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Weekly Working Hours and Serum Vitamin D 3 Levels Among Korean Wage Workers : Evidence From KNHANES 2022-2023
1From the Department of Pediatrics, Chung-Ang University Hospital, Seoul, Korea (Y.H.C.); and Department of Occupational and Environmental Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea (J.A.).
Objective:
To examine whether weekly working hours are associated with serum vitamin D levels among Korean wage workers.
Methods:
This cross-sectional study used data from 2988 adults in the 2022-2023 Korea National Health and Nutrition Examination Survey. Serum 25(OH)D 2 and 25(OH)D 3 were measured by liquid chromatography-mass spectrometry. Associations with weekly working hours were analyzed using multivariable linear regression, adjusting for age, sex, education, and occupation.
Results:
Each additional weekly working hour was associated with a 0.057-ng/mL decrease in 25(OH)D 3 levels, with no significant association for 25(OH)D 2 . The inverse association was stronger among white-collar, highly educated, and obese workers.
Conclusions:
Long working hours are significantly linked to lower serum vitamin D 3 levels. These findings highlight working hours as a modifiable occupational determinant of vitamin D deficiency, particularly in indoor or white-collar settings.
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