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Biomedical subjects

S E Chia

Publications and source records attributed to S E Chia.

At least 19 recordsLinked to original sources
PubMed2005

Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore.

BACKGROUND: 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. AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSION: A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.

Administrative Personnel↗
PubMed2003

Parental occupations and other risk factors associated with nonchromosomal single, chromosomal single, and multiple birth defects: a population-based study in Singapore from 1994 to 1998.

OBJECTIVE: The purpose of this study was to evaluate the association between the prevalence of birth defects among maternal and paternal occupation groups in Singapore for live births between January 1, 1994, and December 31, 1998, and to determine whether there are certain demographic risk factors and maternal and/or paternal occupation groups that are associated with an increased risk for birth defects versus chromosomal single birth defect, nonchromosomal single birth defect, and multiple birth defects. STUDY DESIGN: This was a retrospective study. Information on live births (Singapore National Registry of Births and Deaths) and birth defect cases (National Birth Defects Register) were studied. Other information included the mother's date of birth, ethnic group, highest educational qualification, and the occupation of the mother and the father. Cox regression analysis was used to determine whether certain demographic and occupational factors were associated with the three groups of birth defects. RESULTS: Of a total of 237,755 live births, there were 3276 birth defect cases (nonchromosomal single birth defect, 1869 cases; chromosomal single birth defect, 197 cases; and multiple birth defects, 1210 cases). Increased risks for all types of birth defects were observed with advancing gestational age. Occurrence of nonchromosomal single birth defect and multiple birth defects were significantly higher for multiple births compared to singleton births. Significant associations were found with the use of "legislators, senior officers, and managers" as reference: Maternal occupation of "cleaners, laborers, and related workers" with chromosomal single birth defect anomalies (adjusted risk ratio, 4.86; 95% CI, 1.07-22.14); paternal occupation of "plant and machine operators and assemblers" (adjusted risk ratio, 1.50; 95% CI, 1.14-1.98) with nonchromosomal single birth defect; "production craftsmen and related workers" and "cleaners and laborers and related workers" with nonchromosomal single birth defect (adjusted risk ratio, 1.42; 95% CI, 1.10-1.82; and adjusted risk ratio, 1.43; 95% CI, 1.07-1.91 respectively); and multiple birth defects (adjusted risk ratio, 1.42; 95% CI, 1.03-1.94; and adjusted risk ratio, 1.47; 95% CI, 1.03-2.09, respectively). CONCLUSION: Maternal delivery age is an important risk factor for all birth defects. Mothers and fathers who work as "cleaners and laborers and related workers" appear to have a higher risk of giving birth to children with chromosomal single birth defect and nonchromosomal single birth defect and multiple birth defects, respectively. Further in-depth study would be needed to confirm these observations.

Abnormalities, Multiple↗
PubMed2003

Can salivary lead be used for biological monitoring of lead exposed individuals?

BACKGROUND: Measurement of blood lead (BPb) is the usual method for biomonitoring of persons exposed to inorganic lead. AIM: To explore the use of salivary lead (SPb) as an alternative. METHODS: BPb and SPb levels were measured in a group of 82 lead exposed adults. RESULTS: 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. CONCLUSION: The study findings do not support the use of SPb for biomonitoring at BPb levels ranging from 10 to 50 microg/dl.

Adult↗
PubMed2002

Prevalence of birth defects and parental work in Singapore live births from 1994 to 1998: a population-based study.

The aims of the study were to assess the prevalence of birth defects (BDs) among different occupational groups and non-working parents, and to identify possible risk factors associated with BDs in Singapore live births born between 1 January 1994 and 31 December 1998. To do this, information on live births (from the Singapore National Registry of Births and Deaths) and BD cases [from the National Birth Defects Register (NBDR)] was obtained from 1 January 1994 to 31 December 1998. There were a total of 237 755 live births in Singapore between 1 January 1994 and 31 December 1998. Over the same period, 3293 cases of BDs were reported to the NBDR, giving an overall rate of 13.9 per 1000 live births. A downward trend with time was noted. Of the live born with BDs in this series, 36.7% presented with multiple anomalies. The overall occurrence of malformation (per 1000 live births) among working versus non-working mothers was 13.4 versus 14.2, respectively, and 13.8 for working fathers compared with 16.8 for non-working fathers. Parents in the occupational group 'Legislators, Senior Officers & Managers' had the lowest prevalence rates of congenital anomalies (9.4 per 1000 for mothers and 10.3 per 1000 for fathers), while the 'Agricultural & Fishery Workers' had the highest rates (40.0 per 1000 for mothers and 23.4 per 1000 for fathers). However, the very small number of workers in this latter group makes the rate unreliable. The prevalence of BDs in Singapore is comparable to those in other countries. Parental work per se is not correlated with BDs.

