Occupational exposure to metals and risk of meningioma: a multinational case-control study

Abstract

The aim of the study was to examine associations between occupational exposure to metals and meningioma risk in the international INTEROCC study.INTEROCC is a seven-country population-based case-control study including 1,906 adult meningioma cases and 5,565 population controls. Incident cases were recruited between 2000 and 2004. A detailed occupational history was completed and job titles were coded into standard international occupational classifications. Estimates of mean workday exposure to individual metals and to welding fumes were assigned based on a job-exposure-matrix. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression.Although more controls than cases were ever exposed to metals (14% vs. 11%, respectively), cases had higher median cumulative exposure levels. The ORs for ever vs. never exposure to any metal and to individual metals were mostly greater than 1.0, with the strongest association for exposure to iron (OR=1.26, 95%CI 1.0-1.58). In women, an increased OR of 1.70 (95%CI 1.0-2.89) was seen for ever vs never exposure to iron (OR in men 1.19 (95% CI 0.91-1.54), with positive trends in relation with both cumulative and duration of exposure. These results remained after consideration of other occupational metal or chemical co-exposures.In conclusion, an apparent positive association between occupational exposure to iron and meningioma risk was observed, particularly among women. Considering the fact that meningioma is a hormone dependent tumor, the hypothesis that an interaction between iron and estrogen metabolism may be a potential mechanism for a carcinogenic effect of iron should be further investigated.6

Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study

“…It is unclear whether the reduced ORs observed for chemicals in the low ELF group in the 1–4 year ETW, particularly for glioma and metals, were due to chance or some sort of bias. The reduced ORs were generally attenuated using alternate ETWs; further, in analysis overall (1-year lag), significant positive associations were observed for some metals for meningioma 31. There were also multiple tests performed, raising the possibility of a false significant finding.…”

“…Although there was no clear evidence for associations between occupational exposure to combustion products, dusts and other chemical agents29 or solvents30 and either glioma or meningioma risk in INTEROCC, we recently observed evidence for positive associations between occupational metal exposures, particularly iron exposure in women, as well as oil mist exposure overall, and meningioma risk (Ref. 31 and McElvenny et al , personal communication, 2017).…”

The INTEROCC case-control study: risk of meningioma and occupational exposure to selected combustion products, dusts and other chemical agents

“…Previously, we reported on the association between exposure to metals and welding fumes and risk of meningioma 14. The major finding was an association of iron with increased risk of developing meningioma.…”

“…Participants with a prevalence of exposure ≥5 but <25% as well as with exposure duration of <1 year were excluded from the analysis. Although we are aware that meningioma potentially has a latency of 20 years or more,1 the analyses presented incorporate a 5-year lag for consistency with a previous analysis of the data investigating possible associations with various metals 14. Sensitivity analyses were conducted by looking at lags of 1 and 10 years and using different cut-points on the probability of exposure scale for distinguishing exposed and unexposed (ie, p ≥ 5% and p≥50%), as well as excluding proxy respondents and subjects aged over 69 years.…”

“…We previously published results investigating link between meningioma and occupational exposures for a number of families of organic solvents (aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons and other organic solvents) or specific solvents (benzene, gasoline, methylene chloride, perchloroethylene, trichloroethylene, 1,1,1-trichloroethylene and toluene), which failed to show significant associations between meningioma and any of the solvents 13. The analyses of a number of metals failed to show significant associations, apart from a positive borderline significant association for iron exposure in women 14. Because these tumours occur more often in women than in men1 and supported by some findings of an association between meningioma and hormone replacement therapy,15 16 it has been suggested that hormones play a role in the aetiology of meningioma.…”