To quantify inequality, the researchers calculated an age-standardized Concentration Index for each study year, using 3 socioeconomic measures: mean and median equivalized household income (adjusted for household size) and the proportion of residents with a bachelor’s degree or higher. A negative Concentration Index value indicates mortality disproportionately concentrated among lower socioeconomic divisions; linear trend analyses were applied to the yearly index values and to crude mortality rates to see whether these patterns changed over time.
Non-Hodgkin Lymphoma Mortality Became More Concentrated Among Disadvantaged Groups
Crude Hodgkin lymphoma mortality declined significantly across Canada, driven largely by declines in the Prairie provinces and Ontario. British Columbia and Eastern Canada showed no significant change. Crude non-Hodgkin lymphoma mortality told a different story, remaining largely unchanged nationally, with only the Prairies registering a modest decline. Sex-stratified results diverged further: non-Hodgkin lymphoma mortality fell significantly among women nationally and in the Prairies and Ontario, while among men it held steady overall and rose significantly in Eastern Canada.
The age-standardized concentration index was negative in most years for both lymphoma types, meaning mortality was persistently concentrated in divisions with lower income and education. For Hodgkin lymphoma, that gap did not change significantly over the 2 decades. For non-Hodgkin lymphoma, trend analyses found the opposite: concentration among lower-income and lower-education populations grew significantly more pronounced over time, most consistent when income was measured as mean household income and among women, who showed stronger, more frequent income-related inequality than men.
“The persistent and widening socioeconomic inequalities observed in [Hodgkin lymphoma] and NHL mortality, respectively, in Canada underscore the need for targeted public health interventions and more equitable distribution of resources to address systematic and avoidable differences in cancer outcomes associated with socioeconomic disadvantage,” the researchers wrote.
The authors situated that widening gap within Canada’s universal healthcare system, noting coverage alone does not guarantee equitable outcomes. They pointed to a California study of more than 33,000 patients with diffuse large B-cell lymphoma that found roughly 24% higher lymphoma-specific mortality among those in lower-socioeconomic neighborhoods, framing the Canadian findings as part of a broader pattern: advances including rituximab may have disproportionately benefited more advantaged patients.
Ecological Data Limit Conclusions About Individual Risk
The authors were explicit that their reliance on area-level income and education measures, rather than individual-level data, raises the possibility of ecological bias: a census division’s average income or education does not necessarily reflect the circumstances of any single person who died of Hodgkin lymphoma or non-Hodgkin lymphoma within it. Because the design is cross-sectional and ecological, the study can identify associations but cannot establish cause and effect between socioeconomic status and lymphoma mortality for any patient.
Additional limitations included analyzing Hodgkin lymphoma and non-Hodgkin lymphoma as broad categories rather than by subtype, stage, or treatment, which may obscure gradients specific to more aggressive or treatable disease forms. Census and survey data, collected every 5 years, were linked to the closest mortality year, introducing potential temporal mismatch, and crude mortality trends were not age-standardized, meaning they may partly reflect Canada’s aging population rather than age-specific risk alone.
For population health teams and equity-focused payers, the findings argue for treating socioeconomic status as a clinical variable when designing cancer screening and adherence programs, rather than assuming universal coverage closes the gap. Addressing non-medical barriers, including transportation, paid leave, and navigation support, may keep future gains in non-Hodgkin lymphoma care from bypassing the patients who need them most.
References
1. Zhang K, Kiadaliri A, Hajizadeh M. Socioeconomic inequalities in the mortality of Hodgkin and non-Hodgkin lymphoma: a two-decade trend analysis. Curr Oncol. 2026;33(8):470. doi:10.3390/curroncol33080470
2. McNulty R. Study shows significant disparities in worldwide rates of non-Hodgkin lymphoma. AJMC®️. June 22, 2022. Accessed October 8, 2026. https://www.ajmc.com/view/study-shows-significant-disparities-in-worldwide-rates-of-non-hodgkin-lymphoma