Meat intake and type 2 diabetes among Japanese workers: a prospective study.

Red meat and processed meat intake has been linked to increased risk of type 2 diabetes; however, evidence from Asia is limited and inconsistent. We prospectively examined the association of intake of total meat and its subtype with type 2 diabetes in a Japanese working population. Participants were 2709 workers aged 18-78 years who reported no history of diabetes when they responded to a health survey for the first time between 2012 and 2019. Dietary intake was assessed using a validated self-administered diet history questionnaire. The incidence of type 2 diabetes was assessed via annual health checkups from baseline through March 2023. Type 2 diabetes was defined as fasting blood glucose ≥ 126 mg/dl, casual blood glucose ≥ 200 mg/dl, HbA1c ≥ 6·5 %, self-report of diabetes or current use of anti-diabetic drugs. Hazard ratios according to tertile of meat intake were estimated using Cox proportional hazards regression. During 16 119 person-years of follow-up, 135 (5·0 %) workers developed type 2 diabetes. Intakes of total meat, red meat, processed meat and poultry were not associated with risk of type 2 diabetes. After adjustment for covariates, hazard ratios for the highest v. lowest tertile of meat intake were 1·01 (95 % CI 0·63, 1·62) for total meat, 1·02 (95 % CI 0·66, 1·58) for red meat, 0·99 (95 % CI 0·65, 1·49) for processed meat and 1·13 (95 % CI 0·71, 1·80) for poultry. Our findings suggest that meat intake is not associated with the risk of type 2 diabetes among Japanese workers.

[Identification of dietary patterns and their relationship with zinc intake in male and female workers].

Objectives　Deficiency of zinc, an essential trace element in the body, adversely affects taste, wound healing, and immunity. This study aimed to identify the dietary patterns of male and female workers using factor analysis and clarify the relationship between dietary patterns and zinc intake.Methods　The participants were 395 municipal employees (193 men and 202 women) in Northern Kyushu aged 19-71 years. To obtain the dietary intake data, participants were asked to complete a lifestyle and health questionnaire and brief self-administered dietary history questionnaire. Zn intake was evaluated per 1,000 kcal (mg/1,000 kcal). The values were adjusted for energy using the density method, and multiple regression analysis was performed.Results　Three dietary patterns were identified for each participant. Among men, "main and side dish type pattern" characterized by higher intakes of potatoes, legumes, vegetables, seafood, meat, and low for cereals, "snack type pattern" characterized by higher intakes of sweets and coffee, and "Mediterranean diet pattern" characterized by higher intakes of bread, pasta, fruits, eggs, and milk, and low for miso soup and rice were identified. For women, a "vegetarian diet type pattern" characterized by higher intakes of beans, vegetables, mushrooms, and seaweed, "main and side dish type pattern" characterized by low intake of rice, and "dinner-time drinking pattern" characterized by higher intakes of alcoholic beverages were identified. Zinc intake was positively associated with the "main and side dish type pattern" and "Mediterranean diet pattern" in men and "vegetarian diet" and "main and side dish type pattern" in women. Additionally, zinc intake was negatively associated with the "dinner-time drinking pattern" among women.Conclusion　Despite adjusting for age, BMI, marriage, occupation, smoking habits, and exercise habits, the "main and side dish type pattern" and "Mediterranean diet pattern" were positively correlated with zinc intake in men and the "vegetarian diet" and "main and side dish type pattern" in women. The data suggest awareness of the dietary patterns that are conducive to ensuring zinc intake.

Association between Fish Intake and Serum Testosterone Levels in Older Males: The Hitachi Health Study II.

Background: Fish are rich in omega-3 polyunsaturated fatty acids and vitamin D, which can promote testosterone synthesis and secretion. However, some contaminants present in fish may disrupt testosterone production. Objective: This study aimed to investigate the association between fish intake (total, fatty, and lean fish) and serum testosterone levels in older males. Methods: This cross-sectional study included 1545 Japanese males aged 60-69 y who participated in the baseline survey of the Hitachi Health Study II. Fish intake was estimated using a validated brief-type self-administered diet history questionnaire. Total testosterone levels were measured by chemiluminescence immunoassay. Multivariable linear regression analysis was used to analyze the association between fish intake and serum testosterone levels. Results: Higher total fish intake was associated with higher levels of serum testosterone, with an adjusted mean [95% confidence interval (CI) of 5.63 (5.43, 5.83) and 5.99 (5.78, 6.20)] ng/mL for the 1st and 4th quartiles of total fish intake, respectively (P for trend = 0.06). When analyzing fatty and lean fish separately, higher intake of lean fish, but not fatty fish, was associated with higher levels of serum testosterone: adjusted mean (95% CI): 5.63 (5.43, 5.82) and 6.00 (5.79, 6.20) ng/mL for the 1st and 4th quartiles of lean fish intake, respectively (P for trend = 0.01). Conclusions: Among older males, higher intake of total fish, particularly lean fish, was associated with higher serum testosterone levels. Curr Dev Nutr 20xx;x:xx.