Adult↗
PubMed2002

Self perceived work related stress and the relation with salivary IgA and lysozyme among emergency department nurses.

AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Adult↗
PubMed2002

Effluents from a pulp and paper mill: a skin and health survey of children living in upstream and downstream villages.

OBJECTIVES: A health survey of three villages (upstream village Rantau Baru and two downstream villages, Sering and Pelalawan) in the vicinity of a pulp and paper mill along the Kampar river in the province of Riau, Indonesia was conducted to find whether exposure to the effluents from the mill was related to skin conditions and ill health. METHODS: A cross sectional survey was carried out of children living in the three villages. RESULTS: Common skin conditions such as dermatitis, fungal infections, insect bites, and miliaria were found. No significantly increased risk of dermatitis or any illness in general was found with increasing levels of exposure to river water for downstream villages when compared with the upstream village. However, there was an increased risk of diarrhoea in Sering especially with drinking water directly from the river (prevalence rate ratio (PRR) 4.9, 95% confidence interval (95% CI) 0.4 to 63.9). An increased risk was also found within the upstream village Rantau Baru (PRR 2.3, 95% CI 0.9 to 5.8) and downstream village Sering (PRR 1.4, 95% CI 0.4 to 5.2) when children who drank water directly from the river were compared with those who never did. Analysis of the river water also showed physical and chemical variables within the acceptable range except for faecal coliforms (6 MPN/100 ml) found in the sample taken from Sering. CONCLUSIONS: The effluent from the mill is unlikely to be causing skin conditions and ill health. Diarrhoea may be due to faecal coliform contamination of the water because all raw sewerage is deposited in the river. Community health outreach programmes are being implemented based on these findings.

Child↗
PubMed2001

Monthly variation in human semen quality in male partners of infertile women in the tropics.

The aim of the study was to determine whether there were significant 'seasonal' variations in the rhythm of sperm parameters (i.e. semen volume and sperm density) of men who reside in the tropics. A total of 7656 semen analysis results from the department of obstetrics and gynaecology of a tertiary general hospital was analysed. These samples were obtained as part of an initial screening for male partners of couples with problems trying to conceive who were attending a fertility clinic from 1991 to 1995. The subjects' mean semen volume and sperm density of 2.9 ml and 26.9x10(6)/ml respectively were within the World Health Organization reference values. There were no significant month-to-month variations in the adjusted (for age of subject, year of test and technologist who performed the analysis by analysis of co-variance, ANCOVA) mean semen volume and sperm density over the 5 year period. Variations in semen volume and density observed in the temperate climates are not seen in this study, which was conducted in subjects staying in the tropics. This observation may be related to relative constant temperature and hours of light exposure among men who reside in the tropics. As this study is, so far, published data from only one country, Singapore, it may not truly reflect the actual situation for individuals who are residing in the tropics.

Adult↗
PubMed2001

A review of studies on maternal occupational exposures and birth defects, and the limitations associated with these studies.

The proportion of pregnant women who work during pregnancy is increasing as more women move into previously male-dominated occupations. With this move, occupational exposure to chemical or physical factors during pregnancy could be further increased. In the last decade, there have been many reports on the causes of birth defects. Unfortunately, most reported associations between occupational exposures and adverse reproductive outcomes in epidemiological studies are equivocal and often controversial. Many reported associations are only suggestive. More information is needed before firm conclusions can be drawn. The major reasons for ambiguous findings are due to limitations of study methodology, e.g. inappropriate endpoints, multiple confounders, low study power and inadequate analysis methods. It must also be noted that maternal work, and therefore exposure, may also differ greatly from country to country.

