A cohort study of shift work type, physical labor intensity, and their joint association with type 2 diabetes
- VernacularTitle:轮班类型、体力劳动强度及其联合作用与2型糖尿病关联的队列研究
- Author:
Haixia LU
1
;
Lan LIN
2
;
Changxue HUANG
1
;
Yuxin JIN
1
;
Yulong LIAN
1
Author Information
- Publication Type:Selectedarticle
- Keywords: shift type; physical labor intensity; cohort study; type 2 diabetes mellitus; joint exposure effect
- From: Journal of Environmental and Occupational Medicine 2026;43(8):936-943
- CountryChina
- Language:Chinese
- Abstract: Background Shift work is increasingly common in modern industries as economic globalization continues to advance, and has been associated with type 2 diabetes mellitus (T2DM). Objective To investigate the independent and interactive effects of shift work types and physical labor intensity on the risk of T2DM within an occupational cohort of petroleum workers, aiming to provide a scientific basis for reducing the risk of T2DM among workers engaged in shift work and physical labor. Methods This cohort study enrolled petroleum workers who underwent occupational health examinations at Karamay Central Hospital in Xinjiang from 2013 to 2015. Using stratified sampling, employees aged 20–60 years who had been actively employed and had been working in their current positions for at least one year were selected. A total of 3720 participants completed the baseline questionnaire survey and health examination, and follow-up was conducted in 2023. T2DM was diagnosed according to the 2020 Chinese Guidelines for the Prevention and Treatment of Type 2 Diabetes. Shift work type was categorized into fixed day shift, two-shift rotation, three-team two-shift rotation, four-team three-shift rotation, and other shift schedules. Physical labor intensity was classified as light, moderate, heavy, and extremely heavy according to the Classification of Physical Labor Intensity for Petroleum Field Operations (SY/T 6358—2008). Poisson regression models were used to estimate the associations of shift work type, physical labor intensity, and their joint exposure categories with T2DM risk after adjustment for potential confounders. Results A total of 3473 participants completed follow-up. Poisson regression analysis showed that shift work type was associated with T2DM risk. After adjustment for confounders, compared with fixed day shift workers, those engaged in two-shift rotation, three-team two-shift rotation, four-team three-shift rotation, and other shift schedules had higher risks of T2DM, with RRs of 2.17 (95%CI: 1.44, 3.27), 1.86 (95%CI: 1.16, 2.97), 1.85 (95%CI: 1.17, 2.93), and 2.15 (95%CI: 1.20, 3.88), respectively. T2DM risk also differed across physical labor intensity groups, with the extremely heavy group showing the highest risk (RR=2.26, 95%CI: 1.44, 3.56), followed by the heavy group (RR=1.91, 95%CI: 1.29, 2.82). Compared with workers exposed to fixed day shift + light intensity, increased T2DM risks were observed in those exposed to fixed day shift + heavy intensity (RR=2.38, 95%CI: 1.16, 4.72) or extremely heavy intensity (RR=2.64, 95%CI: 1.13, 5.82); two-shift rotation + light (RR=2.71, 95%CI: 1.11, 6.14), moderate (RR=3.38, 95%CI: 1.43, 7.34), heavy (RR=3.61, 95%CI: 1.52, 7.84), or extremely heavy intensity (RR=4.93, 95%CI: 1.87, 11.12); three-shift two-team rotation + light (RR=2.75, 95%CI: 1.14, 6.19), moderate (RR=3.08, 95%CI: 1.14, 7.51), or heavy/extremely heavy intensity (RR=4.06, 95%CI: 1.77, 8.50); four-shift three-team rotation + heavy/extremely heavy intensity (RR=3.89, 95%CI: 1.78, 7.84); and other shift types + heavy/extremely heavy intensity (RR=4.57, 95%CI: 1.55, 11.30). Conclusion This study demonstrates that various types of shift work significantly increase the risk of T2DM, and that concurrent exposure to high physical labor intensity exacerbates this risk. Regular blood glucose monitoring and targeted health interventions are recommended for workers exposed to rotating shift schedules and high physical work intensity.