Antioxidant Vitamin Intake and LOX-Index in Japanese Municipal Workers.

Antioxidant vitamin intake has been reported to be associated with decreased risk of cardiovascular diseases. To date, however, no study has examined the association between antioxidant vitamin intake and LOX-index, a predictive biomarker of cardiovascular disease. We investigated the cross-sectional association between antioxidant vitamin (α-carotene, ß-carotene, α-tocopherol, and vitamin C) intake and LOX-index in Japanese municipal workers. Participants were 346 workers (171 men and 175 women aged 19-71 y) who received a health check-up and participated in a nutrition and health survey. Antioxidant vitamin intake was assessed using a validated brief self-administered diet history questionnaire. LOX-index was calculated by multiplying serum concentrations of the soluble form of lectin-like oxidized LDL receptor 1 by those of LOX-1 ligands containing apolipoprotein B. Multiple regression analysis was used to estimate the geometric mean of LOX-index according to tertile of each antioxidant vitamin intake. Overall, α-carotene, ß-carotene, α-tocopherol, and vitamin C intake were not associated with LOX-index. However, in stratified analyses by sex, geometric means of LOX-index tended to decrease with antioxidant vitamin intake in women, but not in men. The geometric means of LOX-index for the lowest through highest tertile of α-carotene intake were 771 (604-984), 639 (511-799), and 564 (469-677) (p for trend=0.07). Our results suggest that there is no association between antioxidant vitamin intake and LOX-index in Japanese workers. The suggestive inverse association between antioxidant vitamin intake and LOX-index in women warrants further investigation.

Eating behaviors and depressive symptoms among Japanese workers: the Furukawa Nutrition and Health Study.

BACKGROUND/OBJECTIVES: In addition to the potential effects of nutrients on mood, eating behaviors have been suggested to be associated with depressive symptoms. We investigated the prospective association between the accumulation of unhealthy eating behaviors and depressive symptoms in a Japanese working population. METHODS: Participants were 914 workers (aged 19-68 years) who did not have depressive symptoms at baseline (April 2012 and May 2013) and attended a 3-year follow-up survey (April 2015 and May 2016). Unhealthy eating behaviors (skipping breakfast, eating dinner just before bedtime, and snacking after dinner) were assessed at baseline. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale at follow-up. Multiple logistic regression was used to estimate the odds ratio of depressive symptoms (CES-D score ≥16) at follow-up according to the number of unhealthy eating behaviors. RESULTS: In a model with adjustment of background factors, participants having 2-3 unhealthy eating behaviors at baseline had significantly higher risk of developing depressive symptoms (OR, 2.02; 95% CI, 1.21-3.38) compared with those having no such behaviors. After adjustment for occupational and lifestyle factors, the association was slightly attenuated but remained significant (OR, 1.87; 95% CI, 1.10-3.21). This association was further attenuated and became statistically non-significant after additional adjustment for nutritional factors (OR, 1.67; 95% CI, 0.96-2.90). CONCLUSIONS: Our results suggest that the accumulation of unhealthy eating behaviors is associated with an increased risk of depressive symptoms and that this association may be partly ascribed to a lower intake of nutrients with mood-improving effects.

Isoflavone intake and depressive symptoms among workers.

