Annals of Occupational and Environmental Medicine

Review

Reframing welders’ parkinsonism: from the “idiopathic” label to biological causation and legal recognition: Chul Gab Lee; Ann Occup Environ Med 2026;38:e20. Published online June 17, 2026; DOI: https://doi.org/10.35371/aoem.2026.38.e20

Abstract Abstract in Korean PDF Supplementary Material: In Korea, welders diagnosed with “idiopathic Parkinson's disease (iPD)” often face denial of workers’ compensation, as “idiopathic” is interpreted as excluding occupational contribution. This narrative review examines whether a categorical distinction between iPD and “toxic parkinsonism” is defensible on diagnostic, pathological, neuroimaging, epidemiological, causal-inference, and legal grounds. The 2024 NSD-ISS (Neuronal α-synuclein disease Integrated Staging System) and SynNeurGe (Synuclein-Neurodegeneration-Gene) frameworks challenge categorical use of the “idiopathic” label by defining Parkinson's disease (PD)–related disease biologically, irrespective of etiology. Nonhuman primate studies show that chronic low-dose manganese exposure can produce nigrostriatal deficits and α-synuclein aggregation overlapping with PD biology. Dichotomous use of FP-CIT dopamine transporter imaging or levodopa responsiveness to separate manganese poisoning from iPD is therefore scientifically unsound, as chronic welding exposure can induce presynaptic dysfunction and treatment responses indistinguishable from PD. Epidemiological findings diverge methodologically: direct clinical examination has reported elevated parkinsonism prevalence among welders, whereas administrative cohorts have generally found no increased PD risk. This divergence is plausibly explained by differences in case ascertainment, exposure assessment, healthy-worker-survivor selection, and disease latency. Bradford Hill and Rothman frameworks support a causal interpretation, although validated biomarkers and dose-response thresholds remain undefined. Under Korea’s Industrial Accident Compensation Insurance Act, causation is evaluated as a “proximate causal relationship” rather than strict scientific proof. A multi-hit model integrating genetic predisposition, aging, and cumulative environmental exposure supports recognition under this standard, and compensation eligibility should not depend on whether the diagnosis label is ‘PD’ or ‘parkinsonism.’ When parkinsonian symptoms occur in welders with at least approximately 20,000 exposure-weighted welding hours, or with substantial high-intensity exposure such as confined-space welding, inadequate ventilation, or flux-cored arc welding, occupational contribution should be considered under a weight-of-evidence approach. This criterion is sufficient for recognition but is not a necessary condition.; 용접공 파킨슨증(welder’s parkinsonism)의 재조명: '특발성(idiopathic)' 명명에서 생물학적 인과성과 법적 인정으로 (용접 노출과 파킨슨증의 생물학적 인과관계)
우리나라에서 '특발성 파킨슨병(idiopathic Parkinson's disease, iPD)'으로 진단받은 용접공은 산업재해보상에서 배제되는 경우가 적지 않다. 이는 '특발성(idiopathic)'이라는 용어가 직업적 기여를 배제하는 의미로 해석되기 때문이다. 본 종설(narrative review)에서는 특발성 파킨슨병과 독성 파킨슨증(toxic parkinsonism)을 범주적으로 구분하는 것이 진단학적, 병리학적, 신경영상학적 (neuroimaging), 역학적, 인과추론적(causal inference), 법적 측면에서 타당한지를 검토한다.
2024년 제안된 NSD-ISS와 SynNeurGe 체계는 파킨슨병 관련 질환을 병인과 무관하게 생물학적으로 정의함으로써 ‘특발성’이라는 명칭을 범주적으로 사용하는 관행에 문제를 제기한다. 비인간 영장류(nonhuman primate, NHP) 연구에 따르면, 만성 저용량 망간(manganese) 노출은 흑질선조체(nigrostriatal) 결손과 파킨슨병의 생물학적 특징과 중첩되는 알파-시누클레인(α-synuclein) 응집을 유발할 수 있다. 따라서 FP-CIT 도파민 운반체 영상(FP-CIT DAT imaging)이나 레보도파(levodopa) 반응성을 기준으로 망간 중독과 특발성 파킨슨병을 구분하는 것은 과학적으로 타당하지 않다. 만성 용접 노출은 PD와 구별하기 어려운 시냅스전(presynaptic) 기능장애와 치료 반응을 일으킬 수 있기 때문이다.
역학 연구의 결과는 방법론에 따라 갈린다. 직접적인 임상 진찰을 시행한 연구에서는 용접공의 파킨슨증 유병률이 높게 보고된 반면, 행정자료 기반 코호트(administrative cohort) 연구에서는 대체로 파킨슨병 위험 증가가 확인되지 않았다. 이러한 차이는 파킨슨병 사례 확인(case ascertainment) 방식, 노출 평가, 건강근로자 생존효과(healthy-worker-survivor effect), 질병 잠복기의 차이로 설명할 수 있다. 검증된 생체표지자(biomarker)와 용량-반응 기준 값은 아직 확립되지 않았으나, 힐(Bradford Hill)과 로스만(Rothman)의 인과추론 틀은 인과성과의 양립 가능성을 뒷받침한다.
우리나라 「산업재해보상보험법」에서 인과관계는 엄격한 과학적 증명이 아니라 '상당인과관계(proximate causal relationship)’로 판단한다. 유전적 소인, 노화, 누적 환경 노출을 통합하는 다중타격모형(multi-hit model)은 이 기준에 따른 업무관련성 인정을 뒷받침한다. 진단명이 '파킨슨병'인지 '파킨슨증'인지에 따라 보상 여부가 좌우되어서는 안 된다. 누적 노출가중 용접작업 시간(exposure-weighted welding hours)이 약 20,000시간 이상이거나, 밀폐공간 용접·불충분한 환기, 플럭스코어드 아크용접(flux-cored arc welding)과 같이 고강도 노출이 상당한 용접공에게 파킨슨증 증상이 발생한 경우에는, 증거 종합(weight-of-evidence) 접근에 따라 직업적 기여를 고려하여야 한다. 다만 이 기준은 인정을 위한 충분조건이지 필요조건은 아니다.

