The author reviewed recent reports about the blood levels and dietary intake of polychlorinated dibenzo‐p‐dioxins (PCDDs)/furans (PCDFs)/dioxin‐like polychlorinated biphenyls (DL‐PCBs) to investigate ...the trends of dioxin exposure, and epidemiologic studies on the associations of blood levels of dioxins with metabolic diseases. In recent years, dietary intake of dioxins has been decreasing, and the means are equal to or less than 1.0 pg Toxic Equivalents (TEQ)/kg/day in the general populations of several countries. The blood levels of dioxins are also decreasing, probably because of reduced dietary intake. Many cross‐sectional studies reported positive associations between blood levels of some isomers or TEQ‐based concentrations of PCDDs/PCDFs/DL‐PCBs and diabetes in general populations. Three cohort studies on populations with heavy exposure and two nested case‐control studies on general populations have also been published, but the results are inconsistent. Three large‐scale cross‐sectional studies and two cohort studies reported an association between blood levels of some isomers or TEQ‐based concentrations of PCDDs/PCDFs/DL‐PCBs and metabolic syndrome. In addition, three cross‐sectional studies reported significant positive associations with gout/hyperuricemia. Further prospective studies and experimental studies are needed to establish cause‐effect relationships, and to clarify the biological mechanisms for the association between background exposure to dioxins and potential health effects. J. Med. Invest. 65:151‐161, August, 2018
Backgrounds: The fatty liver index (FLI) is a good non-invasive approach for fatty liver disease diagnosis. The objective of this study was to examine the associations of nutrient patterns with ...non-alcoholic fatty liver disease (NAFLD) in a Japanese population.Methods: A total of 1,588 subjects (789 men and 799 women) aged 35–69 years were recruited in the baseline survey of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study in Tokushima Prefecture. Factor analysis was applied to energy-adjusted intake of 21 nutrients, and nutrient patterns were extracted. Multiple logistic regression analysis was used to analyze the relationships between nutrient patterns and the high FLI category (≥60).Results: Four nutrient patterns were extracted: Factor 1, vitamins, dietary fiber, iron and potassium pattern; Factor 2, fats and fat-soluble vitamins pattern; Factor 3, saturated fat, calcium, vitamin B2 and low carbohydrate pattern; and Factor 4, sodium, protein and vitamin D pattern. After adjustment for sex, age, and other potential confounding variables, higher Factor 1 scores were significantly associated with lower odds ratios of NAFLD (P for trend <0.05). Analysis of each component of FLI showed that there were significant inverse associations between Factor 1 scores and high body mass index and large waist circumference.Conclusion: The present findings suggest that a nutrient pattern rich in vitamins, fiber, iron, and potassium was associated with lower prevalence of NAFLD in a Japanese population. Obesity and abdominal obesity may be intermediate variables for the association between this nutrient pattern and NAFLD.
To quantify the 1-year cumulative incidence of capitellar osteochondritis dissecans (OCD) in preadolescent baseball players and identify the risk factors associated with this condition.
In total, ...1,275 school-aged baseball players (aged 6-11 years) without an established diagnosis of capitellar OCD were enrolled in this longitudinal, observational study. One year later, all players underwent ultrasonographic examination of the throwing elbow on the playing field. Elbows with abnormal ultrasonographic findings at this time then underwent radiographic examination. Data for the groups with and without capitellar OCD were analyzed using multivariate logistic regression models.
The 1-year cumulative incidence of capitellar OCD was 1.8% (95% confidence interval, 1.1%-2.7%). On multivariate analysis, players aged 10 to 11 years were 3.96 times more likely to have capitellar OCD (95% confidence interval, 1.10-18.97) than those aged 6 to 9 years; however, starting baseball at an earlier age, number of years played, training hours per week, player position, and history of elbow pain were not significantly associated with capitellar OCD. Only 34.8% of players with capitellar OCD reported elbow pain.
The risk of OCD of the capitellum developing within a 1-year period in preadolescent baseball players was 1.8%. Players aged 10 to 11 years had a significantly greater risk of capitellar OCD development than those aged 6 to 9 years.
Level III, local nonrandom sample cohort.
Impacts of chronic systemic inflammation and body size and their interaction effect on insulin resistance in Asian populations, in whom obesity is less common, are not fully understood. This study ...evaluated combined relationships of systemic inflammation and body size with insulin resistance in a Japanese cohort.