BACKGROUND & AIM: High intake of isoflavones has been reported to be associated with decreased prevalence of depressive symptoms. However, no prospective study has examined this association. We prospectively investigated the association between isoflavone intake and depressive symptoms in a Japanese working population. METHODS: Participants were 1162 workers (1033 men and 129 women aged 18-68 years) without depressive symptoms at baseline. Dietary intake was assessed using a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Cox proportional hazards regression for interval-censored data was used to estimate the hazard ratio of depressive symptoms (CES-D ≥16) according to the tertile of isoflavone intake with adjustment for covariates. RESULTS: During 5065 person-years of follow-up, 276 (23.8 %) workers were newly identified as having depressive symptoms. Isoflavone intake was not associated with risk of depressive symptoms. After adjustment for lifestyle and dietary factors and baseline CES-D score, the multivariable-adjusted hazard ratios (95 % confidence interval) for the lowest through highest tertile of isoflavone intake were 1.00 (reference), 0.93 (0.66-1.31), and 0.93 (0.62-1.38) (P for trend = 0.70). CONCLUSIONS: Our findings suggest that higher isoflavone intake is not associated with decreased risk of depressive symptoms among Japanese.

Development of the Scores for Traditional and Modified Japanese Diets.

Increasing attention is being paid to the role of diet quality in the prevention and management of non-communicable diseases. We developed a scoring system for the traditional Japanese diet and its modified version considering the dietary culture in Japan, dietary guidelines for the Japanese, and updated evidence for disease prevention. The traditional Japanese diet comprises white rice, miso soup, soybean products, vegetables, mushrooms, seaweeds, fish and shellfish, high-sodium foods, and green tea. In the modified Japanese diet, unprocessed or minimally refined rice and raw vegetables, milk and dairy products, and fruits were additionally considered, while salty food was reverse-scored. The cutoff for the intake frequency of each food/food group was determined with reference to a health survey of >12,000 workers. Among the participants in the validation study, we confirmed the nutritional gradient with increasing scores in the expected direction. The scores were closely correlated with the respondents' backgrounds, including occupational factors. This simple scoring system can be used for diet quality assessments and epidemiological research.

Association of body mass index and weight change with pneumonia mortality in a Japanese population: Japan Public Health Center-based Prospective Study.

BACKGROUND: Accumulating evidence suggests that pneumonia mortality is lower for individuals with high body mass index (BMI) compared to normal BMI, but it remains unclear whether weight change during adulthood influences subsequent mortality due to pneumonia in Asian populations, who have a relatively lean body mass. This study aimed to examine the association of BMI and weight change over 5 years with the subsequent risk of pneumonia mortality in a Japanese population. METHODS: The present analysis included 79,564 Japan Public Health Center (JPHC)-based Prospective Study participants who completed a questionnaire between 1995 and 1998 were followed for death through 2016. BMI was categorized into four groups: underweight (<18.5 kg/m2), normal weight (BMI: 18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (BMI: ≥30.0 kg/m2). Weight change was defined as the difference of body weight between questionnaire surveys with a 5-year interval. Cox proportional hazards regression was used to estimate hazard ratios of baseline BMI and weight change for pneumonia mortality. RESULTS: During a median follow-up of 18.9 y, we identified 994 deaths from pneumonia. Compared with participants with normal weight, an elevated risk was observed among those who were underweight (hazard ratio = 2.29, 95% confidence interval [CI]: 1.83-2.87), whereas a decreased risk was found among those who were overweight (hazard ratio = 0.63, 95% CI: 0.53-0.75). Regarding weight change, the multivariable-adjusted hazard ratio (95% CI) of pneumonia mortality for a weight loss of 5 kg or more versus a weight change of less than 2.5 kg was 1.75 (1.46-2.10), whereas that for a weight gain of 5 kg or more was 1.59 (1.27-2.00). CONCLUSION: Underweight and greater weight change was associated with an increase in the risk of pneumonia mortality in Japanese adults.

Vitamin D intake and all-cause and cause-specific mortality in Japanese men and women: the Japan Public Health Center-based prospective study.

While higher circulating 25-hydroxyvitamin D concentrations have been reported to be associated with decreased risk of all-cause mortality, evidence on dietary vitamin D intake is limited and inconsistent. We investigated whether vitamin D intake is associated with all-cause and cause-specific mortality among Japanese adults. Participants were 42,992 men and 50,693 women who responded to the second survey of the Japan Public Health Center-based Prospective Study (1995-1998) and who were followed up for mortality through 2018. Dietary intake was ascertained using a validated food frequency questionnaire. Hazard ratios of deaths from the second survey to December 2018 were estimated using Cox proportional hazard regression analysis. During follow-up, we identified 22,630 deaths. Overall, the third and fourth quintiles, but not the highest quintile, of vitamin D intake were each associated with a significantly lower risk of all-cause mortality. In subgroups characterized by low sunlight exposure, risk of all-cause mortality decreased linearly with increasing vitamin D intake. The multivariable-adjusted hazard ratios (95% confidence intervals) of all-cause mortality for the highest versus lowest quintile of vitamin D intake were 0.87 (0.79-0.95) in women and 0.88 (0.79-0.97) in residents of higher latitude areas. Lower risk was also observed for all-cause mortality in participants with hypertension and for heart disease mortality in those with higher calcium intake. Higher vitamin D intake was associated with decreased risk of ischemic stroke and pneumonia mortality. Higher dietary vitamin D was associated with a lower risk of mortality among individuals with low sunlight exposure or hypertension. Individuals with potentially low vitamin D may benefit from increasing dietary vitamin D intake for the prevention of premature death.

