Historically, young Black men and women have been diagnosed with and died of lung cancer at higher rates than young white men and women. Now that racial disparity has all but disappeared, in large part due to a decline in the popularity of smoking among Black people.

Tobacco use and exposure to secondhand smoke cause a staggering 80% of the deaths from lung cancer nationwide each year. Tobacco smoke contains a variety of carcinogens, including arsenic, ammonia, formaldehyde and hydrogen cyanide.

To investigate the relationship between race- and sex-specific smoking patterns and rates of lung cancer, Ahmedin Jemal, DVM, PhD, the vice president of the American Cancer Society’s Surveillance and Health Services Research Program, and colleagues analyzed data on lung cancer incidence between 1997 and 2016 and data on smoking prevalence between 1970 and 2016.

They found that lung cancer incidence decreased in both white and Black men born after 1947 and in white and Black women born after 1957. But the decline was particularly steep in men and women who identified as non-Hispanic Black—a statistical trend that corresponded with a reduction in cigarette use in Black communities.

For some age demographics, the researchers observed, the decrease eliminated the racial disparity entirely. In men born between 1967 and 1972, there was no longer a difference in rates of lung cancer diagnoses and deaths between Blacks and whites; in women born after 1967, the disparity was actually reversed—white women were more likely than Black women to be diagnosed with and die of lung cancer.

In fact, the researchers wrote in JNCI Cancer Spectrum earlier this month, lung cancer incidence increased for Blacks in only one demographic: men born between 1977 and 1982.

“This increase likely reflects the steep rise in initiation of smoking among Black adolescents in the 1990s, which coincided with the R.J. Reynolds tobacco advertisement campaign targeting African Americans,” the researchers wrote, noting that “between 1991 and 1997, the prevalence of current cigarette use among Black high school students doubled from 14.1% to 28.2%.”

The researchers attribute the decrease in racial disparity to the success of public health policies and campaigns designed to raise awareness of the dangers of smoking. However, they point to the data on men born between 1977 and 1982 as proof that more work needs to be done to close the gap entirely.

“While these patterns herald progress in reducing racial disparities in lung cancer occurrence and the success of tobacco control in the Black community,” they wrote, “the increasing lung cancer incidence rates in Black men born circa 1977–1982 is concerning and underscores the need for targeted tobacco prevention interventions.”

As the leading cause of cancer-related death in the United States, lung cancer will kill roughly 135,720 of the 606,520 Americans projected to die of cancer in 2020.

Racial disparities in diagnosis, treatment and mortality have been documented for a wide variety of cancers. There are many causes, including unequal access to health insurance. To learn more about racial disparities and cancer, click here. And to learn more about how smoking increases your risk of a variety of cancers, including lung, head, neck and throat cancers, click here.