Multiethnic Epigenetic Study: Smoking's Impact Across Racial and Ethnic Groups

March 12, 2024

Researchers from the University of Hawaiʻi Cancer Center collaborated on a study recently that sheds light on the complex links between smoking habits, epigenetics (the factors beyond DNA sequence that impact gene activity), and the risk of smoking-related diseases, such as lung cancer.

The study was published in the American Journal of Human Genetics.

In Hawaiʻi, lung cancer stands as the second most prevalent cancer and the leading cause of cancer-related mortality in both men and women. It is crucial to grasp the intricate effects of tobacco exposure on health, particularly considering its diverse impacts on different demographic segments.

The study investigated epigenetic signatures associated with smoking dose in six distinct racial and ethnic groups: African Americans, Chinese, Japanese Americans, Latinos, Native Hawaiians, and whites; and found that smoking dose was associated with changes in DNA methylation, a process where small chemical tags are added to the DNA molecule, at sites across the genome.

“This study is of particular importance as it may help to improve our understanding of mechanisms that contribute to the observed racial and ethnic differences in risk of smoking-related diseases,” said UH Cancer Center researcher Lani Park, senior author of the paper.

The study included participants from three large prospective cohort studies: the Multiethnic Cohort Study (MEC) based at the UH Cancer Center, the Singapore Chinese Health Study (SCHS), and the Southern Community Cohort Study (SCCS). It also accounted for both internal (measured from a urinary biomarker) and self-reported measures of smoking dose, providing a comprehensive understanding of the complex interplay between tobacco exposure and epigenetics.

Disparities revealed in specific ethnic groups

They found that many epigenetic signatures due to the internal nicotine dose are consistent across race and ethnicity. However, there were two sites where the methylation differed across race and ethnicity. One site was only associated with African Americans, while the other had a stronger association with Latinos.

These findings represent a significant step in understanding the molecular structure of smoking-related diseases and underscore the importance of tailored interventions to address health disparities across diverse populations.