The eGFR Decline as a Risk Factor for Metabolic Syndrome in the Korean General Population: A Longitudinal Study of Individuals with Normal or Mildly Reduced Kidney Function

Metabolic syndrome (MS) is a risk factor for the development and progression of chronic kidney disease (CKD). However, it is unclear whether decreased renal function affects MS. Through a longitudinal study, we investigated the effect of estimated glomerular filtration rate (eGFR) changes on MS in participants with an eGFR above 60 mL/min/1.73 m2. A cross-sectional (n = 7107) and a 14-year longitudinal study (n = 3869) were conducted to evaluate the association between MS and eGFR changes from the Korean Genome and Epidemiology Study data. The participants were categorized by their eGFR levels (60–75, 75–90, and 90–105 versus ≥ 105 mL/min/1.73 m2). In a cross-sectional analysis, the MS prevalence was significantly increased with a decline in the eGFR in a fully adjusted model. The odds ratio of individuals with an eGFR of 60–75 mL/min/1.73 m2 was observed to be the highest (2.894; 95% confidence interval (CI), 1.984–4.223). In the longitudinal analysis, incident MS significantly increased with an eGFR decline in all the models, with the highest hazard ratio in the lowest eGFR group (1.803; 95% CI, 1.286–2.526). In joint interaction analysis, all covariates showed a significant joint effect with an eGFR decline on the incident MS. MS incidents are associated with eGFR changes in the general population without CKD.

Impact of Reduced Working Hours and Night Work Hours on Metabolic Syndrome: A Quasi-Experimental Study

Objectives

Epidemiological evidence linking long working hours and shift work to metabolic syndrome remains inadequate. We sought to evaluate the impact of reducing working hours on metabolic syndrome.

Methods

We compared the prevalence of metabolic syndrome among male manual workers in a manufacturing company (N = 371) before and after the introduction of policy to reduce daily work hours from 10 to 8 hours. Components of metabolic syndrome were measured in periodic health examinations before the intervention, 6-9 months after, and 1.5-2 years after the intervention. Generalized estimating equation models were used to estimate changes in the prevalence of metabolic syndrome. Analyses were stratified by day work versus shift work.

Results

The results showed a significantly decreased prevalence of metabolic syndrome 6-9 months following the intervention in day workers (risk ratio = 0.68, 95% confidence interval 0.52-0.88), but the benefit disappeared after 1.5-2 years. Shift workers showed a decreased prevalence of metabolic syndrome for the whole follow-up duration after the intervention, although the change was not statistically significant.

Conclusion

Reducing working hours was associated with short-term improvement in metabolic syndrome in male manual workers.

Metabolic and Obesity Phenotype Trajectories in Taiwanese Medical Personnel

The distribution of metabolic and obesity phenotypes in Taiwanese medical personnel is unknown. In this study, trajectory analysis with repeated measurements was used to explore the development and associated risk factors of different metabolic and obesity phenotypes in hospital staff from a Taiwanese medical center. The results demonstrated that metabolically unhealthy workers presented with a higher body mass index (BMI) compared with their metabolically healthy counterparts. Male and aged > 40 years hospital workers were more likely to be in a deleterious metabolic/obesity state. Meanwhile, profession and working hours were not significantly associated with the development of certain phenotypes in our study. These results shed light on the necessity of adequate data retrieval regarding working hours, and a nuanced examination of working conditions among different professions. Our findings are helpful for the development of advanced guidance regarding health promotion in hospital workers.

