Masafumi Eguchi

Prevalence of diabetes and pre-diabetes among workers: Japan Epidemiology Collaboration on Occupational Health Study.

AIMS Few studies have examined the prevalence of diabetes using glycated hemoglobin (HbA1c), a newly recommended diagnostic test. We examined the prevalence of diabetes and pre-diabetes using both HbA1c and fasting plasma glucose (FPG) and their associations with risk factors for type 2 diabetes in a large-scale Japanese working population. METHODS Participants were 47,172 men and 8280 women aged 20-69 years who received periodic health checkup in nine companies which participated in the Japan Epidemiology Collaboration on Occupational Health study. Participants were categorized into diabetes (HbA1c≥6.5% (≥48mmol/mol), FPG≥126mg/dl (≥7.0mmol/L), or medication for diabetes), pre-diabetes (HbA1c 6.0-6.4% (42-46mmol/mol) or FPG 110-125mg/dl (6.1-6.9mmol/L) among those without diabetes), and normal glucose regulation. RESULTS The prevalence of diabetes was 8.0% and 3.3% in men and women, respectively. Of individuals with diabetes, approximately 80% were defined by HbA1c≥6.5% (≥48mmol/mol) criterion. The prevalence of pre-diabetes was 14.1% in men and 9.2% in women. Prevalence of these glucose abnormalities increased with advancing age, especially during mid-40s and 50s. Higher body mass index and waist circumference, hypertension, dyslipidemia, and current smoking were each associated with higher prevalence of diabetes in both men and women. CONCLUSIONS Using HbA1c and FPG criteria or current medication, one in 13 men and one in 30 women had diabetes in the present Japanese working population. Interventions targeted for those in an early stage of impaired glucose metabolism would be required to prevent diabetes.

Macronutrient intake and depressive symptoms among Japanese male workers: the Furukawa nutrition and health study

This study was aimed to examine the cross-sectional association of protein, carbohydrate, and fat intake with depressive symptoms among 1794 Japanese male workers aged 18-69 years who participated in a health survey. Dietary intake was assessed with a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Odds ratio of depressive symptoms (CES-D scale of ≥16) was estimated by using multiple logistic regression with adjustment for covariates including folate, vitamin B6, vitamin B12, polyunsaturated fatty acid, magnesium, and iron intake. Multivariable-adjusted odds ratio of depressive symptoms for the highest quartile of protein intake was 26%, albeit not statistically significant, lower compared with the lowest. The inverse association was more evident when a cutoff value of CES-D score ≥19 was used. The multivariable-adjusted odds ratios (95% confidence intervals) for the highest through lowest quartile of protein intake were 1.00 (reference), 0.69 (0.47-1.01), 0.69 (0.44-1.09), and 0.58 (0.31-1.06) (P for trend=0.096). Neither carbohydrate nor fat intake was associated with depressive symptoms. Our findings suggest that low protein intake may be associated with higher prevalence of depressive symptoms in Japanese male workers.

Development of Risk Score for Predicting 3-Year Incidence of Type 2 Diabetes: Japan Epidemiology Collaboration on Occupational Health Study

Objective 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. Methods 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. Results 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. Conclusions 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.

Dietary patterns derived by reduced rank regression (RRR) and depressive symptoms in Japanese employees: The Furukawa nutrition and health study

Depression has been linked to the overall diet using both exploratory and pre-defined methods. However, neither of these methods incorporates specific knowledge on nutrient-disease associations. The aim of the present study was to empirically identify dietary patterns using reduced rank regression and to examine their relations to depressive symptoms. Participants were 2006 Japanese employees aged 19-69 years. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Diet was assessed using a validated, self-administered diet history questionnaire. Dietary patterns were extracted by reduced rank regression with 6 depression-related nutrients as response variables. Logistic regression was used to estimate odds ratios of depressive symptoms adjusted for potential confounders. A dietary pattern characterized by a high intake of vegetables, mushrooms, seaweeds, soybean products, green tea, potatoes, fruits, and small fish with bones and a low intake of rice was associated with fewer depressive symptoms. The multivariable-adjusted odds ratios of having depressive symptoms were 0.62 (95% confidence interval, 0.48-0.81) in the highest versus lowest tertiles of dietary score. Results suggest that adherence to a diet rich in vegetables, fruits, and typical Japanese foods, including mushrooms, seaweeds, soybean products, and green tea, is associated with a lower probability of having depressive symptoms.

