Prevalence and determinants of asthma, COPD and allergy to common airborne allergens in northern Vietnam

Introduction: While a large amount of data about the epidemiology of asthma, allergy, COPD, chronic bronchitis and respiratory symptoms are available from developed countries, the information about these diseases and conditions in developing countries in south-east Asia are scarce. There are, however, several reports indicating an increase in asthma and allergy parallel to urbanization in developing countries. The proportion of smoking men in south-east Asia including Vietnam is large. Aim: The aim of this thesis was to assess the prevalence of obstructive airway diseases and symptoms and their relation with demographic data including smoking habits among adults in rural and urban Vietnam. Special interest was paid to asthma, rhinitis, allergic sensitization and COPD. Methods: The study was conducted in two parts. A random sample of subjects aged 21 -70 years were invited; 3008 subjects living in an inner city area of Hanoi, Hoankiem, and 4000 in a rural area of Bavi in northern Vietnam. An internationally used questionnaire was delivered by field workers to the study subjects. From the questionnaire responders, a randomly selected sample of 750 subjects from each of the two areas was invited to the second part of the study. The second part consisted of clinical examinations including structured interview, dynamic spirometry, skin prick testing (SPT) and bronchial provocation testing with methacholine. The SPT panel included ten common indoor and outdoor allergens. For the structured interview a modified GA 2 LEN study questionnaire was used. The spirometry followed the American Thoracic Society guidelines and East Asian reference values were used. COPD was defined by using the fixed ratio of FEV1/FVC < 0.7. Results: The response rate to the questionnaire was 92% in Bavi and 70% in Hoankiem. Of men in Bavi 67.8% (Hoankiem 49.7%; p < 0.001) were smokers, while of women 4.2% were smokers in Hoankiem (Bavi 1.2%; p < 0.001). The prevalence of ever having had asthma was in Hoankiem 5.6% (Bavi 3.9%; p = 0.003) with no major gender difference. The most common symptom was longstanding cough (Hoankiem 18.1%, Bavi 12.0%; p < 0.001) followed by sputum production, while the prevalence of symptoms common in asthma was considerably lower. Respiratory symptoms were slightly more common in men than women. Allergic rhinitis ever or chronic nasal symptoms were reported by 50.2%. The prevalence of allergic rhinitis was considerably higher in the urban area compared to the rural, 29.6% vs 10.0% (p<0.001). Allergic rhinitis ever and chronic nasal symptoms were both significantly associated with asthma and respiratory symptoms (p<0.001). Exposure to gas, dust or fumes at work was significantly associated with all rhinitis conditions. No major gender differences were found, and smoking was not significantly associated with the nasal conditions. The participation rate in the clinical part was 46%. The representativeness of the participants was good as no statistical difference in prevalence of symptoms was found between the participants and all responders in the questionnaire survey. Of men 36.9% and of women 31.0% (n.s.) had positive SPT to at least one allergen. The most common sensitizer was the storage mite, Blomia tropicalis (men 27.7%; women 18.7%, p = 0.013). Sensitization to mites and cockroach were common (26.1%; 13.2%), and was strongly associated with allergic rhinitis. Young age, male sex and occupational exposure to gas, dust and fumes were risk factors for allergic sensitization to mites or cockroach. A significant positive association between the number of positive SPT reactions and airway hyper-reactivity was found. The overall prevalence of COPD was 7.1% (men 10.9%; women 3.9%), and the prevalence increased considerably by age. The distribution of COPD by disease severity was 12.5% severe or very severe COPD (FEV1<50% of predicted), 40% moderate COPD (FEV1 ≥50 <80% of pred.) and 47.5% mild COPD (FEV1≥80% of pred.). Among men with COPD all but one was current or ex-smokers, while the women with COPD were all never smokers. Among men, COPD was strongly related to the number of pack-years of tobacco consumption and a half of smokers aged ≥60 years had developed COPD. Conclusions: The prevalence of asthma in adults may have increased in both urban and rural Vietnam, as the few previous estimates have found 2% of adults having asthma. The majority of men were smokers versus a few percent of women. A half of the studied population had rhinitis conditions with allergic rhinitis being more common in the urban area, however, a difference in the knowledge about what allergy is may have contributed to this urban-rural difference. The pattern and prevalence of allergic sensitizers conforms to results from other areas with a similar climate. Taking into account the young population of Vietnam, the prevalence of COPD must be considered as high particularly among smoking men. Except increasing age and a previous history of asthma, no other risk factors for COPD among women could be demonstrate

