Effect of Pesticides on Lung Function in the Canadian General Population

• Author / Creator

  Ye, Ming

• Although pesticide exposures have been associated with respiratory problems in humans, particularly in occupational settings, little is known about the effect of pesticides on lung function in the general population. The objective of this thesis is to characterize the association between pesticide exposure and lung function among the Canadian general population using data from the Canadian Health Measure Survey (CHMS), a nation-wide cross-sectional health survey. In this thesis, the effect of organophosphate insecticides, pyrethroid insecticides, the organochlorine pesticide DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], and the phenoxy herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) on lung function was investigated using human biomonitoring data of pesticide exposures and spirometric measures of lung function among CHMS-Cycle 1 participants aged 6 to 79 years, a representative sample of the Canadian general population. In addition, dietary predictors of exposures to organophosphate (OP) and pyrethroid (PYR) insecticides were also investigated. Multiple linear regression was used to examine the association between pesticide exposures and lung function after controlling potential confounders, including demographic factors, socioeconomic factors, lifestyle factors and environmental factors. The main findings in this thesis were: 1) Urinary detections of the organophosphate and pyrethroid insecticide metabolites were highly prevalent among the CHMS participants, with dietary consumption of fruit and vegetables being a significant predictor of exposures to OP insecticides and dietary consumption of vegetables, and pulses/nuts for exposures to PYR insecticides; 2) Among adult participants aged 20-79 years, one unit increase in log transformed urinary concentration (nmol/g creatinine) of total dialkyl phosphates (DAP, metabolites of OP insecticides excreted in urine) was associated with a 32.6 mL reduction in forced vital capacity (FVC, p=0.014), a 32.6 mL reduction in forced expiratory volume in 1 second (FEV1, p=0.02), a 0.3% reduction in FEV1/FVC ratio (p=0.36) and a 53.1 mL/s reduction in forced expiratory flow between 25% and 75% of FVC (FEF25%-75%, p=0.081); 3) One unit increase in log transformed urinary concentration (nmol/g creatinine) of total pyrethorid insecticide metabolites (PYR) was associated with a 17.4 mL reduction in FEV1 (p=0.045) among participants aged 6-11 years, and a 37.1 mL reduction in FVC (p=0.05) among participants aged 12-19 years; 4) Among adult participants aged 20-79 years, individuals with detectable p,p’-DDT had significantly lower mean FVC (difference=310.7mL; p=0.003) and FEV1 (difference=231.8mL; p=0.015) than those without, and every 100 units (ng/g lipid) increase in the concentrations of p,p’-DDE [1,1-bis-(4-chlorophenyl)-2,2-dichloroethene], a metabolite of insecticide DDT, was associated with an 18.8 mL decrease in FVC (p-value=0.002) and an 11.8 mL decrease in FEV1 (p-value=0.013); and 5) No significant association was observed between urinary concentrations of herbicide 2,4-D and lung function among the CHMS-Cycle 1 participants. In conclusion, results of this thesis demonstrated a prevalent detection of pesticide metabolites in urine and confirmed the dietary sources of pesticide exposures among the Canadian general population. Urinary concentrations of OP metabolites were significantly associated with impaired lung function in the adult population. The potential adverse effect of pyrethroid insecticides on lung function was mainly significant among children and adolescents. Although it has been banned for more than thirty years in Canada, the environmentally persistent pesticide DDT was associated with decremented lung function among the Canadian adult population. Findings of this thesis provide the first population-based evidence of the adverse effect of pesticides on lung function in the Canadian general population.

• Subjects / Keywords

  • Pesticides
  • Lung function
  • Canadian general population

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R30C4SR7X

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.