Low Serum 25-Hydroxyvitamin D Concentrations Are Associated with Increased Likelihood of Having Depressive Symptoms among Japanese Workers

BACKGROUND Accumulating evidence suggests a protective role of vitamin D against mood disorders; however, epidemiologic studies are scarce in working populations. OBJECTIVE We investigated cross-sectionally the association of serum vitamin D status and depressive symptoms among Japanese workers. METHODS Participants were 1786 employees (9% women), aged 19-69 y, who received health check-ups and participated in a nutrition and health survey. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured with the use of a competitive protein binding assay. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression was used to estimate ORs with adjustment for potential confounding variables including dietary factors. RESULTS Overall, 92% of study participants had suboptimal vitamin D status [25(OH)D <30 μg/L]. Depressive symptoms were inversely associated with 25(OH)D. Compared with those with a 25(OH)D concentration of <20 μg/L, multivariable-adjusted ORs (95% CIs) for depressive symptoms (CES-D scale score ≥16) were 0.75 (0.59, 0.95) and 0.66 (0.41, 1.06) for those with a 25(OH)D concentration of 20-29 μg/L and ≥30 μg/L, respectively (P-trend = 0.01). After further adjustment for leisure-time physical activity and shift work (factors closely related to photo-initiated vitamin D production), the OR (95% CI) for the highest category of 25(OH)D was 0.70 (0.43, 1.14). The association between 25(OH)D and depressive symptoms appears to be linear, according to restricted cubic spline regression. CONCLUSION Results suggest that lower concentrations of circulating vitamin D are associated with increased likelihood of having depressive symptoms among apparently healthy workers.

Hba1c, Blood Pressure, and Lipid Control in People with Diabetes: Japan Epidemiology Collaboration on Occupational Health Study.

Aims The control of blood glucose levels, blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) levels reduces the risk of diabetes complications; however, data are scarce on control status of these factors among workers with diabetes. The present study aimed to estimate the prevalence of participants with diabetes who meet glycated hemoglobin (HbA1c), BP, and LDL-C recommendations, and to investigate correlates of poor glycemic control in a large working population in Japan. Methods The Japan Epidemiology Collaboration on Occupational Health (J-ECOH) Study is an ongoing cohort investigation, consisting mainly of employees in large manufacturing companies. We conducted a cross-sectional analysis of 3,070 employees with diabetes (2,854 men and 216 women) aged 20–69 years who attended periodic health examinations. BP was measured and recorded using different company protocols. Risk factor targets were defined using both American Diabetes Association (ADA) guidelines (HbA1c < 7.0%, BP < 140/90 mmHg, and LDL-C < 100 mg/dL) and Japan Diabetes Society (JDS) guidelines (HbA1c < 7.0%, BP < 130/80 mmHg, and LDL-C < 120 mg/dL). Logistic regression models were used to explore correlates of poor glycemic control (defined as HbA1c ≥ 8.0%). Results The percentages of participants who met ADA (and JDS) targets were 44.9% (44.9%) for HbA1c, 76.6% (36.3%) for BP, 27.1% (56.2%) for LDL-C, and 11.2% (10.8%) for simultaneous control of all three risk factors. Younger age, obesity, smoking, and uncontrolled dyslipidemia were associated with poor glycemic control. The adjusted odds ratio of poor glycemic control was 0.58 (95% confidence interval, 0.46–0.73) for participants with treated but uncontrolled hypertension, and 0.47 (0.33–0.66) for participants with treated and controlled hypertension, as compared with participants without hypertension. There was no significant difference in HbA1c levels between participants with treated but uncontrolled hypertension and those with treated and controlled hypertension. Conclusion Data from a large working population, predominantly composed of men, suggest that achievement of HbA1c, BP, and LDL-C targets was less than optimal, especially in younger participants. Uncontrolled dyslipidemia was associated with poor glycemic control. Participants not receiving antihypertensive treatment had higher HbA1c levels.

Smoking, Smoking Cessation, and the Risk of Type 2 Diabetes among Japanese Adults: Japan Epidemiology Collaboration on Occupational Health Study

Aims To examine the association of smoking status, smoking intensity, and smoking cessation with the risk of type 2 diabetes (T2D) using a large database. Methods The present study included 53,930 Japanese employees, aged 15 to 83 years, who received health check-up and did not have diabetes at baseline. Diabetes was defined as fasting plasma glucose ≥126 mg/dl, random plasma glucose ≥200 mg/dl, HbA1c ≥6.5% (≥48 mmol/mol), or receiving medication for diabetes. Cox proportional-hazards regression models were used to investigate the association between smoking and the risk of diabetes. Results During 3.9 years of median follow-up, 2,441 (4.5%) individuals developed T2D. The multivariable-adjusted hazard ratios (95% CI) for diabetes were 1 (reference), 1.16 (1.04 to 1.30) and 1.34 (1.22 to 1.48) for never smokers, former smokers, and current smokers, respectively. Diabetes risk increased with increasing numbers of cigarette consumption among current smokers (P for trend <0.001). Although the relative risk of diabetes was greater among subjects with lower BMIs (< 23 kg/m2), attributable risk was greater in subjects with higher BMIs (≥ 23 kg/m2). Compared with individuals who had never smoked, former smokers who quit less than 5 years, 5 to 9 years, and 10 years or more exhibited hazards ratios for diabetes of 1.36 (1.14 to 1.62), 1.23 (1.01 to 1.51), and 1.02 (0.85 to 1.23), respectively. Conclusions Results suggest that cigarette smoking is associated with an increased risk of T2D, which may decrease to the level of a never smoker after 10 years of smoking cessation.