We analyzed cross-sectional data from 1,074 eligible subjects (536 men and 538 women) aged 35-69 years who participated in the baseline survey of a cohort study in Tokushima Prefecture, Japan. Systemic inflammation level was assessed by serum high-sensitivity C-reactive protein (hs-CRP), and the degree of insulin resistance and beta-cell function were evaluated by the homeostasis model assessment insulin resistance (HOMA-IR) and beta-cell function (HOMA-β), respectively. Overweight and obesity were defined as a body mass index (BMI) of 23.0-24.9 kg/m2 and ≥25.0 kg/m2, respectively. Associations between serum hs-CRP (assessed as quartiles and additionally continuous values after log-transformation) and indices of glucose homeostasis were analysed adjusting for probable covariates, including BMI (quartiles). Combined associations of serum hs-CRP (≤median, >median) and body size (normal, overweight, obese) with insulin resistance as well as their interaction effect on insulin resistance were also evaluated.
Serum hs-CRP was dose-dependently associated with HOMA-IR, but not HOMA-β, after adjustment for probable covariates, including BMI. Subjects with obesity and elevated serum hs-CRP (>median) showed a high multivariable-adjusted HOMA-IR value of 1.32 (95% confidence interval (CI) 1.23, 1.41) compared with subjects with normal BMI and low serum hs-CRP (≤median) whose multivariable-adjusted HOMA-IR value was 1.14 (95% CI 1.06, 1.21). The interaction effect between body size (normal, overweight, obese) and serum hs-CRP (≤median, >median) on HOMA-IR was significant (P for interaction <0.001).
Our study suggests that elevated systemic inflammation is dose-dependently associated with increased insulin resistance, independent of the known risk factors, in a Japanese population. Concomitant obesity and elevated systemic inflammation may synergistically contribute to increased insulin resistance.
Background: Nutrients have been proposed to be related to metabolic syndrome (MetS). The aims of this study were to identify dietary patterns that correlated with several nutrients using reduced rank ...regression (RRR) and to examine the association between extracted dietary patterns and prevalence of MetS in a Japanese population. Methods: The study population comprised 1,092 Japanese men and women (35–69 years old) who had participated in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study in Tokushima Prefecture. Dietary patterns were derived with RRR using 46 food items as predictors and six established nutrients (potassium, calcium, vitamin D, vitamin C, insoluble dietary fiber, and carotene) as response variables. Associations between extracted dietary patterns and MetS were then examined with logistic regression models. Results: Among the six dietary patterns, dietary pattern 1 (DP1) explained the largest proportion (60.1%) of variance in the six nutrients. Therefore, only DP1 was selected for further analysis. DP1 was characterized by high intake frequency of vegetables, fruits, fish and small fish, natto (fermented soybeans), and deep-fried tofu. After adjustment for potential confounders, significant inverse associations were found between DP1 score and MetS (odds ratio OR for each quartile: 1.00, 0.58, 0.60, 0.52; Ptrend = 0.02); DP1 and high blood pressure (Ptrend = 0.0002); and DP1 and high blood glucose (Ptrend = 0.02). Conclusion: A dietary pattern characterized by high intake of vegetables, fruits, fish and small fish, natto, and deep-fried tofu was associated with reduced prevalence of MetS in a Japanese population.
It is unclear whether consumption of coffee and green tea is associated with metabolic syndrome.
This cross-sectional study enrolled 554 adults who had participated in the baseline survey of the ...Japan Multi-Institutional Collaborative Cohort (J-MICC) Study in Tokushima Prefecture, Japan. Consumption of coffee and green tea was assessed using a questionnaire. Metabolic syndrome was diagnosed using the criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) and the Japan Society for the Study of Obesity (JASSO). Logistic regression analysis was used to examine the association between consumption of coffee and green tea and prevalence of metabolic syndrome and its components.
After adjustment for sex, age, and other potential confounders, greater coffee consumption was associated with a significantly lower prevalence of metabolic syndrome, as defined by NCEP ATP III criteria (P for trend = 0.03). Participants who drank more coffee had a lower odds ratio (OR) for high serum triglycerides (P for trend = 0.02), but not for increased waist circumference or high blood pressure. Using JASSO criteria, moderate coffee consumption (1.5 to <3 cups/day) was associated with a significantly lower OR for high plasma glucose (OR = 0.51, 95% CI 0.28-0.93). Green tea consumption was not associated with the prevalence of metabolic syndrome or any of its components.
Coffee consumption was inversely correlated with metabolic syndrome diagnosed using NCEP ATP III criteria, mainly because it was associated with lower serum triglyceride levels. This association highlights the need for further prospective studies of the causality of these relationships.
