Long-term monitoring of indoor, outdoor, and personal exposure to gaseous chemical compounds

Seasonal variations of chemical compounds in indoor air and outdoor air and personal exposure to these chemicals were continuously monitored for 6 years using four types of passive sampling devices: PSD-BPE/DNPH packed with 2,4-dinitrophenylhydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; PSD-VOC packed with Carboxen 572 or Active Carbon Beads particles for volatile organic compounds; PSD-TEA packed with triethanolamine impregnated silica for acid gases; and PSD-TEA packed with phosphoric acid impregnated silica for basic gases. Many chemical compounds except for nitrogen dioxide, formic acid, and benzene showed seasonal variations with high concentrations in summer and low concentrations in winter. In particular, formaldehyde, nonanal, 2-ethyl-1-hexanol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and ammonia concentrations showed remarkable seasonal variation. For example, the concentration of formaldehyde in February and August was 5.9 and 40 μg/m3, respectively, a difference of about 7 times. Although there were large differences in the concentrations in each house, the fluctuation pattern was almost the same every year in each house. By contrast, nitrogen dioxide, formic acid, and benzene concentrations were low in summer and high in winter. These compounds were generated by kerosine and gas stoves in winter. Long-term continuous monitoring revealed that annual mean concentrations could be estimated using data from February and August. Personal exposure concentrations could be classified into four patterns: chemicals affected by the indoor environment such as formaldehyde, chemicals affected by the outdoor environment such as ozone, chemicals affected by the occupational environment such as hexane, and background level chemicals such as benzene (without kerosine and gas stoves). Indoor and outdoor measurements are means to investigate the "health" of each environment. Personal exposure measurement using PSD-samplers is suitable for assessing the health risk of chemical compounds to humans.

Eye lens dose in spine surgeons during myelography procedures: a dosimetry study

To determine the eye lens dose (3 mm dose equivalent [Hp(3)]) received by spine surgeons during myelography and evaluate the effectiveness of radiation-protective glasses and x-ray tube system positioning in reducing radiation exposure. This study included spine surgeons who performed myelography using over- or under-table x-ray tube systems. Hp(3) was measured for each examination using a radio-photoluminescence glass dosimeter (GD-352M) mounted on radiation-protective glass. This study identified significantly high Hp(3) levels, especially in the right eye lens in spinal surgeons. The median Hp(3) values in the right eye were 524 (391-719) and 58 (42-83)μSv/examination for over- and under-table x-ray tube systems, respectively. Further, Hp(3)AK, which was obtained by dividing the cumulative air kerma from Hp(3), was 8.09 (6.69-10.21) and 5.11 (4.06-6.31)μSv mGy-1for the over- and under-table x-ray tube systems, respectively. Implementing radiation-protective glasses resulted in dose reduction rates of 54% (50%-57%) and 54% (51%-60%) for the over- and under-table x-ray tube systems, respectively. The use of radiation protection glasses significantly reduced the radiation dose in the eye lens during myelography, with the most effective measures being the combination of using radiation protection glasses and an under-table x-ray tube system.

Characterization of small radiophotoluminescence dosemeter in terms of HP(0.07) for extremity dose monitoring of medical personnel

An additional extremity monitoring using a ring badge must be appropriately conducted for inhomogeneous exposure around radiation workers' extremity. Commercially available glass dosemeters are characterized in terms of Hp(0.07) for the application of additional extremity monitoring. A series of experiments demonstrated that the response of the model GD-352M radiophotoluminescence dosemeter fully matched the IEC's criteria for an extremity dosemeter for medical personnel. Although the model GD-302M has excellent angular dependence, the material and the shape of energy compensation filter still need to be optimized to improve its energy dependence in the range between 30 and 100 keV. The combine use of both types of glass dosemeters for 'paired dosemeter' together with introduction of a simple algorithm may be a promising method to improve the response in the energy range below 20 keV.

Occupational radiation dose on the hand of assisting medical staff in diagnostic CT scans

Chronic radiation exposure increases the risk of skin damage of medical personnel engaged in radiology. However, hand dose measurements in computed tomography (CT) for diagnostic purposes have not been evaluated. The occupational radiation dose to the hands of CT assistants was herein investigated to evaluate its compliance with the equivalent dose limit for the hand (500 mSv/year). The occupational doses of nine CT assistants were measured in 89 cases (April 2017-May 2018) by installing radio-photoluminescence glass dosemeters (GD-302 M) (70-μm dose-equivalent conversion coefficient = 0.37) on the dorsal aspect of both hands. The occupational dose to the hand was the highest with head holding (right: 1.14 mSv/CT scan, left: 1.07 mSv/CT scan). Considering the results for annual work, even for head holding, the hand dose of the CT-assisting personnel was insignificant. However, CT assistants should be mindful of the possibility of locally higher doses to hands.

Estimation of inhomogeneous occupational exposure to the lens of the eyes and the extremities of radiation workers in a research accelerator facility

We performed an experimental investigation on occupational exposure of the eye lens and the extremity of radiation workers engaged in handling of highly activated materials in a small research accelerator facility. Using a simplified physical phantom to simulate the relevant inhomogeneous radiation exposure situations, the personal dose equivalents obtained at the eye lens and the extremities of radiation workers handling heavily radioactive converters were measured together with the dose measured by personal dosemeters worn on their trunk. Results of mockup experiments and the Monte Carlo calculations suggest that the quantitative estimation of the eye lens doses can be estimated from the trunk dose, while the extremity doses vary considerably from the dose readings from the trunk, depending on the use of simple point-source or volume source geometry.

Associations between welding fume exposure and neurological function in Japanese male welders and non-welders

OBJECTIVES

There are some studies reporting the association between (manganese [Mn]) exposure to welding fume and neurological dysfunction. This study examined the relationship between Mn exposure and neurological behavior in Japanese male welders and non-welders using biological samples, which to date has not been assessed in Japan.

METHODS

A total of 94 male welders and 95 male non-welders who worked in the same factories were recruited. The blood and urine samples were obtained from all the participants to measure Mn exposure levels. Neurological function tests were also conducted with all participants. The sampling of the breathing air zone using a personal sampler was measured for welders only.

RESULTS

The odds ratios (ORs) for the Working Memory Index (WMI) scores were significantly higher among all participants in the low blood Mn concentration group than those in the high blood Mn concentration group (OR, 2.77; 95% confidence interval [CI], 1.24, 6.19; P = .013). The association of WMI scores and blood Mn levels in welders had the highest OR (OR, 3.73; 95% CI, 1.04, 13.38; P = .043). Although not statistically significant, a mild relationship between WMI scores and blood Mn levels was observed in non-welders (OR, 2.09; 95% CI, 0.63, 6.94; P = .227).

CONCLUSIONS

The results revealed a significant positive relationship between blood Mn and neurological dysfunction in welders. Furthermore, non-welders at the same factories may be secondarily exposed to welding fumes. Further research is needed to clarify this possibility.

The spread of heated tobacco product (HTP) use across various subgroups during 2015-16 and 2017-18 in Japan

BACKGROUND

Heated tobacco product (HTP) use has increased substantially between 2016 and 2017 in Japan. This study aims to clarify how HTP use (IQOS, Ploom, and glo) spread across the different combustible cigarette smoking statuses during 2015-16 and 2017-18 in Japan.

