Socioeconomic position and the risk of brain tumour: a Swedish national population-based cohort study
- Amal R Khanolkar1,2,
- Rickard Ljung2,
- Mats Talbäck2,
- Hannah L Brooke2,
- Sofia Carlsson2,
- Tiit Mathiesen3,
- Maria Feychting2
- 1Institute of Child Health, University College London, London, UK
- 2Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden
- 3Department of Clinical Neuroscience, Karolinska Hospital, Solna, Sweden
- Correspondence to Dr Amal R Khanolkar, Institute of Child Health, University College London, 30, Guildford Street, London WC1N 1EH, UK;
- Received 24 November 2015
- Revised 15 April 2016
- Accepted 7 May 2016
- Published Online First 20 June 2016
Background The aim was to investigate associations between different measures of socioeconomic position (SEP) and incidence of brain tumours (glioma, meningioma and acoustic neuroma) in a nationwide population-based cohort.
Methods We included 4 305 265 individuals born in Sweden during 1911–1961, and residing in Sweden in 1991. Cohort members were followed from 1993 to 2010 for a first primary diagnosis of brain tumour identified from the National Cancer Register. Poisson regression was used to compute incidence rate ratios (IRR) by highest education achieved, family income, occupational group and marital status, with adjustment for age, healthcare region of residence, and time period.
Results We identified 5735 brain tumours among men and 7101 among women during the study period. Highly educated men (≥3 years university education) had increased risk of glioma (IRR 1.22, 95% CI 1.08 to 1.37) compared to men with primary education. High income was associated with higher incidence of glioma in men (1.14, 1.01 to 1.27). Women with ≥3 years university education had increased risk of glioma (1.23, 1.08 to 1.40) and meningioma (1.16, 1.04 to 1.29) compared to those with primary education. Men and women in intermediate and higher non-manual occupations had increased risk of glioma compared to low manual groups. Compared to those married/cohabiting, being single or previously married/cohabiting was associated with decreased risk of glioma in men. Men in non-manual occupations had ∼50% increased risk of acoustic neuroma compared to men in low manual occupations.
Conclusions We observed consistent associations between higher SEP and higher risk of glioma. Completeness of cancer registration and detection bias are potential explanations for the findings.