Preliminary Scientific Evaluation of the Possible Public Health Effects of Menthol Versus Nonmenthol Cigarettes: Executive Summary
Menthol is widely used in consumer and medicinal products and has long been used in cigarettes, often as a flavor-characterizing additive. In medical products, menthol is regulated as a drug with restrictions on allowable doses and use. There are no product standards for menthol when used in cigarettes.
Approximately one-fourth of all cigarettes sold in the United States are menthol (Giovino, 2004). The vast majority (88%) of adult smokers in the United States start to smoke before age 18 (U.S. Department of Health and Human Services, 2012). Thus, youth and young adulthood appear to be a critical age-span for initiation of cigarette smoking, and research suggests that menthol cigarettes may have an impact on initiation rates that differ from nonmenthol cigarettes. Further, the impact of menthol cigarettes on dependence, cessation, and health risks has been the topic of scientific inquiry and intense debate.
The Federal Food, Drug, and Cosmetic Act (FD&C Act) (Section 907 (e)) requires FDA's Tobacco Products Scientific Advisory Committee (TPSAC) to submit a report and recommendation to the Secretary of Health and Human Services (HHS) on the impact of the use of menthol in cigarettes on public health – including use among children, women, African Americans, Hispanics, and other racial or ethnic minorities – by March 23, 2011. In March 2010, TPSAC began its process of reviewing the available evidence as well as soliciting and receiving valuable input from researchers, tobacco industry representatives, consultants to the tobacco industry, representatives of the public health sector, and others. On July 21, 2011, TPSAC voted on its final report and recommendations on menthol, which concluded “removal of menthol cigarettes from the marketplace would benefit public health in the United States.” TPSAC noted that a variety of options were available for FDA to consider, and they made no specific suggestions for follow-up by FDA should the agency decide it should pursue this recommendation. In addition, the non-voting industry representatives of TPSAC submitted a separate document reflecting the industry perspective. That document acknowledged the inherent risks of all tobacco products, including those that have menthol as a characterizing flavor, and raised the possibility of countervailing effects, including potential risks of contraband menthol products, should a ban be imposed.
Independently, FDA has undertaken a thorough review of the available science concerning menthol cigarettes. To accomplish this task, FDA weighed the collective body of evidence for the impact of the use of menthol in cigarettes on public health. One of the first considerations in weighing the value of a particular study was the relevance of the information to the consumption of menthol cigarettes in the United States. Findings that were replicated in different studies, especially different types of studies, were given greater weight. FDA also considered the source of information, the type of study, and the quality of study methods and data. In drawing conclusions, more consideration was given to peer-reviewed studies, studies in humans, and studies that were appropriately powered and designed. In this process, FDA evaluated the peer- reviewed literature, industry submissions and other materials provided to TPSAC, and performed or commissioned additional an*lyses in an attempt to fill in and inform some of the gaps in the literature.
In making its a**essment, FDA used a “weight of scientific evidence” approach. Studies were evaluated to determine the strength of both negative and positive a**ociations of menthol in cigarettes with the impact under consideration. Scientific determinations fell into one of five categories, where x is the impact under consideration:
- The weight of evidence supports the conclusion that menthol in cigarettes is a**ociated with x
- The weight of evidence supports the conclusion that menthol in cigarettes is likely a**ociated with x
- The weight of evidence supports the conclusion that menthol in cigarettes is likely not a**ociated with x
- The weight of evidence supports the conclusion that menthol in cigarettes is not a**ociated with x
- The evidence is not sufficient to support a conclusion of an a**ociation of menthol in cigarettes with x
The purpose of this evaluation was to determine whether there are independent a**ociations between menthol in cigarettes and various outcomes of interest. In doing so, FDA evaluated the weight of evidence, taking into account potential threats to validity, such as bias or confounding, and whether the findings were generalizable to the U.S. population. The evaluations were not an attempt to establish causality. In reviewing the science of menthol smoking, FDA divided the scientific evidence into the following broad categories:
Smoke Chemistry and Nonclinical Toxicology: This review a**essed information on in vitro and in vivo studies, as well as studies that examined menthol alone or tobacco smoke from menthol cigarettes. Two particular areas of interest were the comparison of menthol to nonmenthol cigarettes and whether the addition of menthol impacted the presence and levels of harmful and potential harmful constituents in the smoke. The studies examined did not show increased toxicity in menthol cigarettes compared to the already-toxic nonmenthol cigarettes. From the available studies, the weight of evidence supports the conclusion that, from a nonclinical toxicity standpoint, menthol in cigarettes is not a**ociated with increased or decreased smoke toxicity.