METHODS

We compared the two periods of (i) 2015 to 2016 (N = 5,366) and (ii) 2017 to 2018 (N = 3,422) from a longitudinal study randomly sampling members from the Japan "Society and New Tobacco" Internet Survey (JASTIS). Multivariable logistic regression models for current HTP use in the previous 30 days by combustible cigarette smoking status in the previous year were used adjusting for socio-demographic factors.

RESULTS

HTP use increased by 10 times in the 2017-18 cohort compared with the 2015-16 cohort according to the adjusted odds ratio (95% confidence interval) for current HTP use as 10.2 (7.03-14.8). According to smoking status, significantly higher adjusted ORs (95% CIs) of current HTP use for the after period were observed: 2.60 (1.37-4.94) for never smokers, 7.82 (3.64-16.8) for former smokers, 21.1 (5.73-77.9) for current smokers with intention to quit, and 17.0 (9.58-30.3) for current smokers without intention to quit.

CONCLUSION

During 2015 to 2018 in Japan, HTP use dramatically increased in all subgroups except for never smokers.

Regulatory implementation of the occupational equivalent dose limit for the lens of the eye and underlying relevant efforts in Japan

In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens. Such a new occupational lens dose limit has thus far been implemented in many countries, and there are extensive discussions toward its regulatory implementation in other countries. In Japan, discussions in the Japan Health Physics Society (JHPS) began in April 2013 and in Radiation Council in July 2017, and the new occupational lens dose limit was implemented into regulation in April 2021. To share our experience, we have published a series of papers summarizing situations in Japan: the first paper based on information available by early 2017, and the second paper by early 2019. This paper (our third paper of this series) aims to review updated information available by mid-2022, such as regarding regulatory implementation of the new occupational lens dose limit, recent discussions by relevant ministries based on the opinion from the council, establishment process of safety and health management systems, the JHPS guidelines on lens dose monitoring and radiation safety, voluntary countermeasures of the licensees, development of lens dose calibration method, and recent studies on exposure of the lens in nuclear workers and biological effect on the lens.

The effect of mask fit test on the association between the concentration of metals in biological samples and the results of time-weighted average personal exposure: A study on Japanese male welders

OBJECTIVES

The mask fit test confirms whether the wearing condition of the wearer's face and the facepiece of the respirators are used appropriately. This study aimed to examine whether the results of the mask fit test affect the association between the concentration of metals related to welding fumes in biological samples and the results of time-weighted average (TWA) personal exposures.

METHODS

A total of 94 male welders were recruited. Blood and urine samples were obtained from all participants to measure the metal exposure levels. Using personal exposure measurements, the 8-h TWA (8 h-TWA) of respirable dust, TWA of respirable Mn, and 8-h TWA of respirable Mn were calculated. The mask fit test was performed using the quantitative method specified in the Japanese Industrial Standard T8150:2021.

RESULTS

Fifty-four participants (57%) passed the mask fit test. Only in the Fail group of the mask fit test, it was observed that blood Mn concentrations be positively associated with the results of TWA personal exposure after adjusting for multivariate factors (8-h TWA of respirable dust; coefficient, 0.066; standard error (SE), 0.028; P = 0.018, TWA of respirable Mn: coefficient, 0.048; SE, 0.020; P = 0.019, 8 h-TWA of respirable Mn: coefficient, 0.041; SE, 0.020; P = 0.041).

CONCLUSIONS

The results clarify that welders with high concentrations of welding fumes in their breathing air zone are exposed to dust and Mn if there is leaking air owing to the lack of fitness between respirators and the wearer's face when using human samples in Japan.

The Effect of Pre-Operative Verbal Confirmation for Interventional Radiology Physicians on Their Use of Personal Dosimeters and Personal Protective Equipment

Interventional radiology (IR) physicians must be equipped with personal passive dosimeters and personal protective equipment (PPE); however, they are inconsistently used. Therefore, we aimed to explore practical measures to increase PPE usage and ascertain whether these measures could lead to an actual decrease in exposure doses to IR physicians. Dosimeters and PPE were visually inspected. Then, a pre-operative briefing was conducted as a direct intervention, and the use of dosimeters and PPE was verbally confirmed. Finally, the intervention effect was verified by measuring the use rates and individual exposure doses. Because of the intervention, the use rate markedly improved and was almost 100%. However, both the effective dose rate (effective dose/fluoroscopy time) and the lens equivalent dose rate (lens equivalent dose/fluoroscopy time) showed that the intervention led to a statistically significant increase in exposure (effective dose rate: p = 0.033; lens equivalent dose rate: p = 0.003). In conclusion, the proper use of dosimeters and PPE raised the radiation exposure values for IR physicians immediately after the intervention, which was hypothesized to be due to the inclusion of exposure overlooked to date and the changes in the dosimeter management method from a single- to a double-dosimeter approach.

Health Risk Assessment Based on Exposure to Chemicals in Air

Few studies have investigated personal exposure concentrations of not only some volatile organic compounds but also more types of chemicals including acidic gases and acrolein. We measured the personal exposure concentrations of 35 chemicals including these chemicals in indoor and outdoor air in Chiba-shi, Japan, for 7 days in summer and winter to assess the associated health risks in 22 people. The personal exposure concentrations of nitrogen dioxide were higher in winter than in summer, and those of formaldehyde, p-dichlorobenzene, and tetradecane were higher in summer than in winter. The personal exposure concentrations were mostly equal to or lower than the concentrations in indoor air, contrary to the results of a lot of previous studies. The high-risk chemicals based on personal exposure concentrations were identified as acrolein (max. 0.43 μg/m³), benzene (max. 3.1 μg/m³), and hexane (max. 220 μg/m³) in summer, and acrolein (max. 0.31 μg/m³), nitrogen dioxide (max. 320 μg/m³), benzene (max. 5.2 μg/m³), formic acid (max. 70 μg/m³), and hexane (max. 290 μg/m³) in winter. In addition, we estimated personal exposure concentrations according to the time spent at home and the chemical concentrations in indoor and outdoor air. We found that the estimated concentrations of some participants largely differed from the measured ones indicating that it is difficult to estimate personal exposure concentrations based on only these data.

CONTRIBUTION OF ORGAN-BASED TUBE CURRENT MODULATION TO THE REDUCTION OF LENS EXPOSURE DOSE IN HEAD 4D CT IMAGING: A PHANTOM STUDY

The purpose of this study was to evaluate the effectiveness of organ effect modulation (OEM) in reducing the lens dose in 4D computed tomography (CT) of the head in volume-acquisition (NVA) mode. Six radiophotoluminescent dosemeters were placed on the head of a RANDO phantom. The doses absorbed by the organs and image noise change rate were determined. The lens doses without OEM (i.e. in the OEMoff case) were higher than those with the same target standard deviation and volume-computed tomography dose index (CTDIvol) as in the OEMoff case (p < 0.01). The image noise change rate was 11%. OEM reduced the lens dose during head 4D CT imaging in the NVA mode by 18%. Furthermore, the feasibility of lens dose reduction while ensuring sufficient image quality was confirmed under the condition in which OEM was employed with the same CTDIvol as in the OEMoff case.

