| 1. |
- Lim, Fang Lee, et al.
(author)
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Asthma, Airway Symptoms and Rhinitis in Office Workers in Malaysia : Associations with House Dust Mite (HDM) Allergy, Cat Allergy and Levels of House Dust Mite Allergens in Office Dust
- 2015
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
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Journal article (peer-reviewed)abstract
- A prevalence study was conducted among office workers in Malaysia (N= 695). The aim of this study was to examine associations between asthma, airway symptoms, rhinitis and house dust mites (HDM) and cat allergy and HDM levels in office dust. Medical data was collected by a questionnaire. Skin prick tests were performed for HDM allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cat allergen Felis domesticus. Indoor temperature and relative air humidity (RH) were measured in the offices and vacuumed dust samples were analyzed for HDM allergens. The prevalence of D. pteronyssinus, D. farinae and cat allergy were 50.3%, 49.0% and 25.5% respectively. Totally 9.6% had doctor-diagnosed asthma, 15.5% had current wheeze and 53.0% had current rhinitis. The Der p 1 (from D. pteronyssinus) and Der f 1 (from D. farinae) allergens levels in dust were 556 ng/g and 658 ng/g respectively. Statistical analysis was conducted by multilevel logistic regression, adjusting for age, gender, current smoking, HDM or cat allergy, home dampness and recent indoor painting at home. Office workers with HDM allergy had more wheeze (p= 0.035), any airway symptoms (p= 0.032), doctor-diagnosed asthma (p= 0.005), current asthma (p= 0.007), current rhinitis (p= 0.021) and rhinoconjuctivitis (p< 0.001). Cat allergy was associated with wheeze (p= 0.021), wheeze when not having a cold (p= 0.033), any airway symptoms (p= 0.034), doctor-diagnosed asthma (p= 0.010), current asthma (p= 0.020) and nasal allergy medication (p= 0.042). Der f 1 level in dust was associated with daytime breathlessness (p= 0.033) especially among those with HDM allergy. Der f 1 levels were correlated with indoor temperature (p< 0.001) and inversely correlated with RH (p<0.001). In conclusion, HDM and cat allergies were common and independently associated with asthma, airway symptoms and rhinitis. Der f 1 allergen can be a risk factor for daytime breathlessness.
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| 2. |
- Lim, Fang Lee, et al.
(author)
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Fractional exhaled nitric oxide (FeNO) among office workers in an academic institution, Malaysia - associations with asthma, allergies and office environment.
- 2016
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In: Journal of Asthma. - : Informa UK Limited. - 0277-0903 .- 1532-4303. ; 53:2, s. 170-178
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Journal article (peer-reviewed)abstract
- OBJECTIVE: There are few studies on fractional exhaled nitric oxide (FeNO) and respiratory symptoms among adults in tropical areas. The aim was to study associations between FeNO and selected personal factors, respiratory symptoms, allergies, office characteristics and indoor office exposures among office workers (n = 460) from a university in Malaysia.METHODS: Information on health was collected by a questionnaire, skin prick test and FeNO measurement. Temperature, relative air humidity, carbon monoxide and carbon dioxide were measured in the offices. Settled dust was vacuumed in the offices and analyzed for endotoxin, (1,3)-β-glucan and house dust mites allergens, namely Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). Two-level linear mixed models and multiple logistic regression were used to analyze the associations.RESULTS: One-fourth (25.9%) of the office workers had elevated FeNO level (≥25 ppb) and 61.5% had HDM, cat, seafood or pollen allergy. Male gender (p < 0.001), current smoking (p = 0.037), height (p < 0.001) and atopy (p < 0.001) were associated with FeNO. The amount of vacuumed dust was associated with FeNO among atopic subjects (p = 0.009). Asthma and rhinitis symptoms were associated with FeNO (p < 0.05), especially among atopic subjects. In particular, a combination of atopy and elevated FeNO were associated with doctor-diagnosed asthma (p < 0.001), rhinitis (p < 0.001) and airway symptoms last 12 months (p < 0.001).CONCLUSION: Gender, smoking, height and atopy are important risk factors for elevated FeNO levels. A combination of allergy testing and FeNO measurement could be useful in respiratory illness epidemiology studies and patient investigations in tropical areas.
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| 3. |
- Lim, Fang-Lee, et al.
