Yeyong Choi

Nationwide Study of Humidifier Disinfectant Lung Injury in South Korea, 1994-2011. Incidence and Dose-Response Relationships.

RATIONALE Humidifier disinfectant lung injury is an acute lung disease attributed to recurrent inhalation of certain disinfectant aerosols emitted from room humidifiers. An outbreak of this toxic lung injury occurred in South Korea from 1995 until all humidifier disinfectant products were recalled from the consumer market by the government in 2011. OBJECTIVES A nationwide study was conducted to ascertain and classify all potential cases of humidifier disinfectant lung injury in Korea and to assess dose-response relationships. METHODS By several mechanisms, clinicians and the general public were invited to report all suspected cases of humidifier disinfectant lung injury to public health officials in South Korea. A committee was convened to define diagnostic criteria based on pathologic, radiologic, and clinical findings for index cases, combined with assessment of environmental exposure to humidifier disinfectants. Clinical review and environmental assessments were performed and later combined to determine overall likelihood of disease for each study participant, classified as definite, probable, possible, or unlikely. Survival time from exposure to onset of symptoms was analyzed to assess dose-response relationships. Three broad categories of risk factors were examined: (1) biological susceptibility, (2) temporal cycle of exposure and recovery, and (3) spatial conditions and density of disinfectant. MEASUREMENTS AND MAIN RESULTS Of 374 possible cases identified and reviewed, 329 were unanimously classified by the diagnostic committee, as follows: 117 definite, 34 probable, 38 possible and 140 unlikely cases. A total of 62 individuals with definite or probable disease died. Risk factors examined for polyhexamethyleneguanidine phosphate exposure that were found to be significant in shortening survival included age 4 years or younger at onset, use of disinfectant for 7 days per week, airborne density of 800 μg/m(3) or more of disinfectant, and daily exposure 11 or more hours in duration. CONCLUSIONS Dose-response analysis indicated that development of humidifier disinfectant lung injury and death were associated strongly with recurrent, intense, acute exposure without sufficient recovery time between exposures, more so than long-term cumulative exposure. These findings may explain some reversible or clinically unapparent cases among coexposed family members.

Why some, but not all, countries have banned asbestos

Abstract Background: Out of 143 countries that consumed asbestos between 2003 and 2007, only 44 have banned asbestos. This study tried to explain why some countries have banned asbestos while others have not, based on a synthesis that asbestos ban policy of a country will rely on a process of cognition of threats and exploration of safer alternatives. Method: As we hypothesized that increased social cost of mesothelioma, capacity of health-related infrastructures, and policy diffusion from adjacent countries were related to asbestos ban adoption, published databases of asbestos ban years, mesothelioma mortality, country rankings in health care and human rights standings, and distribution of banning countries over 14 regions were analyzed accordingly. Results: The average mesothelioma death rate was significantly higher for countries with asbestos bans than in those with no ban (4·59 versus 1·83/million). No-ban countries had less well-developed health-related infrastructures. Among European countries, there was a tendency toward geographical diffusion of asbestos ban policy from Nordic to Western and then other European countries over the years. Even though aberrant cases were also noted where bans were instituted even without mesothelioma database, these were rather exceptions than rules. Conclusion: Risk cognition is a complex process, but the presence of well-functioning health infrastructures, as well as the increased social cost of mesothelioma, that can make the plight of asbestos victims visible to the eyes of public and policy makers, may have contributed to this process. Asbestos ban policy from adjacent countries might have facilitated the adoption of alternative solutions.

Relationship between Exposure to Household Humidifier Disinfectants and Risk of Lung Injury: A Family-Based Study

Background In South Korea, a cluster of acute lung disease patients included lung injury disease suspected of being caused by the use of humidifier disinfectants. We examined the relationship between humidifier disinfectant exposure and clinically diagnosed humidifier disinfectant-associated lung injury (HDLI) in a family-based study. Methods This case-control study included 169 clinically confirmed HDLI cases and 303 family controls who lived with the HDLI patients. A range of information on exposure to humidifier disinfectants was obtained using a structured questionnaire and field investigations. Odds ratios (ORs) and confidence intervals (CIs) were estimated using unconditional logistic regression models that were adjusted for age, sex, presence of a factory within 1 km of residence, and the number of household chemical products used. Results HDLI risk increased approximately two-fold or more among the highest quartile compared with the lowest quartile in terms of the hours sleeping in a room with an operating humidifier treated with disinfectant (adjusted OR = 2.0, 95 % CI = 1.1-3.7), average hours of disinfectant-treated humidifier use per day (adjusted OR = 2.1, 95 % CI = 1.0-4.5), airborne disinfectant intensity (adjusted OR = 2.6, 95% CI = 1.2-5.3), and cumulative disinfectant inhalation level (adjusted OR = 2.0, 95% CI = 1.0-4.1). HDLI risk increased as the distance of the bed from humidifier gets shorter; compared with longer distance (> 1 m), the odds ratio was 2.7 for 0.5 to 1 m (95 % CI = 1.5-5.1) and 13.2 for <0.5 m (95 % CI = 2.4-73.0). Conclusions The use of household humidifier disinfectants was associated with HDLI risk in a dose-response manner.

