Dietary soy and increased risk of bladder cancer: the Singapore Chinese Health Study.
The association between soyfood consumption and subsequent bladder cancer risk was investigated in a population-based cohort study, the Singapore Chinese Health Study. As of December 31, 2000, 329,848 person-years of follow-up were accrued. Sixty-one histologically confirmed incident bladder cancer cases were identified. Information on soyfood consumption at baseline was obtained through in-person interviews using a validated dietary questionnaire. Relative risks and 95% confidence intervals were calculated using the Cox proportional hazard regression method. High intake of soyfood was statistically significantly related to an elevated risk of bladder cancer. Relative to the lowest quartile of energy-adjusted total soy intake (<36.9 g/1000 Kcal), the highest quartile of total soy intake (> or =92.5 g/1000 Kcal) was associated with a 2.3-fold increase in bladder cancer risk (95% confidence interval = 1.1-5.1) after adjustment for cigarette smoking and level of education. Similar results were obtained for intakes of soy protein and soy isoflavones. The soyfood-bladder cancer risk association did not differ significantly between men and women and was not explained by other dietary factors. The soy-cancer relationship became stronger when the analysis was restricted to subjects with longer (> or =3 years) duration of follow-up. To our knowledge, this is the first epidemiological report on the effect of dietary soy on bladder cancer risk.
Sun
Can-Lan
CL
USC/Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90089, USA. canlan@hsc.usc.edu
Yuan
Jian-Min
JM
Arakawa
Kazuko
K
Low
Siew-Hong
SH
Lee
Hin-Peng
HP
Yu
Mimi C
MC
D017677:Age Distribution; D000368:Aged; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D011336:Probability; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution; D012846:Singapore / Q000453:epidemiology; D030262:Soybean Proteins / Q000009:adverse effects*; D015996:Survival Rate; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology
D030262:Soybean Proteins