DOSE MEASUREMENT PRECISION OF AN RPLD-BASED EYE LENS DOSEMETER APPLICABLE TO THE MEDICAL SECTOR

We demonstrate a practical calibration method and its applicability for a commercially available radiophotoluminescence dosemeter (RPLD), i.e. the GD-352M (AGC Techno Glass, Shizuoka, Japan) to eye lens dose monitoring, by performing the calibration according to the ISO recommendations. The calibration was then verified through a series of experiments. For verification of the derived calibration factor (1.21 ± 0.04, k = 1) of the RPLD, we performed standard irradiations in the ISO narrow series X-ray reference fields and the simulation measurements in the actual radiation fields in a hospital. The TLD-based commercially available dosemeters, DOSIRIS™ was also put on the ISO cylinder phantom and the RANDO phantom together with the GD-352M in the verification experiments. The personal dose equivalents Hp(3) obtained from the GD-352M and those obtained from the DOSIRIS™ were in good agreement with each other. Our results demonstrate the proper calibration of a commercially available RPLD that is applicable to the additional monitoring of the lens of the eyes for medical staff.

Association between Fathers’ Use of Heated Tobacco Products and Urinary Cotinine Concentrations in Their Spouses and Children

Heated tobacco products (HTPs) have become increasingly popular among smokers, especially among young adults in Japan in recent years. Assessments of secondhand tobacco smoke (SHS) exposure due to HTPs are scarce. The present study aimed to assess the urinary levels of total nicotine metabolites (TNMs) of non-smoking spouses and their children following SHS exposure due to their fathers’ use of HTPs. A total of 41 families including 129 participants were recruited between 2018 and 2021. The number of non-smoking spouses and children of the fathers who smoke combustion cigarettes, the fathers who use HTPs, and the fathers who are non-users or have never smoked was 27, 66, and 36, respectively. The urinary levels of TNMs, including cotinine (Cot) and 3′-hydroxycotinine (3-OHCot), were measured using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The spouses and children of fathers who use HTPs had significantly higher levels of TNMs in their urine compared to those with fathers who were non-smokers or non-users. The current study is the first to assess SHS exposure due to HTP use, and to suggest the importance of strategies to prevent exposure to SHS from HTP use in public places and educational strategies to protect non-smokers from secondhand HTP aerosol exposure in households and other private places.

Analysis of whole-blood antioxidant capacity after chronic and localized irradiation using the i-STrap method

Ionizing radiation exposure affects the redox state in vivo. Recently, whole-blood antioxidant capacity (WBAC) has been reported to decrease in a dose-dependent manner after acute total body irradiation (TBI). However, changes in WBAC after localized and chronic irradiations have not been reported. This study analyzed changes to WBAC in mice after either localized irradiation (irradiation of the left hind leg only) or chronic TBI using the i-STrap method. Leg-localized irradiation exerted limited effects on WBAC, while WBAC decreased in a dose rate-dependent manner after TBI. Further, the WBAC reached the minimum value in a shorter period at a smaller dose rate. Our results suggest that changes in WBAC do not directly reflect absorbed dose, but may reflect radiation-induced biological damage at the systemic level. This study will contribute to the understanding of radiation-induced injuries and diseases, and will facilitate the establishment of biomarkers for radiation exposure.

Potential factors affecting chronic chemical intolerance associated with constitutional predisposition or lifestyle and environment during childhood: From a six-year follow-up study

OBJECTIVE

The Japanese chemical intolerance (JCI) study was conducted in January 2012 with a cohort of 7245 adults from population-based sampling. This study aimed to investigate the childhood constitutional and environmental factors involved in the development of chronic CI from the prospective cohort study.

METHODS

In the cohort, 4683 persons were identified after six years. Self-reported questionnaires were administered to the subjects to obtain information on CI status; medical history; constitution, lifestyle, and housing environment during childhood; and recent psychosomatic states. We assessed the differences between individuals with persisting CI status during the follow-up (defined as chronic CI) and controls not having CI status during the follow-up.

RESULTS

A total of 2500 individuals responded. Multiple logistic regression analyses revealed significant associations between chronic CI and motion sickness to car or bus and allergic conjunctivitis during childhood. Significant associations between a possible increased risk of CI and the existence of high-voltage power lines close to housing, the use of vinyl covering in wall material, the use of strong perfume by a family member, and the experience of stinky odor of paint or wax at elementary school were observed. However, the use of carpet in floor material and plaster coating in wall material was associated with a possible decreased risk of CI.

CONCLUSIONS

Some potential constitutional predisposition from childhood, including inherent susceptibility in the autonomic nervous system may be involved in the development of CI.

Spatial Variations of Indoor Air Chemicals in an Apartment Unit and Personal Exposure of Residents

Indoor air quality (IAQ) can greatly affect health in people spending much time indoors. However, the influence of IAQ on personal exposure to chemical compounds in Japan remains poorly investigated. Hence, this study aimed to clarify this influence thoroughly within one apartment. We surveyed the concentrations of 61 chemical compounds in the air in nine different spaces within an apartment unit, as well as the personal exposure of two residents in Japan. Using three kinds of diffusive samplers, this study was conducted continuously for 7 days in summer and winter. Health risks were evaluated by calculating the margin of exposure (MOE) using the measured concentrations. Some chemical concentrations showed large spatial variations and the personal exposure concentrations of these compounds also differed among residents. According to the calculated MOE, the chemicals with the highest health risk were acrolein, p-dichlorobenzene, and acetaldehyde in summer and acrolein, nitrogen dioxide, formic acid, p-dichlorobenzene, and benzene in winter. The IAQ of the house could be divided in two, and the IAQ in the space where residents spent much time (i.e., bedroom) highly affected each of the residents' exposure. Investigating chemical concentrations in multiple spaces (including bedroom and living room) is necessary to understand the effect of IAQ on personal exposure.

Strategy to Reduce the Collective Equivalent Dose for the Lens of the Physician's Eye Using Short Radiation Protection Curtains to Prevent Cataracts

A short curtain that improves on the low versatility of existing long curtains was developed as a dedicated radiation protective device for the over-table tube fluorographic imaging units. The effect of this short curtain in preventing cataracts was then examined. First, the physician lens dose reduction rate was obtained at the position of the lens. Next, the reduction rate in the collective equivalent dose for the lens of the physician's eye was estimated. The results showed that lens dose reduction rates with the long curtain and the short curtain were 88.9% (literature-based value) and 17.6%, respectively, higher with the long curtain. In our hospital, the reduction rate in the collective equivalent dose for the lens of the physician's eye was 9.8% and 17.6% with a procedures mixture, using the long curtain where technically possible and no curtain in all other procedures, and the short curtain in all procedures, respectively, higher with the short curtain. Moreover, a best available for curtains raised the reduction rate in the collective equivalent dose for the lens of the physician's eye a maximum of 25.5%. By introducing the short curtain, it can be expected to have an effect in preventing cataracts in medical staff.

Smoking and Long-Term Sick Leave in a Japanese Working Population: Findings of the Japan Epidemiology Collaboration on Occupational Health Study

Background

Few studies have investigated the association between tobacco smoking and sick leave (SL) in Japan.

