more reactance than control messages. Smoking messages also elicited higher perceived effectiveness for discouraging vaping. Including traditional harms in messages about vaping elicited higher perceived effectiveness for discouraging vaping (p <0.05), but including COVID-19 harms did not.

Conclusions

Messages linking smoking with COVID-19 may hold promise for discouraging smoking and may have the added benefit of also discouraging vaping.

The Influence of Various Smoking Categories on The Risk of Gestational Hypertension and Pre-Eclampsia

The relationship between smoking and the risk of pregnancy-induced hypertension (PIH) is not clearly established. Therefore, we conducted an analysis of cigarette smoking in a Polish cohort of women, recruited in the first trimester of a single pregnancy in 2015–2016. We evaluated the women who subsequently developed PIH (n = 137) (gestational hypertension—GH (n = 113) and pre-eclampsia—PE (n = 24)), and the women who remained normotensive (n = 775). The diseases odds ratios (and 95% CI—confidence intervals) were calculated in a multivariate logistic regression. In the PIH cases (vs. normotensive women) we found more smokers (25.6% vs. 17.2%, p = 0.020) including smokers in the first trimester (14.6% vs. 4.8%, p < 0.001). The average number of cigarettes smoked daily per smokers in the first trimester was 11.2 (range 2–30), and the average number of years of smoking was 11.6 (range 2–25). The number of years of smoking was a stronger risk factor for GH and PE than the number of cigarettes/day. Compared to the women who have never smoked, smoking ever before pregnancy was associated with a higher GH risk (AOR = 1.68; p = 0.043), and with no effect on PE risk (OR = 0.97; p = 0.950). Smokers in the first trimester had a higher odds ratio of GH (AOR = 4.75; p < 0.001) and PE (OR = 2.60; p = 0.136). Quitting smoking before pregnancy (ex-smokers) was associated with a lower odds ratio of GH (AOR = 0.83; p = 0.596) and PE (OR = 0.33; p = 0.288). However, quitting smoking during pregnancy was associated with a higher risk of GH (AOR = 11.63; p < 0.0001) and PE (OR = 3.57; p = 0.238). After dissection of the cohort into pre-pregnancy body–mass index (BMI) categories, smoking in the first trimester was associated with the higher hypertension risk in underweight women (OR = 22.00, p = 0.024). Conclusions: The factors that increased the risk of GH and PE were smoking in the first trimester and (paradoxically and more strongly) smoking cessation during pregnancy. Our results suggest that women of childbearing potential should be encouraged to quit smoking before pregnancy.

Effects of positive-negative antismoking messages to quit smoking among male college students: A randomized field study

AIM

Based on the main concept of reasoned action theory, this study aimed to examine which of the attitude and subjective norms affect the intention of smoking cessation by using four types of antismoking messages: (1) positively and( 2) negatively stimulating one's attitude toward smoking cessation; and (3) positively and (4) negatively reflected subjective norms for second-hand smoking.

METHODS

We conducted a randomized field study in smoking areas in universities located in D city of South Korea. Two hundred and eighty-seven male students who smoke daily were recruited in the field and randomly divided into four experimental groups and one control group. The participants in each experimental group were asked to read attitude/positive, attitude/negative, norm/positive, and norm/negative message. The data of attitude, subjective norm, and intention to stop smoking were collected.

RESULTS

There were significant differences in the intention to quit smoking in attitude/negative messages (F = 4.311, p = .015) and norm/positive messages (F = 4.353, p = .014). The effects of subjective norm were greater than those of attitude (p < .001).

CONCLUSION

Emphasizing the positive subjective norm for smoking cessation among young smokers might be effective in persuading them to quit smoking.

An Eye Tracking Study of Anti-Smoking Messages on Toxic Chemicals in Cigarettes

The US Food and Drug Administration is tasked with communicating information to the public about the harmful chemicals in cigarette smoke. Our study used eye tracking method to test the effectiveness of messages about the harmful chemicals in cigarettes smoke among adult smokers. A sample size of 211 current cigarette smokers viewed four communication messages that included: Health effects of a chemical in cigarette smoke and an image depicting the health effect. The messages focused on arsenic, formaldehyde, uranium, and general health. Eye tracking recorded the length of time participants viewed the text and the image. After each message, the participants were asked about the messages' effectiveness in changing attitudes towards smoking. We analyzed the data using multilevel modeling, and of the 211 smokers, 59.7% were female, 36.5% were Black, and 21.3% had a high school degree or less. Compared to the general message, the messages about formaldehyde and uranium were more discouraging to smoking (p < 0.05). Messages about formaldehyde were more believable and made participants want to quit more than the general messages. Increasing message dose was significantly associated with discouraging participants from smoking and made participants want to quit (p < 0.05). Our findings suggest that anti-smoking messages, containing chemical information, can successfully increase negative attitudes toward smoking cigarettes and potentially encourage quitting.

