Proportionate mortality study of the United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry

The impact of vinyl chloride exposure on the health of Italian workers: an evaluation from SIREP compliance data

The aim of the study is to investigate exposures to vinyl chloride monomer (VCM) at workplace in Italy and the related burden of diseases. Measurements data was collected from a nation-wide occupational exposure registry (SIREP, 1996-2016). Potentially exposed workers were estimated for some industrial sectors. Concurrent exposures were investigated using cluster analysis. Proportionate mortality ratios were calculated linking data to national mortality statistics (2005-2015). Overall 8,460 measurements were analyzed. Most exposures occurred in the manufacture of chemicals and plastic products. A total of 12,148 workers potentially exposed was estimated (64% male). Concurrent exposures were detected frequently (83%). An elevated proportion of deaths for liver cancer was found in male exposed workers. Although VCM is a known carcinogen for humans, there are still many exposure situations, albeit at low doses, in the chemical and plastic industries.

Associations of welding and manganese exposure with Parkinson disease: review and meta-analysis

OBJECTIVE

To examine associations of welding and manganese exposure with Parkinson disease (PD) using meta-analyses of data from cohort, case-control, and mortality studies.

METHODS

Epidemiologic studies related to welding or manganese exposure and PD were identified in a PubMed search, article references, published reviews, and abstracts. Inclusion criteria were 1) cohort, case-control, or mortality study with relative risk (RR), odds ratio (OR), or mortality OR (MOR) and 95 confidence intervals (95% CI); 2) RR, OR, and MOR matched or adjusted for age and sex; 3) valid study design and analysis. When participants of a study were a subgroup of those in a larger study, only results of the larger study were included to assure independence of datasets. Pooled RR/OR estimates and 95% CIs were obtained using random effects models; heterogeneity of study effects were evaluated using the Q statistic and I(2) index in fixed effect models.

RESULTS

Thirteen studies met inclusion criteria for the welding meta-analysis and 3 studies for the manganese exposure meta-analysis. The pooled RR for the association between welding and PD for all study designs was 0.86 (95% CI 0.80-0.92), with absence of between-study heterogeneity (I(2) = 0.0). Effect measures for cohort, case-control, and mortality studies were similar (0.91, 0.82, 0.87). For the association between manganese exposure and PD, the pooled OR was 0.76 (95% CI 0.41-1.42).

CONCLUSIONS

Welding and manganese exposure are not associated with increased PD risk. Possible explanations for the inverse association between welding and PD include confounding by smoking, healthy worker effect, and hormesis.

Welding occupations and mortality from Parkinson's disease and other neurodegenerative diseases among United States men, 1985-1999

Metal welding produces gaseous fumes that contain manganese, resulting in potential occupational exposure to welders. It has been hypothesized that occupational exposure among welders could increase risk of Parkinson's disease and other neurodegenerative diseases. The present study examines welding occupation and mortality from neurodegenerative diseases among men in the United States using the National Cause of Death databases 1985 to 1999. Information was abstracted from death certificates for states that collected data on occupation. Of 4,252,490 men who died during the study period, 107,773 had welding-related occupations. Multivariable logistic regression models were used to calculate mortality odds ratios (MOR) and 95% confidence intervals (CI) for odds of dying from Parkinson's disease or other neurodegenerative diseases among men who were welders as compared with men of other occupations, adjusting for attained age, race, region of residence, and year of death. During the study period, 49,174 deaths were attributed to Parkinson's disease, 54,892 to Alzheimer's disease, and 19,018 to presenile dementia. There was no evidence of an increased odds of Parkinson's disease mortality among welders as compared with men with other occupations (MOR = 0.83, 95% CI 0.78-0.88). Furthermore, welding occupation was unrelated to the odds of mortality from Alzheimer's disease (MOR = 0.94, 95% CI 0.89-1.00) or presenile dementia (MOR = 0.96, 95% CI 0.87-1.06). Earlier research suggested that welding exposures could predispose individuals to earlier onset Parkinson's disease. However, there was no evidence in this data of an increased mortality odds ratio associated with welding occupations among men younger than 65 (MOR = 1.03, 95% CI 0.74-1.44); while there was a suggestion of a lower odds Parkinson's disease death among men age 65 years and older (MOR = 0.82, 95% CI 0.77-0.88). Data from this large study do not support an association between welding occupations and death from Parkinson's disease or other neurodegenerative diseases, nor that welders are at increased odds of dying from Parkinson's disease at a younger age.