Bias↗
PubMed2001

Occupational risk for male infertility: a case-control study of 218 infertile and 227 fertile men.

The aim of the study was to determine if certain occupations pose an increased risk for infertility (of no known cause) among a group of infertile men compared with a group of fertile men. A total of 640 consecutive men whose spouses were unable to conceive were recruited from an infertility clinic. Of these, 218 men (cases) were found to have no known cause for their infertility. A total of 227 men whose spouses were pregnant at the time of the study were recruited as controls. The Singapore Standard Occupational Classification was used to code the subjects' occupations. Semen parameters (density, total sperm counts, motility, viability, and normal morphology) in all of the cases were significantly poorer than those in the controls. The risk for infertility is associated with smoking adjusted odds ratio (OR) 2.85 and 95% confidence interval (CI) 1.91 to 4.24. Work, independently, is not a risk factor for infertility. Engineering technicians (adjusted OR, 2.75; 95% CI, 1.36 to 5.54), finance analysts (adjusted OR, 4.66; 95% CI, 1.90 to 11.40), corporate and computing managers (adjusted OR, 2.49; 95% CI, 1.04 to 5.98), and teachers (adjusted OR, 7.72; 95% CI, 1.86 to 32.10) were at a greater risk of infertility compared with "services and clerical workers." Using services and clerical workers as a reference group, certain occupations are at a higher risk for infertility. Higher work demands and possible electromagnetic field exposure could be contributory factors for infertility.

Adult↗
PubMed2001

Salivary cortisol levels and work-related stress among emergency department nurses.

The objective of this study was to assess and compare the self-perceived work-related stress of emergency department (ED) and general ward (GW) nurses and to assess the relationship between self-perceived stress and salivary cortisol levels in these groups of nurses. Seventy-three female ED (n = 23) and GW (n = 50) nurses from a general hospital completed a self-administered questionnaire. A modified mental health professional stress scale (PSS) was used to measure self-perceived work-related stress. Salivary samples were collected at the start and end of morning shiftwork. An enzyme-linked immunosorbent assay method was used to determine the salivary cortisol concentration (nmol/L). ED nurses perceived that nursing was more stressful (mean, 1.58; 95% confidence interval [CI], 1.35 to 1.81) than did GW nurses (mean, 1.30; 95% CI, 1.18 to 1.40). On the PSS subscales, scores of organizational structure and process, lack of resources, and conflict with other professionals were higher in ED nurses (all P < 0.01). The morning cortisol was significantly lower in ED (geometric mean, 9.10; 95% CI, 6.62 to 12.42 nmol/L) than in GW (geometric mean, 15.45; 95% CI, 11.86 to 20.14 nmol/L) nurses. Log morning salivary cortisol was negatively correlated with PSS (r = -0.255), scores of organizational structure and process, and conflict with other professionals (all P < 0.05). The difference between morning and afternoon cortisol concentration in ED nurses (geometric mean, 6.35; 95% CI 4.14 to 9.93 nmol/L) was lower than in GW nurses (geometric mean, 12.42; 95% CI, 9.38 to 16.28 nmol/L). The log value of the difference correlated marginally with PSS (r = -0.21, P = 0.07) and significantly with scores of organizational structure and process, lack of resources, and conflict with other professionals (all P < 0.05). There was no difference between the two groups in afternoon salivary cortisol level. ED nurses perceived more stress compared with GW nurses. Morning salivary cortisol concentration is better correlated with PSS compared with the morning-afternoon salivary cortisol difference. The result raises the possibility of using a single morning salivary cortisol sample to reflect self-perceived stress.

Adult↗
PubMed2001

[Comparison of seminal vitamin B12, folate, reactive oxygen species and various sperm parameters between fertile and infertile males].

