A recent study conducted by Harvard scientists has shed light on an alarming cancer threat posed by supposedly “safe” levels of air pollution. The findings of this study indicate that even low levels of exposure to pollutants can significantly increase the risk of developing cancer.
For years, experts have warned about the detrimental effects of air pollution on our health. However, the general perception has been that as long as the pollution levels are within the limits set by regulatory bodies, the risk of severe health implications is minimal. This study, however, challenges this notion.
The research team analyzed data from over 60 million Medicare recipients and air pollution levels across the United States. Astonishingly, the results revealed that exposure to even slightly elevated levels of fine particulate matter (PM2.5) and ozone increased the risk of cancer, especially lung cancer.
PM2.5 is a mixture of solid and liquid particles suspended in the air, while ozone is a molecule typically found in the Earth’s atmosphere. Though typically considered safe, these pollutants can have severe health consequences, as Harvard’s study suggests.
Notably, the risk of developing cancer increased with even minimal exposure. In fact, the researchers found that a one-unit increase in PM2.5 was associated with an approximately 10% increase in the cancer risk for several organs in the body.
These findings emphasize the crucial need for stricter pollution control measures and reevaluating what is considered “safe” pollution levels. Regulatory bodies and policymakers must acknowledge the grave health implications of even marginal increases in air pollution levels.
Moreover, individuals can take proactive steps to reduce their exposure to pollutants. These include using air purifiers in their homes, limiting outdoor activities in areas with high pollution levels, and advocating for cleaner energy sources.
With the significant health risks associated with seemingly harmless air pollution levels, it is essential that we prioritize our actions and work towards a cleaner and safer environment for all. The findings of this study should serve as a wake-up call for governments, regulatory bodies, and individuals to take immediate action towards curbing air pollution and protecting public health.
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Long-term exposure to particulate matter in the air (PM2.5) and nitrogen dioxide (NO2) could increase the risk of non-lung cancer in the elderly, according to recent research led by the Harvard TH Chan School of Public Health. In a study of millions of Medicare recipients, researchers found that exposure to PM2.5 and NO2 over a ten-year period increased the risk of developing colorectal cancer and prostate cancer. The findings also indicated that even minimal exposure to air pollution could predispose individuals to developing breast and endometrial cancer.
“Our findings reveal the biological plausibility of air pollution as a crucial risk factor in the development of specific cancers, bringing us one step closer to understanding the impact of air pollution on human health,” said Yaguang Wei, research fellow at the Department of Environmental Health. “To ensure equitable access to clean air for all populations, we must fully define the impacts of air pollution and then work to reduce them.”
The research was recently published in the journal Environmental epidemiology.
Expanding the scope of air pollution research
Although air pollution is a risk factor for lung cancer and has been linked to breast cancer risk, few studies have looked at its effects on the risk of prostate, colorectal and endometrial cancer.
Researchers analyzed data from national Medicare beneficiaries aged 65 or older, collected between 2000 and 2016. All subjects were cancer-free for at least the first ten years of the study period. The researchers created separate cohorts for each type of cancer – breast, colorectal, endometrial and prostate cancer – with between 2.2 million and 6.5 million subjects in each cohort. Separate analyzes looked at cancer risk under the impact of air pollutants for different subgroups based on factors including age, sex (for colorectal cancer only), race/ethnicity, average BMI, and socioeconomic status.
Analysis of the data: findings and implications
Using several air pollution data sources, the researchers developed a predictive map of PM2.5 and NO2 concentrations in the contiguous US. This was then linked to the postal codes of the recipients’ places of residence, allowing the researchers to estimate individual exposure over a ten-year period. period of time.
Findings from the national analysis showed that chronic exposure to PM2.5 and NO2 increased the risk of developing colorectal cancer and prostate cancer, but was not associated with the risk of endometrial cancer. For breast cancer, exposure to NO2 was associated with a reduced risk, while for PM2.5 the association was inconclusive. The researchers suggested that the mixed associations may be due to variations in the chemical composition of PM2.5, a complex mixture of solid and liquid particles.
When the analysis was limited to regions where air pollution levels were significantly below national standards and the composition of PM2.5 remained fairly stable, their effect on breast cancer risk was greater. Stronger associations between exposure to both pollutants and endometrial cancer risk were also found at lower pollution levels.
In their analysis of risks by subgroup, the researchers found evidence that communities with higher average BMI may be at disproportionately higher risk of all four cancers due to NO2 exposure, and that Black Americans and those enrolled in Medicaid may are more sensitive to cancer risks (prostate cancer). and chest) due to exposure to PM2.5.
The researchers noted that even communities with apparently clean air were not immune to cancer risk. They found substantial links between exposure to the two pollutants and the risks of all four cancers, even at pollution levels lower than the recently updated World Health Organization guidelines (which are lower than current U.S. standards).
“The key message here is that U.S. air pollution standards are inadequate in protecting public health,” said senior author Joel Schwartz, professor of environmental epidemiology. “The Environmental Protection Agency recently proposed stricter standards for PM2.5, but their proposal does not go far enough in regulating this pollutant. Current NO2 standards are also woefully inadequate. Unless all these standards become much, much stricter, air pollution will continue to result in thousands of unnecessary cases of multiple cancers every year.”
Reference: “Additive effects of 10-year exposures to PM2.5 and NO2 and primary cancer incidence in US older adults” by Yaguanga Wei, Mahdieh Danesh Yazdi, Tszshan Ma, Edgar Castro, Cristina Su Liu, Xinye Qiu, James Healy, Bryan N .Vu, Cuicui Wang, Liuhua Shi and Joel Schwartz, August 1, 2023, Environmental epidemiology.
Other Harvard Chan School authors include Edgar Castro, Cristina Su Liu, Xinye Qiu, James Healy, and Bryan Vu.
Funding for the research came from the National Institutes of Health grants R01ES032418 and P30ES000002.