Neighborhood socioeconomic status and Hodgkin's lymphoma incidence in California

Hodgkin's lymphoma occurrence has long been noted to associate with higher socioeconomic status (SES). However, the Hodgkin's lymphoma-SES association has not been examined recently or across important, possibly etiologically distinct, patient subgroups. In ∼150 million person-years of observation in the multiethnic population of California, we examined the association of Hodgkin's lymphoma incidence with a composite measure of neighborhood-level SES in patient subgroups defined by age, sex, race/ethnicity, and Hodgkin's lymphoma histologic subtype. Using population-based cancer registry data on 3,794 Hodgkin's lymphoma patients diagnosed 1988 to 1992 and 1990 census data, we assigned a previously validated, multidimensional SES index to census block groups of patient residence. We then calculated neighborhood SES-specific incidence rates and estimated rate ratios using Poisson regression. Positive neighborhood SES gradients in Hodgkin's lymphoma incidence were observed only in young adults (ages 15-44 years at diagnosis) with nodular sclerosis Hodgkin's lymphoma and older adult (ages ≥45 years) White and Hispanic males with mixed cellularity Hodgkin's lymphoma. For young adults, associations were marked in Hispanic and Asian women, weaker in Hispanic and White men and White women, and subtle to nonexistent in Blacks and Asian men. Neighborhood SES gradients in Hodgkin's lymphoma incidence varied by age, sex, race/ethnicity, and histologic subtype, underscoring etiologic complexity in Hodgkin's lymphoma. Racial/ethnic gradients were not entirely explained by neighborhood SES. In California, etiologically relevant exposures for young adult Hodgkin's lymphoma, the most common form, could associate more with race/ethnicity or foreign birthplace than neighborhood SES and may be modified by reproductive or other sex-specific factors.