It’s only natural to assume that urban areas are not as healthy as rural areas. Residents of urban areas seem more likely to get sick due to the noticeable difference in air quality as well as the fast-paced, congested atmosphere produced by the most populous American cities.

And now a new study appears to have finally confirmed our suspicions about the relationship between cities with poor environmental quality and cancer.

Researchers led by Jyotsna Jagai, assistant professor in environmental and occupational health sciences at the University of Illinois at Chicago, examined cancer rates in approximately 2,700 urban, suburban, and rural counties. The data was collected in regions all throughout the US between 2006 and 2010 by the US National Cancer Institute.

Jagai’s team also reviewed information collected in accordance with the US Environmental Quality Index (EQI) between 2000 and 2005.

The EQI assigns a grade to each county based on more than 200 environmental factors, including water quality, air quality, exposure to pesticides and contaminants, transportation and housing safety, and exposure to crime. Each factor is tallied together to reveal a single environmental health grade. The counties with the lowest scores have the poorest water quality, air quality, housing safety, etc.

After comparing cancer incidence with EQI scores, the researchers found that counties with poorer environmental health had higher rates of cancer, both in men and women.

"Overall environmental quality was very strongly associated with increased cancer risk,” Jagai said.
For every 100,000 residents in each county, those with the lowest EQI scores had 39 more cases of cancer than those with the highest EQI scores. Prostate cancer posed the biggest threat for male residents of counties with the lowest EQI scores compared to breast cancer for female residents.

The study did not establish a direct link between cancer and heavily populated cities but residents of urban communities were more likely to live in an environment with a low EQI score and a higher risk of cancer.

"We did not consider regional differences," Jagai said. "However, we did consider differences based on 'urbanicity.' Overall environmental quality was strongly associated with cancer risk across all urban and suburban counties."

This discovery isn’t much of a surprise considering a 2014 study by the US Centers for Disease Control and Prevention found that New York and Pennsylvania, home to two of the largest cities in the US, are among the states with the greatest risk of cancer. The states with the lowest risk of cancer included rural Alaska and the environmentally conscious California.

About 1,600 Americans died from cancer each day of the year that study was conducted. Cancer is currently attributed to 1 in 4 deaths in the US.

Scarlett Lin Gomez, a research scientist at the Cancer Prevention Institute of California in Fremont, published an editorial to accompany Jagai’s research.

"Studies such as this," she wrote, "give us the tools to identify the 'where' and the 'what' we should be focusing on."

The findings are also a reminder of the importance of environmental data “collected and maintained by the Environmental Protection Agency,” Gomez added.

Thanks to the study, the editorial says, it cannot be denied that such data plays a major role in helping scientists “understand the root causes for these geographical disparities and how best to remediate them.”