A Large Prospective Cohort Study in the United States Reveals Potential Links Between Outdoor Air Pollution and Subtypes of Adult Hematologic Cancers

Background and Purpose

In recent years, the impact of outdoor air pollution on human health has garnered extensive attention. Since 2013, the International Agency for Research on Cancer (IARC) has classified outdoor air pollution and particulate matter (PM) as Group 1 human carcinogens, primarily based on evidence from lung cancer studies. Although current research data suggest a certain link between air pollution and hematologic cancers, such studies often overlook a detailed distinction of cancer subtypes due to the pathological heterogeneity of these cancers, leading to ambiguous and inconsistent conclusions. To better understand the association between air pollution and various subtypes of hematologic cancers, this study selected the American Cancer Society’s Cancer Prevention Study-II Nutrition Cohort, exploring the relationship between outdoor pollutants at residential locations and hematologic cancers.

Literature Source

This study was conducted by W. Ryan Diver, Lauren R. Teras, Emily L. Deubler, and Michelle C. Turner, and was published in 2024 in the British Journal of Cancer.

Methodology

The research team selected 108,002 participants and tracked health data from 1992 through 2017. Air pollutant data collected at residential addresses included PM2.5, PM10, PM10-2.5, nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), and carbon monoxide (CO). Using the Cox proportional hazards regression model, the researchers assessed the correlation and hazard ratios (HR) with 95% confidence intervals (CI) between changing pollutant concentrations and the incidence of hematologic cancer subtypes.

Main Results

Among 2659 cases of hematologic cancers, higher PM10-2.5 concentrations were associated with mantle cell lymphoma (HR=1.43 for every 4.1 μg/m³ increase), NO2 was associated with Hodgkin lymphoma (HR=1.39 for every 7.2 ppb increase) and marginal zone lymphoma (HR=1.30 for every 7.2 ppb increase), while CO was significantly associated with marginal zone lymphoma (HR=1.30 for every 0.21 ppm increase) and T cell lymphoma (HR=1.27 for every 0.21 ppm increase).

Conclusion and Significance

This study suggests that previous research may have underestimated the potential impact of air pollutants on these cancers by not fully considering the heterogeneity of hematologic cancer subtypes. The findings indicate that future studies examining the relationship between air pollution and hematologic cancers should take into account the various subtypes of these cancers.