Searching for a relationship between manganese and welding and Parkinson’s disease

Abstract

Abstract-Research into the causes of Parkinson disease (PD) has accelerated recently with the discovery of novel gene mutations. The majority of PD cases, however, remain idiopathic and in those cases environmental causes should be considered. Several recent reports have focused on welding and manganese toxicity as potential risk factors for parkinsonism and some have even proposed that welding is a risk factor for PD. The controversy has stimulated this review, the primary aim of which is to critically and objectively examine the evidence or lack of evidence for a relationship among welding, manganese, parkinsonism, and PD. NEUROLOGY 2005;64:2021-2028 Parkinson disease (PD) is one of the most common neurodegenerative disorders, affecting approximately 1 million Americans and 1 to 2% of those over age 60 worldwide.1-3 With the lifetime risk of 2% and an increasing incidence with age, coupled with aging of the population, the prevalence of PD is expected to triple over the next 50 years.Despite the growing number of newly identified genetic causes of parkinsonism, 4,5 in the majority of cases the cause is unknown, hence the enormous interest in the role of environmental factors in various parkinsonian disorders.6,7 While numerous toxins have been found to produce nigrostriatal degeneration in experimental animals, 8 there is no evidence that any environmental toxin causes PD. A variety of environmental and occupational exposures, however, have been implicated in the etiology of PD. These include exposure to well water, pesticides, herbicides, rural living, certain metals, fuel oil, magnetic fields, and employment in the steel/alloy industry, wood/pulp plants, farming, carpentry, cleaning, orchards, planer mill, forestry, logging, mining, as well as certain occupations such as body and fender repairmen, auto painters, railroad and car shop mechanics, and workers in oil and gas fields. [9][10][11][12][13][14][15][16][17] In the recent past, several reports have also suggested that welders may be at a higher risk for developing parkinsonism, and some have even proposed that welding is a risk factor for PD.18,19 These claims have entered the legal system and numerous lawsuits have been filed on behalf of welders alleging that toxic fumes generated by the welding rods have caused not only parkinsonism, but also PD. In this review, we intend to examine the evidence for and against a relationship among welding, manganese, parkinsonism, and PD.With the discovery of new causes of parkinsonism and with the recognition that the same etiology (e.g., a single gene mutation) can be associated with markedly diverse pathology, the traditional view that pathologic examination is the gold standard in the diagnosis of PD has been recently challenged. 20,21 In this review, unless a specific etiologic cause is identified, we will define PD based on clinical-pathologic criteria.22 This approach is supported by several studies demonstrating that when PD is diagnosed clinically by expert parkinsonologists, the autopsy confirms the diagn...

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

“…By the beginning of the 19 th century, it was noted that high manganese exposure caused parkinsonian symptoms, although clinically distinct from PD [375]. There are also case reports on parkinsonism induced by lead exposure [376].…”

Correlation between airborne manganese concentration at the workstations in the iron foundry and manganese concentration in workers’ blood

“…Researchers have pointed out that the consequences of exposure to manganese in the workplace and uptake of this element in the body will bring about the central nervous system disorder, which would be called manganism, as the complications; there are many similarities with Parkinson's disease [5][6][7][8][9][10][11][12]. One of the most important scientific methods, particularly to determine the exposure to pollutants, is biological monitoring of workplaces [13][14][15].…”

Direct effects of manganese compounds on dopamine and its metabolite Dopac: An in vitro study

“…Manganese (Mn) is one of the most common elements in the earth's crust and an essential metal present in several dietary sources including nuts, grains, and tea (Jankovic, 2005). The recommended dietary intake for Mn is 2.3 and 1.8 mg/day for men and women, respectively.…”