Air pollution and survival in patients with malignant mesothelioma and asbestos-related lung cancer: a follow-up study of 1591 patients in South Korea.

BACKGROUND: Despite significant advancements in treatments such as surgery, radiotherapy, and chemotherapy, the survival rate for patients with asbestos-related cancers remains low. Numerous studies have provided evidence suggesting that air pollution induces oxidative stress and inflammation, affecting acute respiratory diseases, lung cancer, and overall mortality. However, because of the high case fatality rate, there is limited knowledge regarding the effects of air pollution exposures on survival following a diagnosis of asbestos-related cancers. This study aimed to determine the effect of air pollution on the survival of patients with malignant mesothelioma and asbestos-related lung cancer. METHODS: We followed up with 593 patients with malignant mesothelioma and 998 patients with lung cancer identified as asbestos victims between 2009 and 2022. Data on five air pollutants-sulfur dioxide, carbon monoxide, nitrogen dioxide, fine particulate matter with a diameter < 10 µm, and fine particulate matter with a diameter < 2.5 µm-were obtained from nationwide atmospheric monitoring stations. Cox proportional hazard models were used to estimate the association of cumulative air pollutant exposure with patient mortality, while adjusting for potential confounders. Quantile-based g-computation was used to assess the combined effect of the air pollutant mixture on mortality. RESULTS: The 1-, 3-, and 5-year survival rates for both cancer types decreased with increasing exposure to all air pollutants. The estimated hazard ratios rose significantly with a 1-standard deviation increase in each pollutant exposure level. A quartile increase in the pollutant mixture was associated with a 1.99-fold increase in the risk of malignant mesothelioma-related mortality (95% confidence interval: 1.62, 2.44). For lung cancer, a quartile increase in the pollutant mixture triggered a 1.87-fold increase in the mortality risk (95% confidence interval: 1.53, 2.30). CONCLUSION: These findings support the hypothesis that air pollution exposure after an asbestos-related cancer diagnosis can negatively affect patient survival.

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.

Effects of chewing exercises on the occlusal force and masseter muscle thickness in community-dwelling Koreans aged 65 years and older: A randomised assessor-blind trial.

Chewing exercises have been applied in clinical settings to improve the occlusal force and function of the masseter muscle in elderly individuals. However, the clinical relevance and effects of chewing exercises are unclear. This study aimed to investigate the effects of bilateral chewing exercises on the occlusal force and masseter muscle thickness in community-dwelling Koreans aged 65 years. Forty community-dwelling healthy elderly individuals were enrolled in this study. They were assigned to the experimental or the control group. The experimental group performed chewing exercises using medical equipment developed to facilitate such exercises. The chewing exercises were divided into isometric and isotonic types and were performed for 20 min/d, 5 days/wk, for 6 weeks. The control group did not perform any chewing exercises. The outcome measures were occlusal force and masseter muscle thickness, which were evaluated using an occlusometer and ultrasound device, respectively. A paired t test and an independent t test were used to evaluate the training effects. Within-group comparisons showed that occlusal force and masseter muscle thickness improved significantly in the experimental group (P < .001 for both), while the control group showed no significant improvements (P = .098 and .130). Between-group comparisons showed that the experimental group had a greater increase in occlusal force and masseter muscle thickness (P < .05 for both) compared to the control group. These results suggest that chewing exercises are effective in improving occlusal force and masseter muscle thickness in healthy elderly individuals.