Low area-level income, education linked to higher odds of

Residents of low area-level income and education areas had higher odds of having late-stage non-small cell lung cancer at diagnosis than residents of high area-level income and education areas, according to study results.

The findings, published in Cancer, showed the association independent of facility type and among both those with government and private insurance. They also noted that Black patients in the highest income and highest education quartiles had a higher likelihood of late-stage NSCLC diagnosis than their white counterparts in the lowest income and lowest education quartiles.

Rationale and methods

“Lung cancer is the most common cancer type in the U.S. and there are stark racial disparities in outcomes, including advanced stage and mortality,” Tomi F. Akinyemiju, BS, researcher in the department of population health sciences at Duke University School of Medicine, told Healio. “This study aimed to estimate the socioeconomic gradient in lung cancer risk among U.S. adults and to determine if this gradient varied across different racial and ethnic groups, because the findings can help target prevention strategies to population groups at highest risk.”

Tomi F. Akinyemiju

Akinyemiju and colleagues used data from the National Cancer Database of 1,329,972 patients aged between 18 and 89 years diagnosed with stage zero to stage IV NSCLC.

The researchers grouped patients according to stage at diagnosis and categorized area-level socioeconomic status according to a patient’s zip code level. They stratified models according to race/ethnicity, insurance status and health care facility type.

Key findings

Overall, 50% of Black patients and 17% of white patients resided in areas within the lowest income quartile, and 44% vs. 18% resided in areas that had the highest percentage of adults who did not finish high school.

Researchers observed higher odds of advanced-stage disease at diagnosis among those residing in the lowest vs. highest area-level education (adjusted OR = 1.12; 95% CI, 1.1-1.13) and income areas (adjusted OR = 1.13; 95% CI, 1.11-1.14), which persisted among white (63% vs. 60% and 63% vs. 60%), Black (71% vs. 66% and 71% vs. 67%) and Hispanic patients (69% vs. 65% and 70% vs. 66%).

Results of multilevel, multivariable regression models showed patients who resided in areas with the lowest education levels had a 12% higher likelihood of advanced-stage disease at diagnosis compared with those who resided in areas with the highest education levels (adjusted OR = 1.12; 95% CI, 1.1-1.13). The associations persisted in race-stratified analyses among white (adjusted OR = 1.04; 95% CI, 1.03-1.05), Black (adjusted OR = 1.15; 95% CI, 1.1-1.21), Hispanic (adjusted OR = 1.14; 95% CI, 1.05-1.24) and Asian patients (adjusted OR = 1.09; 95% CI, 1.01-1.17).

In addition, patients residing in the lowest-income areas had a 13% higher likelihood of late-stage disease compared with patients residing in the highest-income areas (adjusted OR = 1.13; 95% CI, 1.11-1.14), and the association persisted among white (adjusted OR = 1.02; 95% CI, 1-1.03), Black (adjusted OR = 1.13; 95% CI, 1.08-1.17), Hispanic (adjusted OR = 1.14; 95% CI, 1.06-1.21) and Asian patients (adjusted OR = 1.11; 95% CI, 1.01-1.22).

Moreover, patients in low-education areas who had government (adjusted OR = 1.12; 95% CI, 1.1-1.14) and private insurance (adjusted OR = 1.11; 95% CI, 1.09-1.14), but not those without insurance (adjusted OR = 1.04; 95% CI, 0.95-1.13), were more likely to be diagnosed with advanced-stage disease.

Results also showed patients who resided in low-income areas had a higher likelihood of being diagnosed with advanced-stage disease if they had private (adjusted OR = 1.12; 95% CI, 1.09-1.14) or government insurance (adjusted OR = 1.13; 95% CI, 1.11-1.15).

When the researchers stratified by facility type, they found patients who resided in low-income areas had a higher likelihood of late-stage disease if they received treatment at a community cancer facility (adjusted OR = 1.06; 95% CI, 1.01-1.11), academic/research program (adjusted OR = 1.16; 95% CI, 1.14-1.19), comprehensive community program (adjusted OR = 1.09; 95% CI, 1.07-1.11) and integrated care program (adjusted OR = 1.14; 95% CI, 1.1-1.18).

They also observed a higher likelihood among patients in the lowest education quartile regardless of treatment facility type, including academic/research programs (adjusted OR = 1.18; 95% CI, 1.15-1.2), comprehensive community programs (adjusted OR = 1.07; 95% CI, 1.05-1.09) and integrated care programs (adjusted OR = 1.1; 95% CI, 1.06-1.14).

Implications

“Clinicians and public health professionals should consider the social environment where individuals reside as part of comprehensive assessment of lung cancer risk,” Akinyemiju said. “Clinical strategies that incorporate resources to ensure timely and quality care will be more effective in improving health outcomes for lung cancer patients. In terms of prevention, smoking cessation and lung cancer screening programs targeting low socioeconomic status neighborhoods will be highly impactful in reducing lung cancer incidence and enhancing early diagnosis.”

Additional epidemiological and clinical studies are needed to clarify the drivers of advanced lung cancer among Black patients and guide targeted prevention strategies. For example, studies incorporating measures of systemic racism could potentially identify additional social and molecular mechanisms placing Black individuals at significantly higher risk compared with other racial groups, she added.

This study is among many that support the importance of place and social determinants of health in relation to outcomes, Erica T. Warner, ScD, MPH, assistant professor in the department of medicine at Harvard Medical School, wrote in an accompanying editorial.

“An important takeaway is that although the greatest impacts of structural racism are observed among Black patients, the group that these structures were often designed to disenfranchise, its effects are felt more broadly. Living in these areas was associated with a higher proportion of late-stage diagnoses in all racial/ethnic groups, and individual-level factors such as having insurance and receiving care at an academic medical center were not sufficient to eliminate this difference,” Warner wrote. “A clear and concerted effort is needed to increase the early detection of NSCLC. We know where the highest need is, and we must meet people where they are.”

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Tomi F. Akinyemiju, BS, can be reached at Duke University School of Medicine, 215 Morris St., Durham, NC 27708; email: [email protected].