D Koh

National Skin Centre, Tumasik, Singapore

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Publications (79)174.35 Total impact

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    ABSTRACT: Although vacuum cleaning is recommended to reduce allergen levels and improve asthma and allergic rhinitis symptoms, some studies suggest it may increase allergen load in homes. We conducted a cross-sectional study to determine if home floor vacuuming was associated with sensitization to dust-mites and cockroaches, and serum eosinophil cationic protein (ECP), a biomarker for atopy, in 102 physician-diagnosed spirometry-confirmed asthmatics. We collected data on floor type, floor cleaning method and frequency, asthma severity, allergy medications used, serum ECP and skin prick tests (SPT) to three dust-mites [Dermatophagoides pteronyssisinus (Der p), Dermatophagoides farinae (Der f) and Blomia tropicalis (Blo t)] and two cockroaches [Periplanata americana (Per a) and Blatella germanica (Bla g)]. Those who vacuumed had increased sensitization to three dust-mites [adjusted ORs (95%CI) = Der p: 26.6 (1.8-405.2); Der f: 44.8 (3.2-620.9); Blo t: 14.1 (1.8-108.1)] but not to cockroaches, adjusted for cleaning frequency and other methods of floor cleaning. Subjects who vacuumed their floor had higher levels of serum ECP than those who did not [adjusted median difference (95%CI): 9.4 (1.1-17.7)], adjusted for use of nasal corticosteroids among those with allergic rhinitis. Vacuuming is associated with increased sensitization to dust-mite allergens and higher serum ECP. PRACTICAL IMPLICATIONS: We found an association between floor vacuuming and increased sensitization to dust-mite allergens and higher levels of an atopy biomarker. Current recommendations to use vacuuming to control allergen exposure and allergic conditions may need to be reconsidered until further studies are performed.
    Indoor Air 09/2009; 19(6):468-73. DOI:10.1111/j.1600-0668.2009.00610.x · 4.20 Impact Factor
  • Indoor Air 01/2009; DOI:10.1111/j.0905-6947.2009.00610.x · 4.20 Impact Factor
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    ABSTRACT: Aims/hypothesis The involvement of chronic inflammation in albuminuria and renal function was investigated in a cross-sectional study of 320 type 2 diabetic Chinese patients from the Singapore Diabetes Cohort Study. Methods Plasma levels of TNF-α and its two cellular receptors and of IL-6 and C-reactive protein (CRP) were measured. A composite TNF-α score was extracted using principal component analysis. Multiple linear regression analysis was implemented to evaluate the relationship between log e (ln) albumin:creatinine ratio (ACR) and estimated GFR (eGFR) with the inflammatory variables and other clinical covariates. A Bonferroni correction was applied based on the total number of variables entered into regression analyses. Results ln ACR was significantly associated with TNF-α score independently of eGFR even after a Bonferroni correction. TNF-α score was also significantly associated with eGFR independently of ln ACR even after correction for multiple testing. These findings were similar when the individual molecules of the TNF-α system were analysed separately instead of using the composite TNF-α score. No association was observed for IL-6 and CRP with either renal trait. Diabetes duration was a significant predictor for ln ACR but not eGFR. Conversely, age was significantly associated with eGFR but not ln ACR. Conclusions/interpretation Activation of the TNF-α system may potentially exert independent effects on ln ACR and eGFR in type 2 diabetes. Because of the study design, one may also consider the possibility that changes in these renal traits may conversely be responsible for such an inflammatory response.
