title: Respiratory symptoms and occupational exposures in New Zealand plywood mill workers.
abstract: OBJECTIVE
  To study work exposure and respiratory symptoms in New Zealand plywood mill workers.
  
  
  METHODS
  Personal inhalable dust (n = 57), bacterial endotoxin (n = 20), abietic acid (n = 20), terpene (n = 20) and formaldehyde (n = 22) measurements were taken and a respiratory health questionnaire was administered to 112 plywood mill workers.
  
  
  RESULTS
  Twenty-six percent of the dust exposures exceeded 1 mg/m(3), however, none of the samples exceeded the legal limit of 5 mg/m(3) [geometric mean (GM) = 0.7 mg/m(3), geometric standard deviation (GSD) = 1.9]. Workers in the composer area (where broken sheets are joined together) were significantly (P < 0.01) more highly exposed. Endotoxin levels were low to moderate (GM = 23.0 EU/m(3), GSD = 2.8). Abietic acid levels ranged from 0.3 to 2.4 micro g/m(3) (GM = 0.7 micro g/m(3), GSD = 1.8) and were significantly (P < 0.05) higher for workers in the composer area of the process. Geometric mean levels of alpha-pinene, beta-pinene and Delta(3)-carene were 1.0 (GSD = 2.7), 1.5 (GSD = 2.8) and 0.1 (GSD = 1.4), respectively, and alpha-pinene and beta-pinene levels were significantly (P < 0.001) higher for workers in the 'green end' of the process, up to and including the veneer dryers. Formaldehyde levels ranged from 0.01 to 0.74 mg/m(3) [GM = 0.08 mg/m(3) (= 0.06 p.p.m.), GSD = 3.0]. Asthma symptoms were more common in plywood mill workers (20.5%, n = 112) than in the general population [12.8%, n = 415, adjusted OR (95% CI) = 1.5 (0.9-2.8)]. Asthma symptoms were associated with duration of employment and were reported to lessen or disappear during holidays. No clear association with any of the measured exposures was found, with the exception of formaldehyde, where workers with high exposure reported more asthma symptoms (36.4%) than low exposed workers [7.9%, adjusted OR (95% CI) = 4.3 (0.7-27.7)].
  
  
  CONCLUSIONS
  Plywood mill workers are exposed to inhalable dust, bacterial endotoxin, abietic acid, terpenes and formaldehyde, and they appear to have an increased risk of developing work-related respiratory symptoms. These symptoms may be due to formaldehyde exposure, although a potential causal role for other exposures cannot be excluded.
authors.affiliation: Centre for Public Health Research, Massey University Wellington Campus, Private Box 756, Wellington, New Zealand.
authors.forename: Wouter
authors.initials: W
authors.lastname: Fransman
authors.forename: Dave
authors.initials: D
authors.lastname: McLean
authors.forename: Jeroen
authors.initials: J
authors.lastname: Douwes
authors.forename: Paula A
authors.initials: PA
authors.lastname: Demers
authors.forename: Victor
authors.initials: V
authors.lastname: Leung
authors.forename: Neil
authors.initials: N
authors.lastname: Pearce
mesh_terms: D045784:Abietanes; D000328:Adult; D004224:Diterpenes / Q000009:adverse effects; D004391:Dust; D005260:Female; D005557:Formaldehyde / Q000009:adverse effects; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D010616:Phenanthrenes / Q000009:adverse effects; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000209:etiology*; D013729:Terpenes / Q000009:adverse effects; D014934:Wood
chemical_list: D045784:Abietanes; D004224:Diterpenes; D004391:Dust; D010616:Phenanthrenes; D013729:Terpenes; D005557:Formaldehyde; C023710:abietic acid