Contemporary Modifiable Exposures and Cancer Across the Cancer Control Continuum

Overview

Cancer risks and outcomes are influenced by modifiable environmental factors. In recent time, millions of people in the United States (U.S.) are exposed to a multitude of emerging exposures/products whose impact on cancer is unclear and/or epidemiologic evidence is limited. These contemporary modifiable exposures include, but are not limited to, cannabis use, e-cigarette use, anti-obesity medications, perfluoroalkyl and polyfluoroalkyl substances (PFAS), chemical hair relaxers, and microplastics.

For cannabis (i.e., marijuana), an estimated 18.7% of Americans (52.5 million) aged 12 years or older reported using it at least once in 2021. In 2022, an estimated 8.3% of 8th graders, 19.5% of 10th graders, and 30.7% of 12th graders reported using cannabis/hashish in the past 12 months. Electronic cigarettes (e-cigarettes) are the most used tobacco product among American youths today and are additionally used by a growing number of adults. In 2022, 2.6 million U.S. middle and high school students used e-cigarettes in the past 30 days, including 3.3% of middle school students and 14.1% of high school students. Yet, the health and cancer impact of cannabis, e-cigarettes, and other emerging tobacco products is largely unknown.

Approximately 36% of American adults are obese. Obesity affects some groups more than others with variation across race/ethnicity, socio-economic status (SES), and geography. Approximately 48% of non-Hispanic Black and 43% of Hispanic adults have obesity compared to 34% of non-Hispanic White adults. Almost 40% of adults with household income less than 350% of federal poverty level have obesity compared to 31% with obesity above 350% of the federal poverty level. There is also variation in obesity rates by geography in the U.S. with prevalence rates ranging from 23% to 38% across various states. Anti-obesity medications have been viewed as a breakthrough to address this striking public health crisis and an increasing number of anti-obesity drugs have been approved by the Food and Drug Administration (FDA). Use of anti-obesity medications, including off-label usage, is increasing. However, the impact of these medications on cancer across the cancer control continuum is unknown.

Up to 95% of self-identified adult Black women in the U.S. reported ever use of chemical hair relaxers. The composition of these products is proprietary but may contain potentially harmful toxicants such as endocrine disrupting chemicals and carcinogens such as formaldehyde and heavy metals. There is some evidence that chemical hair relaxers are associated with increased cancer risk, but relatively few studies have been conducted. Additionally, microplastics, which are now ubiquitous in the environment, is a growing public health concern, but there is a lack of epidemiological studies to assess links to cancer.

Of note, individuals from environmental justice communities (historically underrepresented in cancer research or underserved based on race/ethnicity, SES, or geography such as U.S. South and rural) have much higher rates of obesity and tobacco use, but the use and impact of emerging exposures (such as those described above) on health disparities is largely unknown. Studies funded by current Division of Cancer Control and Population Science (DCCPS) grants provide an ideal opportunity to fulfill the goals of this supplement because many recruit from known environmental hotspots and from populations under-represented in cancer research.