Daytime napping is associated with elevated risk of CVD mortality as well as non-cardiovascular/non-cancer and external deaths. Daytime napping may elevate risk of CVD death through some biological effects but, to a larger extent, some comorbid disorders causing weight loss or associated with non-regular employment and low education level could explain this association.

Lung cancer has increased and is the leading cause of cancer death among Japanese males. The associations of dietary habits with the risk of lung cancer death were evaluated by sex and smoking habits in this study. In the Japan Collaborative Cohort (JACC) Study, a cohort established in 1988-90 and consisting of 42 940 males and 55 308 females was observed for lung cancer deaths up to the end of 1997. During the observation period, 446 males and 126 females died of lung cancer. A self-administered food frequency questionnaire was used as the baseline survey. Hazard ratios for dietary factors were calculated by Cox's proportional hazards model. Among males, a high intake of ham and sausages, cheese, green-leafy vegetables, oranges, and other fruits significantly and dose-dependently decreased the risk of lung cancer death. Among females, a high intake of miso-soup, ham and sausages, and liver significantly and almost dose-dependently increased the risk. Vegetables and fruits rich in antioxidative and carcinogenic agents reduced the risk of lung cancer deaths among male smokers more than among female nonsmokers. The results among female nonsmokers were partially consistent with the hypothesis that high fat consumption increases the risk of lung cancer, especially that of adenocarcinoma.

Estimating the proportion of lung cancer deaths that can be avoided is important in assessing the potential impact of antismoking efforts on the reduction of lung cancer deaths. We calculated the population attributable risk (PAR) and absolute risk of lung cancer death according to smoking status based on the Japan Collaborative Cohort (JACC) Study. The analytic cohort included 45,010 males and 55,724 females aged 40 -79 years. Cox proportional hazards model was used to determine age-adjusted relative risks and PAR according to smoking status. We also computed lung cancer mortality according to age and smoking status. In males, 52.2% and 14.8% of lung cancer deaths were attributable to current and former cigarette smoking, respectively. In females, the corresponding figures were 11.8% and 2.8%. Among current male smokers, the relative risk was strongly correlated with the intensity and duration of cigarette smoking. In contrast, the PAR was associated with an intermediate level of smoking except for the years of smoking: the largest PARs were observed in those with 20 -29 cigarettes per day, 40 -59 pack-years and 20 -22 years old at starting smoking. Absolute risks were estimated to increase with age and duration of smoking and not to decrease even after cessation. These findings suggest that avoidable lung cancer deaths are primarily among light to moderate smokers who are considered amenable to population-based antismoking strategies. For all current smokers, immediate cessation is encouraged because it offers the only realistic way to avoid a substantial increase in lung cancer mortality brought about by further continuation of smoking. © 2003 Wiley-Liss, Inc. Key words: lung cancer; cigarette smoking; cohort study; population attributable risk; mortalityLung cancer is one of the most commonly occurring malignancies and the major cause of cancer death in the world. 1 In Japan, lung cancer is the leading cause of cancer death in males and the third most common cause in females, and the mortality rates are still increasing. 2 Epidemiologic studies have extensively examined the relative risk of lung cancer according to smoking status and repeatedly shown a strong association between lung cancer risk and the intensity and duration of cigarette smoking. 3 In contrast, relatively few studies 4 -6 have estimated the population attributable risk (PAR), an estimate of the proportion of lung cancers attributable to cigarette smoking. Furthermore, most of these studies estimated only overall PAR due to cigarette smoking and did not focus on partial PARs for population strata according to smoking status. However, assessment of partial PARs should be important in public health practice because it identifies smoker subgroups in particular need of intensive antismoking intervention, 7 for the goal of reducing smoking-attributable lung cancer deaths. In addition, partial PAR analysis can help to estimate the proportion of lung cancers that can be prevented exclusively by smoking cessation. Therefore, PARs according to smoki...

Chronic inflammation contributes to the process of carcinogenesis, but few epidemiologic studies have examined associations with risk of lung cancer. Relationships between lung cancer risk and serum levels of both heat shock protein 70 (Hsp70) and high-sensitivity C-reactive protein (hsCRP) were investigated in a case-control study nested in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. Serum samples and lifestyle information were collected at baseline from 39,242 men and women between 1988 and 1990. Of these, 240 deaths from lung cancer were identified through 1999, and 569 controls were matched for sex, age, and study area. Serum levels were measured in 189 cases and 377 controls for Hsp70 and in 209 cases and 425 controls for hsCRP. Odds ratios (95% confidence intervals) across quartiles, adjusted for confounding factors, including smoking habits, were 0.83 (0.44-1.58), 1.41 (0.77-2.60), and 1.84 (0.92-3.71) for Hsp70 (P trend = 0.042) and 1.13 (0.67-1.91), 0.66 (0.38-1.16), and 1.19 (0.70-2.02) for hsCRP (P trend = 0.941). In males, odds ratios (95% confidence intervals) across quartiles were 1.30 (0.59-2.84), 1.74 (0.83-3.67), and 2.49 (1.06-5.85) for Hsp70 (P trend = 0.029). High levels of serum Hsp70 might thus be associated with increased risk of lung cancer among Japanese males, although further studies are needed to clarify associations between chronic inflammation and lung cancer.

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