Risk factors for decompression sickness among commercial divers in Qingdao, China — a single-center, retrospective study

BACKGROUND: Decompression sickness (DCS) is a major occupational hazard for commercial divers. This study aimed to analyze the clinical characteristics and risk factors associated with DCS severity in com-mercial divers in Qingdao, China. MATERIAL AND METHODS: A single-center retrospective study was conducted on 80 commercial divers with DCS treated at a tertiary hospital from 2017 to 2022. Demographic, diving-related, and clinical data were collected. Statistical analyses included independent-samples t-tests, chi-square tests, Mann-Whitney Utest, and Pearson correlation analysis. RESULTS: Most patients were male (98.8%) with a mean age of 41.7 ± 10.2 years. Type I DCS accounted for 77.5% (n = 62) and type II for 22.5% (n = 18). Type II patients were significantly older (47.3 ± 7.1 vs. 40.1 ± 10.4 years, p = 0.007) and had longer diving experience (18.8 ± 9.6 vs. 13.7 ± 8.4 years, p =0.030) than type I patients. No significant differences were found in diving depth, number of recent dives, or time to symptom onset between groups. Age strongly correlated with diving experience (r = 0.772, p < 0.001). The incidence of type II DCS was highest in the 41-50 age group (36.4%) and among divers with > 25years of experience (50%). All patients improved with hyperbaric oxygen therapy, but full recovery was only observed in type I cases. CONCLUSIONS: Increasing age and longer diving experience are significant risk factors for severe (type II) DCS. Targeted health monitoring and safety education for this high-risk group are critical to reduce the incidence of severe DCS.