The Association between Shift Work and Bone Mineral Density : analysis of 2008-2009 Korean National Health and Nutrition Examination Survey / 대한산업의학회지

OBJECTIVES: The objectives of this study were to explore the association between shift work and the bone mineral density in a representative sample of Korean workers. METHODS: He data from the Fourth Korean National Health and Nutrition Examination Survey (2008-2009) was used. The participants were Korean workers aged 16 to 60 years. Logistic regression analysis was applied to determine the association between shift work and the bone mineral density after controlling for covariates using the SAS version 9.3 package program. RESULTS: The blood vitamin D level in shift workers was significantly lower than that of day workers in both males and females. In male shift workers, shift work was significantly associated with a decreased bone mineral density in the femoral neck (odds ratio(OR) 1.42, 95% confidence interval(CI)=1.05~1.92) and lumbar spine (OR 1.53, 95% CI=1.09~2.15) compared to day workers. After controlling for covariates, this association was still significant. In the case of female shift workers, shift work was significantly related to a decreased bone mineral density in the total femur (OR 2.84, 95% CI=1.69~4.79) and lumbar spine (OR 1.58, 95% CI=1.12~2.24). After controlling for covariates, this risk was not statistically significant. CONCLUSIONS: The blood vitamin D level of shift workers was significantly lower than that of day workers. In male shift workers, shift work can decrease the bone mineral density in the femoral neck and lumbar spine. Prospective studies with information on the shift work intensity and duration and exposuredata to explain mechanisms will be needed.

The Effect of Shift Work on the Level of Self-Rated Health / 대한산업의학회지

OBJECTIVES: The present study was designed to determine the characteristics of shift work and the relationship between shift work and the level of self-rated health using the Korean Labor and Income Panel Study (KLIPS) data, which represents urban households in Korea. METHODS: Using the 9th wave of KLIPS, this study analyzed 2,087 male workers aged 25 to 64 years; participants missing data were excluded from analysis. To determine the impact of shift work on the level of self-rated health, logistic regression analysis was applied that controlled for socio-demographic characteristics, labor environment, and health-related behaviors. RESULTS: Shift workers comprised 13.4% of study subjects overall. The majority(69.2%) of participants were in 2-teams and in 2-shifts. Week 1 shift cycle changes were the highest, 56.3%. The risk of poor self-rated health was not significantly higher among shift workers compared to non-shift workers (OR=1.08, 95% CI=0.79~1.48). When divided by tenure, shift workers with more than 10-years experience (OR=1.79, 95% CI=0.91~3.50) tended to show greater risk than non-shift workers at marginal significance. CONCLUSIONS: In the present study, a significantly higher risk of self-rated poor health among shift workers was not observed. However, shift workers with more than 10-years experience tended to show increased health risk compared to non-shift workers. Further studies are required to determine time-series data and to consider both healthy worker effect and information bias.