(author)
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Sick building syndrome (SBS) among office workers in a Malaysian university - Associations with atopy, fractional exhaled nitric oxide (FeNO) and the office environment
- 2015
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 536, s. 353-361
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Journal article (peer-reviewed)abstract
- There are few studies on sick building syndrome (SBS) including clinical measurements for atopy and fractional exhaled nitric oxide (FeNO). Our aim was to study associations between SBS symptoms, selected personal factors, office characteristics and indoor office exposures among office workers from a university in Malaysia. Health data were collected by a questionnaire (n = 695), skin prick test (SPT) (n = 463) and FeNO test (n = 460). Office settled dust was vacuumed and analyzed for endotoxin, (1,3)-beta-glucan and house dust mites (HDM) allergens group 1 namely Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). Office indoor temperature, relative air humidity (RH), carbon monoxide (CO) and carbon dioxide (CO2) were measured by a direct reading instrument. Associations were studied by two-levelsmultiple logistic regression with mutual adjustment and stratified analysis. The prevalence of weekly dermal, mucosal and general symptoms was 11.9%, 16.0% and 23.0% respectively. A combination of SPT positivity (allergy to HDM or cat) and high FeNO level (>= 25 ppb) was associated with dermal (p = 0.002), mucosal (p <0.001) and general symptoms (p = 0.05). Der f1 level in dust was associated with dermal (p < 0.001), mucosal (p < 0.001) and general (p = 0.02) symptoms. Among those with allergy to D. farinae, associations were found between Der f 1 levels in dust and dermal (p = 0.003), mucosal (p = 0.001) and general symptoms (p = 0.007). Office-related symptoms were associated with Der f 1 levels in dust (p = 0.02), low relative air humidity (p = 0.04) and high office temperature (p = 0.05). In conclusion, a combination of allergy to cat or HDM and high FeNO is a risk factor for SBS symptoms. Der f 1 allergen in dust can be a risk factor for SBS in the office environment, particularly among those sensitized to Der f 1 allergen.
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| 4. |
- Norback, Dan, et al.
(author)
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Respiratory symptoms and fractional exhaled nitric oxide (FeNO) among students in Penang, Malaysia in relation to signs of dampness at school and fungal DNA in school dust
- 2017
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 577, s. 148-154
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Journal article (peer-reviewed)abstract
- Few health studies exist on dampness and mould in schools in the tropics. We studied associations between fraction of exhaled nitric oxide (FeNO), respiratory symptoms and airway infections among students and dampness and fungal DNA in schools in Malaysia. A total of 368 randomly selected students from 32 classrooms in 8 secondary schools in Penang, Malaysia, participated (58% participation rate). Information on current respiratory symptoms and the home environment was collected by a standardised questionnaire. FeNO was measured by NIOX MINO (50 ml/min). The classrooms were inspected and dust was collected by vacuuming on special filters and was analysed for five fungal DNA sequences by quantitative PCR. Linear mixed models and 3-level multiple logistic regression (school, classroom, student) were applied adjusting for demographic data and the home environment. Totally 10.3% reported doctor's diagnosed asthma, 15.1% current wheeze, 12.4% current asthma, 37.3% daytime breathlessness, 10.2% nocturnal breathlessness, 38.9% airway infections and 15.5% had pollen or furry pet allergy. The geometric mean of FeNO was 19.9 ppb and 45% had elevated FeNO (>20 ppb). Boys had higher levels of FeNO. Chinese had less daytime breathlessness than Malay (OR = 030: p < 0.001). Indoor carbon dioxide levels were low (380-720 ppm). Dampness "was observed in 18% of the classrooms and was associated with respiratory infections (OR = 3.70; 95% CI 1.14-12.1) and FeNO (p = 0.04), Aspergillus versicolor DNA was detected in 67% of the classrooms. Higher numbers of Aspergillus versicolor DNA in classroom dust were associated with wheeze (p = 0.006), current asthma (p = 0.002), respiratory infections (p = 0.005) and elevated FeNO levels (p = 0.02). In conclusion, respiratory symptoms were common among the students and the high FeNO levels indicate ongoing airway inflammation. Building dampness and the mould Aspergillus versicolor in schools in Malaysia can be risk factors for impaired respiratory health among the students.
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| 5. |
- Norbäck, Dan, et al.
