Shizuka Sasazuki

Daily Total Physical Activity Level and Premature Death in Men and Women: Results From a Large-Scale Population-Based Cohort Study in Japan (JPHC Study)

PURPOSE The impact of daily total physical activity level on premature deaths has not been fully clarified in non-Western, relatively lean populations. We prospectively examined the association between daily total physical activity level (METs/day) and subsequent risk of all-cause mortality and mortalities from cancer, heart disease, and cerebrovascular disease. METHODS A total of 83,034 general Japanese citizens ages 45-74 years who responded to the questionnaire in 1995-1999 were followed for any cause of death through December 2005. Mutlivariate-adjusted hazard ratios were calculated with a Cox proportional hazards model controlling for potential confounding factors. RESULTS During follow-up, a total of 4564 deaths were recorded. Compared with subjects in the lowest quartile, increased daily total physical activity was associated with a significantly decreased risk of all-cause mortality in both sexes (hazard ratios for the second, third, and highest quartiles were: men, 0.79, 0.82, 0.73 and women, 0.75, 0.64, 0.61, respectively). The decreased risk was observed regardless of age, frequency of leisure-time sports or physical exercise, or obesity status, albeit with a degree of risk attenuation among those with a high body mass index. A significantly decreased risk was similarly observed for death from cancer and heart disease in both sexes, and from cerebrovascular disease in women. CONCLUSION Greater daily total physical activity level, either from occupation, daily life, or leisure time, may be of benefit in preventing premature death.

Association between Body-Mass Index and Risk of Death in More Than 1 Million Asians

BACKGROUND Most studies that have evaluated the association between the body-mass index (BMI) and the risks of death from any cause and from specific causes have been conducted in populations of European origin. METHODS We performed pooled analyses to evaluate the association between BMI and the risk of death among more than 1.1 million persons recruited in 19 cohorts in Asia. The analyses included approximately 120,700 deaths that occurred during a mean follow-up period of 9.2 years. Cox regression models were used to adjust for confounding factors. RESULTS In the cohorts of East Asians, including Chinese, Japanese, and Koreans, the lowest risk of death was seen among persons with a BMI (the weight in kilograms divided by the square of the height in meters) in the range of 22.6 to 27.5. The risk was elevated among persons with BMI levels either higher or lower than that range--by a factor of up to 1.5 among those with a BMI of more than 35.0 and by a factor of 2.8 among those with a BMI of 15.0 or less. A similar U-shaped association was seen between BMI and the risks of death from cancer, from cardiovascular diseases, and from other causes. In the cohorts comprising Indians and Bangladeshis, the risks of death from any cause and from causes other than cancer or cardiovascular disease were increased among persons with a BMI of 20.0 or less, as compared with those with a BMI of 22.6 to 25.0, whereas there was no excess risk of either death from any cause or cause-specific death associated with a high BMI. CONCLUSIONS Underweight was associated with a substantially increased risk of death in all Asian populations. The excess risk of death associated with a high BMI, however, was seen among East Asians but not among Indians and Bangladeshis.

Diet and the risk of gastric cancer: review of epidemiological evidence

There are geographic and ethnic differences in the incidence of gastric cancer around the world as well as with its trends for each population over time. The incidence patterns observed among immigrants change according to where they live. All of these factors serve to indicate the close association of gastric cancer with modifiable factors such as diet. This review presents epidemiological evidence on the association between dietary factors and gastric cancer based on previous systematic reviews and subsequent updates. Infection with Helicobacter pylori is a strong and established risk factor of gastric cancer but is not a sufficient cause for its development. Substantial evidence from ecological, case-control, and cohort studies strongly suggests that the risk may be increased with a high intake of various traditional salt-preserved foods and salt per se and decreased with a high intake of fruit and vegetables, particularly fruit. However, it remains unclear which constituents in fruit and vegetables play a significant role in gastric cancer prevention. Among them, vitamin C is a plausible candidate supported by a relatively large body of epidemiological evidence. Consumption of green tea is possibly associated with a decreased risk of gastric cancer, although the protective effects have been, for the most part, identified in Japanese women, most of whom are nonsmokers. In contrast, processed meat and N-nitroso compounds may be positively associated with the risk of gastric cancer. In conclusion, dietary modification by reducing salt and salted food intake, as well as by increasing intake of fruit and vitamin C, represents a practical strategy to prevent gastric cancer.

Salt and salted food intake and subsequent risk of gastric cancer among middle-aged Japanese men and women

Evidence on the association between salt intake and gastric cancer is sparse, especially in prospective studies. We conducted a population-based prospective study in Japan, where the majority of men has been infected with Helicobacter pylori. A total of 18 684 men and 20 381 women aged 40–59 years who reported their dietary habits and did not report any serious disease at baseline were followed from 1990 to 2001. A total of 486 cases, 358 men and 128 women, with histologically confirmed gastric cancer were documented among them. The quintile category of salt intake was dose-dependently associated with gastric cancer risk in men after adjusting for potential confounding factors (P for trend <0.001), while a trend was not clear in women (P for trend=0.48). Although stratification by study area, with varied salt intake and gastric cancer incidence, attenuated the observed clear associations with salt and salted foods, the frequency categories of highly salted foods such as salted fish roe and salted fish preserves were strongly associated with the risk in both sexes. Restriction of salt and salted food intake is a practical strategy to prevent gastric cancer in areas with high risk.