Vitamin B12(VB12), folate and reactive oxygen species(ROS) in human semen from both fertile and infertile males, and their relationships with other parameters were observed. Semen samples from 44 infertile and 176 fentile control subjects were collected and measured based on the guidelines issued by WHO. The results showed that no significant differences on semen VB12 and folate were observed between fertile and infertile groups(P > 0.05). However, the levels of ROS in infertile group were significantly higher than those in fertile group(P < 0.01). The morphological defects and low motility of sperm in infertile group was significantly higher than those in fertile group(P < 0.01). A positive relation was observed between the levels of ROS production and the morphological defect of sperm(P < 0.01). There was a significant negative correlation between the levels of VB12, folate and ROS(P < 0.01) in semen. It is interesting to note that the values of ROS also show a significantly positive correlation with sperm motility (P < 0.01). A significant differences of ROS levels between fertile and infertile group with negative white blood cells in sperm was also observed. It is concluded that the increase of ROS on the morphological defect of sperm is one of the most important factors related to poor sperm quality and human infertility.

Adult↗
PubMed2000

Endocrine disruptors and male reproductive function--a short review.

Semen quality has decline in many countries over the last few decades. There has been an increase in the incidence of testicular cancer world-wide. The incidences of cryptorchidism and hypospadias have also increased in many countries. A biological plausible hypothesis has suggested that man-made chemicals act as endocrine disruptors resulting in altered development of the reproductive tract causing the observed effects. Endocrine disruptors include natural products, pharmaceuticals, industrial products and environmental pollutants. There are limitations in the current in vivo and in vitro assays for the assessment of endocrine disruptors. Epidemiological human studies are necessary to fill in the gap of knowledge. Based on the current knowledge, the impact of endocrine disruptors on the male reproductive function remain to be appreciated.

Cryptorchidism↗
PubMed2000

A South-East Asian perspective.

In order to discuss the subject of occupational medicine in the next century, changes in the present demographic profile and work activity must be considered first. Only then can the challenges be identified, and appropriate strategies be formulated to respond to them. In the diverse countries of South-East Asia, improved health and work conditions, the advent of new technology, a redistribution of work activity, and an ageing workforce can be expected. Two other factors that have specific impact in the region are the recent financial crisis and the occurrence of an international environmental haze from forest fires. The various countries in South-East Asia, which are in different stages of development, and have different problems and priorities, will respond differently to the demands for occupational health. It is likely that there will be a shift in the focus of current health care activities towards specific work sectors, the recognition of new hazards at work, the identification of newly emerging work related diseases, and an increase in health promotion in the workplace. Hopefully, there will be improved training of health professionals to ensure that there are adequate numbers and that they are well prepared to face these changes. Responsive, appropriate and well enforced labour legislation to protect the health of all workers, and international cooperation in occupational and environmental health are also required. As global and regional economic conditions continue to remain unstable and the impact of the crisis further takes its course, the final effect on occupational health in South-East Asia remains to be seen.

Asia, Southeastern↗
PubMed2000

Factors associated with male infertility: a case-control study of 218 infertile and 240 fertile men.

OBJECTIVE: To determine the likely risk factors, such as smoking and drinking habits, and occupational groups, for infertility in a group of infertile men with no known cause, compared with a group of fertile men; and to examine the effects of the semen parameters, such as volume, density, motility, viability and normal morphology, on fertility. DESIGN: A case-control study. SETTING: The department of obstetric and gynaecology of a tertiary general hospital. PARTICIPANTS: Six hundred and forty consecutive male partners of couples trying to conceive were recruited from an infertility clinic. Of these, the cases comprised 218 men who had no known cause for their infertility. Two hundred and forty men whose wives were pregnant at the time of the study were recruited as controls. RESULTS: The semen parameters (e.g. density, total sperm counts, motility, viability and normal morphology) of all cases were significantly poorer than that of the controls. The risk of infertility is associated with smoking (crude OR 2 x 82, 95% CI 1 x 93-4 x 13; adjusted OR 2 x 96; 95% CI 1 x 98-4 x 42). Technicians (adjusted OR 2 x 81; 95% CI 1 x 51-4 x 24) and professional, senior officials and managers were also at a greater risk of infertility (adjusted OR 2 x 36; 95% CI 1 x 26-4 x 40), compared with service and clerical workers. The significant factors predicting infertility were smoking, density of sperm, and viability of sperm. Smoking increased the odds of being infertile. Higher sperm counts and larger percentage of viable sperm decrease the odds of infertility. Based on the multiple logistic regression model, the odds ratio for infertility = (94 x 70) x (2 x 88(smoking)) X (0 x 29(logdensity)) X (0 x 95(viability)). CONCLUSION: Smoking, density of sperm and the viability of sperm are significant predictors for infertility among men.