(author)
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Endotoxin, ergosterol, muramic acid and fungal DNA in dust from schools in Johor Bahru, Malaysia : Associations with rhinitis and sick building syndrome (SBS) in junior high school students
- 2016
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 545, s. 95-103
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Journal article (peer-reviewed)abstract
- This paper studied associations between ocular symptoms, rhinitis, throat and dermal symptoms, headache and fatigue in students by ethnicity and in relation to exposure to chemical microbial markers and fungal DNA in vacuumed dust in schools in Malaysia. A total of 462 students from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated (96% response rate). Dust was vacuumed from 32 classrooms and analysed for levels of five types of endotoxin as 3-hydroxy fatty acids (C10, C12, C14, C16 and C18 3-OH), muramic acid, ergosterol and five sequences of fungal DNA. Multiple logistic regression was applied. Totally 11.9% reported weekly ocular symptoms, 18.8% rhinitis, 15.6% throat and 11.1% dermal symptoms, 20.6% headache and 22.1% tiredness. Totally 21.1% reported pollen or furry pet allergy (atopy) and 22.0% parental asthma or allergy. Chinese students had less headache than Malay and Indian had less rhinitis and less tiredness than Malay. Parental asthma/allergy was a risk factor for ocular (odds ratio = 3.79) and rhinitis symptoms (OR = 3.48). Atopy was a risk factor for throat symptoms (OR = 2.66), headache (OR = 2.13) and tiredness (OR = 2.02). There were positive associations between amount of fine dust in the dust samples and ocular symptoms (p < 0.001) and rhinitis (p = 0.006). There were positive associations between C14 3-OH and rhinitis (p < 0.001) and between C18 3-OH and dermal symptoms (p = 0.007). There were negative (protective) associations between levels of total endotoxin (LPS) (p = 0.004) and levels of ergosterol (p = 0.03) and rhinitis and between C12 3-OH and throat symptoms (p = 0.004). In conclusion, the amount of fine dust in the classroom was associated with rhinitis and other SBS symptoms and improved cleaning of the schools is important. Endotoxin in the school dust seems to be mainly protective for rhinitis and throat symptoms but different types of endotoxin could have different effects. The ethnic differences in symptoms among the students deserve further attention.
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| 6. |
- Norbäck, Dan, et al.
(author)
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Ocular symptoms and tear film break up time (BUT) among junior high school students in Penang, Malaysia - Associations with fungal DNA in school dust
- 2017
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In: International journal of hygiene and environmental health. - : ELSEVIER GMBH, URBAN & FISCHER VERLAG. - 1438-4639 .- 1618-131X. ; 220:4, s. 697-703
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Journal article (peer-reviewed)abstract
- Background: There are few studies on ocular effects of indoor mould exposure in schools, especially in the tropicsObjective: To study associations between eye symptoms and tear film break up time (BUT) in students and demographic data and fungal DNA in schools.Methods: A school environment study was performed among randomly selected students in eight randomly selected secondary schools in Penang, Malaysia. Information on eye symptoms and demographic data was collected by a standardised questionnaire. BUT was measured by two methods, self-reported BUT (SBUT) and by the non-invasive Tearscope (NIBUT). Dust was collected by vacuuming in 32 classrooms and analysed for five fungal DNA sequences. Geometric mean (GM) for total fungal DNA was 7.31*10(4) target copies per gram dust and for Aspergillus/Penicillium DNA 3.34*10(4) target copies per gram dust. Linear mixed models and 3-level multiple logistic regression were applied adjusting for demo-graphic factors.Results: A total of 368 students (58%) participated and 17.4% reported weekly eye symptoms the last 3 months. The median SBUT and TBUT were 15 and 12 s, respectively. Students wearing glasses (OR 2.41, p=0.01) and with a history of atopy (OR= 2.67; p=0.008) had more eye symptoms. Girls had less eye symptoms than boys (OR= 0.34; p=0.006) Indoor carbon dioxide in the classrooms was low (range 380-720 ppm), temperature was 25-30 degrees C and relative air humidity 70-88%. Total fungal DNA in vacuumed dust was associated with shorter SBUT (4s shorter per 10(5) target copies per gram dust; p=0.04) and NIBUT (4s shorter per 105 target copies per gram dust; p < 0.001). Aspergillus/Penicillium DNA was associated with shorter NIBUT (5 s shorter per 105 target copies per gram dust; p=0.01).Conclusion: Fungal contamination in schools in a tropical country can be a risk factor for impaired tear film stability among students.
