title: Urinary 2,5-hexanedione excretion in cryptogenic polyneuropathy compared to the general Swedish population.
abstract: BACKGROUND
  2,5-hexanedione (2,5-HD) is the main neurotoxic metabolite of methyl-n-butyl ketone (MBK) and n-hexane, and known to cause polyneuropathy. The aim of our study was to compare the urinary levels of 2,5-HD between cases with cryptogenic polyneuropathy and the general Swedish population, and to elucidate the role of certain external factors.
  
  
  METHODS
  Morning urine samples were collected from 114 cases with cryptogenic polyneuropathy (77 men and 37 women) and 227 referents (110 men and 117 women) randomly selected from the population registry. None had any current occupational exposure to n-hexane or MBK. The urine samples were analysed by a gas chromatographic method based on acidic hydrolysis.
  
  
  RESULTS
  Cases had statistically higher urinary levels of 2,5-HD (0.48 mg/L) than the general population (0.41 mg/L) and men higher excretion than women (0.48 mg/L and 0.38 mg/L, respectively). There was no difference in 2,5-HD levels between current smokers and non-smokers. Occupational exposure to xylene, alcohol consumption and ever exposed to general anaesthesia were associated with lower excretion in men while for occupational exposure to nitrous oxide in women higher excretion was seen. Higher excretion of 2,5 HD was inversely related to increasing age.
  
  
  CONCLUSIONS
  Significantly higher levels of urinary 2,5-HD were seen in men and cryptogenic polyneuropathy cases seemingly unexposed to n-hexane. Hypothetically, this might be due to either differences in metabolic patterns or some concealed exposure. The difference in means between cases and the general population is small and can therefore not allow any firm conclusions of the causality, however.
authors.affiliation: Division of Neurology and Neurophysiology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden. magnus.vrethem@lio.se.
authors.forename: Bodil
authors.initials: B
authors.lastname: Persson
authors.forename: Magnus
authors.initials: M
authors.lastname: Vrethem
authors.forename: Nicola
authors.initials: N
authors.lastname: Murgia
authors.forename: Jonas
authors.initials: J
authors.lastname: Lindh
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Hällsten
authors.forename: Mats
authors.initials: M
authors.lastname: Fredrikson
authors.forename: Martin
authors.initials: M
authors.lastname: Tondel
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