A research study carried out by the Harvard T.H. Chan School of Public Health has discovered that elderly individuals subjected to PM2.5 and NO2 air contaminants for a period of ten years are more susceptible to colorectal and prostate cancers. Even at relatively low levels of air pollution, the risk for developing breast, endometrial, and the aforementioned cancers is elevated. Through an examination of data concerning Medicare beneficiaries, the study also identified varying levels of cancer risk across diverse communities and demographic groups. These findings highlight the pressing need for reevaluating and fortifying air quality standards in the United States.
Extended exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) may amplify the likelihood of developing non-respiratory system cancers among older adults, according to recent findings led by the Harvard T.H. Chan School of Public Health. The study, which included data from millions of Medicare enrollees, revealed that a decade-long exposure to PM2.5 and NO2 elevated the risks of colorectal and prostate cancers. The results also indicated that even minimal levels of air pollution can increase the probability of developing breast and endometrial cancers.
Yaguang Wei, a research fellow in the Department of Environmental Health, stated, “Our study offers scientific evidence supporting the role of air pollution as a significant risk factor in the genesis of specific types of cancer. This takes us closer to understanding the full impact of air pollution on human health. To guarantee equal access to clean air for everyone, it is imperative to thoroughly comprehend the ramifications of air pollution and to actively work towards diminishing it.”
The research has been recently published in the journal Environmental Epidemiology.
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Broadening the Spectrum of Air Pollution Research
Though air pollution has long been recognized as a risk factor for lung cancer, and emerging evidence has suggested a connection to breast cancer, its impact on colorectal, prostate, and endometrial cancers has been insufficiently explored.
The researchers scrutinized data from Medicare beneficiaries who were 65 years of age or older, gathered from 2000 to 2016. All participants were free of cancer for at least the first ten years of the study. Separate cohorts were established for each cancer type—breast, colorectal, endometrial, and prostate—with a participant count ranging from 2.2 million to 6.5 million per cohort. Individual analyses considered the influence of air pollution on diverse subgroups based on various factors such as age, sex (in the case of colorectal cancer), race/ethnicity, average body mass index (BMI), and socioeconomic standing.
Analytical Outcomes and Implications
Multiple sources of air pollution data were utilized to construct a predictive model of PM2.5 and NO2 levels throughout the contiguous United States. This was then connected to the residential ZIP codes of the beneficiaries, allowing the researchers to estimate individual exposure over a ten-year period.
The nationwide analysis demonstrated that prolonged exposure to PM2.5 and NO2 did elevate the risk of colorectal and prostate cancers, though no connection was found with endometrial cancer risk. For breast cancer, exposure to NO2 was associated with a decreased risk, while the correlation with PM2.5 exposure remained inconclusive. It was posited that such ambiguous associations could be attributed to variations in the chemical makeup of PM2.5, a composite of both solid and liquid particles.
When the study was limited to areas where air pollution levels were considerably below national norms and the composition of PM2.5 remained relatively stable, a stronger correlation with breast cancer risk was observed. Similarly, stronger connections were found between exposure to both pollutants and endometrial cancer risk at lower levels of pollution.
In subgroup analyses, the researchers discovered indications that communities with higher average BMI could be at elevated risk for all four types of cancers from NO2 exposure. Likewise, Black Americans and Medicaid enrollees appeared to be more vulnerable to cancer risks—specifically, prostate and breast cancer—from PM2.5 exposure.
Even communities considered to have cleaner air were not exempt from these cancer risks. Associations between both pollutants and the risks for all four types of cancers were found to be substantial even at pollution levels lower than the recently revised World Health Organization guidelines, which are already more stringent than current U.S. standards.
Joel Schwartz, the senior author of the study and a professor of environmental epidemiology, concluded, “The main takeaway is that current U.S. standards for air pollution are insufficient in safeguarding public health. The Environmental Protection Agency has recently proposed more stringent standards for PM2.5, but these proposed measures fall short of adequately regulating this contaminant. The prevailing NO2 standards are equally lacking. Without considerably stricter regulations, air pollution will continue to be responsible for a myriad of unnecessary cancer cases annually.”
The research was funded by the National Institutes of Health grants R01ES032418 and P30ES000002. Other contributors from the Harvard Chan School included Edgar Castro, Cristina Su Liu, Xinye Qiu, James Healy, and Bryan Vu.
Frequently Asked Questions (FAQs) about Air Pollution and Cancer Risk
What does the Harvard study reveal about air pollution and cancer?
The Harvard study uncovers that prolonged exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) in the air can increase the risk of colorectal and prostate cancers in older adults. It also suggests a potential link between air pollution and breast and endometrial cancers, even at low pollution levels.
Who participated in the research?
The research analyzed data from millions of Medicare beneficiaries aged 65 and older, collected from 2000 to 2016. All participants were initially cancer-free during the first decade of the study.
Were there any demographic variations in cancer risks due to air pollution?
Yes, the study found varying cancer risks across different communities and demographics. For example, communities with higher average BMI appeared to face greater risks of all four cancers from NO2 exposure. Additionally, Black Americans and Medicaid enrollees were more susceptible to specific cancer risks from PM2.5 exposure.
What are the implications of these findings?
The findings underscore the need to revisit and strengthen U.S. air pollution standards. The study suggests that current standards are inadequate in protecting public health, and stricter regulations are required to reduce the risk of cancer associated with air pollution.
Where can I find the full research study?
The research study titled “Additive effects of 10-year exposures to PM2.5 and NO2 and primary cancer incidence in American older adults” was published in the journal Environmental Epidemiology and can be accessed through DOI: 10.1097/EE9.0000000000000265.
4 comments
wow harvard study found air pollution can cause cancer thats crazy!!!
EPA must act, protect people from cancer, stricter standards, now!
this is scary, we need clean air now, no joke!
So, current air standards not enough?! we need better rules ASAP!