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| 7. |
- Norbäck, Dan, et al.
(author)
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Rhinitis, Ocular, Throat and Dermal Symptoms, Headache and Tiredness among Students in Schools from Johor Bahru, Malaysia: Associations with Fungal DNA and Mycotoxins in Classroom Dust.
- 2016
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:2
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Journal article (peer-reviewed)abstract
- There are few studies on rhinitis and sick building syndrome (SBS) among students in tropical countries. We studied associations between levels of five fungal DNA sequences, two mycotoxins (sterigmatocystin and verrucarol) and cat allergen (Fel d 1) levels in schools and rhinitis and other weekly SBS symptoms in the students. Fungal DNA was measured by quantitative PCR and cat allergen by ELISA. Pupils (N = 462) from eight randomly selected schools in Johor Bahru, Malaysia participated (96%). Dust samples were collected by cotton swabs and Petri dishes exposed for one week. None of the schools had a mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures and indoor CO2 levels were low (mean 492 ppm; range 380-690 ppm). Weekly nasal symptoms (rhinitis) (18.8%), ocular (11.6%), throat (11.1%), dermal symptoms, headache (20.6%) and tiredness (22.1%) were common. Total fungal DNA in swab samples was associated with rhinitis (p = 0.02), ocular symptoms (p = 0.009) and tiredness (p = 0.001). There were positive associations between Aspergillus versicolor DNA in Petri dish samples, ocular symptoms (p = 0.02) and tiredness (p = 0.001). The level of the mycotoxin verrucarol (produced by Stachybotrys chartarum) in swab samples was positively associated with tiredness (p = 0.04). Streptomyces DNA in swab samples (p = 0.03) and Petri dish samples (p = 0.03) were negatively associated with tiredness. In conclusion, total fungal contamination, measured as total fungal DNA) in the classrooms, Aspergillus versicolor and verrucarol can be risk factors for rhinitis and SBS symptoms among students in the tropical country Malaysia.
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| 8. |
- Norbäck, Dan, et al.
(author)
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Volatile organic compounds (VOC), formaldehyde and nitrogen dioxide (NO2) in schools in Johor Bahru, Malaysia : Associations with rhinitis, ocular, throat and dermal symptoms, headache and fatigue
- 2017
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 592, s. 153-160
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Journal article (peer-reviewed)abstract
- This paper studied associations between volatile organic compounds (VOC), formaldehyde, nitrogen dioxide (NO2) and carbon dioxide(CO2) in schools in Malaysia and rhinitis, ocular, nasal and dermal symptoms, headache and fatigue among students. Pupils from eight randomly selected junior high schools in Johor Bahru, Malaysia (N = 462), participated (96%). VOC, formaldehyde and NO2 were measured by diffusion sampling (one week) and VOC also by pumped air sampling during class. Associations were calculated bymulti-level logistic regression adjusting for personal factors, the home environment and microbial compounds in the school dust. The prevalence of weekly rhinitis, ocular, throat and dermal symptoms were 18.8%, 11.6%, 15.6%, and 11.1%, respectively. Totally 20.6% had weekly headache and 22.1% fatigue. Indoor CO2 were low(range 380-690 ppm). Indoor median NO2 and formaldehyde concentrations over one week were 23 mu g/m(3) and 2.0 mu g/m(3), respectively. Median indoor concentration of toluene, ethylbenzene, xylene, and limonene over one week were 12.3, 1.6, 78.4 and 3.4 mu g/m(3), respectively. For benzaldehyde, the mean indoor concentration was 2.0 mu g/m(3) (median < 1 mu g/m(3)). Median indoor levels during class of benzene and cyclohexane were 4.6 and 3.7 mu g/m(3), respectively. NO2 was associated with ocular symptoms (p < 0.001) and fatigue (p = 0.01). Formaldehyde was associated with ocular (p = 0.004), throat symptoms (p = 0.006) and fatigue (p = 0.001). Xylene was associated with fatigue (p < 0.001) and benzaldehyde was associatedwith headache (p = 0.03). In conclusion, xylene, benzaldehyde, formaldehyde and NO2 in schools can be risk factors for ocular and throat symptoms and fatigue among students in Malaysia. The indoor and outdoor levels of benzene were often higher than the EU standard of 5 mu g/m(3).
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