ABSTRACT
Study populations were residents recruited from four townships including Tungshan, Chuangwei, Chiaohsi and Wuchieh in the northeastern coast of Taiwan from 1991 to 1994. A standardized questionnaire personal interview were conducted by four well-trained public health nurses. Information collected included demographic characteristics, cigarette smoking and habitual alcohol consumption status, as well as residential and well water consumption history. The arsenic concentration was determined by hydride generation combined with flame atomic absorption spectrometry. The arsenic concentration ranged from undetectable (<0.15 μg/L) to more than 3,000 μg/L. Newly diagnosed urinary cancer was identified by linking each participant’s national identification number to the national cancer registry profiles in Taiwan. Person-years for each participant were calculated from the date of questionnaire interview to the date of cancer diagnosis, death, or December 31, 2006, whichever came first. Relative risks (RR’s) and 95% confidence intervals (CI’s) were estimated by Cox’s proportional hazards regression models.
