Nested case-control study of esophageal cancer in relation to occupational exposure to silica and other dusts.
BACKGROUND
Standardized proportionate mortality ratio (SPMR) was found to be 2.2 (95% CI = 1.3-3.5) for esophageal cancer (EC) among workers exposed to refractory brick dust in a large iron-steel complex in China.


METHODS
A nested case-control design within a cohort of industrial workers. One hundred and twenty-five EC cases and 250 controls were identified from the death registry file. Interviews were conducted of the next of kin for past exposure information on job, domestic, and lifestyle factors. History of occupational exposure to various dusts was reconstructed from personnel files and by interviewing colleagues utilizing a job-exposure matrix.


RESULTS
After adjusting for confounders, occupational exposure to silica dust was the most important risk factor among all variables investigated, with a 2.8-fold risk and a clear dose-response by length of exposure. Alcohol drinking (OR = 1.8) and coal cooking (OR = 2.0) were risk factors and high consumption of fruit diet (OR = 0.5) and meat diet (OR = 0.6) were protective factors.


CONCLUSIONS
The relationship between occupational exposure to silica dust and the risk of EC found in an earlier SPMR study was confirmed. Ingestion of silica particles after lung clearance may increase the risk of EC among workers exposed to silica.
Pan
G
G
Environmental Epidemiology Branch, Liaoning Public Health and Anti-epidemic Station, Shenyang City, P.R. China. beelnps@pub.sy.inpta.net.cn
Takahashi
K
K
Feng
Y
Y
Liu
L
L
Liu
T
T
Zhang
S
S
Liu
N
N
Okubo
T
T
Goldsmith
D F
DF
D000368:Aged; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000706:statistics & numerical data; D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D004391:Dust / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects / Q000706:statistics & numerical data; D004938:Esophageal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D005247:Feeding Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D009790:Occupations / Q000706:statistics & numerical data; D012307:Risk Factors; D012822:Silicon Dioxide / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013223:Statistics as Topic; D013997:Time Factors