Development, Relative Validity, and Reproducibility of a Short Food Frequency Questionnaire for the Japanese.

We have developed a short food frequency questionnaire (FFQ) for use in assessing diet quality for Japan, with special reference to the prevention of non-communicable diseases. Here, we assessed the ranking performance of this FFQ and its reproducibility. We developed a 28-item (21 food groups and 7 beverage) FFQ with consideration to both Japanese dietary culture and evidence of disease prevention. Twenty-four university faculty members participated in the validation study. They completed 3-day photographic food record and answered the FFQ on the next day of the last food record (time 1) and a week later (time 2). We calculated Spearman correlation coefficients between intakes of food groups from photographic food records and the consumption frequency from the FFQs (ranking ability) and between the consumption frequency of food groups from the FFQs (time 1 and time 2) (reproducibility). Spearman correlation coefficients between the food records and FFQ (time 1) ranged from -0.12 to 0.86 (median 0.51). These values were comparable to those in comparison with FFQ (time 2). After energy adjustment of intakes from the food records, the corresponding values were somewhat weakened for many food groups. The correlation coefficients between two FFQs ranged from 0.14 to 0.96 (median 0.79). The short FFQ showed acceptable reproducibility and ability to rank the consumption of most food groups.

Associations of serum amino acids with insulin resistance among people with and without overweight or obesity: A prospective study in Japan.

BACKGROUND & AIMS: Limited evidence exists regarding the prospective associations between amino acids and insulin resistance. In addition, amino acids have been suggested to promote insulin resistance with the requirement of obesity in animal studies, but the interaction between amino acids and obesity on the development of insulin resistance has not been examined in epidemiological studies. We aimed to investigate the differences in the prospective associations of serum amino acids with insulin resistance among adults with and without overweight or obesity. METHODS: Fasting serum concentrations of 25 amino acids were quantified in 1131 non-diabetic Japanese workers aged 22-71 years at baseline. The homeostasis model assessment of insulin resistance (HOMA-IR) was estimated at baseline and the 3-year follow-up. Generalized linear models were used to assess the associations between amino acids at baseline and HOMA-IR at follow-up with adjustment for potential confounding factors. A Bonferroni-corrected threshold of p = 0.001 was considered significant for multiple tests. RESULTS: The associations for the following amino acids with HOMA-IR at the 3-year follow-up significantly varied by obesity status: isoleucine, valine, tyrosine, alanine, and methionine (all p for interaction <0.05). Higher concentrations of serum isoleucine, valine, tyrosine, and alanine (per 1SD) were significantly associated with higher HOMA-IR levels in overweight/obese participants (multivariable-adjusted ß coefficients ranging from 0.09 to 0.12; all p < 0.001), but no association was observed in the underweight/normal-weight participants. The associations for serum methionine were direct among overweight/obese participants, but inverse among underweight/normal-weight participants (all p < 0.001). CONCLUSIONS: This study demonstrated the prospective associations of different individual serum amino acids with insulin resistance, with most pronounced associations being for overweight/obese adults. Our findings support the possibility of heterogeneous effects of individual amino acids, as well as their interplay with obesity in the progression of insulin resistance.

Relationship of chronotype and social jetlag with adherence to the Japanese dietary guidelines among workers.