UNC Perceived Message Effectiveness: Validation of a Brief Scale

BACKGROUND

Interventionists commonly identify promising messages for health communication efforts based on audience members' ratings of perceived message effectiveness (PME).

PURPOSE

We sought to validate a new PME measure that improved on existing scales by focusing on the behavior and respondent, being brief, and having strong psychometric properties.

METHODS

Participants were a national convenience sample of 999 adults and national probability samples of 1,692 adults and 869 adolescents recruited in 2015. Smokers and nonsmokers rated up to six brief messages about the chemicals in cigarette smoke on two PME scales. The first was the new three-item University of North Carolina (UNC) PME Scale that assessed effects perceptions. The second was an established six-item PME scale that assessed message perceptions. We examined the UNC PME Scale's psychometric properties and compared both scales using item factor analysis.

RESULTS

The UNC PME Scale measured the same construct across multiple chemical messages (all factor loadings ≥ 0.86). It exhibited high reliability (>0.85) over very low to moderate levels of PME (z = -2.5 to 0.2), a range that is useful for identifying more promising messages. Samples of adults and adolescents showed a similar pattern of results. As expected, the UNC PME Scale was strongly positively correlated with message perceptions (r = .84). It also exhibited strong psychometric properties among participants regardless of education, reactance, sex, and smoking status.

DISCUSSION

The UNC PME Scale reliably and validly measured PME among adults and adolescents from diverse groups. This brief scale may be used to efficiently evaluate candidate antismoking messages and may be suitable for adaptation to other health risk behaviors.

Impact of e-cigarette health warnings on motivation to vape and smoke

BACKGROUND

A prevailing hypothesis is that health warnings for electronic cigarettes (e-cigarettes) could drive people away from vaping and towards smoking cigarettes. We consider an alternative hypothesis that e-cigarette warnings discourage both vaping and smoking.

METHODS

Participants were a national convenience sample of 2218 US adults who used e-cigarettes, cigarettes or both. In August 2018, we randomised participants to one of three warning types (control text about littering, text-only e-cigarette warning or pictorial e-cigarette warning). We further randomised participants viewing e-cigarette warnings to one of three topics (nicotine addiction, health hazards of use, or both health hazards and harms of use). The preregistered primary outcome was intentions to quit vaping among e-cigarette users. Secondary outcomes included interest in smoking and Tobacco Warnings Model constructs: attention, negative affect, anticipated social interactions and cognitive elaboration.

RESULTS

Text warnings elicited higher intentions to quit vaping than control among e-cigarette users (d=0.44, p<0.001), and pictorial warnings elicited still higher intentions to quit vaping than text (d=0.12, p<0.05). Text warnings elicited lower interest in smoking compared with control among smokers (p<0.05); warnings had no other effects on interest in smoking among smokers or non-smokers. Text warnings about health hazards elicited higher intentions to quit vaping than nicotine addiction warnings. E-cigarette warnings also increased Tobacco Warnings Model constructs.

DISCUSSION

E-cigarette health warnings may motivate users to quit vaping and discourage smoking. The most promising warnings include health hazards (other than nicotine addiction) and imagery. We found no support for the hypothesis that e-cigarette warnings could encourage smoking cigarettes.

Do Smokers Recall Source or Quitline on Cigarette Constituent Messages?

OBJECTIVES

The Food and Drug Administration (FDA) is required under the Family Smoking Prevention and Tobacco Control Act to communicate the risks of tobacco use to the public. Little research exists about methods to communicate the constituents of tobacco in a media campaign. This research examines specific strategies to increase effectiveness of a media campaign for cigarette smoking adults about tobacco constituents by including engagement text about smoking cessation and FDA as the source of the campaign.