    Diabetologia 12/2008; 51(12):2318-2324. DOI:10.1007/s00125-008-1162-1 · 6.88 Impact Factor
  • D Koh, V Ng, Y-H Leow, C L Goh
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    ABSTRACT: Allergy to natural rubber latex (NRL) proteins is a well-recognized health problem among subjects using protective gloves and products made of NRL. There is currently no information on NRL allergen levels in gloves used in Singapore. This study aims to quantify the amount of specific allergens (Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02) found in rubber gloves used in Singapore. It also aims to determine if these levels are above thresholds that may cause NRL allergy. It also compares the levels of these specific allergens in gloves used for different purposes, namely gloves used for examination purposes or for surgical procedures. Forty-nine rubber gloves were obtained from major hospitals and healthcare departments in Singapore and were analysed for their NRL allergen levels. FITkit, based on the enzyme immunometric assay technique, was used to determine the specific allergen levels of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 in the gloves. Examination gloves had higher NRL allergen content compared with surgical gloves, and powdered gloves had higher allergen content compared with nonpowdered gloves. Among the various allergens, Hev b 5 and Hev b 6.02 were present in larger quantities than Hev b 1 and Hev b 3. Only two of 19 (11%) surgical gloves had the sum of the four allergens (Hev b 1, Hev b 3, Hev b 5, Hev b 6.02) in excess of 1 microg g(-1), which is believed to be a clinically relevant threshold. Among the examination gloves, 25 of 30 (83%) exceeded this level. This study shows that NRL allergen levels are present in the majority of examination gloves used by healthcare workers in Singapore at levels high enough to cause NRL allergy among sensitized persons. The information can serve as evidence for a possible requirement for manufacturers to produce gloves with low NRL allergen levels and to state the allergen level in gloves in the product information.
    British Journal of Dermatology 12/2005; 153(5):954-9. DOI:10.1111/j.1365-2133.2005.06820.x · 4.10 Impact Factor
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    ABSTRACT: To assess the longitudinal changes in biometric parameters and associated factors in young myopic children aged 7--9 years followed prospectively in Singapore. Children aged 7--9 years from three Singapore schools were invited to participate in the SCORM (Singapore Cohort study Of the Risk factors for Myopia) study. Yearly eye examinations involving biometry measures were performed in the schools. Only myopic children (n=543) with 3 year follow up data were included in this analysis. The 3 year increases in axial length, anterior chamber depth, lens thickness, vitreous chamber depth, and corneal curvature were 0.89 mm, -0.02 mm, -0.01 mm, 0.92 mm, and 0.01 mm, respectively. Children who were younger, female, and who had a parental history of myopia were more likely to have greater increases in axial length. After adjustment for school, age, sex, race, parental myopia and reading in books per week, the age (p<0.001), sex (p=0.012), and parental myopia (p=0.027) remained significantly associated with the 3 year change in axial length. Reading in books per week, however, was not associated with axial length change. Children with faster rates of progression of myopia had greater increases in axial length (Pearson correlation coefficient (r)=-0.69) and vitreous chamber depth (r=-0.83). The 3 year change in axial length of Singapore children aged 7--9 years at baseline was high and greater in younger children, females, and children with a parental history of myopia. Myopia progression was driven largely by vitreous chamber depth increase.
    British Journal of Ophthalmology 12/2005; 89(11):1489-94. DOI:10.1136/bjo.2005.071118 · 2.81 Impact Factor
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    ABSTRACT: INTRODUCTION: We describe how the curriculum of community, occupational and family medicine (COFM) has evolved in response to social and educational forces and local health needs. Challenges in the teaching of the curriculum are also discussed. CURRICULUM: The COFM Department aims to produce medical undergraduates and graduates with the skills to critically appraise evidence, prevent and manage diseases, and promote health in the community and primary healthcare setting. Its teaching programmes consist of the medical undergraduate programme and the Master of Medicine programmes in Occupational Medicine, Public Health and Family Medicine. The undergraduate modules consist of evidence-based medicine, public health in the community, disease prevention and control, occupational medicine practice, health promotion and behaviour, and communication with patients. The university's first completely online module on SARS was jointly implemented by the Department and the Centre for Instructional Technology for the entire student population last year. The COFM curriculum has shifted from giving students factual information through lectures to developing students' critical thinking and problem-solving skills through small group teaching, case studies and community health projects. Innovative assessment methods such as open-book examinations; objective structured communication stations with simulated patients; and evaluation of students' participation in group work are used to assess students' skills in problem-solving, communication and teamwork respectively. CONCLUSION: While the Department has made significant progress in developing a relevant and updated curriculum based on appropriate learning and assessment approaches, it will strive to do more to develop students' critical thinking skills by using newer approaches.