Physiology: FDA considered information on menthol's effect on cooling, desensitization, anesthesia, and potential effect on nicotine and tobacco specific nitrosamines (TSNAs). FDA reviewed both in vitro and in vivo studies in human and animal models. In addition, an*lysts reviewed studies looking at the effect of menthol on smoking topography. There are some in vivo and in vitro studies that show menthol has cooling, desensitizating, and proan*lgesic effects. Menthol acts primarily through receptors on sensory nerves. From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is likely a**ociated with altered physiological responses to tobacco smoke.
Biomarkers: FDA an*lyzed studies measuring biomarkers of exposure in smokers of menthol and nonmenthol cigarettes. Biomarkers included levels of smoke constituents or their metabolites in exhaled air, saliva, blood, and urine such as expired carbon monoxide (CO) and plasma carboxyhemoglobin (COHb) for levels of CO exposure; cotinine (main nicotine metabolite) and other nicotine equivalents in plasma and urine for exposure to nicotine. Some studies show that smoking menthol cigarettes modulates the exposure or metabolism of nicotine and tobacco-specific nitrosamines (TSNAs), while other studies fail to show a significant a**ociation. From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is likely not a**ociated with increased or decreased levels of biomarkers of exposure.
Patterns of Use: FDA reviewed scientific literature focusing on the general trends and patterns in menthol smoking. Articles reporting data on national estimates or very large representative populations were given highest priority in order to draw estimations of patterns of use that would be applicable and generalizable for the U.S. population overall. Data support that a majority of African American smokers smoke menthol cigarettes, but other minority groups are also more likely to smoke menthol cigarettes as compared to Whites. Further, younger populations have the highest rate of smoking menthol cigarettes, and female smokers are more likely to smoke menthol cigarettes than male smokers. Also, the use of menthol cigarettes is a**ociated with lower socioeconomic status (SES). From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is a**ociated with particular patterns of smoking.
Marketing and Consumer Perception of risk: FDA reviewed studies of brand preference, advertising receptivity, marketing strategies, and consumer perception of risk in an effort to determine what role, if any, marketing and consumer perception of risk play in the use of menthol cigarettes. Of particular interest was whether there is a stronger relationship between marketing and/or consumer perceptions and the use of menthol among subpopulations (e.g. youth, African Americans, Hispanics, women). The available data show that advertising is a strong driver of brand preference among adolescents and that it is likely that the standard marketing mix approach of price, promotion, product, and place has been used to drive menthol cigarette preference among the urban African American community. From the available studies, the weight of evidence supports the conclusion that, like nonmenthol cigarettes, the marketing of menthol cigarettes is a**ociated with brand preference. The marketing of menthol cigarettes is a**ociated with menthol brand preference among adolescents and the African American community. Given the limited data reviewed and mixed results reported, the weight of evidence is not sufficient to support a conclusion that consumer perceptions are a**ociated with the use of menthol cigarettes.
Initiation and Progression to Regular Use: FDA a**essed data on the possible impact of menthol cigarettes on initiation and progress to regular use of cigarette smoking with a particular focus on smoking behavior by youth and young adults. Included in the an*lysis were studies looking at differences in prevalence rates, age of first cigarette, and progression to regular smoking. Data show that newer smokers prefer menthol at levels substantially above that of the general population, with an inverse correlation between age and menthol preference that reaches a plateau in adulthood. From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is likely a**ociated with increased initiation and progression to regular of cigarette smoking.
