Effects of polymorphic variations in tumor necrosis factor alpha and occupational exposure to grain dust on longitudinal decline in pulmonary function.
BACKGROUND
Longitudinal declines in pulmonary function are associated with individuals experiencing occupational exposure to organic dusts in combination with lifestyle factors such as cigarette smoking and with genetic factors, and interactions between these factors.


OBJECTIVE
To investigate the relationship between polymorphism of genes encoding Tumor Necrosis Factor Alpha (TNF-alpha) and longitudinal lung function decline in grain workers exposed to grain dust.


METHODS
Male grain handlers who participated in the Saskatchewan Grain Workers Surveillance Program from 2002 through 2005 provided demographic, occupational, lifestyle, and respiratory symptoms information as well as pulmonary function measurements and DNA for genotyping. Marginal models using the generalized estimating equations approach were fitted by using a SAS PROC GENMOD to predict the annual decline in Forced Expired Volume in one second (FEV(1)) and Forced Vital Capacity (FVC).


RESULTS
Smoking intensity contributed to the decline in FEV(1.)Among *1/*1 homozygotes and *1/*2 heterozygotes, grain workers with <10 years in the grain industry had significantly lower FEV(1)declines compared to those of the other two exposure groups (>10 and < or =20 years, and >20 years in the grain industry). The annual declines in FEV(1)for grain workers who were either *1/*1 homozygote or *1/*2 heterozygote and had been in the grain industry for <10 years were lower by comparison to those of grain workers who were *2/*2 genotype and had been in the industry for <10 years.


CONCLUSIONS
This research demonstrates that years in the grain industry is an effect modifier between TNF-alpha 308 genotype and longitudinal decline in FEV(1)in male subjects exposed to grain dust.
Pahwa
Punam
P
Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Royal University Hospital, Saskatoon, Canada. pup165@mail.usask.ca
Nakagawa
Kazuko
K
Koehncke
Niels
N
McDuffie
Helen H
HH
D000328:Adult; D004391:Dust; D002523:Edible Grain / Q000009:adverse effects*; D015987:Effect Modifier, Epidemiologic; D005838:Genotype; D006801:Humans; D008168:Lung / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D012525:Saskatchewan / Q000453:epidemiology; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D004391:Dust; D014409:Tumor Necrosis Factor-alpha