    Annals of the Academy of Medicine, Singapore 08/2005; 34(6):102C-107C. · 1.22 Impact Factor
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    ABSTRACT: Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths. To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use. A self-administered questionnaire survey of 14,554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May-July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis. A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were "useful in protecting from contracting SARS". Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW's job title, reported contact with SARS patients, area of work, and Impact Events Scale scores. A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.
    Occupational and environmental medicine 08/2005; 62(7):473-7. DOI:10.1136/oem.2004.015024 · 3.23 Impact Factor
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    ABSTRACT: Epidemiological data on latex sensitisation among Asian healthcare workers is lacking. The aim of the study is to determine the rate of latex sensitisation in our healthcare workers. We recruited 313 healthcare workers, of which 46.6% were operating theatre staff and 53.4% were non-operating theatre staff. Seventy-one administrative staff served as controls. All participants answered a self-administered questionnaire relating to latex exposure and glove-related symptoms. Latex sensitisation was determined by skin prick testing to latex and latex-specific IgE detection. The prevalence of latex sensitisation among healthcare workers was 9.6%, with no difference between operating theatre and nonoperating theatre staff. Glove-related symptoms were reported in 13.7% of all healthcare workers, of which 22.9% were sensitised to latex. Only 26.7% of latex-sensitised healthcare workers had glove-related symptoms while the rest were asymptomatic. The most common symptoms were itch and hand eczema but the most important discriminating symptom was contact urticaria. Personal history of atopy was more common in sensitised healthcare workers (40.0%) compared to non-sensitised workers (31.8%). Only 1 out of 9 (11.2%) symptomatic latex-sensitised subjects had sought previous medical attention for the problem. Latex sensitisation among healthcare workers in Singapore should be considered a significant occupational health risk, as it is in the West. Increased screening and awareness of this problem is essential to identify those at risk.
    Annals of the Academy of Medicine, Singapore 07/2005; 34(5):376-82. · 1.22 Impact Factor
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    ABSTRACT: The ACE insertion/deletion polymorphism has been examined for association with diabetic nephropathy over the past decade with conflicting results. To clarify this situation, we conducted a comprehensive meta-analysis encompassing all relevant studies that were published between 1994 and 2004 and investigated this potential genetic association. A total of 14,727 subjects from 47 studies was included in this meta-analysis. Cases (n=8,663) were type 1 or 2 diabetic subjects with incipient (microalbuminuria) or advanced diabetic nephropathy (proteinuria, chronic renal failure, end-stage renal disease). Control subjects (n=6,064) were predominantly normoalbuminuric. No obvious publication bias was detected. Using a minimal-case definition based on incipient diabetic nephropathy, subjects with the II genotype had a 22% lower risk of diabetic nephropathy than carriers of the D allele (pooled odds ratio [OR]=0.78, 95% CI=0.69-0.88). While there was a reduced risk of diabetic nephropathy associated with the II genotype among Caucasians with either type 1 or type 2 diabetes, the association was most marked among type 2 diabetic Asians (Chinese, Japanese, Koreans) (OR=0.65, 95% CI=0. 51-0.83). This OR is significantly different from the OR of 0.90 (95% CI= 0.78-1.04) that was obtained for type 2 diabetic Caucasians (p=0.019). Using a stricter case definition based on advanced diabetic nephropathy, a comparable risk reduction of 24-32% was observed among the three subgroups, although statistical significance was reached only among Asians. The results of our meta-analysis support a genetic association of the ACE Ins/Del polymorphism with diabetic nephropathy. These findings may have implications for the management of diabetic nephropathy using ACE inhibitors especially among type 2 diabetic Asians.
