Risk of urinary bladder cancer: a case-control analysis of industry and occupation
BMC Cancer
Risk of urinary bladder cancer: a case-control analysis of industry and occupation
Adrian Cassidy 0
Wei Wang 0
Xifeng Wu 0
Jie Lin 0
0 Address: Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center , Houston, Texas , USA
Background: Uncertainty remains about urinary bladder cancer (UBC) risk for many occupations. Here, we investigate the association between occupation, industry and UBC. Methods: Lifetime occupational history was collected by in-person interview for 604 newly diagnosed UBC patients and 604 cancer-free controls. Each job title was assigned a two-digit industry code and a three-digit occupation code. Odds ratios (ORs) for UBC associated with ever being employed in an industry or occupation were calculated by unconditional logistic regression adjusting for age, gender and smoking status. We also examined UBC risk by duration of employment (>0 to <10, ≥10 years) in industry or occupation. Results: Significantly increased risk of UBC was observed among waiters and bartenders (OR 2.87; 95% CI 1.05 to 7.72) and occupations related to medicine and health (OR 2.17; 95% CI 1.21 to 3.92), agricultural production, livestock and animal specialties (OR 1.90; 95% CI 1.03 to 3.49), electrical assembly, installation and repair (OR 1.69; 95% CI 1.07 to 2.65), communications (OR 1.74; 95% CI 1.00 to 3.01), and health services (OR 1.58; 95% CI 1.02 to 2.44). For these occupations we also observed a significant excess risk of UBC for long-term work (i.e. ≥10 years), with the exception of waiters and bartenders. Employment for 10 years or more was associated with increased risk of UBC in general farmers (OR 9.58; 95% CI 2.18 to 42.05), agricultural production of crops (OR 3.36; 95% CI 1.10 to 10.27), occupations related to bench working (OR 4.76; 95% CI 1.74 to 13.01), agricultural, fishery, forestry & related (OR 4.58; 95% CI 1.97 to 10.65), transportation equipment (OR 2.68; 95% CI 1.03 to 6.97), and structural work (OR 1.85; 95% CI 1.16 to 2.95). Conclusions: This study provides evidence of increased risk of UBC for occupations that were previously reported as at-risk. Workers in several occupation and industry groups have a significantly higher risk of UBC, particularly when duration of employment is 10 years or more.
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Background
Urinary bladder cancer (UBC) ranks the fourth most
common cancer in men and ninth in women in the United
States, accounting for an estimated 70,980 new cases in
2009[1]. Numerous studies have demonstrated that the
primary modifiable risk factors for UBC are cigarette
smoking and occupational exposure to carcinogens. An
updated review of the literature estimates that between 5
and 25% of all UBC cases are attributable to workplace
exposures[2]. The variance in attributable fraction
suggests that, despite numerous studies investigating the
association between UBC risk and occupational
exposures, results have been inconsistent. To date, only a few
occupations and industries, such as those exposed to
aromatic amines, have been unequivocally associated with
increased risk of UBC.
Previous reported high-risk occupation/industry groups
include dyestuff workers, rubber workers, painters,
printers, metal workers, textile workers, truck drivers, chemical
workers and employment in industries involving leather,
petrochemical production, plastics production and
hairdressing. [3-13] Excess risk of UBC has also been reported
among health service workers and farmers[3,4,6,14-16].
However, uncertainty remains about UBC risk for many
occupations[17]. Using data from a large on-going
casecontrol study of UBC in Houston, Texas, we sought to
investigate the association between occupation, industry
and UBC, and to identify general patterns and trends in
UBC risk in the study population.
Methods
Urinary bladder cancer patients were enrolled from an
ongoing case-control study of UBC at M.D. Anderson Cancer
Center, Houston, Texas, which began recruitment in
1999. The procedures for patient recruitment and
eligibility criteria have been described elsewhere[18]. Briefly,
UBC patients were recruited from the University of Texas
M.D. Anderson Cancer Center and Baylor College of
Medicine. Patients were defined as newly diagnosed and
histopathologically confirmed UBC patients who had not
previously received chemotherapy or radiotherapy. There
were no recruitment restrictions on age, gender, ethnicity
or cancer-stage. The controls were recruited in
collaboration with the Kelsey-Seybold clinics, the largest private
multi-specialty physician group consisting of more than
23 clinics and over 300 physicians in the Houston
metropolitan area. The majority of controls visited the clinics for
annual health check-ups. Controls were frequency
matched to case by age (± 5 years), gender and ethnicity.
Controls had no prior history of cancer (except
nonmelanoma skin cancer). After obtaining written, informed
consent from the patients and controls, trained M.D.
Anderson Cancer Cente (...truncated)