Background: School children have been increasingly recognized as health messengers for malaria control. However, little evidence is available. The objective of this study was to determine the impact of school-based malaria education intervention on school children and community adults. Methods: This study was conducted in the Dangme-East district of the Greater Accra Region, Ghana, between 2007 and 2008. Trained schoolteachers designed participatory health education activities and led school children to disseminate messages related to malaria control to their communities. Three schools and their respective communities were chosen for the study and assigned to an intervention group (one school) and a control group (two schools). Questionnaire-based interviews and parasitological surveys were conducted before and after the intervention, with the intervention group (105 children, 250 community adults) and the control group (81 children, 133 community adults). Chi-square and Fisher's Exact tests were used to analyse differences in knowledge, practices, and parasite prevalence between pre- and post-intervention. Results: After the intervention, the misperception that malaria has multiple causes was significantly improved, both among children and community adults. Moreover, the community adults who treated a bed net with insecticide in the past six months, increased from 21.5% to 50.0% (p < 0.001). Parasite prevalence in school children decreased from 30.9% to 10.3% (p = 0.003). These positive changes were observed only in the intervention group. Conclusions: This study suggests that the participatory health education intervention contributed to the decreased malaria prevalence among children. It had a positive impact not only on school children, but also on community adults, through the improvement of knowledge and practices. This strategy can be applied as a complementary approach to existing malaria control strategies in West African countries where school health management systems have been strengthened.

Risk models and scores have been developed to predict incidence of type 2 diabetes in Western populations, but their performance may differ when applied to non-Western populations. We developed and validated a risk score for predicting 3-year incidence of type 2 diabetes in a Japanese population. Participants were 37,416 men and women, aged 30 or older, who received periodic health checkup in 2008–2009 in eight companies. Diabetes was defined as fasting plasma glucose (FPG) ≥126 mg/dl, random plasma glucose ≥200 mg/dl, glycated hemoglobin (HbA1c) ≥6.5%, or receiving medical treatment for diabetes. Risk scores on non-invasive and invasive models including FPG and HbA1c were developed using logistic regression in a derivation cohort and validated in the remaining cohort. The area under the curve (AUC) for the non-invasive model including age, sex, body mass index, waist circumference, hypertension, and smoking status was 0.717 (95% CI, 0.703–0.731). In the invasive model in which both FPG and HbA1c were added to the non-invasive model, AUC was increased to 0.893 (95% CI, 0.883–0.902). When the risk scores were applied to the validation cohort, AUCs (95% CI) for the non-invasive and invasive model were 0.734 (0.715–0.753) and 0.882 (0.868–0.895), respectively. Participants with a non-invasive score of ≥15 and invasive score of ≥19 were projected to have >20% and >50% risk, respectively, of developing type 2 diabetes within 3 years. The simple risk score of the non-invasive model might be useful for predicting incident type 2 diabetes, and its predictive performance may be markedly improved by incorporating FPG and HbA1c.

The association between meat consumption and colorectal cancer remains inconsistent among Asians. The present study systematically evaluated and meta-analyzed epidemiologic studies on the association between consumption of total and specific meats and colorectal cancer risk among Japanese. Original data were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented with manual searches. The associations were evaluated based on the strength of evidence, the magnitude of association and biologic plausibility. A meta-analysis was performed according to total meat, red and processed meat as well as poultry and site-specific cancers. Six cohort studies and 13 case–control studies were identified. In cohort studies, most investigations found no association between total meat consumption and colon/rectal cancer, and several studies showed a weak-to-moderate positive association of red meat and processed meat consumption with colon/rectal cancer. The majority of case–control studies showed no association between total meat consumption and colon and rectal cancer; however, several ones reported a weak-to-strong positive association of red and processed consumption with colon and rectal cancer. In meta-analysis, the summary relative risks (95% confidence interval) for the highest versus lowest categories of red meat consumption were 1.16 (1.001–1.34) and 1.21 (1.03–1.43) for colorectal and colon cancer, respectively, and those for processed meat consumption were 1.17 (1.02–1.35) and 1.23 (1.03–1.47) for colorectal and colon cancer, respectively. Poultry consumption was associated with lower risk of rectal cancer; summary relative risk (95% confidence interval) was 0.80 (0.67–0.96). High consumption of red meat and processed meat possibly increases risk of colorectal cancer or colon cancer among the Japanese population.

Japanese diets contain a relatively high amount of carbohydrates, and its high dietary glycemic index and glycemic load may raise the risk of diabetes in the Japanese population. The current study evaluated the associations between the dietary glycemic index, glycemic load, and the risk of type 2 diabetes in a population based cohort in Japan.

Metabolic syndrome has become a major public health concern, but the role of diet in the etiology of this syndrome is not well understood. This study investigated the association between major dietary patterns and prevalence of metabolic syndrome in a Japanese working population. This cross-sectional study was conducted among 460 municipal employees (284 men and 176 women), aged 21–67 years, who participated in a health survey at the time of periodic checkup. Dietary patterns were derived by using the principal component analysis of the consumption of 52 food and beverage items, which were assessed by a validated brief diet history questionnaire. Metabolic syndrome was defined according to the modified NCEP-ATP III criteria. Logistic regression was used to examine the association between dietary patterns and metabolic syndrome with adjustment of potential confounding variables. Three dietary patterns were identified. Westernized breakfast pattern characterized by high intakes of bread, confectionaries, and milk and yogurt but low intakes of rice and alcoholic beverages was inversely associated with prevalence of metabolic syndrome and high blood pressure (P for trend = 0.02 and 0.049, respectively). Animal food pattern characterized by high intakes of fish and shellfish, meat, processed meat, mayonnaise, and egg was not associated with prevalence of metabolic syndrome, but was positively associated with high blood glucose (P for trend = 0.03). Healthy Japanese dietary pattern characterized by vegetables and fruits, soy products, mushrooms, and green tea was not appreciably associated with prevalence of metabolic syndrome or its components. The results suggest that westernized breakfast pattern may confer some protection against metabolic syndrome in Japanese. The causality of these associations needs to be confirmed.

Leisure-time physical activity is associated with a lower risk of depression. However, the precise shape of the dose–response relationship remains elusive, and evidence is scarce regarding other domains of activity. We prospectively investigated associations of physical activity during leisure, work, and commuting with risk of depressive symptoms in Japanese workers. We conducted a cohort study of 29 082 Japanese workers aged 20–64 years without psychiatric disease (including depressive symptoms) at baseline with a maximum 5-year follow-up. Physical activity was self-reported. Depressive symptoms were assessed by 13 self-report questions on subjective symptoms. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for incidence of depressive symptoms were calculated using Cox regression analysis. During a mean follow-up of 4.7 years, 6177 developed depressive symptoms. Leisure exercise showed a U-shaped association with risk of depressive symptoms adjusting for potential confounders. Additional adjustment for baseline depression scores attenuated the association, but it remained statistically significant (P for trend = 0.037). Compared with individuals who engaged in sedentary work, the HR (95 % CI) was 0.86 (0.81, 0.92) for individuals who stand or walk during work and 0.90 (0.82, 0.99) for those who are fairly active at work. However, the association disappeared after adjusting for baseline depression scores. Walking to and from work was not associated with depressive symptoms. The findings suggest that leisure-time exercise has a U-shaped relation with depressive symptoms in Japanese workers. Health-enhancing physical activity intervention may be needed for individuals who engage in sedentary work.