While late chronotype and greater social jetlag have been associated with poor dietary behavior among the general population, these associations have not been investigated among workers, who struggle to align their sleep timings with work schedules. We aimed to explore the cross-sectional association of social jetlag and a late chronotype with adherence to a healthy diet among Japanese workers. Participants were 1,435 non-shift workers (18-78 years) who attended a nutritional survey. Social jetlag was defined as the difference in the midpoint of sleep times between weekdays and weekends, while chronotype was estimated using the mid-sleep time on weekends that was corrected with sleep debt on weekdays. We calculated the adherence score of the Japanese Food Guide Spinning Top (JFGST) - healthy diet guidelines for Japanese. Multivariable linear regression analyses were used to calculate the adjusted means and 95% confidence intervals (CI) for adherence scores of social jetlag and chronotype. We found that greater social jetlag was associated with a lower JFGST score. The multivariable-adjusted mean (95% CI) of JFGST scores were 39.7 (39.1-40.2), 38.7 (37.9-39.6), and 38.1 (36.6-39.7) for <1 hour, 1 to <2 hours, and ≥2 hours of social jetlag, respectively (P-trend = 0.02). Workers with late chronotypes had significantly lower adherence scores on JFGST [36.3 (34.7-37.8); P-trend = 0.002]. Results suggest that a late chronotype and social jetlag are inversely associated with adherence to a healthy diet among Japanese workers.

Green tea consumption and SARS-CoV-2 infection among staff of a referral hospital in Japan.

BACKGROUND & AIM: This study examined the association between green tea consumption and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among Japanese. METHODS: Participants were staff of a large referral hospital in Tokyo. Green tea consumption was ascertained via a questionnaire. SARS-CoV-2 infection was identified through in-house records of PCR-confirmed COVID-19 cases or antibody tests. Multiple logistic regression was used to estimate the odds ratio of SARS-CoV-2 infection according to green tea consumption. RESULTS: Of 2640 participants (767 men and 1873 women; aged 21-75 years), 74 (2.8%) were confirmed or suspected to have been infected with SARS-CoV-2 during the epidemic. Overall, SARS-CoV-2 infection was not significantly associated with green tea consumption. There was a suggestion of a decrease in the odds of this infection associated with green tea consumption of ≥4 cups/day (odds ratio 0.51, 95% confidence interval 0.20-1.31). CONCLUSIONS: Green tea consumption was not appreciably associated with the risk of SARS-CoV-2 infection. A lower odds of infection among those who consumed high green tea consumption deserves further investigation.

Prospective association of confectionery intake with depressive symptoms among Japanese workers: the Furukawa Nutrition and Health Study.

High intake of sweet foods such as cakes, cookies, chocolate and ice cream has been reported to be associated with depressive symptoms. However, prospective studies are scarce and no study has been conducted in Asian populations. We prospectively investigated the association between confectionery intake and depressive symptoms in a Japanese working population. Participants were 911 workers (812 men and 99 women; aged 19-68 years) without depressive symptoms at baseline who completed a 3-year follow-up survey. Dietary intake was assessed using a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Multiple logistic regression was used to estimate the OR of depressive symptoms according to tertile of confectionery intake with adjustment for covariates. At the time of the 3-year follow-up survey, 153 (16·8 %) workers were newly identified as having depressive symptoms (CES-D score ≥ 16). Confectionery intake was significantly associated with increased odds of developing depressive symptoms. The multivariable-adjusted OR of depressive symptoms for the highest v. lowest tertile of confectionery intake was 1·72 (95 % CI 1·03, 2·86) after adjustment for covariates including dietary factors such as folate, vitamin B6, vitamin B12, n-3 PUFA, Mg, Zn and soft drink (Pfor trend = 0·012). Our results suggest that confectionery intake is associated with a higher risk of depressive symptoms in a Japanese working population predominantly comprised of men.

Low-carbohydrate diet and risk of cancer incidence: The Japan Public Health Center-based prospective study.