Healthy Lifestyle Score and Incidence of Glaucoma: The Sun Project

Background: The relationship between modifiable risk factors, such as diet and lifestyle, and glaucoma remains controversial. We analyse the effect of the Mediterranean lifestyle (ML) on glaucoma incidence in the “Seguimiento Universidad de Navarra” (SUN) Project. Methods: The SUN Healthy Lifestyle Score (SHLS) includes 10 healthy habits: never having smoked, moderate to high physical activity, Mediterranean diet adherence, moderate alcohol consumption, low television exposure, no binge drinking, short afternoon napping, meeting up with friends, working at least 40 h/wk, and low body mass index. The information was collected biennially through self-reported questionnaires. The relationship between new glaucoma cases and the SHLS was assessed by Cox regression using hazard ratios. Crude, multi-adjusted, and sensitivity analyses were performed. Results: During a median of 12 years of follow-up, 261 (1.42%) new cases of glaucoma were identified among 18,420 participants. After adjusting for potential confounders, participants in the healthiest SHLS category showed a significantly reduced risk of glaucoma compared to those in the lowest SHLS category (adjusted HR = 0.51, 95% CI = 0.28–0.93). For each point added to the SHLS, the risk of glaucoma relatively dropped 5%. Conclusions: Higher adherence to a ML, measured by the SHLS, was significantly associated with a lower risk of developing glaucoma. Based on our study, the ML is a protective factor for glaucoma incidence.

Health problems associated with single, multiple, and the frequency of months of objectively measured long working hours: a cohort study by the National Institute of Occupational Safety and Health, Japan

Purpose

We aimed to examine the prospective associations of monthly working hours measured in a month, the 6-month averaged hours, and the frequency of long working hours (≥ 205 h/month) during the past 6 months with health indicators.

Methods

This study included 6,806 Japanese company workers (response rate = 86.6%). Data on the workers’ monthly attendance during the second half of fiscal year 2016 and annual health checkups in fiscal years 2016 and 2017 were collected. We evaluated the association of the above three types of monthly working hours with subsequent health checkup data in fiscal year 2017. We adjusted for the corresponding data in fiscal year 2016.

Results

Multivariate logistic regression analyses revealed significant associations between monthly working hours and workers’ systolic and diastolic blood pressure as well as aspartate aminotransferase, alanine aminotransferase, low-density lipoprotein cholesterol (LDL), and triglyceride levels. However, the associations were not consistent between months. The average monthly working hours were significantly associated with higher LDL levels for the 220–240 h/mo group (OR: 1.49, 95%CI: 1.07–2.08) and lower triglyceride levels for the < 140 h/mo group (OR: 0.15, 95%CI: 0.03–0.77), compared to the 140–180 h/mo group. The frequency of long working hours was significantly associated with higher LDL levels.

Conclusions

Working hours over several months produced various associations with health indicators compared to those measured in a single month. Our present data suggest that the effects of average or frequency of long working hours during the past 6 months are likely to appear in LDL levels.

Association between shift work or long working hours with metabolic syndrome: a systematic review and dose-response meta-analysis of observational studies

This meta-analysis investigates the relationship between both shift work and long working hours and risk of developing metabolic syndrome (MetS). PubMed, EMBASE, and Web of Science databases were searched from the outset to December 10, 2019. Two reviewers independently screened studies, extracted data, and assessed the risk of bias of included studies. A total of 36 (30 cross-sectional, 5 cohort, and a nested case-control) studies, involving 274,263 participants, were included. The pooled odds ratio of shift work and development of MetS was 1.35 (95% confidence interval: 1.24-1.48), and the pooled odds ratio of long working hours and development of MetS was 1.19 (95% confidence interval: 0.97-1.46). In the subgroup analysis stratified by gender, the pooled odds ratios for male and female shift workers were 1.25 (95% confidence interval: 1.14-1.37) and 1.47 (95% confidence interval: 1.18-1.82), respectively. The dose-response (number of years of shift work and development of MetS) analysis showed the pooled odds ratio for 5 years of shift work was 1.07 (95% confidence interval: 1.05-1.09) and for 10 years of shift work 1.11 (95% confidence interval: 1.06-1.15). Our meta-analysis confirmed shift work is significantly associated with risk of metabolic syndrome, but the relationship between long working hours and MetS was not substantiated. Additionally, there was a nonlinear dose-response relationship between the number of years of shift work and risk of MetS, showing positive relationship to about 20 years of shift work but not for longer than 20 years. Prospective cohort studies regarding specific shift work schedules are needed to confirm these results.

