TABLE 2.
Development of CKD according to weekly working hours
| Weekly working hours | Person‐years (PY) | Incident cases | Incidence density (per 104 PY) (95% CI) | Multivariable‐adjusted HR (95% CI)a | HR (95% CI)b in model using time‐dependent variables | |||
|---|---|---|---|---|---|---|---|---|
| Model 1 | Model 2 | Model 3 | Model 4 | |||||
| 35‐40 | 67 954.0 | 24 | 3.53 (2.37‐5.27) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) |
| 41‐52 | 209 011.2 | 95 | 4.55 (3.72‐5.56) | 1.55 (0.98‐2.46) | 1.54 (0.97‐2.45) | 1.51 (0.95‐2.40) | 1.51 (0.95‐2.40) | 1.50 (0.95‐2.39) |
| >52 | 106 395.2 | 66 | 6.20 (4.87‐7.90) | 2.06 (1.27‐3.34) | 2.07 (1.28‐3.36) | 1.98 (1.22‐3.22) | 1.99 (1.22‐3.25) | 1.95 (1.20‐3.18) |
| P for trend | .002 | .002 | .004 | .005 | .006 | |||
Model 1 was adjusted for age, sex, and year of screening examination.
Model 2: model 1 plus adjustment for center, alcohol intake, smoking status, regular exercise, education level, history of dyslipidemia, and medication for dyslipidemia.
Model 3: model 2 plus adjustment for BMI, systolic blood pressure, fasting blood glucose, HOMA‐IR, uric acid, and hsCRP.
Model 4: model 3 plus adjustment for work shift schedule and total KOSS‐SF score.
Abbreviations: BMI, body mass index; CI, confidence interval; CKD, chronic kidney disease; HOMA‐IR, homeostasis model assessment of insulin resistance; HR, hazard ratio; hsCRP, high‐sensitivity C‐reactive protein; KOSS‐SF, Korean Occupational Stress Scale‐Short Form.
Estimated from Cox proportional hazard models.
Estimated from Cox proportional hazard models with alcohol intake, smoking status, regular exercise, BMI, systolic blood pressure, fasting blood glucose, HOMA‐IR, uric acid, hsCRP and total KOSS‐SF score as time‐dependent variables and baseline age, sex, center, year of screening examination, education level, weekly working hours, work shift schedule, history of dyslipidemia, and medication for dyslipidemia as time‐fixed variables.