METHODS

In an eye tracking study of 211 current cigarette smokers, participants randomly viewed 4 cigarette constituent messages that varied engagement text for quitting (benefits of quitting and quitline number, presence, absence) and by FDA source (presence, absence). After the eye tracking session, participants were asked about recall of the national quitline number and the source of message.

RESULTS

Participants in conditions with engagement text were significantly more likely than those in the no engagement conditions to recall the national quitline number. Few participants saw or recalled the FDA source.

CONCLUSIONS

Engagement text for smoking cessation on constituent communication campaign messages significantly increases recall of the quitline, an important resource for smokers.

Increasing Effectiveness of Messages about Chemicals in Cigarette Smoke

OBJECTIVES

Federal law requires informing the public on toxic chemicals in cigarette smoke. We sought the public's advice about communicating information about these chemicals.

METHODS

Adolescents, young adults, and adults (N = 59), including smokers and non-smokers, participated in 9 focus groups that discussed inclusion of messages about toxic chemicals on cigarette packs, in media campaigns, and on a website. We transcribed, coded, and analyzed focus group audio-recordings.

RESULTS

Participants had 3 suggestions for message content to increase the impact of messages about cigarette smoke chemicals. First, they wanted to see messages rotated more frequently to increase message novelty. Second, they recommended using stories and pictures to help connect people to the abstract idea of chemicals in smoke. Third, they cautioned against making messages that might seem overblown and could appeal to the rebellious nature of adolescents. Some participants mentioned that chemical information on a website might discourage people from smoking; others mentioned that people might use it to choose which brand to smoke.

CONCLUSIONS

Legislation provides the impetus to design new chemical disclosure messages for cigarette packs and other media. Our findings can help increase the impact of these messages.

Cigarette pack messages about toxic chemicals: a randomised clinical trial

Background

The USA can require tobacco companies to disclose information about harmful and potentially harmful chemicals in cigarette smoke, but the impact of these messages is uncertain. We sought to assess the effect of placing messages about toxic chemicals on smokers’ cigarette packs.

Methods

Participants were 719 adult cigarette smokers from California, USA, recruited from September 2016 through March 2017. We randomly assigned smokers to receive either factual messages about chemicals in cigarette smoke and their health harms (intervention) or messages about not littering cigarette butts (control) on the side of their cigarette packs for 3 weeks. The primary trial outcome was intention to quit smoking.

Results

In intent-to-treat analyses, smokers whose packs had chemical messages did not have higher intentions to quit smoking at the end of the trial than those whose packs had control messages (P=0.56). Compared with control messages, chemical messages led to higher awareness of the chemicals (28% vs 15%, P<0.001) and health harms (60% vs 52%, P=0.02) featured in the messages. In addition, chemical messages led to greater negative affect, thinking about the chemicals in cigarettes and the harms of smoking, conversations about the messages and forgoing a cigarette (all P<0.05).

Discussion

Chemical messages on cigarette packs did not lead to higher intentions to quit among smokers in our trial. However, chemical messages informed smokers of chemicals in cigarettes and harms of smoking, which directly supports their implementation and would be critical to defending the messages against cigarette company legal challenges.

Trial registration number

NCT02785484.

Identifying principles for effective messages about chemicals in cigarette smoke

US law requires the Food and Drug Administration (FDA) to disclose information on harmful and potentially harmful chemicals in cigarette smoke (i.e., constituents) to the public. To inform this effort, we sought to identify principles for creating constituent messages that effectively discourage smoking. Participants were an online convenience sample of 1148 US smokers ages 18+. We developed a library of 76 messages about constituents only and constituents plus contextualizing information (i.e., toxic products that also contain the chemical, health effects, or both). We randomized smokers to receive 1 message from each of 7 message panels in a mixed between-/within-subjects experiment. Participants rated each message on perceived message effectiveness. Results indicated that smokers perceived messages about arsenic, formaldehyde, lead, uranium, and ammonia as more effective than messages about nitrosamines. Messages that contained information on toxic products, health effects, or both received higher effectiveness ratings than constituent-only messages. Among constituent-only messages, those that referenced multiple constituents received higher effectiveness ratings than those with fewer constituents. We conclude that chemical messages may have more impact if they pair known constituents with toxic product or health effect information. These message principles can be used to inform studies examining the impact of constituent messages on smoking beliefs and behavior.