Dietary patterns and sleep symptoms in Japanese workers: the Furukawa Nutrition and Health Study

OBJECTIVE Experimental studies have shown that some nutrients are involved in initiating and maintaining sleep, but epidemiological evidence on overall dietary patterns and insomnia is scarce. We investigated the relationship between dietary patterns and sleep symptoms in a Japanese working population. METHODS The participants were 2025 workers, aged 18-70 years, who participated in a health survey during a periodic checkup in 2012 and 2013. Dietary intake was assessed with a self-administered diet history questionnaire. Dietary patterns were extracted by principal component analysis on the basis of the energy-adjusted intake of 52 food and beverage items. Sleep duration, difficulty initiating and maintaining sleep, and poor quality of sleep were self-reported. Logistic regression was used to estimate the odds ratios of each sleep symptom according to quartile categories of each dietary pattern with adjustment for potential confounding variables. RESULTS We identified three major dietary patterns. A healthy pattern, characterized by a high intake of vegetables, mushrooms, potatoes, seaweeds, soy products, and eggs, was associated with a decreased prevalence of difficulty initiating sleep once or more a week (P for trend = 0.03); the multivariate adjusted odds ratio in the highest quartile of this score compared with the lowest was 0.75 (95% CI: 0.57-0.99). This association persisted after the exclusion of individuals with severe depressive symptoms. However, there was no significant association with difficulty initiating sleep at least three times a week. CONCLUSIONS Our findings suggest that a healthy dietary pattern may be associated with difficulty initiating sleep at least once a week.

Overtime Work and Prevalence of Diabetes in Japanese Employees: Japan Epidemiology Collaboration on Occupational Health Study

Objective Epidemiologic evidence on long working hour and diabetes has been conflicting. We examined the association between overtime work and prevalence of diabetes among Japanese workers. Methods The subjects were 40,861 employees (35,170 men and 5,691 women), aged 16 to 83 years, of 4 companies in Japan. Hours of overtime were assessed using self-reported questionnaires. Diabetes was defined as a fasting plasma glucose ≥126 mg/dl (7.0 mmol/l), hemoglobin A1c ≥6.5% (48 mmol/mol), or current use of anti-diabetic drug. Multiple logistic regression analysis was used to calculate odds ratio of diabetes for each category of overtime. Results After adjustment for age, sex, company, smoking, and BMI, there was a suggestion of U-shaped relationship between overtime work and prevalence of diabetes (P for quadratic trend = 0.07). Compared with those who worked <45 hours of overtime per month, the adjusted odds ratios (95% confidence interval) of diabetes were 0.86 (0.77–0.94), 0.69 (0.53–0.89), and 1.03 (0.72–1.46) for those who worked 45–79, 80–99, and ≥100 hours of overtime per month, respectively. In one company (n = 33,807), where other potential confounders including shift work, job position, type of department, alcohol consumption, sleep duration, leisure time physical activity, and family history of diabetes was additionally adjusted for, similar result was obtained (P for quadratic trend = 0.05). Conclusions Long hours of overtime work may not be associated with increased prevalence of diabetes among Japanese workers.

Association of overtime work and hypertension in a Japanese working population: A cross-sectional study

Long working hours have been associated with an increased risk of cardiovascular disease, but its relationship with hypertension remains unclear. The objective of this study is to examine the relationship between overtime and presence of hypertension using data from a large-scale multi-company study in Japan. Participants were 52 365 workers of four companies that provided both health-checkup data and self-reported data on overtime worked. Hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, and/or the use of antihypertensive drug. Logistic regression analysis was performed to determine the odds ratio for hypertension for each category of overtime work (<45, 45–79, 80–99 or ≥100 h/month) with adjustments for age, sex, company, smoking status and body mass index. The prevalence of hypertension tended to decrease with increasing overtime work: 17.5, 12.0, 11.1 and 9.1% for the shortest (<45 h/month) through the longest overtime category (≥100 h/month). The age-, sex- and company-adjusted odds ratios (95% confidence interval) were 1.00 (reference), 0.81 (0.75–0.86), 0.73 (0.62–0.86), 0.58 (0.44–0.76), respectively (p for linear trend <0.001). In a sub-cohort, the inverse association remained statistically significant after an additional adjustment for other potential confounders. Results of the present large-scale study among Japanese workers suggest an inverse association between overtime work and presence of hypertension.