Soy Product and Isoflavone Consumption in Relation to Prostate Cancer in Japanese Men

The incidence of prostate cancer is much lower in Asian than Western populations. Environmental factors, such as dietary habits, may play a major role in the causation of prostate cancer. Although isoflavones have been suggested to show a preventive effect against prostate cancer in animal experiments, the results of epidemiologic studies are inconsistent. Here, we conducted a population-based prospective study in 43,509 Japanese men ages 45 to 74 years who generally have a high intake of isoflavones and low incidence of prostate cancer. Participants responded to a validated questionnaire, which included 147 food items. During follow-up from 1995 through 2004, 307 men were newly diagnosed with prostate cancer, of which 74 cases were advanced, 220 cases were organ localized, and 13 cases were of an undetermined stage. Intakes of genistein, daidzein, miso soup, and soy food were not associated with total prostate cancer. However, these four items decreased the risk of localized prostate cancer. In contrast, positive associations were seen between isoflavones and advanced prostate cancer. These results were strengthened when analysis was confined to men ages >60 years, in whom isoflavones and soy food were associated with a dose-dependent decrease in the risk of localized cancer, with relative risks for men in the highest quartile of genistein, daidzein, and soy food consumption compared with the lowest of 0.52 [95% confidence interval (95% CI), 0.30-0.90], 0.50 (95% CI, 0.28-0.88), and 0.52 (95% CI, 0.29-0.90), respectively. In conclusion, we found that isoflavone intake was associated with a decreased risk of localized prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(3):538–45)

Gastric cancer screening and subsequent risk of gastric cancer: A large‐scale population‐based cohort study, with a 13‐year follow‐up in Japan

We prospectively investigated the association between gastric cancer screening and subsequent risk of gastric cancer in a large‐scale population‐based prospective cohort study, with a 13‐year follow‐up in Japan. Data were analyzed from a population‐based cohort of 42,150 (20,326 men and 21,824 women) subjects. Approximately 36% of subjects reported that they had undergone screening photofluorography during the preceding 12 months, and were regarded as the screened group. A total of 179 gastric cancer deaths and 636 incident gastric cancers were identified during the follow‐up period. We observed a 2‐fold decrease in gastric cancer mortality in screened versus unscreened subjects (RR = 0.52; 95% CI = 0.36–0.74). The extent of the reduction in mortality for gastric cancer was greater than in death from all causes excluding gastric cancer (RR = 0.71; 95% CI = 0.65–0.78). A significant decrease in the incidence of advanced gastric cancer was observed in screened subjects (RR = 0.75; 95% CI = 0.58–0.96), although the overall incidence rate did not differ significantly between the screened and unscreened subjects (RR = 1.06; 95% CI = 0.90–1.25). In age‐stratified analyses, a significant reduction in gastric cancer mortality was seen in screened subjects aged 40–49 years at baseline, compared with a lesser reduction in screened subjects aged 50–59 (RR = 0.30, 95% CI = 0.13–0.72; and RR = 0.60, 95% CI = 0.40–0.88, respectively). These findings suggest that gastric cancer screening may be associated with a reduced risk of mortality from gastric cancer.

Plasma Isoflavone Level and Subsequent Risk of Breast Cancer Among Japanese Women: A Nested Case-Control Study From the Japan Public Health Center-Based Prospective Study Group

PURPOSE Because they have large variations in consumption, Asian countries are suitable settings for studies of the effect of relatively high-dose isoflavone intake on breast cancer risk. Nevertheless, no prospective study from Asia has assessed blood or urine levels as biomarkers of isoflavone intake. PATIENTS AND METHODS A total of 24,226 women ages 40 to 69 years in the Japan Public Health Center-based prospective study who responded to the baseline questionnaire and provided blood in 1990 to 1995 were observed to December 2002. During a mean 10.6 years of follow-up, 144 patients newly diagnosed with breast cancer were identified. Two matched controls for each patient were selected from the cohort. Isoflavone levels were assessed by plasma level and food frequency questionnaire, and the odds ratio of breast cancer according to isoflavone level was estimated using a conditional logistic regression model. RESULTS We found a statistically significant inverse association between plasma genistein and risk of breast cancer, but no association for plasma daidzein. Adjusted odds ratios for the highest versus lowest quartile of plasma level were 0.34 for genistein (95% CI, 0.16 to 0.74; P for trend, .02) and 0.71 for daidzein (95% CI, 0.35 to 1.44; P for trend, .54). Median plasma genistein values in the control group were 31.9 ng/mL for the lowest and 353.9 ng/mL for the highest quartile groups. Regarding dietary intake of isoflavones, nonsignificant inverse associations were observed for both genistein and daidzein. CONCLUSION This nested case-control study found an inverse association between plasma genistein and the risk of breast cancer in Japan.

