New Study Finds No Association Between Welding and
First Epi-Cohort Study to Focus on Welders Confirms
Welders Not at Increased Risk of Neurodegenerative Disorders
Washington DC, May 12, 2005 – The Welding Information Center announced today that an important new epidemiological study published in the May 2005 issue of the Journal of Occupational and Environmental Medicine concludes that there is no link between welding or exposure to welding fumes and an increased risk of Parkinson’s disease or any other similar neurodegenerative disorder. Entitled “A Cohort Study of Parkinson’s Disease and Other Neurodegenerative Disorders in Danish Welders,” it is the first epidemiological cohort study of Parkinson’s disease and other neurodegenerative disorders undertaken among men employed as welders.
Dr. Mark Roberts, Fellow and Board Member of the American College of Occupational and Environmental Medicine, stated, “This is an excellent study that provides important information about the health of welders. It is the largest cohort study to date to look at the issue of welding and Parkinson's disease and other parkinsonisms. It has a well-defined study population, excellent long-term follow-up and is the only cohort study to look at the rate of incidence of Parkinson's disease in this context. The results of this study show that welders in this large population are not at an increased risk of developing Parkinson’s disease or other similar movement disorders.”
The cohort of 27,839 males identified as working in metals manufacturing, were drawn from all Danish males with hospitalization and out-patient records from the period 1977 through 2000. 9,817 of these men worked in departments where welding occurred, and 6,163 of those in such departments were classified as actual welders. The standardized disease-specific hospitalization ratio (SHR) incidence of Parkinson’s disease in these three groups was then compared to the SHRs for the same diseases in the general population. The resulting SHRs for Parkinson’s disease were .9 for all workers in metals manufacturing, 1.0 for those in welding departments, and .9 for welders themselves. An SHR below 1.0 indicates the studied cohort was less likely to contract the disease than the general public, an SHR of 1.0 means the risk is the same as the general public, and an SHR above 1.0 suggests an increased risk for the studied group. Similar non-association SHRs were computed for the other neurodegenerative diseases.
The study concluded “this cohort of Danish welders with more than 20 years of systematic follow-up had rates of PD and other neurological conditions consistent with those of the general population of Denmark,” and notes its clinical significance by saying, “this relatively large cohort study offers assurances that men in mild and stainless steel welding do not have increased hospitalizations for PD or other neurodegenerative disorders."
The lead author of the study was epidemiologist Dr. Jon Fryzek of the International Epidemiological Institute, in Rockville MD. A grant funding this research was provided by a group of current and former manufacturers of welding consumables.