Methods

We followed 70 896 workers aged 20–59 years (60 133 males, 10 763 females) between April 2012 and March 2017. A Cox proportional hazards model was used to investigate the associations between smoking (smoking status and intensity) and long-term SL (ie, SL lasting ≥30 consecutive days). Cause-specific analyses were also conducted.

Results

A total of 1777 people took long-term SL during a follow-up of 307 749 person years. Compared with never-smokers, current smokers were at a higher risk of long-term SL (hazard ratio [HR] = 1.32; 95% confidence interval [CI] = 1.19 to 1.48). Cause-specific analyses revealed that current smoking was associated with a higher risk of SL due to all physical disorders (HR = 1.44, 95% CI = 1.22 to 1.69), cancer (HR = 1.49, 95% CI = 1.10 to 2.01), cardiovascular disease (CVD; HR = 2.16, 95% CI = 1.31 to 3.55), and injuries/external causes (HR = 1.83, 95% CI = 1.31 to 2.58). Former smokers were at a higher risk of SL due to cancer at a borderline significance level (HR = 1.38, 95% CI = 0.99 to 1.92). Low-intensity smoking (ie, 1–10 cigarettes smoked per day) was associated with all-cause SL, SL due to CVD, and SL due to injuries/external causes compared with never-smokers.

Conclusion

In a large cohort of working-age Japanese, smoking was associated with a greater risk of long-term SL. Greater effort is needed to mitigate disease burden associated with smoking at workplace in Japan.

Implications

Our study contributes to the literature on the association between smoking and SL in several ways. First, the study was conducted among a Japanese working population. While the association has been extensively studied in Western setting, few attempts have been made elsewhere. Second, cause-specific analyses were undertaken in our study. Third, we paid attention to the effect of low-intensity smoking on SL given that there is growing evidence of an elevated health risk associated with low-intensity smoking.

Indoor Formaldehyde Concentration, Personal Formaldehyde Exposure and Clinical Symptoms during Anatomy Dissection Sessions, University of Medicine 1, Yangon

The formaldehyde (FA) embalming method, the world's most common protocol for the fixation of cadavers, has been consistently used in medical universities in Myanmar. This study was designed to examine the indoor FA concentrations in anatomy dissection rooms, an exposed site, and lecture theater, an unexposed control site, and to access personal exposure levels of FA and clinical symptoms of medical students and instructors. In total, 208 second year medical students (1/2019 batch) and 18 instructors from Department of Anatomy, University of Medicine 1, participated. Thirteen dissection sessions were investigated from February 2019 to January 2020. Diffusive sampling devices were used as air samplers and high-performance liquid chromatography was used for measurement of FA. Average indoor FA concentration of four dissection rooms was 0.43 (0.09-1.22) ppm and all dissection rooms showed indoor concentrations above the occupational exposure limits and short-term exposure limit for general population. Personal FA exposure values were higher than indoor FA concentrations and the instructors (0.68, 0.04-2.11 ppm) had higher exposure than the students (0.44, 0.06-1.72 ppm). Unpleasant odor, eye and nose irritations and inability to concentrate were frequently reported FA-related symptoms, and the students were found to have significantly higher risks (p < 0.05) of having these symptoms during the dissection sessions than during lecture.

Occupational radiation dose to the lens of the eye of medical staff who assist in diagnostic CT scans

PURPOSE

We investigated occupational dose to the lens of the eye for CT-assisting personnel for diagnostic purposes using a radio-photoluminescent glass dosimeter (RPLD) and evaluate compliance with the new equivalent dose limit for the lens of the eye (20 mSv/year). Further, we proposed the implementation of "multiple protective measures" and estimated its effect.

METHOD

An eye lens dosimeter clip was developed specifically to attach RPLDs inside radiation safety glasses in an L-shape. Using a total of six RPLDs attached to the radiation safety glasses, the 3-mm dose-equivalent (Hp(3)) to the lens of the eye for medical staff (n = 11; 6 intensive care physicians, 2 pediatricians, 3 radiological technologists) who assisted patients during CT scan for "diagnostic" purpose (n = 91) was measured. We evaluated the dose reduction efficiencies with radiation safety glasses and bag-valve-mask extension tube. We also estimated the protection efficiency with radiation protection curtain introduced in front of the staff's face via the phantom experiment.

RESULTS

Without wearing radiation safety glasses, Hp(3) to the lens of the eye was greatest for intensive care physicians (0.49 mSv/procedure; allowing 40 procedures to be performed annually), followed by pediatricians (0.30 mSv/procedure; 66 procedures annually) and radiological technologists (0.28 mSv/procedure; 71 procedures annually). Use of each type of protective tools: radiation safety glasses (0.07-mm-Pb), bag-valve-mask extension tube (20 cm) and radiation protective curtain (0.25-mm-Pb), reduced Hp(3) to the lens of the eye by 51%, 31% and 61%, respectively.

CONCLUSION

Intensive care physicians perform most assisted ventilations with the bag-valve-mask during "diagnostic" CT scans, and may exceed the equivalent dose limit for the lens of the eye if radiation safety glasses are not worn. If "multiple protective measures" are implemented, compliance with the equivalent dose limit for the lens of the eye should be achievable without placing significant burdens on physicians or medical institutions.

A multicenter study of radiation doses to the eye lenses of clinical physicians performing radiology procedures in Japan

PURPOSE

We investigated occupational dose to the lens of the eye for physicians engaged in radiology procedures. We evaluated the potential for compliance with the new-equivalent dose limits to the lens of the eye. Further, a "multiple radiation protection" protocol was proposed according to the basic principles of occupational health, and its effectiveness was estimated.

METHODS

Physicians engaged in radiology procedure at medical facilities in Japan were included in this study. The eye lens dose (3-mm dose equivalent: Hp (3)) for each participant was measured using a small radio-photoluminescence glass dosimeter mounted on lead glasses. Physicians were directed to procedure multiple radiation protection measures to evaluate their usefulness.

RESULTS

The Hp (3) was reduced by multiple radiation protection in all physicians. In particular, the Hp (3) reduced from 207.7 to 43.2 μSv/procedure and from 21.6 to 10.2 μSv/procedure in cardiovascular internal physician and cerebrovascular physician, respectively, after the implementation of the proposed multiple radiation protection measures. The dose reduction rate of these measures was 53% (range: 37%-79%).

CONCLUSIONS

The radiation doses received by the eye lenses of physicians engaged in radiology procedure may exceed the dose limits to the lens of the eye if radio-protective equipment and imaging conditions are not properly controlled. However, based on the lens equivalent dose data, the implementation of "multiple radiation protection" according to the basic principles of occupational health can ensure compliance with the new-equivalent dose limits to the lens of the eye without placing an undue burden on individual physicians or medical facilities.