Epidemiological evidence on the effects of a long-term low-carbohydrate diet (LCD) on cancer incidence remains sparse. We investigate the association between LCD and the risk of overall and specific cancer site incidence in a Japanese population-based prospective cohort study among 90 171 participants aged 45-74. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During a median 17.0 y of follow-up, we identified 15 203 cancer cases. A higher overall LCD score was associated with increased overall cancer risk (HR = 1.08 [CI: 1.02-1.14], P-trend = .012), while it was associated with decreased gastric cancer (GC) risk (0.81 [0.71-0.93], P-trend = .006). A higher animal-based LCD score was associated with higher risk of overall cancer (1.08 [1.02-1.14], P-trend = .003), colorectal cancer (CRC) (1.11 [0.98-1.25], P-trend = .018), rectal cancer (RC) (1.24 [1.00-1.54], P-trend = .025), lung cancer (LC) (1.16 [1.00-1.34], P-trend = .042), and lower risk of GC (0.90 [0.79-1.01], P-trend = .033). Furthermore, we found that plant-based LCD score was related to lower GC incidence (0.87 [0.77-0.99], P-trend = .031). Additionally, adjusted for plant fat intake amplified the adverse associations (overall cancer: 1.08 [1.02-1.14] vs. 1.11 [1.05-1.18]; CRC: 1.08 [0.95-1.22] vs. 1.13 [0.99-1.30]; LC: 1.14 [0.98-1.33] vs. 1.19 [1.01-1.41]). We conclude that LCD enriching with animal products was associated with increased overall cancer, CRC, and LC incidence. These adverse associations could be attenuated by plant fat consumption. LCD reduces the risk of developing GC. Long-term adherence to LCD without paying attention to the balance between animal and plant food source consumption might cause adverse overall cancer incidence consequences.

Serum sodium and risk of hypertension: a cohort study.

This study aimed to investigate the cross-sectional association between serum sodium and blood pressure at baseline and, more importantly, investigate the prospective association between serum sodium and the risk of incident hypertension. We used data from 1 638 workers aged 18 to 71 years who participated in 2015-2016 survey of the Furukawa Nutrition and Health Study. During a maximum follow-up of 3 years, 229 participants developed hypertension. Multivariable linear regression models were used to evaluate the cross-sectional association. The Cox proportional hazards model was used to calculate the hazard ratio and 95% confidence interval of incident hypertension across quartiles of serum sodium (137-140, 141-142, 143, and 144-147 mmol/L). In the cross-sectional analysis, we did not observe a significant association between serum sodium and blood pressure at baseline. In the prospective analysis, the multivariable-adjusted hazard ratios (95% confidence intervals) for incident hypertension were 1.03 (0.71-1.51), 1.35 (0.87-2.08), and 1.46 (0.97-2.20) for the upper three quartiles of the serum sodium levels compared with the lowest quartile (P for trend=0.02). When serum sodium was treated as a continuous variable, the multivariable-adjusted hazard ratio for hypertension was 1.10 (1.03-1.18). The association was slightly attenuated after additionally adjusting for baseline blood pressure, with a hazard ratio of 1.08 (1.00-1.16) for a 1 mmol/L increase in serum sodium. In conclusion, an elevated serum sodium level was associated with an increased risk of developing hypertension, suggesting that serum sodium could be a potential risk factor for hypertension.

Diagnosis-specific Cumulative Incidence of Return-to-work, Resignation, and Death Among Long-term Sick-listed Employees: Findings From the Japan Epidemiology Collaboration on Occupational Health Study.

BACKGROUND: While it is essential to understand how long is sufficient for return-to-work when designing paid sick-leave systems, little attempt has been done to collect cause-specific information on when and how many of sickness absentees returned to work, became unemployed, or passed away. METHODS: We studied the first sick-leave episode of ≥30 consecutive days in those ≤55 years of age during 2012-2013 among employees of 11 Japanese private companies (n = 1,209), which were followed until 2017. Overall and disease-specific cumulative incidences of return-to-work, resignations, and deaths were estimated using competing risk analysis. RESULTS: During the 3.5-year period (follow-up rate: 99.9%), 1,014 returned to work, 167 became unemployed, and 27 died. Overall, return-to-work occurred within 1 year in 74.9% of all absentees and in 89.3% of those who successfully returned to work. Resignation occurred within 1 year in 8.7% of all absentees and in 62.9% of all subjects who resigned. According to ICD-10 chapters, the cumulative incidence of return-to-work ranged from 82.1% for mental disorders (F00-F99) to 95.3% for circulatory diseases (I00-I99). The cumulative incidence of return-to-work due to mental disorders ranged from 66.7% in schizophrenia (F20) to 95.8% in bipolar affective disorders (F31). Death was rarely observed except for cases of neoplasms (C00-D48), of which the cumulative incidence of death reached 14.2% by 1.5 years. CONCLUSION: Return-to-work and resignations occurred commonly within 1 year of sick leave among long-term sickness absentees in the Japanese private companies. Our findings may assist occupational physicians and employers in developing effective social protection schemes.

Total, low-fat, and full-fat dairy consumption and risk of metabolic syndrome among workers.