ENGLISH TEACHERS’ QUESTIONS IN A VIETNAMESE HIGH SCHOOL READING CLASSROOM

Recently, developing students’ thinking, especially critical thinking (CT), has become a hot issue. Critical thinking has been claimed to have an important impact on learners’ reading comprehension because it can help them analyze, evaluate, construct their thinking, solving problems and reasoning (Ennis, 1989). However, the extent that teachers’ classroom activities contribute to developing students’ critical thinking has rarely been researched. The current case study was conducted with six EFL high school teachers and 10 reading lessons in Vietnam to explore the teachers’ use of questions and to analyze if these questions could facilitate the students’ critical thinking. Classroom observations and the cognitive domain of Bloom’s taxonomy were adapted as the research instruments. The study results reveal common types of questions are often used by high school teachers in their reading lessons. Suggestions are made on types of questions that teachers should function more in their class in order to enhance students’ critical thinking

A Research on the Quality of Public Transportation Services by Bus in Vietnam

This study was conducted to assess the status of the quality of public passenger transport services by bus in Hanoi. Data were collected from regular passengers using buses as a means of transportation in the city, including passengers standing at stations, waiting shelters and on vehicles to make trips and students of some universities who use buses as a means of transportation. We employ descriptive statistics and hierarchical analysis to learn about the topic of research. The results indicate that the quality of public transport services by buses in Hanoi, which was judged by passengers quite well. In particular, the safety level, convenience, security and hygiene is up to 70%, which was higher than the highest quality level. Quality of fast level and reliability are low. Keywords: quality of services, public passenger transport, buses, Vietnam. DOI: 10.7176/RJFA/10-13-04 Publication date:July 31st 201

CONCEPTS AND AWARENESS ABOUT SELF-HARM AND SUICIDAL THOUGHTS AMONG HIGH SCHOOL STUDENTS CURRENTLY

The article focuses on understanding concepts and awareness of suicidal thoughts and self – harm behaviors based on quantitative and qualitative data. The quantitative database will be taken from a survey of high school students living and studying in Ho Chi Minh City. The qualitative database is taken from in-depth interviews focusing on teachers, parents, and students. The article presents the main results of the research. First, focus on the research basis including subjects, objects, and research methodology. Second, include views on suicidal thoughts and self-harm from many different perspectives, manifestations and causes of these behaviors, the prevalence of self-harm/suicidal thoughts, and consequences. Third, conclude and propose some recommendations to minimize the problem

ARSENIC REMOVAL FROM GROUND WATER : RESEARCHES AND PRACTICAL IMPLEMENTATION CONDUCTED AT INSTITUTE OF CHEMISTRY, VIETNAMESE ACADEMY OF SCIENCE AND TECHNOLOGY

Joint Research on Environmental Science and Technology for the Eart

Ecological and behavioural risk factors of scrub typhus in central Vietnam: a case‑control study

Background: The risk factors for scrub typhus in Vietnam remain unknown. Scrub typhus caused by Orientia tsutsugamushi often presents as an undifferentiated febrile illness and remains under appreciated due to the limited availability of diagnostic tests. This tropical rickettsial illness is increasingly recognized as an important cause of non-malaria acute undifferentiated fever in Asia. This study aimed to investigate behavioural and ecological related risk factors of scrub typhus to prevent this potentially life-threatening disease in Vietnam. Methods: We conducted a clinical hospital-based active surveillance study, and a retrospective residence-enrolment date-age-matched case-control study in Khanh Hoa province, Vietnam, from August 2018 to March 2020. Clinical examinations, polymerase chain reaction and enzyme-linked immunosorbent assay IgM tests were applied to define cases and controls. All enrolled participants filled out a questionnaire including demographic socio-economic status, personal behaviors/protective equipment, habitat connections, land use, and possible exposure to the vector. Multivariable conditional logistic regression was used to define the scrub typhus associated risk factors. Results: We identified 44 confirmed cases and matched them with 152 controls. Among cases and controls, the largest age group was the 41-50 years old and males accounted for 61.4% and 42.8%, respectively. There were similarities in demographic characteristics between the two groups, with the exception of occupation. Several factors were significantly associated with acquisition of scrub typhus, including sitting/laying directly on household floor [adjusted OR (aOR) = 4.9, 95% CI: 1.6-15.1, P = 0.006], household with poor sanitation/conditions (aOR = 7.9, 95% CI: 1.9-32.9, P = 0.005), workplace environment with risk (aOR = 3.0, 95% CI: 1.2-7.6, P = 0.020), always observing mice around home (aOR = 3.7, 95% CI: 1.4-9.9, P = 0.008), and use of personal protective equipment in the field (aOR = 0.4, 95% CI: 0.1-1.1, P = 0.076). Conclusions: Ecological and household hygiene-related factors were more associated with scrub typhus infection,than individual-level exposure activities in the hyper-endemic area. These findings support local education and allow people to protect themselves from scrub typhus, especially in areas with limitations in diagnostic capacit

