From: Exposure to environmental chemicals and cancer risk: epidemiological evidence from Japanese studies
Reference | Study period | Design | Â | Study subjects | Â | Exposure assessment | Exposure | Exposure level (median or range among control group) | Category | Relative risk | 95% confidence interval | P for trend | Confounding factors |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Definition | Age range | Number of subjects | |||||||||||
Sawada et al. [66] | Enrolment 1995–1998, follow-up to 2006 | Population-based cohort | Residents in 10 public health center areas in Japan | 45–74 years old at enrolment | 402 breast cancer cases among 48,351 women | Food frequency questionnaire | Dietary intake (ug/day) | 19.2 | Tertile 1 | 1 |  | 0.41 | Adjusted for age, area, body mass index, smoking status, frequency of alcohol intake, leisure-time physical activity, intake of meat, soybean, vegetable, and fruit, menopausal status, and use of exogenous female hormones |
24.9 | Tertile 2 | 1.16 | (0.87–1.54) |  | |||||||||
32.3 | Tertile 3 | 0.87 | (0.61–1.23) |  | |||||||||
Itoh et al. [69] | Enrolment 2001–2005 | Hospital-based case–control | Cases: histopathologically confirmed, Controls: medical check-up examinees matched by age and area of residence | 20–74 years old | 390 cases and 390 controls | Food frequnecuy questionnaire | Dietary intake (ug/day) | 21.4 | Tertile 1 | 1 |  | 0.39 | Adjusted for menopausal status, moderate physical activity in the past five years, smoking status, family history of breast cancer, number of births, isoflavone intake, vegetable intake, and total energy intake |
26.2 | Tertile 2 | 1.19 | (0.79–1.79) |  | |||||||||
31.5 | Tertile 3 | 1.23 | (0.76–2.00) |  | |||||||||
Nagata et al. [70] | Enrolment 2000–2002 | Hospital-based case–control | Cases: histopathologically confirmed, Controls: examinees of breast cancer mass screening matched by age, menopausal status, and period of urine sampling | 25–70 + years old | 153 cases and 431 controls | Spot urine samples measured by flameless atomic absorption spectrometry | Urinary cadmium (ug/g creatinine) |  < 1.674 | Tertile 1 | 1 |  |  < 0.01 | Adjusted for age, years of education, age at menarche, number of births, age at first birth, body mass index, smoking status, alcohol intake, and family history of breast cancer among first-degree relatives |
1.674–2.620 | Tertile 2 | 2.25 | (1.17–4.37) |  | |||||||||
 > 2.620 | Tertile 3 | 6.05 | (2.90–12.62) |  |