Dependence: FDA reviewed studies utilizing a variety of measures of nicotine dependence and/or craving. This included studies measuring: time to first cigarette (TTFC), cigarettes per day (cpd), the f*gerström Test for Nicotine Dependence (FTND), and craving.
Night waking to smoke was also included since it is emerging as a reliable indicator of strength of dependence. Data are included on other scales of nicotine dependence and craving if there were direct menthol versus nonmenthol a**essments. There were consistent findings that menthol smokers are more likely to smoke their first cigarette within five minutes of waking. From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is likely a**ociated with increased dependence.
Cessation: FDA an*lyzed studies addressing questions of whether menthol smokers were differentially successful in smoking cessation. These included cross-sectional studies, community-based or population-based prospective cohort studies, and clinical trial cessation studies. None of the studies were specifically designed to prospectively evaluate the effect of menthol on cessation. Several of the studies that failed to find an a**ociation between menthol smoking and cessation may have “over-adjusted” their an*lyses by controlling for the level of dependence. In the reviewed studies, menthol smokers, especially African American menthol smokers, were less likely to successfully stop smoking than their nonmenthol smoking counterparts. This is consistent with the observation that menthol smokers appear to be more nicotine dependent than nonmenthol smokers which can be an important factor in smoking cessation success. From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is likely a**ociated with reduced success in smoking cessation, especially among African American menthol smokers.
Disease Risk: FDA an*lyzed studies that addressed the impact of smoking menthol cigarettes on disease risk as compared to those risks posed by smoking nonmenthol cigarettes. Studies investigating impact on lung cancer, non-lung smoking-related cancers (esophageal cancer, oropharyngeal cancer), cardiovascular disease, and respiratory outcomes in addition to one study that evaluated health wellness and health conditions such as body ma** index (BMI) and emergency room visits were reviewed. No studies found an increased risk of cancer or non- cancer diseases in menthol smokers compared to nonmenthol smokers. From the available
studies, the weight of evidence supports the conclusion that menthol in cigarettes is not a**ociated with an increase in disease risk to the user compared to non-menthol cigarette smokers.
Summary of Evidence
The impact of cigarette smoking upon public health is indisputable. More than 400,000 d**hs per year in the United States are caused by tobacco use. Consistent patterns have emerged as a result of FDA's evaluation of the scientific evidence relevant to the impact of menthol tobacco products on public health. While there is little evidence to suggest that menthol cigarettes are more or less toxic or contribute to more disease risk to the user than nonmenthol cigarettes, adequate data suggest that menthol use is likely a**ociated with increased smoking initiation by youth and young adults. Further, the data indicate that menthol in cigarettes is likely a**ociated with greater addiction. Menthol smokers show greater signs of nicotine dependence and are less likely to successfully quit smoking. These findings, combined with the evidence indicating that menthol's cooling and anesthetic properties can reduce the harshness of cigarette smoke and the evidence indicating that menthol cigarettes are marketed as a smoother alternative to nonmenthol cigarettes, make it likely that menthol cigarettes pose a public health risk above that seen with nonmenthol cigarettes.
This document is a scientific a**essment of public health issues related to the use of menthol in cigarettes. This document does not constitute a decision about what regulatory action, if any, FDA might take with respect to menthol in cigarettes. If FDA determines, after reviewing all of the available information from this a**essment and the anticipated public comments, from the TPSAC report and a**ociated public comments, and from the tobacco industry perspective document, that restrictions on the sale and/or distribution of menthol cigarettes or product standards should be established, the Agency would do so pursuant to rulemaking procedures that include public notice and an opportunity for public comment. There is no required deadline or timeline for FDA to make a determination about what regulatory action, if any, is appropriate.