Decreased blood pressure associated with in-vehicle exposure to carbon monoxide in Korean volunteers.

BACKGROUND: Carbon monoxide (CO) is one of the primary components of emissions from light-duty vehicles, and reportedly comprises 77% of all pollutants emitted in terms of concentration. Exposure to CO aggravates cardiovascular disease and causes other health disorders. The study was aimed to assess the negative effects by injecting different amounts of CO concentration directly to human volunteers boarding in the car. METHODS: Human volunteers were exposed to CO concentrations of 0, 33.2, and 72.4 ppm, respectively during the first test and 0, 30.3, and 48.8 ppm respectively during the second test while seated in the car. The volunteers were exposed to each concentration for approximately 45 min. After exposure, blood pressure measurement, blood collection (carboxyhemoglobin [COHb] analysis), medical interview, echocardiography test, and cognitive reaction test were performed. RESULT: In patients who were exposed to a mean concentration of CO for 72.4 ± 1.4 ppm during the first exposure test and 48.8 ± 3.7 ppm during the second exposure test, the COHb level exceeded 2%. Moreover, the diastolic blood pressure was decreased while increasing in CO concentration after exposure. The medical interview findings showed that the degree of fatigue was increased and the degree of concentration was reduced when the exposed concentration of CO was increased. CONCLUSION: Although the study had a limited sample size, we found that even a low concentration of CO flowing into a car could have a negative influence on human health, such as change of blood pressure and degree of fatigue.

Heavy metal exposure linked to metabolic syndrome in Korean male firefighters: FRESH cohort cross-sectional analysis.

This study aimed to identify the relationship between blood lead and Cadmium (Cd) concentrations and metabolic syndromes (MetS), including its components (central obesity, hypertriglyceridemia, low high-density lioioritein, hypertension, and hyperglycemia) among Korean firefighters. A total of 965 firefighters of the Enhancement of Safety and Health cohort were analyzed in this study. MetS was defined according to the 2005 revised National Cholesterol Education Program-Adult Treatment Panel III criteria and the Korean Society for the Study of Obesity criteria for waist circumference. The collected data were analyzed using a logistic regression model. Of the 965 participants, 190 (19.7%) had MetS. After adjusting for age, body mass index, smoking, drinking, exercise, shift duty, and main duty position, the Cd level was significantly associated with an increased risk of MetS in the Korean firefighter population (odds ratio [OR] = 1.62, 95% confidence interval [CI] 1.07, 2.46). This association was significant among non-smokers and ex-smokers (OR = 1.58, 95% CI 1.03, 2.43), non-drinkers and ex-drinkers (OR = 1.77, 95% CI 1.06, 2.94), firefighters aged 40 year or older (OR = 1.77, 95% CI 1.10, 2.86), and office administrators (OR = 3.85, 95% CI 1.42, 10.39). This outcome suggests that exposure to Cd is likely to increase risk of MetS among firefighters.

The effect of polycyclic aromatic hydrocarbons on changes in the brain structure of firefighters: An analysis using data from the Firefighters Research on Enhancement of Safety & Health study.

Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete combustion of organic matter, and firefighters are highly exposed to these toxic compounds at fire sites. Exposure to PAHs can cause cognitive decline and neurodegeneration; however, to date, few studies have examined the potential effects of PAH exposure on structural changes in the brain. We aimed to investigate the association between the four types of PAH metabolites and the corresponding changes in neuroimaging markers based on smoking status and hypertension in male firefighters. For this, we utilized the 2-year follow-up data of 301 Korean male firefighters aged over 40 years. The concentrations of four PAH metabolites in urine were measured. Subcortical volume and cortical thickness were estimated using 3 T magnetic resonance imaging of the brain. A generalized linear model was used to investigate the effects of PAHs on changes in the subcortical volume and cortical thickness. We found an association between 1-hydroxyphenathrene (1-OHPHE) and 2-hydroxyfluorene (2-OHF) and changes in several brain regions in all the study participants. Individuals who had never smoked showed significantly thinner frontal (p < 0.001), parietal (p < 0.001), temporal (p < 0.001), and cingulate lobes (p < 0.001) with 1% increase each in the urinary concentration of 1-OHPHE. Hypertension interacted with the concentration of 1-OHPHE to reduce the volume of gray matter and cause cortical thinning in the frontal, parietal, and temporal lobes. Exposure to PAHs may reduce cortical thickness and subcortical volume, which are definitive markers of neurodegeneration. Notably, hypertension can accelerate the degenerative effects of PAHs.

