Changing trends in the prevalence of H. pylori infection in the general population over time are thought to be the main driving force behind the declining gastric cancer mortality in Japan. However, whether the prevalence of H. pylori infection itself shows a birth-cohort pattern needs to be corroborated. We performed a systematic review of studies that reported the prevalence of H. pylori infection among Japanese individuals. Meta-regression was conducted in the framework of a generalized additive mixed model (GAMM) to account for heterogeneity in the prevalence of H. pylori infection as a function of birth year. The prevalence of H. pylori infection confirmed a clear birth cohort pattern: the predicted prevalence (%, 95% CI) was 60.9 (56.3–65.4), 65.9 (63.9–67.9), 67.4 (66.0–68.7), 64.1 (63.1–65.1), 59.1 (58.2–60.0), 49.1 (49.0–49.2), 34.9 (34.0–35.8), 24.6 (23.5–25.8), 15.6 (14.0–17.3), and 6.6 (4.8–8.9) among those who were born in the year 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, 1990, and 2000, respectively. The present study demonstrated a clear birth-cohort pattern of H. pylori infection in the Japanese population. The decreased prevalence of H. pylori infection in successive generations should be weighed in future gastric cancer control programs.

BackgroundFindings regarding the association between milk consumption and all-cause mortality reported by studies carried out in Western populations have been inconsistent. However, no studies have been conducted in Japan on this issue. The present study aimed to investigate the association of milk drinking with all-cause, cardiovascular, and cancer mortality in Japan.MethodsThe data were obtained from the Japan Collaborative Cohort (JACC) study. A total of 94 980 Japanese adults aged 40–79 years who had no history of cancer, stroke, or chronic cardiovascular diseases were followed between 1988 and 2009. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of mortalities were assessed using a Cox proportional hazard regression model and taking the lowest milk consumption group as the reference.ResultsDuring a median of 19 years of follow-up, there were 21 775 deaths (28.8% and 35.3% from cardiovascular diseases and cancer, respectively). Drinking milk 1–2 times a month was associated with lower all-cause mortality in men compared to those who never drank milk (multivariable-adjusted HR 0.92; 95% CI, 0.85–0.99). In women, those who drank 3–4 times a week also had a lower mortality risk compared with those who never drank milk (HR 0.91; 95% CI 0.85–0.98). Inverse associations between drinking milk and mortality from cardiovascular diseases and cancer were found only in men.ConclusionsDrinking milk at least 1–2 times a month was associated with lower all-cause mortality in men compared to never drinking milk. An inverse association was also found between drinking milk and mortality from both cardiovascular diseases and cancer. However, lower all-cause mortality in women was found only in those who drank milk 3–4 times/week.

These findings imply that higher hs-CRP itself or existence of chronic systemic inflammation precedes onset of T2DM independent of obesity and smoking.

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Excess intake of iodine is a suspected risk factor for thyroid cancer. Previous epidemiological research from Japan reported that daily intake of seaweed was associated with a four-fold higher risk in postmenopausal women, whereas others reported a null association. A major source of iodine intake in Japan is from edible seaweeds, and it is reported to be among the highest in the world. We examined the association between seaweed intake frequency and the risk of thyroid cancer in women in the Japan Collaborative Cohort Study followed from 1988 to 2009. Seaweed intake, together with other lifestyle-related information was collected using a self-administered questionnaire at baseline. Seaweed intake frequency was categorized as follows: 1-2 times/week or less, 3-4 times/week, and almost daily. Hazard ratios and the 95% confidence intervals of thyroid cancer incidence according to seaweed intake frequency were estimated using Cox proportional hazards regression. During 447 876 person-years of follow-up (n=35 687), 94 new cases of thyroid cancer were identified. The crude incidence rate was 20.9 per 100 000 person-years. The hazard ratio of thyroid cancer in women who consumed seaweed daily compared with women who ate it 1-2 times/week or less was 1.15 (95% confidence interval: 0.69-1.90, P for trend=0.59). Further analyses did not indicate any association between seaweed intake and the risk of thyroid cancer on statistically adjusting for potential confounding variables as well as on stratification by menopausal status. The present study did not find an association between seaweed intake and thyroid cancer incidence in premenopausal or in postmenopausal women.

Smoking has been consistently associated with the risk of colorectal cancer (CRC) in Western populations; however, evidence is limited and inconsistent in Asian people. To assess the association of smoking status, smoking intensity and smoking cessation with colorectal risk in the Japanese population, we performed a pooled analysis of 10 population‐based cohort studies. Study‐specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox's proportional hazards model and then pooled using a random‐effects model. Among 363 409 participants followed up for 2 666 004 person‐years, 9232 incident CRCs were identified. In men, compared with never smokers, ever smokers showed higher risk of CRC. The HRs (95% CI) were 1.19 (1.10‐1.29) for CRC, 1.19 (1.09‐1.30) for colon cancer, 1.28 (1.13‐1.46) for distal colon cancer and 1.21 (1.07‐1.36) for rectal cancer. Smoking was associated with risk of CRC in a dose‐response manner. In women, compared with never smokers, ever smokers showed increased risk of distal colon cancer (1.47 [1.19‐1.82]). There was no evidence of a significant gender difference in the association of smoking and CRC risk. Our results confirm that smoking is associated with an increased risk of CRC, both overall and subsites, in Japanese men and distal colon cancer in Japanese women.

Rapid urine-HpAb test had excellent specificity but relatively low sensitivity.