Cross-sectional association between long working hours and liver function: the Kangbuk Samsung Health Study

OBJECTIVES

Although the effects of long working hours on liver function remain unclear, in South Korea, there is a social perception that long working hours are associated with poor liver function. Thus, long working hours have recently become a major issue. This study aimed to determine the association between long working hours and liver function, as indicated by the alanine transaminase (ALT) levels.

DESIGN

Cross-sectional study.

SETTING

Large university hospitals in Seoul and Suwon, South Korea.

PARTICIPANTS

Workers in formal employment who underwent a comprehensive health examination at the Kangbuk Samsung Hospital Total Healthcare Centre clinics in Seoul and Suwon, South Korea, between January 2011 and December 2018. Of the 386 488 participants, 212 421 met the inclusion criteria and were included in the analysis.

PRIMARY OUTCOME MEASURE

ALT elevation.

RESULTS

The participants were predominantly well-educated (86.1%), male (69.3%) and in their 30s (49.6%). In total, 13.4% of the participants presented ALT elevation (>40 IU/L). There was no significant association between working hours and ALT elevation in the general population and in the hepatitis B surface antigen (HBsAg)-negative group. Conversely, in the HBsAg-positive group, working >60 hours per week compared with 35-40 hours per week was significantly associated with ALT elevation. The association was more pronounced in those with ALT levels >80 IU/L (OR 1.94, 95% CI 1.24 to 3.01) than in those with ALT levels >40 IU/L (OR: 1.45, 95% CI 1.20 to 1.75). The p values for trend were <0.05.

CONCLUSIONS

Long working hours were associated with ALT elevation only in hepatitis B virus carriers and not in the general population. Provided that there is adherence to the legal working hours, there is no need to further restrict working hours for liver health, irrespective of HBsAg status.

Lifestyle behavior and the risk of type 2 diabetes in the Seguimiento Universidad de Navarra (SUN) cohort

BACKGROUND AND AIMS

We prospectively assessed the association between a healthy lifestyle score (HLS) and the risk of type 2 diabetes mellitus (T2DM) in a Mediterranean cohort.

METHODS AND RESULTS

We followed up 11,005 participants initially free of diabetes diagnosis in the "Seguimiento Universidad de Navarra" (SUN) cohort. We evaluated the influence of lifestyle-related factors based on a score previously related to a lower risk of cardiovascular disease. Only one incident case of T2DM was found among those with a baseline BMI ≤22 kg/m². Therefore, we excluded the BMI item and restricted the analysis to participants with a baseline BMI >22 kg/m². We measured the baseline adherence of a HLS that included: never smoking, physical activity, Mediterranean diet adherence, moderate alcohol consumption, avoidance of binge drinking, low television exposure, taking a short nap, spending time with friends and working hours. Incident cases of T2DM were self-reported by participants and confirmed by a physician. Cox proportional-hazards regression models were fitted to assess the association between HLS and the incidence of T2DM. After a median follow-up of 12 years, 145 incident cases of T2DM were observed. Among participants with a BMI >22 kg/m², the highest category of HLS adherence (7-9 points) showed a significant 46% relatively decreased hazard of T2DM compared with the lowest category (0-4 points) (multivariable adjusted HR: 0.54; 95% CI: 0.30-0.99).

CONCLUSIONS

Higher adherence to a HLS, including some factors not typically studied, may reduce T2DM risk. Preventive efforts should preferentially focus on weight control. However, this score may promote a comprehensive approach to diabetes prevention beyond weight reduction.

Objective and subjective working hours and their roles on workers' health among Japanese employees

This study investigated the correlation between objective and subjective working hours (OWH and SWH, respectively) and their relation to the workers' health. The study included 6,806 workers of a Japanese company (response rate=86.6%). OWH were collected as the monthly data during fiscal year 2017 from the company record. SWH were self-reported as the weekly data during the past month in November 2017. Both OWH and SWH corresponded to the same period of one month (October 2017). Additionally, the data for the annual health checkup in fiscal year 2017 and self-reported mental health in November 2017 were collected. The results indicated that the longer OWH was related to more underestimation of SWH. The analyses of covariance adjusted for the selected variables showed that irrespective of OWH or SWH, significant relationships were found for stress responses but not for body mass index, aspartate and alanine aminotransferase, fasting blood glucose, hemoglobin A1c, high-density lipoprotein cholesterol, or triglyceride. However, significant relationships with only OWH were noted for systolic and diastolic blood pressure, low-density lipoprotein cholesterol, gamma-glutamyl transpeptidase, and positive work-related state of mind. The present findings show that SWH should be used carefully when assessing the health effects of long working hours.

