Central nervous system diseases of organic solvents exposed workers based on nationwide medical surveillance-data in Korea.

BACKGROUND

New light is being shed on the relationship between chronic neurotoxicity of the central nervous system (CNS) and exposure to low-level organic solvents (OS). However, there are few longitudinal studies with a large sample size.

METHODS

A cohort of OS-exposed male workers was selected who had undergone an OS-associated specialized medical check-up at least once between 2000 and 2004 in Korea. The standardized admission ratios (SAR) for CNS diseases were calculated with reference to the Korean adult male population. Adjusted relative risks (ARR) were also estimated in comparison to noise-exposed male workers.

RESULTS

There were 238,574 OS-exposed workers, yielding 954,772 person-years of exposure. OS-exposed workers were at elevated risk of "other extrapyramidal and movement disorders" (G25) with a SAR = 2.95 (95% CI: 1.41-5.42) and "systemic atrophies primarily affecting the CNS" (G10-G13) SAR = 2.08 (95% CI: 1.03-3.74). There were no significant differences between the OS-exposed workers and noise-exposed workers.

CONCLUSIONS

A limited number of CNS diseases identified through hospital admissions data and short observation periods reduced statistical power to determine effect size. OS exposure was positively associated with "other extrapyramidal and movement disorder and systemic atrophies primarily affecting the CNS.