title: Antioxidant supplementation and respiratory functions among workers exposed to high levels of ozone.
abstract: Ozone exposure has been related to adverse respiratory effects, in particular to lung function decrements. Antioxidant vitamins are free-radical scavengers and could have a protective effect against photo-oxidant exposure. To evaluate whether acute effects of ozone on lung functions could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial using a double-blind crossover design. Street workers (n = 47) of Mexico City were randomly assigned to take daily a supplement (75 mg vitamin E, 650 mg vitamin C, 15 mg beta carotene) or a placebo and were followed from March to August 1996. Pulmonary function tests were done twice a week at the end of the workday. During the follow-up, the mean 1-h maximum ozone level was 123 ppb (SD = 40). During the first phase, ozone levels were inversely associated with FVC (beta = -1.60 ml/ppb), FEV1 (beta = -2.11 ml/ppb), and FEF25-75 (beta = -4.92 ml/ppb) (p < 0.05) in the placebo group but not in the supplement group. The difference between the two groups was significant for FVC, FEV1, and FEF25-75 (p < 0.01). During the second phase, similar results were observed, but the lung function decrements in the placebo group were smaller, suggesting that the supplementation may have had a residual protective effect on the lung. These results need to be confirmed in larger supplementation studies.
authors.affiliation: Pan American Health Organization; Instituto Nacional de Salud Publica, Cuernavaca, Mor; Instituto de Investigacion en Matematica Aplicada y Sistemas, Universidad Autonoma de Mexico, Mexico DF. iar9@cdc.gov
authors.forename: I
authors.initials: I
authors.lastname: Romieu
authors.forename: F
authors.initials: F
authors.lastname: Meneses
authors.forename: M
authors.initials: M
authors.lastname: Ramirez
authors.forename: S
authors.initials: S
authors.lastname: Ruiz
authors.forename: R
authors.initials: R
authors.lastname: Perez Padilla
authors.forename: J J
authors.initials: JJ
authors.lastname: Sienra
authors.forename: M
authors.initials: M
authors.lastname: Gerber
authors.forename: L
authors.initials: L
authors.lastname: Grievink
authors.forename: R
authors.initials: R
authors.lastname: Dekker
authors.forename: I
authors.initials: I
authors.lastname: Walda
authors.forename: B
authors.initials: B
authors.lastname: Brunekreef
mesh_terms: D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000627:therapeutic use*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000517:prevention & control; D016273:Occupational Exposure; D010126:Ozone / Q000009:adverse effects*; D012119:Respiration / Q000187:drug effects*; D012129:Respiratory Function Tests; D012140:Respiratory Tract Diseases / Q000517:prevention & control; D013147:Spirometry; D014810:Vitamin E / Q000097:blood; D019207:beta Carotene / Q000097:blood / Q000627:therapeutic use*
chemical_list: D000975:Antioxidants; D019207:beta Carotene; D014810:Vitamin E; D010126:Ozone