Background: The Japan Multi-institutional Collaborative Cohort (J-MICC) study was launched in 2005 to examine gene–environment interactions in lifestyle-related diseases, including cancers, among the ...Japanese. This report describes the study design and baseline profile of the study participants.Methods: The participants of the J-MICC Study were individuals aged 35 to 69 years enrolled from respondents to study announcements in specified regions, inhabitants attending health checkup examinations provided by local governments, visitors at health checkup centers, and first-visit patients at a cancer hospital in Japan. At the time of the baseline survey, from 2005 to 2014, we obtained comprehensive information regarding demographics, education, alcohol consumption, smoking, sleeping, exercise, food intake frequency, medication and supplement use, personal and family disease history, psychological stress, and female reproductive history and collected peripheral blood samples.Results: The baseline survey included 92,610 adults (mean age: 55.2 standard deviation, 9.4 years, 44.1% men) from 14 study regions in 12 prefectures. The participation rate was 33.5%, with participation ranging from 19.7% to 69.8% in different study regions. The largest number of participants was in the age groups of 65–69 years for men and 60–64 years for women. There were differences in body mass index, educational attainment, alcohol consumption, smoking, and sleep duration between men and women.Conclusions: The J-MICC Study collected lifestyle and clinical data and biospecimens from over 90,000 participants. This cohort is expected to be a valuable resource for the national and international scientific community in providing evidence to support longer healthy lives.
Although Escherichia albertii is an emerging intestinal pathogen, it has been associated only with sporadic human infections. In this study, we determined that a human gastroenteritis outbreak at a ...restaurant in Japan had E. albertii as the major causative agent.
Background: Although beneficial associations have been reported between moderate alcohol intake and the serum lipid profile, it is unclear whether polymorphisms in alcohol-metabolizing enzymes can ...modify these associations. Here, we assessed the effects of ADH1B His48Arg (rs1229984), ALDH2 Glu504Lys (rs671), and their combination on these associations. Furthermore, we examined if the findings for ALDH2 could be replicated. Methods: We categorized 889 male participants in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study into two groups based on presence or absence of minor allele(s) or four groups based on genotype combinations. We performed regression analyses of serum lipid concentrations on alcohol intake, with multivariable adjustment. The replication study was conducted among 2,562 men in the Shizuoka part of the J-MICC Study. Results: The ALDH2 Glu/Lys or Lys/Lys groups showed significant decreases in serum low-density lipoprotein (LDL) cholesterol with increasing alcohol consumption; the coefficient per intake increase of 10 g/day was −2.49 mg/dL (95% confidence interval CI, −3.85 to −1.13), and a significant interaction with the polymorphism was confirmed (P for interaction = 0.006). This inverse correlation was more evident among the ADH1B His/His + ALDH2 Glu/Lys or Lys/Lys groups (−3.24 mg/dL, 95% CI, −5.03 to −1.45). Serum triglycerides were positively associated with alcohol consumption in the ADH1B His/His group (P for interaction = 0.020). The stronger association between serum LDL cholesterol and alcohol consumption in the ALDH2 Glu/Lys or Lys/Lys groups was replicated. Conclusions: The ALDH2 Glu504Lys polymorphism can modify the association between alcohol intake and serum LDL cholesterol in Japanese men.
Traditional observational studies have reported a positive association between higher body mass index (BMI) and the risk of colorectal cancer (CRC). However, evidence from other approaches to pursue ...the causal relationship between BMI and CRC is sparse. A two‐sample Mendelian randomization (MR) study was undertaken using 68 single nucleotide polymorphisms (SNPs) from the Japanese genome‐wide association study (GWAS) and 654 SNPs from the GWAS catalogue for BMI as sets of instrumental variables. For the analysis of SNP‐BMI associations, we undertook a meta‐analysis with 36 303 participants in the Japanese Consortium of Genetic Epidemiology studies (J‐CGE), comprising normal populations. For the analysis of SNP‐CRC associations, we utilized 7636 CRC cases and 37 141 controls from five studies in Japan, and undertook a meta‐analysis. Mendelian randomization analysis of inverse‐variance weighted method indicated that a one‐unit (kg/m2) increase in genetically predicted BMI was associated with an odds ratio of 1.13 (95% confidence interval, 1.06‐1.20; P value <.001) for CRC using the set of 68 SNPs, and an odds ratio of 1.07 (1.03‐1.11, 0.001) for CRC using the set of 654 SNPs. Sensitivity analyses robustly showed increased odds ratios for CRC for every one‐unit increase in genetically predicted BMI. Our MR analyses strongly support the evidence that higher BMI influences the risk of CRC. Although Asians are generally leaner than Europeans and North Americans, avoiding higher BMI seems to be important for the prevention of CRC in Asian populations.
Traditional observational studies reported a positive association between higher body mass index (BMI) and colorectal cancer (CRC) risk. However, these studies suffer from biases such as reverse causality and confounding. This Mendelian randomization study consistently showed that the genetically predicted higher BMI was associated with an increased risk of CRC in Japanese populations.