The association between individual and area-level socioeconomic status and mortality from cancer of the head and neck, Belgium 2001-2011

Paulien Hagedoorn, Vrije Universiteit Brussel
Hadewijch Vandenheede, Vrije Universiteit Brussel
Katrien Vanthomme, Vrije Universiteit Brussel
Sylvie Gadeyne, Vrije Universiteit Brussel

Previous studies have observed substantial regional differences in incidence and premature mortality from head and neck cancer (HNC) in Belgium. Although regional variation in deprivation is mentioned as a possible factor for these geographic differences, this has not been studied so far. The aim of this study is to assess to what extent individual and area-level socioeconomic status (SES) are associated to HNC mortality, and to what extent they contribute to regional variation in HNC mortality in Belgium. Data on men aged 40-64 are collected from the 2001 Belgian census linked to register data on all Belgian inhabitants from 2001-2011. Head and neck cancer mortality is defined according to ICD-10 codes C01-C06; C09-C10; C12-C14; C32. Individual SES is measured using education, employment status and housing conditions. Deprivation at municipality level is measured by a deprivation index. Absolute mortality differences are estimated by age standardized mortality rates, using the 2001 Belgian male population as the standard population. Multilevel Poisson models are used to estimate the association and interaction between HNC mortality and individual and area-level SES, and to estimate the regional variation in HNC mortality. The results indicate that male HNC mortality is significantly associated to individual SES and area deprivation. A gradual increase in HNC mortality by area deprivation is observed for men with a high and average SES. Low-SES men, on the other hand, have higher HNC mortality rate ratios regardless of area-level SES. Substantial and significant regional variation in HNC mortality is observed. Differences in population composition explain part of this variation, while area deprivation and cross-level interactions explain little. Future studies should look into additional factors that might explain geographic differences in HNC mortality, such as regional variation in alcohol and tobacco use.