Abstract
OBJECTIVES: To investigate the relationships between abnormal bone mineral density (BMD) and exposure to single or combined occupational hazards in steelworkers by analyzing the correlations between various occupational hazards (night-shift work, high temperature, dust and noise) and abnormal BMD with both a single-risk score model (SRSM) and a hybrid-risk score model (HRSM). METHODS: Participants were selected from a cross-sectional study called "Cohort Study on the Health Effects of the Occupational Population in the Beijing-Tianjin-Hebei Region". A total of 6816 participants were recruited for this study. Night-shift work and high temperature, dust and noise exposure were considered occupational hazards and were analyzed separately and in combination (coexposure). The health risk factor score and partial regression coefficient were used to establish an SRSM and an HRSM. RESULTS: The rate of abnormal BMD in steelworkers was 27.6% (28.0% in males and 23.3% in females). Logistic regression revealed that, compared with that of individuals with 0 cumulative days of night-shift work, the risk of abnormal BMD for individuals with various amounts of night-shift work was as follows: ~927.20 days (OR = 1.40, 95% CI: 1.15 ~ 1.72), ~ 1772.02 days (OR = 1.45, 95% CI: 1.19 ~ 1.77), and ≥ 2573.50 days (OR = 1.55, 95% CI: 1.27 ~ 1.89). Compared with that of the cumulative exposure to high temperatures in the 0 °C·y group, the risk of abnormal BMD in the other groups was as follows: 667.49~°C·y (OR = 1.34, 95% CI: 1.06 ~ 1.71) and ≥ 790.30 °C·y (OR = 1.32, 95% CI: 1.03 ~ 1.69). Compared with that of the cumulative amount of dust exposure in the 0 mg/m(3)·y group, the risk of abnormal BMD for the other groups was as follows: 30.42 ~ mg/m³·y (OR = 1.23, 95% CI: 1.02 ~ 1.49) and ≥ 40.17 mg/m³·y (OR = 1.37, 95% CI: 1.14 ~ 1.65). Compared with that of the cumulative amount of noise exposure in the 0 dB(A)·y group, the risk of abnormal BMD for the other groups was as follows: ≥1707.47 dB(A)·y (OR = 1.17, 95% CI: 1.00 ~ 1.40). When an SRSM was used, compared with that in the control group (score < 0.42), the risk of abnormal BMD in the other groups was as follows: ~0.42 (OR = 1.24, 95% CI: 1.03 ~ 1.19), ~ 0.72 (OR = 1.51, 95% CI: 1.24 ~ 1.83), and ≥ 0.97 (OR = 2.11, 95% CI: 1.71 ~ 2.60). When an HRSM was used, compared with that of the reference group (score < 0.360), the risk of abnormal BMD for the other groups was as follows: ~0.360 (OR = 1.26, 95% CI: 1.05 ~ 1.52), ~ 0.576 (OR = 1.43, 95% CI: 1.18 ~ 1.74), and ≥ 0.779 (OR = 2.08, 95% CI: 1.70 ~ 2.55). CONCLUSIONS: (1) Night-shift work and high temperature and dust exposure may contribute to abnormal BMD in steelworkers. (2) The higher the corresponding risk score of occupational hazard coexposure is, the greater the risk of abnormal BMD in steelworkers. When workers are exposed to multiple occupational hazards at the same time, coexposure models could reveal the relationships between occupational hazard exposure and abnormal BMD in steelworkers more accurately.