Gender discrepancy of incidence and risk factors of metabolic syndrome among rural Chinese from 2012-2013 to 2015-2017

BACKGROUND

We reported a relatively high rate of MetS in rural Northeast residents in 2012-2013. Many strategies like health knowledge propagation and lifestyle modification have been taken to help rural residents decrease metabolic disorders. Hence, we held the present follow-up study in order to figure the changes of metabolic parameters and the possible reasons together with the evaluation of MetS incidence and associated risk factors.

METHODS

A population-based sample of 8147 rural Northeast Chinese residents aged ≥ 35 years at baseline were followed up from 2012-2013 to 2015-2017. MetS was diagnosed following the unify criteria in 2009 using the Asian specific criteria.

RESULTS

Among residents with MetS at baseline, value of systolic, diastolic blood pressure, total cholesterol, HDL-C decreased while waist circumference increased in both genders in follow-up. Discrepancy of trend in body mass index, LDL-C and estimated GFR existed between male and female. Besides, triglyceride increased, and fast glucose decreased in female only. The alterations of dietary pattern might be accountable for those changes. Among residents without MetS at baseline, the cumulative incidence of newly diagnosed MetS was 24.0% (25.8% for male; 22.3% for female). As the number of metabolic disorders increased at baseline, the incidence of MetS also increased (zero metabolic disorder: 8.3%; one metabolic disorder: 17.1%; two metabolic disorders: 35.4%). In male residents, bad living habits like smoking and drinking were associated with increasing risk of Mets while in female, higher risk of MetS was more likely relevant to dietary pattern.

CONCLUSION

Metabolic parameters changes during the past years and seem to be associated with alteration of diet pattern. Incidence of MetS still high among rural Northeast Chinese. The risk factors of higher incidence of MetS show gender discrepancy which make the prophylaxis and control of MetS more effective and directive in rural residents.

Healthy Lifestyle and Incidence of Metabolic Syndrome in the SUN Cohort

We assessed the relationship between a healthy lifestyle and the subsequent risk of developing metabolic syndrome. The “Seguimiento Universidad de Navarra” (SUN) Project is a prospective cohort study, focused on nutrition, lifestyle, and chronic diseases. Participants (n = 10,807, mean age 37 years, 67% women) initially free of metabolic syndrome were followed prospectively for a minimum of 6 years. To evaluate healthy lifestyle, nine habits were used to derive a Healthy Lifestyle Score (HLS): Never smoking, moderate to high physical activity (>20 MET-h/week), Mediterranean diet (≥4/8 adherence points), moderate alcohol consumption (women, 0.1–5.0 g/day; men, 0.1–10.0 g/day), low television exposure (<2 h/day), no binge drinking (≤5 alcoholic drinks at any time), taking a short afternoon nap (<30 min/day), meeting up with friends >1 h/day, and working at least 40 h/week. Metabolic syndrome was defined according to the harmonizing definition. The association between the baseline HLS and metabolic syndrome at follow-up was assessed with multivariable-adjusted logistic regressions. During follow-up, we observed 458 (4.24%) new cases of metabolic syndrome. Participants in the highest category of HLS adherence (7–9 points) enjoyed a significantly reduced risk of developing metabolic syndrome compared to those in the lowest category (0–3 points) (adjusted odds ratio (OR) = 0.66, 95% confidence interval (CI) = 0.47–0.93). Higher adherence to the Healthy Lifestyle Score was associated with a lower risk of developing metabolic syndrome. The HLS may be a simple metabolic health promotion tool.

Work-related psychosocial factors and metabolic syndrome onset among workers: a systematic review and meta-analysis

BACKGROUND

Work-related psychosocial factors have been associated with metabolic syndrome. However, no systematic reviews or meta-analyses have evaluated this association.

