Harvard: Low Air Pollution Levels Pose Cancer Threat

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Harvard Scientists Confirm Low Air Pollution Levels Pose Cancer Threat

A recent study conducted by researchers at Harvard University’s Chan School of Public Health has confirmed that prolonged exposure to air pollutants such as PM2.5 and nitrogen dioxide (NO2) over a decade can increase the risk of colorectal and prostate cancer among older adults.

What’s more, even at lower pollution levels, women are also at a heightened risk of breast cancer, endometrial cancer, and the aforementioned cancers.

By analyzing data from healthcare insurance beneficiaries, the study has also highlighted variations in cancer risk among different communities and demographics, underscoring the urgency of revisiting and strengthening air pollution standards in the United States.

Harvard Scientists Confirm Low Air Pollution Levels Pose Cancer Threat

The latest research led by the Chan School of Public Health at Harvard University reveals that long-term exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) in the air may raise the risk of non-lung cancers among older individuals. In a study encompassing millions of healthcare insurance beneficiaries, researchers discovered that exposure to PM2.5 and NO2 over a 10-year period increases the risk of developing colorectal and prostate cancer. Furthermore, even minimal exposure to air pollution can make individuals more susceptible to breast and endometrial cancers.

Wei Yaguang, an environmental health researcher, said, “Our research findings unveil the biological plausibility of air pollution as a critical risk factor for specific cancer outcomes, bringing us a step closer to understanding the impact of air pollution on human health. To ensure equitable access to clean air for all populations, we must thoroughly recognize the effects of air pollution and then work towards reducing it.”

This study was recently published in the journal “Environmental Epidemiology.”

Expanding the Scope of Air Pollution Research

While air pollution has been identified as a risk factor for lung cancer and a growing link to breast cancer risk, there has been limited research on the impact of air pollution on prostate cancer, colorectal cancer, and endometrial cancer risk.

Researchers analyzed data from nationwide healthcare insurance beneficiaries aged 65 and above collected from 2000 to 2016. All study participants had no history of cancer for at least the initial 10 years of the study. Researchers created separate cohorts for each cancer – breast, colorectal, endometrial, and prostate – with each cohort comprising between 2.2 to 6.5 million individuals. They analyzed the cancer risk associated with air pollutants in various subgroups based on factors such as age, gender (for colorectal cancer), race/ethnicity, average body mass index, and socioeconomic status.

Analyzing the Data: Study Results and Implications

Researchers utilized various sources of air pollution data to generate predictive maps of PM2.5 and NO2 concentrations in contiguous U.S. areas, linking them to beneficiaries’ residential zip codes to estimate individual exposures over 10 years.

Nationwide analysis revealed that prolonged exposure to PM2.5 and NO2 increased the risk of colorectal and prostate cancers but had no association with endometrial cancer. As for breast cancer, exposure to NO2 was linked to a decreased risk, while the relationship with PM2.5 remained inconclusive. Researchers suggest that this mixed association could be due to the differing chemical compositions of PM2.5, a complex mixture of solid and liquid particles.

In sub-analyses by subgroups, there was evidence that communities with higher average body mass indices might face disproportionately higher risks of all four cancers due to NO2 exposure, and African Americans and those on Medicaid were more susceptible to cancer risks (prostate and breast cancer, respectively) associated with PM2.5 exposure.

Researchers noted that even seemingly pristine communities are not immune to cancer risks from air pollution. They found a substantial association between exposure to these pollutants and the risk of all four cancers, even at pollution levels below the most recent World Health Organization standards, and well below the current U.S. standards.

Joel Schwartz, an environmental epidemiology professor and senior author, stated, “The key message here is that current air pollution standards in the United States are insufficient to protect public health. The Environmental Protection Agency has recently proposed stricter PM2.5 standards, but their efforts in regulating this pollutant fall short. The current NO2 standards are also far from adequate. Unless all these standards are significantly strengthened, air pollution will continue to contribute to thousands of unnecessary cases of multiple cancers each year.”