A Review of Occupational Stress among Certain Jobs in Vietnam

Background: Stress in the modern workplace is globally considered a risk factor for workers’ health and safety. However, a review of the prevalence and associated factors of occupational stress in developing countries like Vietnam was largely lacking. This review aimed to describe the situation of occupational stress among certain jobs from studies carried out in Vietnam. Methods: The review was implemented by using key words to search on online and offline, international and national database. After going through 2 stages of selections, total 25 eligible articles were chosen and used for this review. Results: The results showed the prevalence of occupational stress was varied and ranged from 6.4% to 90.4%. The study population focused on health workers, factory workers, students, academic staff and officers. The prevalence of each occupation ranged from 6.4% to 90.4% in health workers; 20.7% to 89.6% in factory workers; and 22.8% to 68.3% in students. Conclusions: In conclusion, the prevalence of occupational stress was very varied between and within each occupation. Therefore, a new way to develop in enhancing the occupational stress data, particularly in developing countries, is urgently needed

SEASONAL VARIATION OF PHYTOPLANKTON FUNCTIONAL GROUPS IN TUYEN LAM RESERVOIR, CENTRAL HIGHLANDS, VIETNAM

Seasonal changes in freshwater phytoplankton assemblages at Tuyen Lam Reservoir in the Central Highlands of Vietnam were classified into 23 functional groups based on physiological, morphological, and ecological characteristics. A total of 168 species were recorded during 10 surveys from 2015 to 2019 at 7 sampling sites, with Chlorophyta dominating in number of species. Phytoplankton abundance varied from 0.18×105 to 21.2×105 cells/L during the study period, mainly due to cyanobacteria. Seven of the 23 functional groups were considered to be dominant (relative density &gt; 5%).  The dominant functional groups were groups M and G in the dry season and groups M, G, P, and E in the rainy season. Group M (Microcystis aeruginosa) was the most common in both seasons, while group P (Closterium, Staurastrum, Aulacoseira), group E (Dinobryon, Synura), and group G (Sphaerocystis, Eudorina) were more common in the rainy season. The Shannon diversity index (H¢) showed that phytoplankton communities were relatively diverse and that most of the study sites were lightly polluted. However, the ecological status has deteriorated at some locations due to the overgrowth of group M, leading to eutrophication in this reservoir. This study highlights the usefulness of functional groups in the study of seasonal changes in phytoplankton dynamics. Functional groups are applied for the first time at Tuyen Lam Reservoir and can be used to predict early-stage cyanobacterial blooms in future studies

Gauge Bosons in the 3-3-1 Model with Three Neutrino Singlets

We show that the mass matrix of electrically neutral gauge bosons in the recent proposed  model based on $\mathrm{SU}(3)_C\otimes \mathrm{SU}(3)_L\otimes \mathrm{U}(1)_X$ group with three neutrino singlets [9] has two exact eigenvalues and corresponding eigenvectors. Hence the neutral non-Hermitian gauge boson $X^0_\mu$ is properly determined.With extra vacuum expectation values of the Higgs fields, there are mixings among charged gauge bosons $W^\pm$ and $Y^\pm$ as well as amongneutral gauge bosons $Z, Z'$ and $X^0$. From the $W$ boson decay width, we get lower bound on  scale of the model about few TeVs