Optimization of the Maximum Skin Dose Measurement Technique Using Digital Imaging and Communication in Medicine-Radiation Dose Structured Report Data for Patients Undergoing Cerebral Angiography

Understanding the maximum skin dose is important for avoiding tissue reactions in cerebral angiography. In this study, we devised a method for using digital imaging and communication in medicine-radiation dose structured report (DICOM-RDSR) data to accurately estimate the maximum skin dose from the total air kerma at the patient entrance reference point (Total Ka,r). Using a test data set (n = 50), we defined the mean ratio of the maximum skin dose obtained from measurements with radio-photoluminescence glass dosimeters (RPLGDs) to the Total Ka,r as the conversion factor, CFKa,constant, and compared the accuracy of the estimated maximum skin dose obtained from multiplying Total Ka,r by CFKa,constant (Estimation Model 1) with that of the estimated maximum skin dose obtained from multiplying Total Ka,r by the functional conversion factor CFKa,function (Estimation Model 2). Estimation Model 2, which uses the quadratic function for the ratio of the fluoroscopy Ka,r to the Total Ka,r (Ka,r ratio), provided an estimated maximum skin dose closer to that obtained from direct measurements with RPLGDs than compared with that determined using Estimation Model 1. The same results were obtained for the validation data set (n = 50). It was suggested the quadratic function for the Ka,r ratio provides a more accurate estimate of the maximum skin dose in real time.

BMI and Medically Certified Long-Term Sickness Absence Among Japanese Employees

OBJECTIVE

In contrast to the association between excess weight and sickness absence (SA), the association in relation to underweight has been under-researched. This study aimed to examine the effects of BMI at both extremes of its distribution on SA.

METHODS

Data came from the Japan Epidemiology Collaboration on Occupational Health study of 77,760 workers aged 20 to 59 years (66,166 males, 11,594 females). Information was collected on medically certified long-term SA (LTSA) (i.e., SA lasting ≥ 30 consecutive days) from April 2012 to March 2017. A sex-specific Cox proportional hazards model was used to investigate the associations.

RESULTS

Among males, both obesity (hazard ratio [HR] = 1.81, 95% CI: 1.50-2.17) and underweight (HR = 1.56, 95% CI: 1.23-1.96) were significantly associated with LTSA compared with normal weight. This U-shaped association between BMI categories and LTSA was observed both for mental and physical disorders. Among females, an elevated risk was observed among those with overweight (HR = 1.54, 95% CI: 1.16-2.05).

CONCLUSIONS

In a cohort of the Japanese working-age population, both obesity and underweight were associated with a greater risk of LTSA in males. Future research should not overlook the excess risk of LTSA associated with underweight.

[Policy recommendation for the regulation of heated tobacco products based on evidence review of their health effects and influence on tobacco control]

Objective This report aimed to present policy recommendations on the regulation of heated tobacco products based on a review of the literature on the use of heated tobacco products, component analysis of harmful chemical substances, and product characteristics as nicotine delivery device, and on an examination of the influence of the product's increasing usage to the main measures of tobacco control.Methods The literature search was performed using Japan Centra Revuo Medicina and PubMED database. The search yielded 11 articles that examined the use of heated tobacco products, component analysis of harmful chemical substances, and product characteristics as nicotine delivery device. Eight articles were additionally collected from reports of public health research in Japan and public reports in foreign countries. The six main policies advocated by World Health Organization as MPOWER (Monitor, Protect, Offer, Warn, Enforce, Raise) were adopted in considering the expected influence of this product's increasing usage this product epidemic on tobacco control. In addition to the abovementioned 19 articles, 26 documents and materials related to the status of tobacco control were collected and used to examine the influence of the product's increasing usage to the main measures of tobacco control.Results In Japan, heated tobacco products have been available since December 2013, and the spread of use has risen remarkably since 2016. As of October 2016, Japan consumed more than 90% of the heated tobacco products sold internationally. Compared with cigarettes, heated tobacco products can reduce exposure to harmful substances except nicotine. However, their use does not lead to reduced risk of illness. The reduction of exposure to harmful substances cannot be expected when used in combination with cigarettes. Heated tobacco products and cigarettes have similar nicotine exposure levels and pharmacokinetics; thus, use of the former results in nicotine dependence and exacerbates the difficulty in discontinuing tobacco consumption. The popularity of heated tobacco products could adversely affect any of the six main measures of tobacco control.Conclusion Although public health concerns have been identified for the popularity of heated tobacco products, evidence remains insubstantial for the formulation of regulatory implications. Additional research is needed on the health effects to users and bystanders, effects on cigarettes use, and influence on tobacco control policy. From the perspective of the precautionary principle of public health, the same regulation as for cigarettes should be implemented as regards heated tobacco products until their health effects are fully elucidated.

Five-year cumulative incidence of overweight and obesity, and longitudinal change in body mass index in Japanese workers: The Japan Epidemiology Collaboration on Occupational Health Study

OBJECTIVE

The present study aimed to estimate cumulative incidence of overweight and obesity and describe 5-year longitudinal changes in body mass index (BMI) in a large occupational cohort in Japan.

METHODS

Participants were 55 229 Japanese employees, who were aged 20-59 years and attended at all subsequent annual health check-ups between 2009 and 2014. Mixed model analysis was performed to examine the effects of age and cohort by gender on BMI change, with age as a random variable. Cumulative incidence of overweight (23.0≤ BMI <27.5 kg/m2 ) and obesity (BMI ≥27.5 kg/m2 ) was calculated. Logistic regression analysis was used to estimate odds ratios for the incidence of overweight and obesity according to age group.

RESULTS

The incidence of overweight and obesity was approximately double in men (28.3% and 6.7%, respectively) compared to women (14.3% and 3.9%, respectively).The incidence of obesity decreased with age in men, but did not differ according to age in women (P for trend: .02 and .89, respectively). Among overweight participants, the incidence of obesity was higher in women (18.9%) than men (14.5%) and decreased with advancing age (P for trend: <.001 in men and .003 in women). Mean BMI was higher in men than women in all age groups throughout the period. Younger cohorts tended to have a higher BMI change compared with older cohorts.

CONCLUSIONS

In this Japanese occupational cohort, transition from overweight to obesity is higher in women than men, and the more recent cohorts had a higher change in mean BMI than the older cohorts.

A novel analytical method for simple and low-cost detection of isocyanates in ambient air

In this study, we developed a novel method for the collection of gaseous and particulate isocyanates in the air using di-n-butylamine (DBA)-coated glass fiber filters and a cation-exchange column (GFF_SCX-DBA) sampler. Our method showed acceptable linearity, accuracy, and precision in the analysis of eleven kinds of isocyanates (ICA, MIC, EIC, PIC, PHI, 1,6-HDI, 2,4-TDI, 2,6-TDI, trans-IPDI, cis-IPDI, and 4,4'-MDI). And, some of them were detected in the air at the plant manufacturing isocyanates and spray polyurethane foam. Actually, 2,4-TDI and 2,6-TDI (11,000 ± 6600 and 5800 ± 3500 ng/m³, respectively) were detected at much higher levels than others at the plant manufacturing isocyanates, and the levels of these isocyanates were comparable with those obtained by using the commercial sampler. Furthermore, PHI and 4,4'-MDI (5800 ± 470 and 3500 ± 1100 ng/m³, respectively) were detected at a relatively higher concentration than the others in the place of spray polyurethane foam. Through this study, we realized that the concentration of isocyanates in various working places could be analyzed using our GFF_SCX-DBA sampler. This method makes it possible to perform a rapid and simplified extraction operation in a shorter time than in the commercial sampler by combining the GFF and SCX samplers.

Association between anthropometric indices of obesity and risk of cardiovascular disease in Japanese men

Objectives

We aimed to compare the association of body mass index (BMI), waist circumference (WC), and waist‐to‐height ratio (WHtR) with risk of cardiovascular disease (CVD) among middle‐aged working Japanese men.