Trades of dangers: A study of asbestos industry transfer cases in Asia

BACKGROUND In a study of asbestos industry transfers in Asia, we examined the transfer of health and safety measures at the time of industry transfer and resulting health outcomes thereafter. METHODS Field surveys were conducted in Japan, Germany, Indonesia, and South Korea over a 5 year period beginning in 2007. The surveys involved interviews and field assessments of health and safety conditions. RESULTS Even when there were transfers of entire engineering plant processes, we observed that the health and safety measures that should have accompanied the transfer, including technical capacities of risk assessment and management, regulatory protection, and cultural practices, were not actually transferred. According to work environment assessment records, there were differences in airborne asbestos levels of approximately 5-6 fibers/cc between the exporting and importing sides of the transfer. This amounted to a 10 years of time delay in comparable health and safety conditions. These differences resulted in repeated adverse health consequences at each factory operation site. CONCLUSIONS Dangerous transfers of asbestos industry technology have occurred repeatedly over the years with the result that Asia has become the largest consumer of asbestos in the world. No effective internationally accepted safety measures have been introduced in the region. The study results support the need for both improved public awareness and international cooperation, such as sharing of substitute material technologies by the exporting countries, and provide the rationale for the creation of an Asian fund for asbestos victims.

Characteristics of Exposure to Humidifier Disinfectant by Lung Injury Patients

In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objective of this study is to characterize exposure to HD among a total of 221 HDLI patients who used HD. Info...

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.

Humidifier disinfectants, unfinished stories

Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

The Fukushima Nuclear Disaster and Nuclear Safety Systems in Korea

Exactly 25 years after the Chernobyl nuclear disaster, 11th of March 2011 the Fukushima nuclear accident occurred in Japan and was ranked at level 7 same to the Chernobyl. A Korean and Japanese joint civil survey was conducted around Fukushima on April 13-17. The radiation survey data clearly shows a large hotspot area between 20 km and 50 km radius north and west direction from the accident reactors, with the highest radiation recorded being 55.64 in the air, 99.89 in the surface air, and 36.16 in a car, respectively. 3.65 in the air and 6.89 in the surface air were detected at the playground of an elementary school in Fukushima City. Spring came with full cherry blossoms in Fukushima, but it was silent spring of radiation contamination. Interviews with Fukushima nuclear refugees reveal serious problems about Japanese nuclear safety systems, such as there was no practical evacuation drill within 1-10 km and no plan at all for 10-30 km areas. Several reforms items for Korean nuclear safety system can be suggested: minimization of accident damage, clear separation of regulatory and safety bureaus with a new and independent administrating agency, community participation and agreement regarding the safety system and levels, which is the major concern of 80% Korean. To tackle threats of nuclear disaster in neighboring nations like China, a new position entitled `Ambassador for nuclear safety diplomacy` is highly necessary. The nuclear safety of Korea should no longer be the monopoly of those nuclear engineers and limited technocrats criticized as a `nuclear mafia`.

The Asbestos Ban in Korea from a Grassroots Perspective: Why Did It Occur?

In 2009, asbestos was finally banned in Korea, about 70 years after the first opening of asbestos mines under Japanese control. After having presented the history of asbestos industry, together with its regulations and health effects over time, we constructed narrative analyses of how the asbestos issue under the prevailing risk system was managed by whom and for what purpose, to provide context for the change. We could identify five different phases: laissez-faire, politico-technical, economic–managerial, health-oriented cultural, and human rights-based post-cultural risk systems. The changes leading to the asbestos ban evolved over different phases, and each phase change was necessary to reach the final ban, in that, without resolving the previous issues by examining different categories of potential alternatives, either the final ban was not possible or, even if instituted, could not be sustained. An asbestos ban could be introduced when all the alternatives to these issues, including legitimate political windows, economic rationalizations, health risk protections, and human rights sensitivities, were available. We think the alternatives that we had were not in perfect shape, but in more or less loosely connected forms, and hence we had to know how to build solidarities between different stakeholders to compensate for the imperfections.

Monitoring and Simulating Environmental Asbestos Dispersion from a Textile Factory

Although workplace asbestos concentrations (AC) have been reported several times, the past environmental AC are relatively poorly studied. Due to the harmful effects of the asbestos industry, production has moved from early industrialized countries (Japan), to late industrialized countries (Korea), and finally to industrializing countries (Indonesia). The purpose of this study was to determine current occupational exposure levels and evaluate neighborhood environmental exposure levels in an Indonesian asbestos textile factory through collaboration among three generation of industrialized countries. Asbestos concentrations were measured inside and outside of the factory and compared with simulated data. ACs in the factory were similar to those of 1980s and 1990s levels in the Korean factory that transferred the machines. Environmental ACs were dispersed according to wind direction. There were no significant differences between monitored and simulated data, and correlation coefficients between downwind, upwind, and middle wind directions were high, with some statistical significance. This study can be used to estimate past environmental ACs to understand the causality of asbestos related diseases. Because of the small sample size and specific weather conditions, a large-scale study of various asbestos exposure sources, including asbestos cement factories, shipyards, and mines, and various atmospheric conditions is required.