METHODS

A systematic literature search was conducted, using PubMed, Embase, PsycINFO, PsycARTICLES and the Japan Medical Abstracts Society. Eligible studies included those that examined the previously mentioned association; had a longitudinal or prospective cohort design; were conducted among workers; provided sufficient data for calculating odds ratios, relative risks or hazard ratios with 95% confidence intervals; were original articles in English or Japanese; and were published no later than 2016. Study characteristics, exposure and outcome variables and association measures of studies were extracted by the investigators independently.

RESULTS

Among 4,664 identified studies, 8 were eligible for review and meta-analysis. The pooled risk of adverse work-related stress on metabolic syndrome onset was significant and positive (RR = 1.47; 95% CI, 1.22-1.78). Sensitivity analyses limiting only the effects of job strain and shift work also indicated a significant positive relationship (RR = 1.75; 95% CI, 1.09-2.79; and RR = 1.59; 95% CI, 1.00-2.54, P = 0.049 respectively).

CONCLUSION

This study reveals a strong positive association between work-related psychosocial factors and an elevated risk of metabolic syndrome onset. The effects of job strain and shift work on metabolic syndrome appear to be significant.

Long working hours, anthropometry, lung function, blood pressure and blood-based biomarkers: cross-sectional findings from the CONSTANCES study

Background

Although long working hours have been shown to be associated with the onset of cardiometabolic diseases, the clinical risk factor profile associated with long working hours remains unclear. We compared the clinical risk profile between people who worked long hours and those who reported being never exposed to long hours.

Methods

A cross-sectional study in 22 health screening centres in France was based on a random population-based sample of 75 709 participants aged 18–69 at study inception in 2012–2016 (the CONSTANCES study). The data included survey responses on working hours (never, former or current exposure to long working hours), covariates and standardised biomedical examinations including anthropometry, lung function, blood pressure and standard blood-based biomarkers.

Results

Among men, long working hours were associated with higher anthropometric markers (Body Mass Index, waist circumference and waist:hip ratio), adverse lipid levels, higher glucose, creatinine, white blood cells and higher alanine transaminase (adjusted mean differences in the standardised scale between the exposed and unexposed 0.02–0.12). The largest differences were found for Body Mass Index and waist circumference. A dose–response pattern with increasing years of working long hours was found for anthropometric markers, total cholesterol, glucose and gamma-glutamyltransferase. Among women, long working hours were associated with Body Mass Index and white blood cells.

Conclusion

In this study, men who worked long hours had slightly worse cardiometabolic and inflammatory profile than those who did not work long hours, especially with regard to anthropometric markers. In women, the corresponding associations were weak or absent.

Long Working Hours and Risk of Cardiovascular Disease

Purpose of Review

To summarize the evidence on the relationship between long working hours and cardiovascular disease, such as coronary heart disease and stroke.

Recent Findings

Large-scale meta-analyses with published and individual participant observational data on more than 740,000 men and women free of cardiovascular disease report a link between long working hours (≥ 55 h a week) and the onset of cardiovascular events. Our meta-analytic update of summary evidence suggests a 1.12-fold (95% CI 1.03–1.21) increased risk associated with coronary heart disease and a 1.21-fold (95% CI 1.01–1.45) increased risk of stroke, although the evidence is somewhat inconsistent and the possibility of residual confounding and bias cannot be ruled out. Few studies have examined the mechanisms which may be stress-related, behavioral, or biological. The recent pooled analyses suggest that increased cardiac electric instability and hypercoagulability might play a role.

Summary

The evidence that long working hours are a risk factor for cardiovascular disease is accumulating and suggests a small risk. Studies on the effects of long working hours in high-risk populations and those with pre-existing cardiovascular disease, mechanistic research, and intervention studies are needed to advance this research field.

Association Between a Healthy Lifestyle Score and the Risk of Cardiovascular Disease in the SUN Cohort

INTRODUCTION AND OBJECTIVES

A healthy lifestyle (HLS) is essential to attaining optimal cardiovascular health. Our objective was to assess the association between a HLS score and the incidence of hard cardiovascular disease (CVD) events.