Methods

A nested case‐control study was performed among middle‐aged male employees who underwent periodic health checkup. A total of 241 CVD cases were identified and matched individually on age, gender, and worksite with 1205 controls. Data on BMI, WC, WHtR, smoking, hypertension, diabetes, and dyslipidemia collected at 4 years before the event/index date were retrieved. Associations between BMI, WC, WHtR, and CVD risk were assessed by using conditional logistic regression models.

Results

The strength of the association of BMI, WC, and WHtR with CVD risk was similar. The smoking‐adjusted odds ratio (95% confidence interval) for CVD was 1.60 (1.38‐1.85), 1.53 (1.33‐1.78), and 1.56 (1.35‐1.81) for a 1 SD unit increase in BMI, WC, and WHtR respectively. After further adjustment for hypertension, diabetes, and dyslipidemia, these associations were attenuated but remained statistically significant.

Conclusions

Measures of general (BMI) and abdominal (WC and WHtR) obesity were similarly associated with CVD in middle‐aged Japanese men.

Global Analysis of Transcriptional Expression in Mice Exposed to Intermediate Frequency Magnetic Fields Utilized for Wireless Power Transfer Systems

BACKGROUND

Intermediate frequency magnetic fields (IF-MFs) at around 85 kHz are a component of wireless power transfer systems used for charging electrical vehicles. However, limited data exist on the potential health effects of IF-MFs. We performed a comprehensive analysis of transcriptional expression in mice after IF-MF exposure.

MATERIALS AND METHODS

We developed an IF-MF exposure system to generate a high magnetic flux density (25.3 mT). The system can expose the IF-MF for a mouse whole-body without considering thermal effects. After 10 days (1 h/day) of exposure, a comprehensive expression analysis was performed using microarray data from both the brain and liver.

RESULTS

No significant differences in transcriptional expression were detected in the 35,240 probe-sets when controlling the false discovery rate (FDR) under a fold change cutoff >1.5. However, several differential expressions were detected without FDR-adjustment, but these were not confirmed by RT-PCR analysis.

CONCLUSIONS

To our knowledge, this is the first in vivo study to evaluate the biological effects of IF-MF exposure with an intense magnetic flux density 253 times higher than the occupational restriction level defined by the International Commission on Non-Ionizing Radiation Protection guidelines. However, our findings indicate that transcriptional responses in the living body are not affected under these conditions.

Epicatechin as a promising agent to countermeasure radiation exposure by mitigating mitochondrial damage in human fibroblasts and mouse hematopoietic cells

Accidental radiation exposure that is due to a nuclear accident or terrorism using radioactive materials has severe detrimental effects on human health, and it can manifest as acute radiation syndrome depending on the dose and distribution of the radiation. Therefore, the development of radiation countermeasure agents is urgently needed to protect humans against radiation injury. Besides nuclear DNA, the mitochondria are important targets of ionizing radiation (IR) because these organelles generate reactive oxygen species (ROS). Recently, we revealed that mitochondrial ROS-activated cell signaling is associated with IR-induced tumor formation. Here, we investigated the effectiveness of ascorbic acid and epicatechin (EC) in scavenging ROS as radiation countermeasure agents by using human cells and mouse. Preradiation and postradiation treatments with EC mitigate ROS-mediated mitochondrial damage, IR-induced oxidative stress responses including reduction of superoxide dismutase activity, and elevated nuclear factor erythroid 2-related factor 2 expression, and they improve human fibroblast survival. As well as in vitro, EC mitigated ROS-mediated mitochondrial damage after exposure to IR in vivo in mouse platelets. Furthermore, oral administration of EC significantly enhanced the recovery of mouse hematopoietic cells from radiation injury in vivo. In summary, EC is a potentially viable countermeasure agent that is immediately effective against accidental IR exposure by targeting mitochondria-mediated oxidative stress.-Shimura, T., Koyama, M., Aono, D., Kunugita, N. Epicatechin as a promising agent to countermeasure radiation exposure by mitigating mitochondrial damage in human fibroblasts and mouse hematopoietic cells.

Factors affecting self-reported chemical intolerance: A five-year follow-up study in Japan

OBJECTIVE

Chemical intolerance (CI) has become a strong public health concern in industrialized countries. The Japanese Chemical Intolerance (JCI) study was conducted in January 2012 with a cohort of 7245 adults from population-based sampling as the baseline. The aim of the present study was to investigate the factors involved in the improvement and development of CI from the five-year follow-up study.

METHODS

From the 7245 cohort, 735 persons with CI (case) were identified, and 1750 controls without CI were randomly selected to match gender and age for case and control groups. Self-reported questionnaires were administered to the subjects of the two groups to obtain information on status of CI; medical history; medical, lifestyle, or physical interventions; changes in living situation or occupation; and psychosomatic states.

RESULTS

A total of 909 individuals responded during the follow-up period. After five years, improvement in CI was observed in 67.7% of the case group. Status of CI was reported in 6.7% of the control group. Multiple logistic regression analyses revealed that baseline atopic dermatitis and negative psychosomatic states including irritability, fatigue, anxiety, depressed mood, and somatic symptoms were significantly associated with development of CI in controls. Appropriate physical activity and maintaining a regular lifestyle including diet or sleep during the last three years of the follow-up period were significant factors for improvement of CI in the case group.

CONCLUSIONS

Ensuring appropriate physical activity and regular lifestyle rather than improving physical environment lead to improvement of CI. Stable psychosomatic state is essential for preventing CI.

Changes in oxidative stress levels during two weeks of smoking cessation treatment and their association with nutritional characteristics in Japanese smokers

Although several experimental studies have reported that oxidative stress levels decrease during smoking cessation, how they change among general smokers has yet to be completely elucidated. In the present study, a total of 23 smokers who underwent smoking cessation treatment were observed for two-week changes in their levels of 8-OHdG and 8-isoprostane. Physical and nutritional characteristics were measured at the initial patient visit, and casual urine samples were collected at the initial visit and at a follow-up visit two weeks later. Oxidative stress was measured by a high performance liquid chromatography electrochemical detector, and the two-week difference in the levels of oxidative stress was assessed according to demographic and nutrient factors. Neither the urinary level of 8-OHdG nor that of 8-isoprostane decreased, although the cotinine level was decreased at two weeks. A Two-way repeated ANOVA revealed a significant interaction for fat intake by time for the change in the 8-OHdG level (P=0.03) and significant interactions for α-tocopherol intake (P=0.03), iron intake, and carbohydrate intake (P=0.03), all of which were time-dependent for the change in the 8-isoprostane level. The 8-OHdG level decreased among smokers with a high fat intake and was increased with a low fat intake. The 8-isoprostane levels were decreased among smokers with a high carbohydrate intake and increased with a low carbohydrate intake, decreased with a low iron intake and increased with a high iron intake and decreased with a low α-tocopherol intake and increased with a high α-tocopherol intake. Although the present study failed to observe a decrease in oxidative stress levels during the two-week smoking cessation period, we hypothesize that the intake levels of specific nutrients when initiating smoking cessation treatment may predict any subsequent changes in the oxidative stress levels.

Diagnosing the double burden of malnutrition using estimated deviation values in low- and lower-middle-income countries

Objective

To examine the possibility of diagnosing the double burden of malnutrition using estimated deviation values in low- and lower-middle-income countries.

