title: Exposure-response analysis and risk assessment for lung cancer in relationship to silica exposure: a 44-year cohort study of 34,018 workers.
abstract: Crystalline silica has been classified as a human carcinogen by the International Agency for Research on Cancer (Lyon, France); however, few previous studies have provided quantitative data on silica exposure, silicosis, and/or smoking. We investigated a cohort in China (in 1960-2003) of 34,018 workers without exposure to carcinogenic confounders. Cumulative silica exposure was estimated by linking a job-exposure matrix to work history. Cox proportional hazards model was used to conduct exposure-response analysis and risk assessment. During a mean 34.5-year follow-up, 546 lung cancer deaths were identified. Categorical analyses by quartiles of cumulative silica exposure (using a 25-year lag) yielded hazard ratios of 1.26, 1.54, 1.68, and 1.70, respectively, compared with the unexposed group. Monotonic exposure-response trends were observed among nonsilicotics (P for trend < 0.001). Analyses using splines showed similar trends. The joint effect of silica and smoking was more than additive and close to multiplicative. For workers exposed from ages 20 to 65 years at 0.1 mg/m(3) of silica exposure, the estimated excess lifetime risk (through age 75 years) was 0.51%. These findings confirm silica as a human carcinogen and suggest that current exposure limits in many countries might be insufficient to protect workers from lung cancer. They also indicate that smoking cessation could help reduce lung cancer risk for silica-exposed individuals.
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Liu
authors.forename: Kyle
authors.initials: K
authors.lastname: Steenland
authors.forename: Yi
authors.initials: Y
authors.lastname: Rong
authors.forename: Eva
authors.initials: E
authors.lastname: Hnizdo
authors.forename: Xiji
authors.initials: X
authors.lastname: Huang
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.forename: Tingming
authors.initials: T
authors.lastname: Shi
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.forename: Tangchun
authors.initials: T
authors.lastname: Wu
authors.forename: Weihong
authors.initials: W
authors.lastname: Chen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004391:Dust; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D008906:Mining; D009784:Occupational Diseases; D016273:Occupational Exposure / Q000009:adverse effects*; D018570:Risk Assessment; D012822:Silicon Dioxide / Q000009:adverse effects*; D012829:Silicosis / Q000453:epidemiology*; D012907:Smoking / Q000453:epidemiology*
chemical_list: D004391:Dust; D012822:Silicon Dioxide
keywords: cohort; exposure-response analysis; lung cancer; risk assessment; silica; silicosis
references.citation: IARC Monogr Eval Carcinog Risks Hum. 1997;68:1-475
references.pmid: 9303953
references.citation: Ind Health. 2004 Jul;42(3):303-14
references.pmid: 15295901
references.citation: J Chronic Dis. 1975 Mar;28(3):135-47
references.pmid: 1123420
references.citation: Occup Environ Med. 2001 Jan;58(1):31-7
references.pmid: 11119632
references.citation: PLoS Med. 2012;9(4):e1001206
references.pmid: 22529751
references.citation: Regul Toxicol Pharmacol. 1987 Sep;7(3):307-20
references.pmid: 3317532
references.citation: J Tongji Med Univ. 1991;11(4):225-9
references.pmid: 1819033
references.citation: J Occup Med. 1992 Mar;34(3):311-6
references.pmid: 1312152
references.citation: Epidemiology. 1995 Nov;6(6):617-24
references.pmid: 8589094
references.citation: Br J Ind Med. 1991 Jan;48(1):53-60
references.pmid: 1847069
references.citation: Ann Epidemiol. 2007 Mar;17(3):227-36
references.pmid: 17320789
references.citation: Crit Rev Toxicol. 2011 May;41(5):404-65
references.pmid: 21548755
references.citation: Isr Med Assoc J. 2006 Feb;8(2):114-8
references.pmid: 16544735
references.citation: J Occup Environ Med. 2000 Jul;42(7):704-20
references.pmid: 10914339
references.citation: Occup Environ Med. 2004 Oct;61(10):854-60
references.pmid: 15377772
references.citation: Int J Occup Med Environ Health. 2008;21(1):1-23
references.pmid: 18482900
references.citation: Am J Epidemiol. 2001 Apr 1;153(7):695-703
references.pmid: 11282798
references.citation: Int Arch Occup Environ Health. 2009 Aug;82(8):997-1004
references.pmid: 19066933
references.citation: Ann Oncol. 2006 Jul;17(7):1039-50
references.pmid: 16403810
references.citation: Int Arch Occup Environ Health. 2007 Feb;80(4):320-6
references.pmid: 16897095
references.citation: Arch Environ Health. 1991 Mar-Apr;46(2):82-9
references.pmid: 2006898
references.citation: Ann Occup Hyg. 2001 Nov;45(8):631-42
references.pmid: 11718659
references.citation: Occup Environ Med. 2001 Jan;58(1):38-45
references.pmid: 11119633
references.citation: Occup Med (Lond). 2009 Mar;59(2):89-95
references.pmid: 19233828
references.citation: Epidemiology. 1992 Sep;3(5):452-6
references.pmid: 1391139
references.citation: Scand J Work Environ Health. 2005 Dec;31(6):450-8
references.pmid: 16425586
references.citation: Br J Ind Med. 1992 Mar;49(3):167-71
references.pmid: 1313281
references.citation: Am J Ind Med. 2000 Mar;37(3):252-9
references.pmid: 10642414
references.citation: Cancer Epidemiol Biomarkers Prev. 2010 Jun;19(6):1602-11
references.pmid: 20501770
references.citation: Epidemiology. 2007 Jan;18(1):36-43
references.pmid: 17149143
references.citation: Scand J Work Environ Health. 2003 Aug;29(4):317-24
references.pmid: 12934726
references.citation: Epidemiology. 2004 Jan;15(1):63-70
references.pmid: 14712148
references.citation: Cancer Causes Control. 2001 Nov;12(9):773-84
references.pmid: 11714104
references.citation: J Natl Cancer Inst. 1986 Oct;77(4):883-9
references.pmid: 3020298
references.citation: Epidemiology. 2007 Jan;18(1):23-4
references.pmid: 17179757