Health effect research on Hebei Spirit Oil Spill (HEROS) in Korea: a cohort profile

Long-term effects of the Hebei Spirit oil spill on the prevalence and incidence of allergic disorders

The Hebei Spirit oil spill accident occurred in December 2007, approximately 10 km off the coast of Taean, South Korea, a location notably close to residential areas. Crude oil substances have been detected in various environmental mediums since the accident, yet previous studies have primarily focused on the acute effects of oil exposure due to the short latency period of allergic diseases. Therefore, this study evaluated the long-term effects of oil spill exposure on allergic disorders. Our study included adult residents who had participated in the Health Effects Research on Hebei Spirit Oil Spill (HEROS) study up to five years post-incident, which was a prospective cohort to monitor the health status of Taean residents. We used two indicators to assess oil spill exposure, namely the distance from the initial contaminated coastline to each participant's residence and the number of days participants had engaged in oil clean-up work. Current symptoms such as asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and multimorbidity were considered allergic disorders. In the baseline survey, the prevalence of asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and allergic multimorbidity symptoms was associated with both exposure indicators; however, these associations were not observed in the two consecutive surveys. Significant longitudinal associations between oil spill exposure indicators and the four allergic disorders, as well as multimorbidity incidences, were observed during a five-year follow-up period. Our results suggest that oil spill exposure can affect acute and long-term allergic symptoms in residents near the accident site.

Association between oil spill clean-up work and thyroid cancer: Nine years of follow-up after the Hebei Spirit oil spill accident

In 2007, an unprecedented oil spill occurred in Taean, Korea. Although crude oil contains chemicals that could increase thyroid cancer risk, few studies have examined the long-term effects of oil exposure during clean-up and thyroid cancer incidence. We investigated the long-term thyroid cancer incidence among participants involved in clean-up work. 1798 participants engaged in at least two surveys since the baseline was tracked from 2008 to 2018. Participants reported the days they participated in oil clean-up works and cancer diagnoses. Cox proportional hazard models were used to estimate the hazard ratios between clean-up work duration and thyroid cancer. Over the 9-year follow-up, 30 thyroid cancer cases were diagnosed. A positive association was observed between clean-up duration and thyroid cancer risk. This effect was more pronounced among residents living <50 m from traffic roads. Our results indicate that crude oil clean-up work participation may increase the thyroid cancer risk.

Exposure to Crude Oil-Related Volatile Organic Compounds Associated with Lung Function Decline in a Longitudinal Panel of Children

BACKGROUND

Children in the affected area were exposed to large amounts of volatile organic compounds (VOCs) from the Hebei Spirit oil spill accident.

OBJECTIVES

We investigated the lung function loss from the exposure to VOCs in a longitudinal panel of 224 children 1, 3, and 5 years after the VOC exposure event.

METHODS

Atmospheric estimated concentration of total VOCs (TVOCs), benzene, toluene, ethylbenzene, and xylene for 4 days immediately after the accident were calculated for each village (n = 83) using a modeling technique. Forced expiratory volume in 1 s (FEV₁) as an indicator of airway status was measured 1, 3, and 5 years after the exposure in 224 children 4~9 years of age at the exposure to the oil spill. Multiple linear regression and linear mixed models were used to evaluate the associations, with adjustment for smoking and second-hand smoke at home.

RESULTS

Among the TVOCs (geometric mean: 1319.5 mg/m³·4 d), xylene (9.4), toluene (8.5), ethylbenzene (5.2), and benzene (2.0) were dominant in the order of air concentration level. In 224 children, percent predicted FEV₁ (ppFEV₁), adjusted for smoking and second-hand smoke at home, was 100.7% after 1 year, 96.2% after 3 years, and 94.6% after 5 years, and the loss over the period was significant (p < 0.0001). After 1 and 3 years, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁. After 5 years, the associations were not significant. Throughout the 5 years' repeated measurements in the panel, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁.

CONCLUSIONS

Exposure to VOCs from the oil spill resulted in lung function loss among children, which remained significant up to 5 years after the exposure.