Methods

A modified version of the Japanese Diagnostic Tool was used. Data on 194 countries were analyzed, including data from the United Nations International Children’s Fund, World Health Organization and World Bank. After conducting a Box–Cox transformation, deviation values were calculated. The degree to which the values deviated relative to a deviation cutoff value of 50 was assessed. Focusing on countries with low- and middle-income economic levels, we examined the utility of this tool to show characteristic nutritional problems in each country.

Results

The deviation values had normal, distorted, bimodal, or trimodal distributions. In the lower-middle-income countries, almost all countries had values ranging from 40 to 60 for education and water environments (urban and rural), and the differences were minimal. However, different causes of noncommunicable disease-related deaths were considered, and the primary cause appeared to be related to lifestyle factors, particularly alcohol consumption and tobacco smoking. In comparison, the deviation values related to death among low-income countries also appeared to be related to differences in education and sanitation in urban and rural areas.

Conclusion

The study results can help to determine the status of nutritional inequalities and plan country-specific strategies to reduce the double burden of malnutrition.

Study Profile: The Japan "Society and New Tobacco" Internet Survey (JASTIS): A Longitudinal Internet Cohort Study of Heat-Not-Burn Tobacco Products, Electronic Cigarettes, and Conventional Tobacco Products in Japan

Background

Japan became the first country where heat-not-burn tobacco products were sold. Therefore, there was no information for actual status on the actual use status or the harms of heat-not-burn tobacco products. The objectives of the study profile are to generate data that can be freely available to external researchers, and to create collaborative research projects in the future.

Methods

The Japan “Society and New Tobacco” Internet Survey (JASTIS) is a longitudinal internet cohort study which investigates perception, attitude, and use of heat-not-burn tobacco, electronic cigarettes (e-cigarettes), and conventional tobacco products in Japan. The survey also includes demographic, health-related, and socioeconomic factors. Participants were randomly selected and invited from internet panelists. The baseline survey was closed when the target number of respondents who had answered the questionnaire was met.

Results

The study includes three cohorts (1–3) from the 2015 baseline survey and a cohort (4) from the 2017 baseline survey: cohorts 1 and 4 were recruited based on sex and age: men and women aged 15–69 years (n = 8,240 for cohort 1 and n = 5,897 for cohort 4); cohorts 2 and 3 were created using status-based recruiting: e-cigarette and/or heat-not-burn tobacco ever users (n = 2,188; cohort 2) and combustible cigarette smokers without e-cigarette/heat-not-burn tobacco experience (n = 724; cohort 3). The completion rates were 8.5% to 9.9%. All subjects were followed and assessed annually. Response rates for the follow-up survey were 65.5% in 2016, 55.3% in 2017, and 50.9% in 2018. Because Internet-based responders are not a representative sample of the general population of Japan, we conducted adjustment to account for “being an internet survey respondent” and reported tobacco product use in Japan. A recent JASTIS study reported that prevalence of IQOS current-use among Japanese adults had rapidly increased from 0.3% in 2015 to 3.6% in 2017.

Conclusion

The JASTIS study provides the first estimates for heat-not-burn tobacco use in the world and e-cigarette use in Japan. For information on collaboration, please contact the corresponding author.

Smoking, Smoking Cessation, and Risk of Mortality in a Japanese Working Population - Japan Epidemiology Collaboration on Occupational Health Study

BACKGROUND

The effect of smoking on mortality in working-age adults remains unclear. Accordingly, we compared the effects of cigarette smoking and smoking cessation on total and cause-specific mortality in a Japanese working population. Methods and Results: This study included 79,114 Japanese workers aged 20-85 years who participated in the Japan Epidemiology Collaboration on Occupational Health Study. Deaths and causes of death were identified from death certificates, sick leave documents, family confirmation, and other sources. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated via Cox proportional hazards regression. During a maximum 6-year follow-up, there were 252 deaths in total. Multivariable-adjusted HRs (95% CIs) for total mortality, cardiovascular disease (CVD) mortality, and tobacco-related cancer mortality were 1.49 (1.10-2.01), 1.79 (0.99-3.24), and 1.80 (1.02-3.19), respectively, in current vs. never smokers. Among current smokers, the risks of total, tobacco-related cancer, and CVD mortality increased with increasing cigarette consumption (P_trend<0.05 for all). Compared with never smokers, former smokers who quit <5 and ≥5 years before baseline had HRs (95% CIs) for total mortality of 1.80 (1.00-3.25) and 1.02 (0.57-1.82), respectively.

CONCLUSIONS

In this cohort of workers, cigarette smoking was associated with increased risk of death from all and specific causes (including CVD and tobacco-related cancer), although these risks diminished 5 years after smoking cessation.

Radiation-Induced Myofibroblasts Promote Tumor Growth via Mitochondrial ROS-Activated TGFβ Signaling

Fibroblasts are a key stromal cell in the tumor microenvironment (TME) and promote tumor growth via release of various growth factors. Stromal fibroblasts in cancer, called cancer-associated fibroblasts (CAF), are related to myofibroblasts, an activated form of fibroblast. While investigating the role of stroma fibroblasts on radiation-related carcinogenesis, it was observed following long-term fractionated radiation (FR) that the morphology of human diploid fibroblasts changed from smaller spindle shapes to larger flat shapes. These cells expressed smooth muscle actin (α-SMA) and platelet-derived growth factor receptors, markers of myofibroblasts and CAFs, respectively. Long-term FR induces progressive damage to the fibroblast nucleus and mitochondria via increases in mitochondrial reactive oxygen species (ROS) levels. Here, it is demonstrated that long-term FR-induced α-SMA-positive cells have decreased mitochondrial membrane potential and activated oxidative stress responses. Antioxidant N-acetyl cysteine suppressed radiation-induced mitochondrial damage and generation of myofibroblasts. These results indicate that mitochondrial ROS are associated with the acquisition of myofibroblasts after long-term FR. Mechanistically, mitochondrial ROS activated TGFβ signaling which in turn mediated the expression of α-SMA in radiation-induced myofibroblasts. Finally, in vivo tumor growth analysis in a human tumor xenograft model system revealed that long-term FR-induced myofibroblasts promote tumor growth by enhancing angiogenesis.Implications: Radiation affects malignant cancer cells directly and indirectly via molecular alterations in stromal fibroblasts such as activation of TGFβ and angiogenic signaling pathways. Mol Cancer Res; 16(11); 1676-86. ©2018 AACR.