Cigarette smoking and subsequent risk of lung cancer by histologic type in middle‐aged Japanese men and women: The JPHC study

In order to update the findings of relative risk associated with cigarette smoking for lung cancer by histologic type in Japan, the data from a population‐based cohort study of 91,738 men and women were analyzed. During 1990–1999, 422 lung cancer incident cases were identified. The relative risk for all incident cases associated with current smokers versus non‐smokers was 4.5 [95% confidence interval (CI): 3.0–6.8] and 4.2 (95% CI: 2.4–7.2), for men and women, respectively. When divided by histologic type, relative risk for squamous cell carcinoma and small cell carcinoma was 12.7 (95% CI: 4.7–34.7) and 17.5 (95% CI: 4.9–62.1), while for adenocarcinoma it was 2.8 (95% CI: 1.6–4.9) and 2.0 (95% CI: 0.8–5.0) for men and women, respectively. We confirmed that the lung cancer risk in men rose with increasing cigarette smoking, especially the duration of smoking among current smokers and decreased after the cessation of smoking among former smokers. Unlike the US or European countries, the relative risk did not increase in this updated study, compared with previous studies in 1960s to 1990s in Japan either for all incident cases or for specific histologic types and the magnitude of relative risks was substantially lower than that observed in the US or European countries, especially for adenocarcinoma.

Relation between green tea consumption and the severity of coronary atherosclerosis among Japanese men and women

PURPOSE To examine the relation between green tea consumption and arteriographically determined coronary atherosclerosis. METHODS Study subjects were 512 patients (302 men and 210 women) aged 30 years or older who underwent coronary arteriography for the first time at four hospitals in Fukuoka City or one hospital in an adjacent city between September 1996 and August 1997. Lifestyle characteristics including green tea consumption were ascertained before arteriography by a questionnaire supported with interview. RESULTS 117 men (38.7%) and 50 women (23.8%) had significant stenosis of one or more coronary arteries. Green tea consumption tended to be inversely associated with coronary atherosclerosis in men, but not in women. An evident, protective association between green tea and coronary atherosclerosis was observed in a subgroup of 262 men excluding those under dietary or drug treatment for diabetes mellitus. In this subgroup, after adjustment for traditional coronary risk factors and coffee, odds ratios of significant stenosis for consumption of 2-3 cups and 4 or more cups per day were 0.5 (95% confidence interval 0.2-1.2) and 0.4 (0.2-0.9), respectively, as compared with a consumption of one cup per day or less. CONCLUSIONS The results indicate that green tea may be protective against coronary atherosclerosis at least in men.

Association between body mass index and cardiovascular disease mortality in east Asians and south Asians: pooled analysis of prospective data from the Asia Cohort Consortium

Objective To evaluate the association between body mass index and mortality from overall cardiovascular disease and specific subtypes of cardiovascular disease in east and south Asians. Design Pooled analyses of 20 prospective cohorts in Asia, including data from 835 082 east Asians and 289 815 south Asians. Cohorts were identified through a systematic search of the literature in early 2008, followed by a survey that was sent to each cohort to assess data availability. Setting General populations in east Asia (China, Taiwan, Singapore, Japan, and Korea) and south Asia (India and Bangladesh). Participants 1 124 897 men and women (mean age 53.4 years at baseline). Main outcome measures Risk of death from overall cardiovascular disease, coronary heart disease, stroke, and (in east Asians only) stroke subtypes. Results 49 184 cardiovascular deaths (40 791 in east Asians and 8393 in south Asians) were identified during a mean follow-up of 9.7 years. East Asians with a body mass index of 25 or above had a raised risk of death from overall cardiovascular disease, compared with the reference range of body mass index (values 22.5-24.9; hazard ratio 1.09 (95% confidence interval 1.03 to 1.15), 1.27 (1.20 to 1.35), 1.59 (1.43 to 1.76), 1.74 (1.47 to 2.06), and 1.97 (1.44 to 2.71) for body mass index ranges 25.0-27.4, 27.5-29.9, 30.0-32.4, 32.5-34.9, and 35.0-50.0, respectively). This association was similar for risk of death from coronary heart disease and ischaemic stroke; for haemorrhagic stroke, the risk of death was higher at body mass index values of 27.5 and above. Elevated risk of death from cardiovascular disease was also observed at lower categories of body mass index (hazard ratio 1.19 (95% confidence interval 1.02 to 1.39) and 2.16 (1.37 to 3.40) for body mass index ranges 15.0-17.4 and <15.0, respectively), compared with the reference range. In south Asians, the association between body mass index and mortality from cardiovascular disease was less pronounced than that in east Asians. South Asians had an increased risk of death observed for coronary heart disease only in individuals with a body mass index greater than 35 (hazard ratio 1.90, 95% confidence interval 1.15 to 3.12). Conclusions Body mass index shows a U shaped association with death from overall cardiovascular disease among east Asians: increased risk of death from cardiovascular disease is observed at lower and higher ranges of body mass index. A high body mass index is a risk factor for mortality from overall cardiovascular disease and for specific diseases, including coronary heart disease, ischaemic stroke, and haemorrhagic stroke in east Asians. Higher body mass index is a weak risk factor for mortality from cardiovascular disease in south Asians.