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Case Report

A Case of Amyotrophic Lateral Sclerosis in a Worker Treating Pesticide Wastes: Soon Choy, Jung Won Kim; Korean Journal of Occupational and Environmental Medicine 2011;23(4):480-487. Published online December 31, 2011; DOI: https://doi.org/10.35371/kjoem.2011.23.4.480

BACKGROUND
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving the motor neuron of the cerebrum, brain stem, and spinal cord. It has been suggested that various occupational or environmental agents could be a cause of ALS. We report upon a case of a person contracting ALS who experienced a long-time exposure to pesticides, implying that pesticides are probable causal agents of ALS.
CASE REPORTS
The patient has been experiencing shoulder pain and limitation of movement that started abruptly about three years ago. Over time, these symptoms have become aggravated despite ongoing therapies including medication. After two years, he was diagnosed with ALS through electromyography, nerve conduction velocity and many laboratory tests at a university hospital in Seoul. His social and medical history was non-specific. The patient had worked for about 15 years at a waste disposal site and mainly destroyed glass bottles containing pesticides. During this period, his respiratory tract and skin were exposed to various raw pesticides without appropriate personal protective equipment. He did this job one or two times a week and worked for two or more hours without a break. Through an investigation into the patient's working environment, significant levels of dichlorvos, one of the organophosphates, were detected.
CONCLUSIONS
The study results revealed that the patient was exposed to considerable doses of pesticides as opposed to men spraying pesticides. Although controversial, pesticide exposures have been associated with ALS. However, we suggest that in this case the possibility that these pesticide exposures acted as a causal agent for the diagnosed ALS based on plausible biological mechanisms and epidemiologic data.

Citations

Citations to this article as recorded by

Amyotrophic Lateral Sclerosis and Agricultural Environments: A Systematic Review
Hyun Kang, Eun Shil Cha, Geun Joo Choi, Won Jin Lee
Journal of Korean Medical Science.2014; 29(12): 1610. CrossRef
Pesticides and human chronic diseases: Evidences, mechanisms, and perspectives
Sara Mostafalou, Mohammad Abdollahi
Toxicology and Applied Pharmacology.2013; 268(2): 157. CrossRef

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Original Article

Use of Screening Dose to Evaluate the Work-relatedness of Cancers Occurring among Korean Radiation Workers: Meeseon Jeong, Young Woo Jin, Hyun Sul Lim, Chong Soon Kim; Korean Journal of Occupational and Environmental Medicine 2007;19(3):196-203. Published online September 30, 2007; DOI: https://doi.org/10.35371/kjoem.2007.19.3.196

Abstract PDF

OBJECTIVES
To propose a screening dose based on the probability of causation (PC) to simplify the evaluation procedure for the work-relatedness of the cancers occurring among Korean radiation workers.
METHODS
Under the PC uncertainty distribution, the screening dose was defined in which the maximum PC is equivalent to 50% for single exposure to radiation, after which the values were calculated according to three significance levels: 90%, 95%, and 99%. By using the screening doses for each cancer, we also predicted the number of compensations for the occupational cancers among the current Korean radiation workers to determine a reasonable criterion for the significance level.
RESULTS
If the cumulative dose received by a radiation worker with cancer is less than the screening dose, then PC can not be greater than 50%, i.e., the case can not be awarded as an occupational disease. The numbers of compensation cases for a future decade were predicted to be 3-5, 4-6, and 6-10 at the significance levels of 90%, 95%, and 99%, respectively.
CONCLUSIONS
The procedure to evaluate the occupational disease was greatly simplified by using the screening dose for evaluation. A criterion of 95% was recommended as the PC upper limit following consideration for the results of the predicted cases for compensation and the economic circumstances in Korea.

Citations

Citations to this article as recorded by

The work-relatedness at a case of acute lymphoblastic leukemia in a radiation oncologist
Bong Hyun Kim, Young-Jun Kwon, Young-Su Ju, Bong Kyu Kim, Hyun Seok Lee, Sang-gil Lee, Yun Kyung Chung
Annals of Occupational and Environmental Medicine.2017;[Epub] CrossRef
A case of chronic myeloid leukemia in a diagnostic radiographer
Chulyong Park, Sungyeul Choi, Dohyung Kim, Jaechan Park, Saerom Lee
Annals of Occupational and Environmental Medicine.2014;[Epub] CrossRef
Ionizing Radiation-induced Diseases in Korea
Young-Woo Jin, Meeseon Jeong, Kieun Moon, Min-Heui Jo, Seong-Kyu Kang
Journal of Korean Medical Science.2010; 25(Suppl): S70. CrossRef
Health Disorders Caused by Physical Factors among Health Care Workers - Focusing on Ionizing Radiation -
Hyun-Sul Lim
Journal of the Korean Medical Association.2010; 53(6): 483. CrossRef

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