Comparison of cancer incidence between production and office workers at a shipyard in Korea: a retrospective cohort study from 1992 to 2005.

BACKGROUND: Cancer is a major concern in shipbuilding. Since 1970s, shipbuilding and repair has been a strategic industry in Korea, which has become currently the world's largest shipbuilding country. The aim of this study is to investigate the cancer incidence in shipyard workers in Korea.
METHODS: The cohort comprised 30,288 male employees (20,647 production workers and 9,641 office workers) ever employed between 1992 and 2005 in a shipyard in Korea. The authors compared the cancer incidence between the groups using the participants' hospital medical records and data received from Korea National Cancer Incidence Database and Korean National Statistical Office.
RESULTS: The total number of cancers was 135 among office workers and 519 among production workers in the shipyard. The age-standardized cancer rates among office and production workers were 136.2 and 179.7 per 100,000 person-years, respectively. The standardized rate ratios for stomach cancer, liver cancer, and lung cancer in production workers compared with office workers were 1.67 (95% CI: 1.12-2.49), 2.13 (95% CI: 1.37-3.36), and 3.71 (95% CI: 1.68-8.19), respectively.
CONCLUSIONS: The observed increase in stomach, liver, and lung cancers among production workers suggests that some occupational factors in the shipyard might have contributed to the increased cancer risk. Further study is needed to clarify the risk of those cancers and to identify the specific factors involved.