Simple Determination of Gaseous and Particulate Compounds Generated from Heated Tobacco Products

As a new form of cigarettes, heated tobacco products (HTPs) have been rapidly distributed worldwide. In this study, an improved method for analyzing gaseous and particulate compounds generated from HTPs is described. Smoke is collected using a GF-CX572 sorbent cartridge with 300 mg of carbon molecular sieves, that is, Carboxen 572 (CX572), and a 9 mm glass-fiber filter (GF). After collection, the CX572 particles from the cartridge are transferred along with the GF and deposited into a vial containing two phases of carbon disulfide and methanol. The CX572 particles settle into the lower carbon disulfide phase, while nonpolar compounds are desorbed. After the sample is allowed to stand, the solution is slowly stirred. The two-phase mixture of carbon disulfide and methanol is combined into a homogeneous solution. Polar compounds are then desorbed, while the desorbed nonpolar compounds remain in solution. For the analysis of carbonyl compounds, an enriched 2,4-dinitrophenylhydrazine solution is added to a portion of the combined solution for derivatization and subsequent high-performance liquid chromatography analysis. For the analysis of volatile organic compounds and water, a portion of the combined solution is analyzed by gas chromatography-mass spectrometry or equipped with a thermal conductivity detector. By applying the proposed GF-CX572 one-cartridge method to the analysis of the mainstream smoke generated from HTPs and traditional cigarettes, several chemical compounds are detected, and the chemical composition of smoke is revealed. The GF-CX572 one-cartridge method can analyze gaseous and particulate chemical compounds from the HTP smoke by utilizing not only the entire puff volume but also one puff volume because the GF-CX-572 cartridge can be replaced with a new cartridge within 3 s. An overview of the chemicals generated from HTPs is obtained in detail by one-puff volume sampling. In addition, the generated chemical compounds strongly depend on the temperature of tobacco leaves in HTPs.

Heat-not-burn tobacco product use in Japan: its prevalence, predictors and perceived symptoms from exposure to secondhand heat-not-burn tobacco aerosol

OBJECTIVES

A heat-not-burn (HNB) tobacco product, IQOS, was first launched in Japan and Italy as test markets and is currently in commerce in 30 countries. Using two data sources, we examined interest in HNB tobacco (IQOS, Ploom and glo), its prevalence, predictors of its use and symptoms from exposure to secondhand HNB tobacco aerosol in Japan, where HNB tobacco has been sold since 2014.

METHODS

Population interest in HNB tobacco was explored using Google search query data. Prevalence of HNB tobacco current use (ie, use in the previous 30 days) was calculated using a longitudinal internet survey of 8240 individuals (15-69 years old in 2015) followed up to 2017. Rates of perceived symptoms from exposure to exhaled aerosol of others' HNB tobacco were also calculated.

RESULTS

The largest internet search volume for IQOS occurred in April 2016 in the week after a popular national entertainment TV show introduced IQOS. For Ploom and glo, search volumes have remained limited since their launch. Prevalence of IQOS users increased from 0.3% in January-February 2015 to 0.6% in January-February 2016 and up to 3.6% in January-February 2017, while estimated rates of use of other HNB tobacco products remained low in 2017. Respondents who had seen the TV programme in 2016 were more likely to have used IQOS than those who had not seen it (10.3% vs 2.7%). Among never-smokers who had been exposed to secondhand HNB tobacco aerosol, nearly half reported at least one acute symptom, although these symptoms were not serious.

CONCLUSIONS

A popular TV programme triggered IQOS diffusion in Japan. Extrapolating from survey results to the general population, around 3.1 million people currently use IQOS in Japan. Tobacco control organisations and governments should closely monitor HNB tobacco and consider how to regulate it.

Determination of Chemical Compounds Generated from Second-generation E-cigarettes Using a Sorbent Cartridge Followed by a Two-step Elution Method

We developed an analytical method for analyzing electronic cigarette (E-cigarette) smoke, and measured the carbonyl compounds and volatile organic compounds generated by 10 brands of second-generation E-cigarettes. A glass filter (Cambridge filter pad) for particulate matter and a solid sorbent tube packed with Carboxen-572 for gaseous compounds were used to collect E-cigarette smoke. These were then analyzed using a two-step elution method with carbon disulfide and methanol, followed by high-performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC/MS). Formaldehyde (FA), acetaldehyde (AA), acetone (AC), acrolein (ACR), propanal (PA), acetol (AT), glyoxal (GO), and methyl glyoxal (MGO) were detected by HPLC in some E-cigarettes. Propylene glycol (PG), glycerol (GLY), and some esters were detected by GC/MS. GO and MGO exist mainly as particulate matter. AA, AC, ACR, PA, and AT exist mainly as gaseous compounds. FA exists as both particulate matter and gaseous compounds. These carbonyl compounds have carbon numbers C1 - C3. The main components of E-liquid are PG (C3) and GLY (C3). Therefore, the oxidation of liquids, such as PG and GLY in E-cigarettes upon incidental contact with the heating element in E-cigarette, is suggested as being a possible cause for carbonyl generation. When the puff number exceeds a critical point, carbonyl generation rapidly increases and then remains constant. The results of this study are now being used to determine the following E-cigarette smoking protocol: puff volume, 55 mL; puff duration, 2 s; and puff number, 30. E-cigarette analysis revealed very large variation in carbonyl concentration among not only different brands, but also different samples of the same product. Typical distributions of carbonyl concentration were not observed in any of the E-cigarettes tested, and the mean values greatly differed from median values.

Spectrophotometric determination of ammonia levels in tobacco fillers of and sidestream smoke from different cigarette brands in Japan

BACKGROUND

The ammonia contained in tobacco fillers and mainstream and sidestream cigarette smoke accelerates nicotine dependence in cigarette smokers. Ammonia has been included in the non-exhaustive priority list of 39 tobacco components and emissions of cigarette published by the World Health Organization (WHO) Study Group on Tobacco Product Regulation. The development of a simple ammonia detection method will contribute to the establishment of tobacco product regulation under tobacco control policies and allow surveys to be conducted, even by laboratories with small research budgets.

METHODS

We developed a simple colorimetric method based on the salicylate-chlorine reaction and absorption spectrometry with two reagents (sodium nitroprusside and sodium dichloroisocyanurate). To compare this method to conventional ion chromatography, we analyzed the ammonia levels in tobacco fillers extracted from 35 Japanese commercially marketed cigarette brands manufactured by four tobacco companies (Japan Tobacco (JT) Inc., British American Tobacco (BAT), Philip Morris Japan, and Natural American Spirit). We also analyzed the ammonia levels in the sidestream smoke from cigarettes of the brands that were found to contain high or low tobacco filler ammonia levels.

RESULTS

The ammonia levels in the reference cigarette (3R4F) measured by our method and ion chromatography were similar and comparable to previously reported levels. The ammonia levels in tobacco fillers extracted from 35 cigarette brands ranged from 0.25 to 1.58 mg/g. The mean ammonia level of JT cigarette brands was significantly higher (0.83 ± 0.28 mg/g) than that of Natural American Spirit cigarette brands (0.30 ± 0.08 mg/g) and lower than those in the other two cigarette brands (1.11 ± 0.19 mg/g for BAT and 1.24 ± 0.15 mg/g for Philip Morris) (p < 0.001 by Bonferroni test). The ammonia levels in the sidestream smoke of CABIN, Marlboro Black Menthol, American Spirit Light, and Seven Stars were 5.89 ± 0.28, 5.23 ± 0.12, 6.92 ± 0.56, and 4.14 ± 0.19 mg/cigarette, respectively. The ammonia levels were higher in sidestream smoke than in tobacco filler.

CONCLUSIONS

Our simple colorimetric could be used to analyze ammonia in tobacco fillers and sidestream smoke. There were significant differences between the ammonia levels of the 35 commercially marketed cigarette brands in Japan manufactured by four tobacco manufacturers. Over 90% of the ammonia in sidestream smoke was in gaseous phase.