BACKGROUND & AIM: Dairy products may play a beneficial role against metabolic syndrome; however, epidemiological evidence is scarce in Asian populations, who consume less dairy than Western populations. We prospectively investigated the association between dairy product intake, both overall and by fat content, and metabolic syndrome in a Japanese working population. METHODS: Participants were 1014 workers (aged 19-68 years) without metabolic syndrome at baseline who completed a 3-year follow-up survey. Dietary intake was assessed using a validated self-administered diet history questionnaire. Metabolic syndrome was defined according to the Joint Interim Statement (JIS) criteria. Multiple logistic regression was used to estimate the odds ratio of metabolic syndrome according to tertile of total, low-fat, and full-fat dairy product intake with adjustment for covariates. RESULTS: At the 3-year follow-up, 66 (6.5%) workers were newly identified as having metabolic syndrome. A trend towards decreased odds of developing metabolic syndrome was observed among those in the highest tertile of total and full-fat dairy product intake: multivariable-adjusted odds ratio for the highest versus lowest tertile was 0.54 (95% CI 0.26-1.12; P for trend = 0.094) for total dairy products and 0.50 (95% CI 0.24-1.05; P for trend = 0.038) for full-fat dairy products. Low-fat dairy intake was not associated with metabolic syndrome. CONCLUSIONS: Our results suggest that higher intake of full-fat, but not low-fat, dairy products may be associated with a lower risk of metabolic syndrome among Japanese.

Prospective study on the association between serum amino acid profiles and depressive symptoms among the Japanese working population.

OBJECTIVE: Accumulating evidence suggests that amino acids, particularly tryptophan and glutamate, play an important role in the pathology of depression, but prospective epidemiologic data on this issue is scarce. We examined the association between circulating amino acids and the risk of depressive symptoms in a Japanese working population. METHODS: Participants were 841 workers who were free from depressive symptoms and provided blood at baseline and completed 3-yr follow-up survey. 30 varieties of amino acid concentrations in serum were measured using liquid chromatography/mass spectrometry. Depressive symptoms were defined using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to calculate the odds ratios of depressive symptoms according to serum amino acids with adjustment for lifestyle factors. RESULTS: A total of 151 (18.0%) workers were newly identified as having depressive symptoms at the follow-up. Baseline tryptophan and glutamate concentrations in serum were not appreciably associated with the risk of depressive symptoms. Risk of depressive symptoms tended to increase with increasing arginine concentrations; the multivariable-adjusted odds ratio for the highest versus lowest tertile of serum arginine was 1.65 (95% confidence interval: 0.96-2.83; P for trend = 0.07). No clear association was found for other amino acids. CONCLUSIONS: Results of the present study do not support a significant role of circulating amino acids in the development of depressive symptoms among Japanese.

Carbohydrate score and rice intake for breakfast, lunch, and dinner and impaired glucose metabolism in a working population: A cross-sectional study.

BACKGROUND & AIM: Few studies have examined the association between carbohydrate intake and diabetes with consideration to time of eating. We investigated the association of carbohydrate score and rice intake for breakfast, lunch, and dinner with impaired glucose metabolism in a Japanese working population. METHODS: Participants were 1416 workers (aged 18-69 years) without a history of diabetes or serious disease who participated in a health survey. Intakes of rice, bread, and noodles at each meal were ascertained using a questionnaire, and carbohydrate score was calculated from these intakes. Impaired glucose metabolism was defined by fasting blood glucose ≥110 mg/dl or HbA1c ≥ 6.0% Logistic regression analysis was used to estimate the odds ratios of impaired glucose metabolism for quartile of carbohydrate score or rice intake for each meal with adjustment for covariates. RESULTS: Carbohydrate score and rice intake for each meal were not significantly associated with impaired glucose metabolism. However, among non-obese participants (BMI <25 kg/m2), a higher intake of rice at dinner was associated with an increased odds of having impaired glucose metabolism (P for trend = 0.02), with a multivariable-adjusted odds ratio for the highest versus lowest quartile of rice intake at dinner of 3.43 (95% confidence interval 1.22-9.70). In contrast, no such association was observed among obese participants (BMI ≥25 kg/m2) (P for interaction = 0.097). CONCLUSIONS: Our results suggest that carbohydrate score and rice intake for each meal are not associated with impaired glucose metabolism. The increased odds of having impaired glucose metabolism associated with higher rice intake at dinner among non-obese participants requires further investigation.