A cohort study into head and neck cancer mortality in Belgium (2001-11): Are individual socioeconomic differences conditional on area deprivation?

Objective: The aim of this study is to assess to what extent individual and area-level socioeconomic position (SEP) are associated to head and neck cancer (HNC) mortality and to what extent they contribute to regional variation in HNC mortality in Belgium.

Materials and methods: Data on men aged 40-64 are collected from a population based dataset based on the 2001 Belgian census linked to register data on emigration and mortality for 2001-2011. Individual SEP is measured using education, employment status and housing conditions. Deprivation at municipal level is measured by a deprivation index. Absolute mortality differences are estimated by age standardised mortality rates. Multilevel Poisson models are used to estimate the association and interaction between HNC mortality and individual and area-level SEP, and to estimate the regional variation in HNC mortality.

Results: HNC mortality rates are significantly higher for men with a low SEP and men living in deprived areas. Cross-level interactions indicate that the association between individual SEP and HNC mortality is conditional on area deprivation. HNC mortality in deprived areas is especially high among high-SEP men. As a result, social disparities appear to be smaller in more deprived areas. Regional variation in HNC mortality was significant. Population composition partially explains this regional variation, while area deprivation and cross-level interactions explains little.

Conclusion: Both individual and area-level deprivation are important determinants of HNC mortality. Underlying trends in incidence and survival, and risk factors, such as alcohol and tobacco use, should be explored further.