    Diabetologia 06/2005; 48(5):1008-16. DOI:10.1007/s00125-005-1726-2 · 6.88 Impact Factor
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    ABSTRACT: We compared the salivary immunoglobulin A (IgA) and lysozyme concentration and secretion rates among mild and severe psoriasis patients and controls in Singapore. Fifty-one psoriasis patients and 24 controls participated in the study. None of the patients were on immunosuppressive therapy. The Psoriasis Area and Severity Index (PASI) was used to assess the severity of psoriasis. Patients were divided into mild and severe groups by the median PASI score. Each subject contributed a 5-minute unstimulated salivary sample. Enzyme-linked immunosorbent assay method was used to determine the salivary IgA and lysozyme levels. Psoriasis patients had lower concentration and secretion rate of IgA (geometric mean [GM], 97.5 micro g/mL and 32.3 micro g/min) and lysozyme (GM, 127.6 micro g/mL and 42.1 micro g/min) than controls (IgA GM 256.3 micro g/mL, 79.1 micro g/min; lysozyme GM 180.9 micro g/mL, 55.8 micro g/min) [P = 0.000 (IgA concentration), P = 0.000 (IgA secretion rate), P = 0.015 (lysozyme concentration) and P = 0.150 (lysozyme secretion rate)]. However, no significant differences were observed between mild and severe patients for both IgA and lysozyme concentrations and secretion rates. PASI score showed negative, but non-significant, correlations with either log salivary IgA (r = -0.22, P = 0.13) or log lysozyme (r = -0.09, P = 0.53) secretion rates. Psoriasis patients had lower concentrations and secretion rates of salivary IgA and lysozyme compared to controls. However, among patients, the salivary IgA and lysozyme levels are variable and not related to severity of psoriasis.
    Annals of the Academy of Medicine, Singapore 06/2004; 33(3):307-10. · 1.22 Impact Factor
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    ABSTRACT: Aim: To examine the association of birth parameters with biometry and refraction in Singapore Chinese schoolchildren. Chinese children aged 7-9 years (n = 1413) from three schools in Singapore were recruited. Birth parameter information on birth weight, head circumference, length at birth, and gestational age were obtained from standard hospital records. Cycloplegic autorefraction, keratometry and biometry measures (axial length, vitreous chamber depth, lens thickness, and anterior chamber depth) were obtained. Across the normal birthweight range (2.0-4.9 kg), children with birth weights > or =4.0 kg had longer axial lengths (adjusted mean 23.65 mm versus 23.16 mm), compared with children with birth weights <2.5 kg, after controlling for age, sex, school, height, parental myopia, and gestational age. For every 1 cm increment in head circumference at birth, the axial length was longer by 0.05 mm. For every 1 cm increment in birth length, the axial length was longer by 0.02 mm in multivariate analysis. Additional week increases in gestational age till 46 weeks resulted in axial lengths that were longer by 0.04 mm, controlling for age, sex, school, parental myopia, and height. Children with larger birth weights, head circumferences, birth lengths, or gestational ages had deeper vitreous chambers and larger corneal curvature radii; however, there were no significant associations with refraction. Children who were born heavier, had larger head sizes or lengths at birth, or who were born more mature had longer axial lengths, and deeper vitreous chambers; but there were no differences in refraction at ages 7-9 years, possibly because of the observed compensatory flattening of the cornea.