Cohort Profile: Firefighter Research on the Enhancement of Safety and Health (FRESH), a Prospective Cohort Study on Korean Firefighters.

Firefighters have a high risk of developing cardiovascular and mental disorders due to their physical and chemical environments. However, in Korea, few studies have been conducted on environmental risk of firefighters. The Firefighter Research on the Enhancement of Safety and Health (FRESH) study aimed to discover the risk factors for cardiovascular disease and mental disorders among firefighters. Former and current firefighters were recruited from three university hospitals. A total of 1022 participants completed baseline health examinations from 2016 to 2017. All participants were scheduled for follow-ups every 2 years. Baseline health survey, laboratory testing of blood and urine samples, blood heavy metal concentration, urine polycyclic aromatic hydrocarbons (PAHs) metabolites, stress-related hormone test, natural killer cell activity, as well as physical and mental health examinations that focused on cardiovascular and mental disorders, were conducted. In addition, 3 Tesla (3T) brain magnetic resonance imaging (MRI) and neuropsychological tests were also performed to investigate structural and functional changes in the brains of 352 firefighters aged >40 years or new hires with less than 1 year of service.

Types of household humidifier disinfectant and associated risk of lung injury (HDLI) in South Korea.

From 2002 through 2015, hundreds of people died of fatal lung injuries associated with the use of humidifier disinfectants (HDs) in Korea. Several chemical disinfectants used for household humidifiers were later clinically confirmed to cause HD-associated lung injury (HDLI). The aim of this study is to evaluate the registered lung disease cases and to compare the distribution of HDLI patients, including deaths, by HD use characteristics including types of HD and HD brands categorized by age group. A total of 530 registered were clinically examined through two rounds of investigations conducted from July 2013 until April 2015. Information on HD use was obtained from a structured questionnaire and home investigations. Approximately one-half of the patients (n=221) were clinically confirmed to be associated with the use of HDs. Pregnant women (n=35, 16%) and pre-school children≤6years old (n=128, 58%) accounted for most of the HD-associated lung injury patients (n=163, 74%). Sixty-seven percent of HDLI patients developed HDLI after less than one year of HD use. HD products containing polyhexamethylene guanidine phosphate (PHMG) were the most frequently used among confirmed HDLI patients (n=123, 55.7%), followed by oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH) (n=24, 10.9%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (n=3, 1.4%). Other HDs did not appear to be linked to HDLI. The majority of the HDLI patients (n=85, 38.5%) was found to use only Oxy Saksak® products containing PHMG. The development of HDLI was clinically found to be associated with the use of several HD products containing PHMG and PGH, and to lesser extent, CMIT/MIT.

Dermatological and nutritional/growth effects among children living in arsenic-contaminated communities in rural Bangladesh.

While many reports have outlined the health risk of chronic arsenic exposure on adult populations, relatively little is known about the effects on children. We have examined the effects of chronic arsenic exposure through consumption of contaminated groundwater among 241 children (age 4-15 yr) living in two rural villages in northern Bangladesh. The arsenic concentrations of the tubewell waters ranged from less than detection limit to 535 ng/mL, and in 72 of 241 (30%) tubewells, the water arsenic concentration exceeded 50 ng/mL, the provisional guideline of Bangladesh. Approximately half of the examined children exhibited dermatological symptoms with relatively obscured dose-response relationship; an observation suggesting that the children were no more susceptible to the dermatological effects of arsenic than the adults living in the same communities. Proportion of the children with lower BMI significantly increased with increasing arsenic exposure level; the dose-response relationship was consistently observed among the subgroups. These results suggested that while mild dermatological manifestations, potentially associated with arsenic exposure, could be found as much as half of the children, nutritional status of the children, evaluated by BMI, might be a sensitive endpoint than the dermatological manifestations among children in this area.