Adult↗
PubMed2000

Prevalence of headache among handheld cellular telephone users in Singapore: a community study.

We carried out a cross-sectional community study in Singapore to determine the prevalence of specific central nervous system (CNS) symptoms among hand-held cellular telephone (HP) users compared to nonusers and to study the association of risk factors and CNS symptoms among HP users. A total of 808 men and women between 12 and 70 years of age, who lived in one community, were selected using one-stage cluster random sampling and responses to a structured questionnaire. The prevalence of HP users was 44.8%. Headache was the most prevalent symptom among HP users compared to non-HP users, with an adjusted prevalence rate ratio of 1.31 [95% confidence interval, 1.00-1.70]. There is a significant increase in the prevalence of headache with increasing duration of usage (in minutes per day). Prevalence of headache was reduced by more than 20% among those who used hand-free equipment for their cellular telephones as compared to those who never use the equipment. The use of HPs is not associated with a significant increase of CNS symptoms other than headache.

Adolescent↗
PubMed1999

Relation between work and myopia in Singapore women.

BACKGROUND: Work and related activities may be connected to myopia development and progression. We investigated the relationship between working activities and the onset as well as worsening of myopia. METHODS: Information on the working status of the mothers of 374 children, the number of hours of close-up work activity, and whether the mother was short-sighted, was obtained by a face-to-face interview. In addition, a subsample of 84 mothers was interviewed over the telephone and asked whether the myopia occurred in adulthood and, if so, the age of cessation of myopia. RESULTS: The adjusted odds ratio for myopia in working women was 1.9 [95% confidence interval (CI) 1.2 to 3.2] and the adjusted odds ratio for high myopia (> -6.0 D) was 1.6 (95% CI 0.8 to 3.0). Women who were working also had higher rates of adult-onset myopia, odds ratio 4.4 (95% CI 0.9 to 21.2), and a later age of cessation of myopia than nonworking women. CONCLUSIONS: In our study, work was related to myopia in Singapore women. Work may be a surrogate for another risk factor, close-up work activities such as reading, writing, and computer use.

Adolescent↗
PubMed1999

Are salivary immunoglobulin A and lysozyme biomarkers of stress among nurses?

Salivary immunoglobulin A (IgA) and lysozyme have been studied as possible biomarkers of stress. This study examined the stress levels among female nurses in various units and the relationship between these stress levels and salivary IgA and lysozyme secretion. One hundred ninety-five (43%) of 457 eligible female nurses from surgical wards/operating theaters (SURG), medical wards (MED), and outpatient clinics/day-surgery theaters (OPD) completed a self-administered questionnaire. From this group of 195 nurses, 124 provided a salivary sample accumulated over 5 minutes. Stress levels were assessed with a ten-point Stress Assessment Score (SAS) for Asians and a direct question on perceived life stress. Enzyme-linked immunosorbent assay and lyso-plate methods were used to determine salivary IgA and lysozyme levels. Forty-five percent of SURG, 35% of MED, and 17% of OPD nurses scored at least four points on the SAS. SURG nurses had the lowest IgA secretion (geometric mean; 95% confidence interval [CI]) rates (43 micrograms/min; 36 to 51 micrograms/min). The other groups had significantly higher salivary IgA secretion rates: MED (96 micrograms/min; 80 to 116 micrograms/min) and OPD (77 micrograms/min; 60 to 98 micrograms/min) Findings for salivary lysozyme (microgram/min) were similar; SURG (9 micrograms/min; 6 to 13 micrograms/min) MED (19 micrograms/min; 12 to 28 micrograms/min) and OPD (16 micrograms/min; 9 to 28 micrograms/min). The salivary IgA (Spearman's r = -0.22, P = 0.01) but not the lysozyme (Spearman's r = -0.01, P = 0.9) secretion rate correlated negatively with SAS. Nurses working in various units under different conditions experienced dissimilar levels of stress. Salivary IgA, but not lysozyme, correlated inversely with self-reported levels of stress. It may thus be a potential biomarker in future studies on stress.

Adult↗