METHODS

The SUN project is a dynamic, prospective, multipurpose cohort of Spanish university graduates with a retention proportion of 92%. In 19 336 participants, we calculated a HLS score ranging from 0 to 10 points: never smoking, physical activity (> 20 METs-h/wk), Mediterranean diet adherence (≥ 4/8 points), low body mass index (≤ 22), moderate alcohol intake (women, 0.1-5g/d; men, 0.1-10g/d), low television exposure (≤ 2h/d), no binge drinking (≤ 5 alcoholic drinks anytime), taking a short afternoon nap (< 30min/d), meeting up with friends> 1h/d and working> 40h/wk.

RESULTS

After a median follow-up of 10.4 years, we identified 140 incident cases of CVD. After adjustment for potential confounders, the highest category of HLS score adherence (7-10 points) showed a significant 78% relative reduction in the risk of primary CVD compared with the lowest category (0-3 points) (adjusted HR, 0.22; 95%CI, 0.11-0.46). Each healthy habit was individually associated with a lower risk of CVD.

CONCLUSIONS

A HLS score including several simple healthy habits was associated with a lower risk of developing primary CVD. This index may be useful to reinforce CVD prevention without the need to include traditional risk factors.

Predictive Capacity and Cutoff Value of Waist-to-Height Ratio in the Incidence of Metabolic Syndrome

The purpose of this study was to compare the predictive ability of waist-to-height ratio (WHtR) compared with other anthropometric indicators in the incidence of metabolic syndrome (MetS) and to propose cutoff values for its early detection in nursing practice. A longitudinal cohort study was conducted on a sample of 630 workers (137 exposed and 493 nonexposed), free of MetS at baseline. WHtR was compared with body mass index (BMI), waist circumference (WC), and the percentage of body fat (BF%). In the Cox regression, the adjusted values of hazard ratio (HR) were 5.4 (confidence interval [CI] = [3.1, 9.5]) for WHtR and 7.4 (CI = [3.7, 14.9]) for components of MetS. WHtR obtained the largest area under the curve 0.82 (CI = [0.76, 0.88]), and with a cutoff value of 0.54, values were obtained for sensitivity (70%) and specificity (77%). WHtR was the best predictor of incidence of MetS, with a cutoff value of 0.54. Nursing can improve the early detection of MetS by measuring WHtR.

Short sleep duration, shift work, and actual days taken off work are predictive life-style risk factors for new-onset metabolic syndrome: a seven-year cohort study of 40,000 male workers

BACKGROUND

This longitudinal study investigated the effects of various lifestyle-related factors - including sleep duration, shift work, and actual days taken off work - on new-onset metabolic syndrome (MetS).

METHODS AND RESULTS

A total of 39,182 male employees (mean age 42.4 ± 9.8 years) of a local government organization in Japan were followed up for a maximum of seven years, between 1999 and 2006. Multivariate analysis (Cox proportional hazard method) identified seven high-risk lifestyle factors that were significantly associated with new-onset MetS or a range of metabolic factors (obesity, hypertension, hyperglycemia, dyslipidemia): (1) short sleep duration (<5 h/day), (2) shift work, (3) insufficient number of days off work, (4) always eating until satiety, (5) not trying to take every opportunity to walk, (6) alcohol intake ≥60 g/day, and (7) smoking. In addition, a higher number of these high-risk lifestyle factors significantly promoted the onset of MetS. The hazard ratio for MetS associated with 0-1 high-risk lifestyle parameters per subject at the baseline was set at 1.00. Hazard ratios associated with the following numbers of high-risk lifestyle parameters were: 1.22 (95% CI 1.15-1.29) for 2-3 of these parameters; and 1.43 (1.33-1.54) for 4-7.

CONCLUSION

An increase in the number of high-risk lifestyle factors - such as short sleep duration, shift work, and an insufficient number of days off work - increased the risk of MetS onset. Comprehensive strategies to improve a range of lifestyle factors for workers, such as sleep duration and days off work, could reduce the risk of MetS onset.