Environmental Risk Factors in Isolated Dystonia: A Systematic Scoping Review.

Area of Science:

• Neurology
• Genetics
• Environmental Health

Background:

• Isolated dystonia is a neurological disorder with complex genetic and environmental causes.
• The influence of environmental triggers on dystonia expression is not well understood.

Purpose of the Study:

• To systematically map and review evidence on environmental risk factors associated with isolated dystonia.

Main Methods:

• Scoping review following PRISMA-ScR guidelines.
• Searched PubMed/MEDLINE, Web of Science, and Google Scholar (1980-2024).
• Assessed study quality using the modified Newcastle-Ottawa Scale (NOS).

Main Results:

• Nineteen studies included; NOS scores varied (4/9 to 8/9).
• Strong links found between peripheral trauma and cervical dystonia, and prolonged writing and writer's cramp.
• Moderate associations noted for cranial trauma (blepharospasm) and betel nut use (oromandibular dystonia); tobacco showed a protective effect for blepharospasm. Gene-environment interaction showed accelerated onset in DYT1 carriers with repetitive tasks (P=0.03).

Conclusions:

• Environmental factors, including trauma, occupation, and lifestyle, are key determinants in isolated dystonia pathogenesis.
• Findings highlight environmental influences but stress the need for standardized metrics and prospective studies due to heterogeneity.