Occupation as a risk factor for progression of chronic kidney disease: a retrospective cohort study.

Objectives: The cause of chronic kidney disease (CKD) remains uncertain in the majority of affected individuals, but the influence of socioeconomic status on CKD progression has recently gained attention. We compared the risk of CKD progression among 18 occupational classifications using an annual health checkup database.

Methods: We used the annual health checkup data and health insurance claims data of the Japan Health Insurance Association in Kyoto prefecture between April 2012 and March 2016. The primary outcome for survival analysis was defined as a more than 30% change in the estimated glomerular filtration rate (eGFR) from the first health checkup. We used the Cox proportional hazards model for time-to-event analyses to estimate the hazard ratios and 95% CIs for the primary outcome, adjusting for age, sex, eGFR, body mass index, blood pressure, blood sugar, dyslipidemia, uric acid, urinary protein, and existence of kidney disease at first health checkup.

Results: We analyzed 239 506 employees, and 1736 (0.7%) individuals whose eGFR had decreased by 30% or more; the mean follow-up period was 2.8 years. When we compared the risk with that for "manufacturing," 5 categories of industries ("information and communications"; "transport and postal services"; "accommodations, eating and drinking services"; "living-related and personal services and amusement service"; "medical, health care and welfare") were associated with a decline in the increased risk of eGFR after adjusting for the confounding factors and/or mediators.

Conclusions: We provide evidence that the risk of CKD progression depends on occupational type. Further research is needed to confirm the mechanism and causal relationships involved.