To confirm the association of lifestyle factors with cancer, largescale population-based studies are believed to give the best evidence. In Japan before about 1985, however, there was only one large-scale cohort study running to evaluate cancer risk in regard to lifestyle, which was called the Six-Prefecture Cohort Study. 1 Though the study demonstrated some useful information for preventing cancer, because of rapid lifestyle change, we conducted another large-scale population-based study in the late 1980s 2, 3 to reveal risk factors and to provide cancer prevention strategies. In this study, not only traditional epidemiological data such as sociodemographic or lifestyle factors but also sera (from one-third of whole subjects) were collected and stocked to investigate risk factors of cancer relating to biochemical substances in blood. Moreover, to consider the magnitude of lifestyle changes in rela-

To investigate the association of alcohol intake, cigarette smoking, occupation, and other factors with the development of idiopathic osteonecrosis of the femoral head, a nationwide multicenter case-control study was conducted in Japan during 1988-1990, comparing 118 cases with no history of systemic corticosteroid use with 236 controls matched for sex, age, ethnicity, clinic, and date of initial examination. The risks of developing femoral head necrosis associated with potential risk factors were estimated by adjusted relative odds obtained by a conditional logistic regression model. The elevated relative odds were observed for occasional drinkers (relative odds = 3.2, 95% confidence interval 1.1-9.2) and regular drinkers (relative odds = 13.1, 95% confidence interval 4.1-42.5) with a significant dose-response relation (p < 0.001). For current drinkers, the relative odds were 2.8, 9.4, and 14.8 for < 320, 320-799, and > or = 800 g/week of ethanol intake, respectively. An increased risk was found for current smokers (relative odds = 4.7, 95% confidence interval 1.5-14.5), but a linear increasing trend in the cumulative effect of smoking was not evident at 20 pack-years or over. A weak but significant dose-response relation was observed for daily occupational energy consumption (p < 0.05). The present study confirmed the strong association of alcohol intake and positive association of cigarette smoking and suggested the role of heavy physical work.

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To explore the association between dietary habits and risk of hepatocellular carcinoma (HCC) mortality in Japan, univariate analyses was performed using data from the JACC Study. A cohort of 46,465 males and 64,327 females aged 40 to 79 in 19 prefectures in Japan completed the baseline survey during 1988-1990 and were followed up until the end of 1999. The hazard ratio (HR) of HCC mortality for each food item by gender, age group (40-59 and 60-79 years) and history of liver diseases was obtained by Cox proportional hazards model. Some categories, such as boiled rice, ham and sausage, chicken, fish and pickles among men without history of liver diseases and those of miso-soup, fish, carrots and squash, and potatoes among women without history of liver diseases showed a significant inverse association with HCC mortality. Frequent intake of eggs was significantly associated with increased HCC mortality in men without history of liver diseases. Potatoes and foods boiled down in soy sauce (tsukudani) showed a significant positive association, and pickles had a significant inverse association with HCC mortality in men with history of liver diseases. Frequent intake of coffee showed a significant inverse association with HCC mortality both in men and women with history of liver diseases. It is considered that further analysis using a multivariate Cox proportional hazards model including other confounding factors will be required for a more meaningful interpretation of the data.

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