Incidence of oral cancer in relation to nickel and arsenic concentrations in farm soils of patients' residential areas in Taiwan.
BACKGROUND
To explore if exposures to specific heavy metals in the environment is a new risk factor of oral cancer, one of the fastest growing malignancies in Taiwan, in addition to the two established risk factors, cigarette smoking and betel quid chewing.


METHODS
This is an observational study utilized the age-standardized incidence rates of oral cancer in the 316 townships and precincts of Taiwan, local prevalence rates of cigarette smoking and betel quid chewing, demographic factors, socio-economic conditions, and concentrations in farm soils of the eight kinds of heavy metal. Spatial regression and GIS (Geographic Information System) were used. The registration contained 22,083 patients, who were diagnosed with oral cancer between 1982 and 2002. The concentrations of metal in the soils were retrieved from a nation-wide survey in the 1980s.


RESULTS
The incidence rate of oral cancer is geographically related to the concentrations of arsenic and nickel in the patients' residential areas, with the prevalence of cigarette smoking and betel quid chewing as controlled variables.


CONCLUSIONS
Beside the two established risk factors, cigarette smoking and betel quid chewing, arsenic and nickel in farm soils may be new risk factors for oral cancer. These two kinds of metal may involve in the development of oral cancer. Further studies are required to understand the pathways via which metal in the farm soils exerts its effects on human health.
Department of Internal Medicine, Changhua Christian Hospital, 135, Nan-Hsiao Street, Changhua 500, Taiwan.
Che-Chun
CC
Su
Yo-Yu
YY
Lin
Tsun-Kuo
TK
Chang
Chi-Ting
CT
Chiang
Jian-An
JA
Chung
Yun-Ying
YY
Hsu
Ie-Bin
IeB
Lian
D000383:Agriculture; D001151:Arsenic / Q000032:analysis*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009062:Mouth Neoplasms / Q000453:epidemiology*; D009532:Nickel / Q000032:analysis*; D012044:Regression Analysis; D012111:Residence Characteristics; D012959:Socioeconomic Factors; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D013624:Taiwan / Q000453:epidemiology
D012987:Soil; D012989:Soil Pollutants; D009532:Nickel; D001151:Arsenic