Objective: To investigate the health status of the thyroid and related influencing factors in the seamen in Zhoushan, China.
Methods: A total of 136 coastal seamen (coastal group), 104 deep-sea seamen (deep-sea group), and 272 base staff (base group) who underwent physical examinations in 2014 were selected. Questionnaire survey and ultrasound were performed, and levels of thyroid hormone and urinary iodine were measured.
Results: Compared with the coastal group and the base group, the deep-sea group had a significantly higher rate of abnormal ultrasound findings (49.04% vs 30.88%/28.67%, P<0.05), as well as a significantly higher rate of abnormal serum free thyroxine (FT4) (25.00% vs 9.56%/6.25%, P<0.05). The logistic regression analysis showed that in the coastal group, the risk factors for thyroid abnormality on ultrasound were obesity shown by body mass index (BMI) (OR=2.55, 95% CI=1.13~4.13) and annual working time>6 months (OR=4.25, 95% CI=2.02~8.26) (both P<0.05); in the deep-sea group, the risk factors for thyroid abnormality on ultrasound were obesity shown by BMI (OR=3.45, 95% CI=1.28~7.02) and annual working time>6 months (OR=5.33, 95% CI=3.18~9.23) (both P<0.05).
Conclusion: The thyroid abnormality in deep-sea seamen is caused by various reasons and is correlated with annual working time, working environment and area, and iodine nutritional status.