    British Journal of Ophthalmology 04/2004; 88(4):538-42. · 2.81 Impact Factor
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    D Koh, G Chan, E Yap
    Occupational and environmental medicine 03/2004; 61(2):180-3. · 3.23 Impact Factor
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    ABSTRACT: To study the perceived sources of stressful events in dental students and the relationship between their self-perceived stress levels and salivary IgA. Undergraduates as well as postgraduates at the Faculty of Dentistry, National University of Singapore were surveyed one month after the new term. A 38-item dental environmental stress (DES) questionnaire, with subscales of academic work (AW), clinical factors (CF), faculty and administration factors (FA) and personal factors (PF), was used to identify the potential stressors in the dental environment. A 4-point perceived stress scale was used to rank their self-perceived stress levels. Enzyme linked immunosorbent assay method was used to determine the salivary IgA level. One hundred and thirty students (81.3%--valid response rate) participated in the study. Overall, students ranked AW with the highest score (mean 2.76), followed by CF (2.67), FA (2.24) and PF (2.16). Among the 38 items of DES questionnaire, 1st year students perceived "fear of being unable to catch up if behind" as the most stressful event (mean 3.30). For 2nd and 3rd year students, examination and grades had the highest scores (mean 3.28, 3.19, respectively). Completing graduation requirements was the most important stressor for 4th year students (mean 3.89). Post graduates perceived atmosphere created by clinical faculty was most stressful to them (mean 3.05). The mean total perceived stress scores were highest (22.1) in 1st year students and lowest (21.0) in postgraduates, however, no significant different among various classes. First year students had had the lowest IgA secretion rates (geometric mean [GM] 46.8 microg/min), significantly lower (p<0.05) than postgraduates (GM 79.4 microg/min). An inverse correlation was noted between perceived stress scale and log IgA secretion rates (r= -0.20, p= 0.002). AW was also significantly inversely correlated with salivary IgA (r= -0.18, p= 0.04). Dental students in different academic years perceived different important stressors. Salivary IgA secretion rate correlated inversely with self perceived stress.
    International journal of immunopathology and pharmacology 01/2004; 17(2 Suppl):49-56. · 2.51 Impact Factor
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    ABSTRACT: Measurement of blood lead (BPb) is the usual method for biomonitoring of persons exposed to inorganic lead. To explore the use of salivary lead (SPb) as an alternative. BPb and SPb levels were measured in a group of 82 lead exposed adults. The mean BPb of the workers was 26.6 microg/dl (SD 8.6, range 10-48) and the mean SPb level 0.77 microg/dl, or 3% of the BPb level. As the SPb distribution was skewed, logarithmic transformation was performed to normalise the distribution. A bivariate scattergram of BPb and logSPb (r = 0.41, p = 0.00) had a line of best fit expressed as BPb = 29.7 + 8.95logSPb. The relation of logSPb and BPb was stronger among non-smokers (r = 0.42) compared to smokers (r = 0.3); and among those without a medical condition (r = 0.44). Multiple linear regression analysis (fitting smoking and medical condition into the model) yielded an R of 0.54, and an adjusted R(2) of 0.26. The study findings do not support the use of SPb for biomonitoring at BPb levels ranging from 10 to 50 microg/dl.
    Occupational and Environmental Medicine 10/2003; 60(9):696-8. DOI:10.1136/oem.60.9.696 · 3.23 Impact Factor
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    ABSTRACT: To determine the prevalence rates and major contributing causes of low vision and blindness in adults in a rural setting in Indonesia A population based prevalence survey of adults 21 years or older (n=989) was conducted in five rural villages and one provincial town in Sumatra, Indonesia. One stage household cluster sampling procedure was employed where 100 households were randomly selected from each village or town. Bilateral low vision was defined as habitual VA (measured using tumbling "E" logMAR charts) in the better eye worse than 6/18 and 3/60 or better, based on the WHO criteria. Bilateral blindness was defined as habitual VA worse than 3/60 in the better eye. The anterior segment and lens of subjects with low vision or blindness (both unilateral and bilateral) (n=66) were examined using a portable slit lamp and fundus examination was performed using indirect ophthalmoscopy. The overall age adjusted (adjusted to the 1990 Indonesia census population) prevalence rate of bilateral low vision was 5.8% (95% confidence interval (CI) 4.2 to 7.4) and bilateral blindness was 2.2% (95% CI 1.1 to 3.2). The rates of low vision and blindness increased with age. The major contributing causes for bilateral low vision were cataract (61.3%), uncorrected refractive error (12.9%), and amblyopia (12.9%), and the major cause of bilateral blindness was cataract (62.5%). The major causes of unilateral low vision were cataract (48.0%) and uncorrected refractive error (12.0%), and major causes of unilateral blindness were amblyopia (50.0%) and trauma (50.0%). The rates of habitual low vision and blindness in provincial Sumatra, Indonesia, are similar to other developing rural countries in Asia. Blindness is largely preventable, as the major contributing causes (cataract and uncorrected refractive error) are amenable to treatment.