Who has sustained psychological symptoms nine years after the Hebei Spirit oil spill?: The Health Effect Research on Hebei Spirit oil spill (HEROS) study

This study evaluated risk factors for sustained psychological symptoms in affected residents, nine years after the Hebei Spirit oil spill in Korea in 2007. The participants included residents of high-exposure areas, living within 2 km from the contaminated coast (n = 2013), among the cohort of the Health Effect Research on Hebei Spirit oil spill study from 2009 to 2016. Symptoms for post-traumatic stress disorder (PTSD), depression, psychosocial distress, and anxiety, as well as sociodemographic information were assessed through questionnaire interviews. Trajectory analysis was conducted to identify the group with sustained symptoms over time and logistic regression analysis was performed to identify risk factors for sustained symptoms adjusted for covariates. A longer duration of clean-up work, lower household income, and presence of a chronic disease in all type of symptoms, and being female, younger age, and higher educational level in all symptoms but PTSD, showed a significant association with increased risk of sustained symptoms. The highest risk was found in the subgroup with a longer clean-up together with offshore and maritime occupations or lower income in PTSD, depression, and anxiety, compared with those with a shorter clean-up and other occupation or higher income. Increased risk of sustained PTSD in relation to a longer clean-up was limited to those with a lower educational level (p-interaction = 0.009). The results suggested that participating longer in clean-up work increased sustained psychological symptoms, synergistically with socioeconomic factors such as offshore and maritime occupations, lower household income, or economic losses related to educational level.

Cross-sectional and longitudinal associations between global DNA (hydroxy) methylation and exposure biomarkers of the Hebei Spirit oil spill cohort in Taean, Korea

The Hebei Spirit oil spill (HSOS) occurred on the west coast of South Korea (Taean county) on December 7, 2007, and studies revealed that exposure to the oil spill was associated with various adverse health issues in the inhabiting population. However, no studies evaluated the association between crude-oil exposure and epigenetic changes. This study aimed to investigate the HSOS exposure-associated longitudinal and cross-sectional variations in global DNA methylation (5-mc) and/or hydroxymethylation (5-hmc) and expression profiles of related genes in Taean cohort participants from 2009 (AH-baseline) and 2014 (AH-follow-up) relative to the reference group (AL). We measured global DNA 5-mc and 5-hmc levels and related gene expression levels in whole blood. We identified significant associations between HSOS exposure and AH-baseline-5-mc, AH-baseline-5-hmc, and AH-follow-up-5-hmc. HSOS exposure was associated with lower %5-mc content and higher %5-hmc content in the same individuals from both the cross-sectional and longitudinal studies. In addition, we found a strong correlation between 5-mc and DNMT3B expression, and between 5-hmc and TET1 expression. Our findings suggested that epigenetic changes are important biomarkers for HSOS exposure and that 5-hmc is likely to be more sensitive for environmental epidemiological studies.

An association between oil spill clean-up work and cardiovascular disease

BACKGROUND

In December 2007, Taean, South Korea, experienced the largest oil spill in Korean history. After about 10 years of follow-up, we evaluated the long-term effect of the disaster on the cardiovascular health of residents and clean-up workers/volunteers.

OBJECTIVE

We examined the relationship between the duration of oil clean-up work and the risk of incident angina and myocardial infarction (MI).

METHODS

We used data from a prospective cohort study, the Health Effects Research of Oil Spill (HEROS); we included adult cohort members free from cardiovascular disease who completed at least the first two surveys (n = 1737). At baseline, members reported the number of days they participated in oil clean-up work; during the subsequent surveys, they reported newly diagnosed cases of angina or MI. We fitted a time-varying interval-censored proportional hazard model, controlling for age, sex, body mass index, smoking status, monthly household income, and distance from the affected seashore to residence.

RESULTS

The risk of incident angina or MI was greater in those with more than 15 days' exposure; those with 15-59 days showed a hazard ratio (HR) of 1.34 (95% confidence interval [CI]: 0.87, 2.06) those with 60-179 days had an HR of 1.31 (0.95, 1.79), and those worked longest (180 or more days) showed the strongest association with a HR of 1.75 (95% CI: 1.17, 2.61).

CONCLUSION

We found that a greater duration of clean-up work was associated with an increased risk of incident angina or MI.