The Upper Midwest Health Study: a case-control study of pesticide applicators and risk of glioma.
BACKGROUND
An excess incidence of brain cancer in farmers has been noted in several studies. The National Institute for Occupational Safety and Health developed the Upper Midwest Health Study (UMHS) as a case-control study of intracranial gliomas and pesticide uses among rural residents. Previous studies of UMHS participants, using "ever-never" exposure to farm pesticides and analyzing men and women separately, found no positive association of farm pesticide exposure and glioma risks. The primary objective was to determine if quantitatively estimated exposure of pesticide applicators was associated with an increased risk of glioma in male and female participants.


METHODS
The study included 798 histologically confirmed primary intracranial glioma cases (45 % with proxy respondents) and 1,175 population-based controls, all adult (age 18-80) non-metropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. The analyses used quantitatively estimated exposure from questionnaire responses evaluated by an experienced industrial hygienist with 25 years of work on farm pesticide analyses. Odds ratios (ORs) and 95 % confidence intervals (CIs) using unconditional logistic regression modeling were calculated adjusting for frequency-matching variables (10-year age group and sex), and for age and education (a surrogate for socioeconomic status). Analyses were separately conducted with or without proxy respondents.


RESULTS
No significant positive associations with glioma were observed with cumulative years or estimated lifetime cumulative exposure of farm pesticide use. There was, a significant inverse association for phenoxy pesticide used on the farm (OR 0.96 per 10 g-years of cumulative exposure, CI 0.93-0.99). No significant findings were observed when proxy respondents were excluded. Non-farm occupational applicators of any pesticide had decreased glioma risk: OR 0.72, CI 0.52-0.99. Similarly, house and garden pesticide applicators had a decreased risk of glioma: OR 0.79, CI 0.66-0.93, with statistically significant inverse associations for use of 2,4-D, arsenates, organophosphates, and phenoxys.


CONCLUSIONS
These results are consistent with our previous findings for UMHS of reported farm pesticide exposure and support a lack of positive association between pesticides and glioma.
National Institute for Occupational Safety and Health, Cincinnati, OH, USA. jcy5@cdc.gov
James H
JH
Yiin
Avima M
AM
Ruder
Patricia A
PA
Stewart
Martha A
MA
Waters
Tania
T
Carreón
Mary Ann
MA
Butler
Geoffrey M
GM
Calvert
Karen E
KE
Davis-King
Paul A
PA
Schulte
Jack S
JS
Mandel
Roscoe F
RF
Morton
Douglas J
DJ
Reding
Kenneth D
KD
Rosenman
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000382:Agricultural Workers' Diseases / Q000139:chemically induced / Q000453:epidemiology*; D001932:Brain Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D016022:Case-Control Studies; D004781:Environmental Exposure; D005260:Female; D005910:Glioma / Q000139:chemically induced / Q000453:epidemiology*; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015146:Midwestern United States / Q000453:epidemiology; D016273:Occupational Exposure; D016017:Odds Ratio; D010575:Pesticides / Q000633:toxicity*; D018570:Risk Assessment; D055815:Young Adult
D010575:Pesticides