    British Journal of Ophthalmology 10/2003; 87(9):1075-8. DOI:10.1136/bjo.87.9.1075 · 2.81 Impact Factor
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    ABSTRACT: There has been an alarming recent increase in skin cancer incidence among fair-skinned populations. Information from Asian populations is less readily available. This study examines time trends and ethnic differences of skin cancers among Asians in Singapore. Data from 1968 to 1997 was obtained from the Singapore Cancer Registry, a population-based registry. Age-standardized incidence rates (ASRs) and age-adjusted average annual percentage change, using the Poisson regression model, were calculated. A total of 2650 basal cell carcinomas (BCCs), 1407 squamous cell carcinomas (SCCs) and 281 melanomas were reported. There was an overall increase of skin cancer from 6.0 per 100000 person years (1968-72) to 8.9 per 100000 person years (1993-97). BCC incidence increased 3% annually, melanoma remained constant, and SCC decreased 0.9% annually. BCC ASRs were highest among Chinese, then Malays and Indians. A similar pattern was noted for SCC and melanomas. The incidence rates of skin cancer increased in Singapore during the period 1968-97. Fairer-skinned Chinese had a higher incidence of skin cancer.
    British Journal of Dermatology 07/2003; 148(6):1161-6. DOI:10.1046/j.1365-2133.2003.05223.x · 4.10 Impact Factor
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    ABSTRACT: To ascertain the utility values of myopic teenage students in Singapore. Children (n=699) aged 15-18 years with myopia (spherical equivalent (SE) at least -0.5 dioptres (D)) in two high schools in Singapore were recruited. Information on time trade-off (years of life willing to sacrifice for treatment of myopia) and standard gamble for blindness (risk of blindness from therapy willing to sacrifice for treatment of myopia) utility values, demographic, and socioeconomic status data were obtained. The time trade-off and standard gamble for blindness utility values were 0.93 (95% confidence interval (CI) 0.93 to 0.94) and 0.85 (95% CI 0.84 to 0.86), respectively. Children with presenting better eye logMAR visual acuity >0.3 had lower time trade-off utility values (mean 0.92 versus mean 0.94), after adjusting for race and sex. There were dose-response relations between standard gamble for blindness values and total family income, as well as both utility values and educational stream (all p values for trend <0.01), after controlling for the same factors. The utility values in myopic students were higher for teenagers with better presenting visual acuity, children who wore spectacles or contact lenses, higher total family income, more "academic" schooling stream, and who were non-Muslims.
    British Journal of Ophthalmology 04/2003; 87(3):341-5. DOI:10.1136/bjo.87.3.341 · 2.81 Impact Factor
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    ABSTRACT: To assess and compare the self perceived work related stress among emergency department (ED) and general ward (GW) nurses, and to investigate its relation with salivary IgA and lysozyme. One hundred and thirty two of 208 (63.5%) registered female ED and GW nurses participated in the study. A modified mental health professional stress scale (PSS) was used to measure self perceived stress. ELISA methods were used to determine the salivary IgA and lysozyme levels. On PSS, ED nurses had higher scores (mean 1.51) than GW nurses (1.30). The scores of PSS subscales such as organisational structure and processes (OS), lack of resources (RES), and conflict with other professionals (COF) were higher in ED than in GW nurses. ED nurses had lower secretion rates of IgA (geometric mean (GM) 49.1 micro g/min) and lysozyme (GM 20.0 micro g/min) than GW nurses (68.2 micro g/min, 30.5 micro g/min). Significant correlations were observed between PSS and log IgA and lysozyme secretion rates. OS, RES, and COF were correlated with log IgA and lysozyme levels. ED nurses, who reported a higher level of professional stress, showed significantly lower secretion rates of salivary IgA and lysozyme compared to GW nurses. Salivary IgA and lysozyme were inversely correlated with self perceived work related stress. As these salivary biomarkers are reflective of the mucosal immunity, results support the inverse relation between stress and mucosal immunity.
