Association between shift work and microalbuminuria: data from KNHANES(2012-2014)

Effect of night shift work on the reduction of glomerular filtration rate using data from Korea Medical Institute (2016-2020)

Background

Shift work increases the risk of chronic diseases, including metabolic diseases. However, studies on the relationship between shift work and renal function are limited. The aim of this study was to investigate the association between shift work and a decreased glomerular filtration rate (GFR).

Methods

Data were evaluated for 1,324,930 workers who visited the Korean Medical Institute from January 1, 2016 to December 31, 2020 and underwent a health checkup. Daytime workers were randomly extracted at a ratio of 1:4 after matching for age and sex. In total, 18,190 workers aged over 40 years were included in the analyses; these included 3,638 shift workers and 14,552 daytime workers. Participants were categorized into the shift work group when they underwent a specific health checkup for night shift work or indicated that they were shift workers in the questionnaire. The odds ratio was calculated using a conditional logistic regression to investigate the relevance of shift work for changes in GFR.

Results

35 workers in the shift group and 54 in the daytime group exhibited an estimated GFR (eGFR) value of < 60 mL/min/1.73m2 (p < 0.01). The difference in eGFR values between two checkups differed significantly depending on the type of work (p < 0.01); the difference in the shift work group (-9.64 mL/min/1.73 m2) was larger than that in the daytime work group (-7.45 mL/min/1.73 m2). The odds ratio for eGFR reduction to < 60 mL/min/1.73 m2 in the shift group versus the daytime group was 4.07 (95% confidence interval: 2.54-6.52), which was statistically significant.

Conclusions

The results of this study suggest that eGFR decreases by a significantly larger value in shift workers than in daytime workers; thus, shift work could be a contributing factor for chronic kidney disease (CKD). Further prospective studies are necessary to validate this finding and identify measures to prevent CKD in shift workers.

Cardiometabolic traits mediate the association of past shift work and chronic kidney disease: the Dongfeng-Tongji cohort study

OBJECTIVE

Present shift work has been associated with chronic disease. But influence of past shift work has not been established. This study is designed to investigate whether shift work in the past is associated with chronic kidney disease (CKD) in retired workers, and whether cardiometabolic traits affect the relationship.

METHODS

Overall, 15,775 retired workers (aged 62.3 ± 7.2 years) without CKD at baseline in the Dongfeng-Tongji cohort were included. Duration of past shift work was obtained through questionnaires, and divided into < 10.0, 10.0-20.0, and ≥ 20.0 years. CKD was diagnosed if individual's estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m². Logistic regression model was used to estimate the association between past shift work and CKD. Mediation analysis was conducted to analyze the mediating effects of cardiometabolic traits.

RESULTS

During the median follow-up of 4.7 years, 1072 (6.8%) incident CKD cases were recorded. Retired workers with past shift work had elevated CKD risk [ORs and 95% CIs for those with < 10.0, 10.0-20.0, and ≥ 20.0 years of past shift work were 1.61 (1.30, 2.00), 0.90 (0.72, 1.12), and 1.33 (1.11, 1.61)]. The associations were more evident among participants with poor or terrible sleep quality (P for interaction, 0.022). Mediation analysis showed that cardiometabolic traits including diastolic blood pressure and high density lipoprotein cholesterol mediated 7.02% and 10.05% of the relationship from past shift work to higher CKD risk.

CONCLUSIONS

Past shift work was related with increased risk of incident CKD among retired workers, and this relationship was partly mediated by cardiometabolic traits.

Rotating Night Shift Work, Exposure to Light at Night, and Glomerular Filtration Rate: Baseline Results from a Chinese Occupational Cohort

The misalignment between the circadian clock and behavioral cycles has been implicated in pathogenesis of many diseases. The main purpose of this study is to examine the association between rotating night shift work, exposure to light at night, and glomerular filtration rate among steelworkers in north China. A total of 6869 steelworkers, aged 22 to 60 years, were included in this study. Multivariable logistic regression was used to examine the association between night shift work, the brightness of bedroom ambient light at night (LAN), and estimated glomerular filtration rate (eGFR), with adjustment for potential confounders. Mediation analysis was performed to examine the mediation effect of potential mediators on the association of duration of night shifts and eGFR. Long duration of night shift work (≥29 years) had elevated odds of decreased eGFR (≤89 mL/min/1.73 m²) (odds ratio (OR), 1.37, 95% confidence interval (CI) 1.09–1.73) compared with day work after adjustment for potential confounders. The association between duration of night shifts and eGFR (continuous) was partially modified by diastolic blood pressure (average causal mediation effect (ACME), –0.077, 95% CI –0.134 to −0.030, p < 0.001). No significant associations were observed among the different brightness of bedroom ambient light levels: middle level (OR, 0.90, 95% CI 0.77–1.05), lightest level (OR, 0.94, 95% CI 0.75–1.18), and decreased eGFR compared with the darkest level. Long-term night-shift work, rather than the brightness of bedroom ambient LAN, is associated with early stage of renal dysfunction in steelworkers, and blood pressure may mediate the relationship between night shift work and decreased eGFR.

Association between night work and dyslipidemia in South Korean men and women: a cross-sectional study

BACKGROUND

Previous studies have reported that an irregular work schedule, particularly nighttime work, is associated with an altered lipid profile. Additionally, a mismatch in circadian rhythm can affect sleeping and eating habits, leading to poor health. This study aimed to examine the association between night work and dyslipidemia among South Korean adults aged ≥30 years.

METHODS

For this study, the data of 5813 participants in the 2013-2016 Korea National Health and Nutrition Examination Survey were analyzed. Diagnoses of dyslipidemia were based on blood sampling tests of total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, and triglyceride levels. Night work was defined as that conducted during evening (6 P.M.-12 A.M.) and overnight hours (12 A.M.-8 A.M.). The association between night work hours and dyslipidemia in South Korean men and women was investigated using a logistic regression analysis.

RESULTS

After adjusting for sociodemographic, economic, health-related, and nutritional factors, an association of night work with dyslipidemia was observed in male participants (odds ratio = 1.53, 95% confidence interval: 1.05-2.24). In subset analyses of male participants, night workers who skipped meals were more likely to have dyslipidemia than their day-working counterparts. Among men who slept < 7 h, night workers had a higher probability of dyslipidemia than day workers. In contrast, no statistically significant association between night work and dyslipidemia was observed in female participants, although the probability of dyslipidemia appeared to increase with advancing age. Furthermore, when women with dyslipidemia were subdivided by occupational categories, night workers in white collar positions were more likely to have dyslipidemia than their day-working counterparts.

CONCLUSION

Our study observed an association of night work with dyslipidemia, particularly in men. Although these findings may support interventions for South Korean night workers, further studies are needed for validation.