Mapping technique reveals spatial clustering of workplace injuries and potential new venues for outreach

A common hurdle in the field of occupational health and safety is delivering what can sometimes be life-saving information to the people who need it most. After all, not all employers are amenable to workplace health and safety education. But what if safety advocates could find and connect with the most at-risk workers out in the community? Perhaps even reach vulnerable workers with safety education before they experience an injury at work?

New research from the University of Illinois-Chicago School of Public Health could help safety advocates do just that. Linda Forst, director of the school’s Division of Environmental and Occupational Health Sciences, knew Hispanic and immigrant workers often face a higher risk of experiencing a severe work-related injury. She also knew that many such workers tend to live in the same communities. And so she wondered if one could map reported occupational injuries to certain neighborhoods. In other words, could researchers pinpoint geographic clusters of severe work-related injuries in a way that could provide insight into which communities are most in need of health and safety outreach?

“How do you reach workers who are difficult to reach in the workplace,” Forst told me. “People who work for small businesses, people who are employed in the cash economy, people employed as temporary workers — how do you reach them with prevention?”

To help answer that question, Forst and her colleagues cross-matched health care and publicly available databases by home ZIP code with incidences of work-related traumatic injuries reported to the Illinois state trauma registry between 2000 and 2009. The registry receives reports from level 1 and level 2 trauma centers. (Forst noted: “These are people hospitalized in a trauma unit for more than 24 hours — short of death, these are some of the worst injuries.”) In their study, which was published in the July supplement of the American Journal of Public Health, the researchers found that among the 23,200 occupational injuries reported, 80 percent of the cases were located in just 20 percent of ZIP codes and clustered in 10 locations. In addition, the numbers and clusters of injuries were associated with immigrant communities. Forst, Lee Friedman, Brian Chin and Dana Madigan write:

Adults generally live where there are opportunities for employment and housing. Low wage, immigrant, and minority workers and other persons employed in dangerous jobs are likely to cluster in areas with similar sociodemographic characteristics, influenced by the need for affordable housing, the familiarity of neighbors who are ethnically and linguistically similar, and services that cater to their cultural preferences. Because segments of low wage, minority, immigrant, and contingent workforces, small business employees and others who are at high risk for injury are difficult to reach in their workplaces, we sought to determine whether the need for occupational health and safety interventions could be identified at the community level.

In mapping the data, researchers found that within the 20 percent of ZIP codes with the highest rates of work-related injuries, nearly 2,750 injuries occurred. The study revealed 10 significant spatial clusters made up of 265 ZIP codes — nearly one-fifth of all ZIP codes in the state of Illinois — and within those clusters, about 8,300 traumatic work-related injuries occurred between 2000 and 2009. Researchers found an inverse relationship between occupational injuries and home ownership, a positive relationship between total employment and injuries, and a strong relationship between injuries and communities where immigrants tend to live.

Spatial clusters were typically found in mid-sized towns, outside of cities. Urban poverty levels were inversely related to work-related injury rates and the spatial clustering of injuries — in other words, the higher the poverty, the lower the injury rate. (Forst noted that this last finding was likely a result of high unemployment.) The study also reported that among the more than 23,000 workplace injuries studied, surgical intervention was required in nearly 51 percent of cases and more than 14 percent were treated in the intensive care unit.

“I wasn’t exactly sure what we would find with the study,” said Forst, who noted that to her knowledge, this was the first study to map the incidence of occupational injuries. “I suspected we would find a greater percentage of occupational injuries in immigrant communities, but I didn’t really know how clearly it would be demonstrated.”

Forst told me the study’s findings and its mapping technique could form the basis of interventions that offer education, occupational health and safety training, and information about labor and wage rights in the community setting, as opposed to the workplace setting. And in fact, because OSHA often struggles with tight budgets — and is now facing even more funding cuts — Forst said the mapping technique could help the agency more precisely target its prevention efforts and perhaps, get a bigger bang for its buck.

“Our investigation, which used existing health surveillance data, suggests that some neighborhoods might be disproportionately affected by traumatic occupational injuries,” the study stated. “On a practical level, predictors of vulnerability to workplace injury at a community level allow public health practitioners to reach at-risk workers in their neighborhoods.”

With growing public health interest in the association between a person’s health and where she or he lives, Forst told me the “relationship between place and work is clearly demonstrated in this project, and work really needs to be taken into account as a determinant in health.”

She noted that while the community-based interventions that could stem from the mapping technique certainly shouldn’t take away from workplace oversight — indeed, the high numbers of traumatic injuries make the case for such oversight even stronger — they could help workers take steps to protect their health and safety.

“I think awareness of labor issues, awareness of the existence of OSHA and workers’ rights, and awareness of some simple steps people can take to protect themselves at work can be transmitted in a community setting,” Forst said. “A lot of injuries don’t take a lot of equipment or a lot of power to prevent, so simple awareness can be very important.”

To read the full study, visit the American Journal of Public Health.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.

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