    Occupational and Environmental Medicine 01/2003; 59(12):836-41. DOI:10.1136/oem.59.12.836 · 3.23 Impact Factor
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    ABSTRACT: To determine prevalence rates, severity, and risk factors for pterygium in adults in provincial Indonesia and to validate a clinical grading scheme in a population based setting. A population based prevalence survey of 1210 adults aged 21 years and above was conducted in five rural villages and one provincial town in Riau province, Sumatra, Indonesia, an area near to the equator. A one stage household cluster sampling procedure was employed: 100 households were randomly selected from each village or town. Pterygia were graded for severity (T1 to T3, by visibility of episcleral vessels) and the basal and apical extent measured by an ophthalmologist (GG) with a hand held slit lamp. Refraction was measured by hand held autorefractor (Retinomax). Face to face household interviews assessed outdoor activity, occupation, and smoking. The participation rate was 96.7%. The mean age was 36.6 years (SD 13.1), 612 were male. The age adjusted prevalence rate of any pterygium was 10.0% (95% confidence intervals (CI) 8.2 to 11.7) and of bilateral pterygia was 4.1% (95% CI 2.9 to 5.3). There was a significant dose-response relation with age (2.9% (95% CI 0.4 to 5.8) for 21-29 years versus 17.3% (95% CI 10.4 to 24.2) 50 years and above; p for trend <0.001) and occupations with more time outdoors (p for trend = 0.02). This was true for both sexes, all grades of lesion (T1 to T3), and bilateral disease. A multivariate logistic regression model showed pterygium was independently related to increasing age and outdoor activity 10 years earlier. The mean basal diameter = 3.3 mm (SD 1.51, range 0.1-9.5) and extent from limbus = 1.4 mm (SD 1.18, range 0.1-8.0). Higher grade pterygia were larger for basal and apical extent (p for trend <0.001). The presence of pterygium was associated with astigmatism (defined as cylinder at least -0.5 dioptres (D); p <0.001). This association increased with increasing grade of lesion (p for trend <0.001). Median cylinder for those with pterygium (-0.50 D) was greater than for those without (-0.25D), (p <0.001), and increased with higher grade of lesion (p for trend <0.001). For eyes with pterygia, magnitude of astigmatism was associated with greatest extent from the limbus, (p = 0.03), but not basal width (p = 0.99). There is a high prevalence rate of pterygia in provincial Sumatra. The independent increase with age and past outdoor activity (a surrogate for sun exposure) is consistent with previous findings. Clinical grading of pterygium morphology by the opacity of the lesion was a useful additional marker of severity.
    British Journal of Ophthalmology 12/2002; 86(12):1341-6. · 2.81 Impact Factor

Publication Stats

1k Citations
174.35 Total Impact Points

Institutions

  • 2005
    • National Skin Centre
      Tumasik, Singapore
  • 2003
    • Tan Tock Seng Hospital
      Tumasik, Singapore
    • Changi General Hospital
      • Department of Accident and Emergency
      Tumasik, Singapore
  • 1998–2003
    • National University of Singapore
      • Saw Swee Hock School of Public Health
      Singapore, Singapore
  • 2002
    • Singapore National Eye Centre
      Tumasik, Singapore
  • 1990–1992
    • University of Birmingham
      Birmingham, England, United Kingdom
    • National Institute for Occupational Health
      Johannesburg, Gauteng, South Africa