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Biomedical subjects

W O Phoon

Publications and source records attributed to W O Phoon.

At least 55 records · Page 3Linked to original sources
PubMed1987

Survey of acute pesticide poisoning among agricultural workers in four Asian countries.

The study investigated the extent of acute pesticide poisoning in selected agricultural communities in Indonesia, Malaysia, Sri Lanka and Thailand, as well as the contributing factors, because it is believed that this type of poisoning is a major problem in developing countries, but not in the industrialized countries, despite their extensive use of pesticides. The study confirmed the existence of this problem, which was found to be due to inadequate knowledge of the safe practices in the use of pesticides among users and to the lack of suitable protective clothing for use by agricultural workers in hot and humid climates.

Acute Disease↗
PubMed1987

Effects of ageing on taxi driving.

The effects of ageing on taxi driving were studied on 256 drivers from the largest taxi co-operative in Singapore. 123 of the drivers were below 45 years (28-44 yrs.) while the other 133 were 45 years or older (45-63 yrs.). The older drivers had a significantly higher prevalence of glucosuria (p less than 0.05) and poor visual acuity (p less than 0.01). In addition, 31.6% of the older drivers had elevated blood pressure as compared to 21.9% of the younger drivers. Psychophysiological test scores for mean reaction times (p less than 0.01), psychomotor dexterity and eye-hand co-ordination (p less than 0.01) and reaction discrimination errors (p less than 0.05) were also significantly poorer for the older drivers. In spite of these findings, the working hours, the average mileage driven, and the accident records of the older drivers were comparable to that of the younger drivers, thus suggesting that age does not play a major role in affecting the work capacity or accident liability of the drivers.

Accidents, Traffic↗
PubMed1987

Mental status of residents in old people's homes.

As part of an intensive survey of institutionalized elderly in 5 non-government homes for the aged in Singapore, mental health assessment of the residents was carried out systematically. Among 359 respondents, 30.1% often felt sad or cried often. Sleep disturbances affected 47.7% of the total respondents. Females were more prone to both depression and insomnia even after controlling for age difference; about 50% of the females aged 60-74 years and 70% of the females aged 75 years and above had frequently experienced these problems. A review of the literature on mental health and suicidal behaviour among the elderly is also presented.

Aged↗
PubMed1987

Influence of age on VDU work.

This study was conducted in a data processing centre with intensive work load. The keying speed and typing errors were monitored daily by the management for performance appraisal. The average keying speed of the operator was about 10,000 key strokes per hour. A survey on the subjective symptoms and feelings of fatigue of 68 experienced data entry operators revealed that there was no significant difference as far as physical health was concerned for the 42 young(18-30 years old) and 26 older operators (31-45 years old). However, there was a higher prevalence of visual strain and musculo-skeletal complaints among the older workers. A follow up study on the performance of 22 operators for 5 years showed that there was a significant reverse correlation between age and keying speed, r = 0.74 (p less than 0.01). A lower but significant correlation was also noted for typing errors and age, r = 0.50, (p less than 0.05). These results suggest that age has a significant influence on speed, accuracy and health of VDU operators. When discussing the ergonomics approach to VDU work, attention must be paid to the effect of this factor.

Adult↗
PubMed1987

Transit time analysis of the forced expiratory spirogram of fire-fighters.

Analysis of the forced expiratory spirogram using time as the primary variable had been shown to be a promising method for detecting small airway dysfunction. This paper describes its application on 277 fire-fighters. Spirometry was performed when the fire-fighters were at rest and had not been fighting fires for the previous 24 hours. The best of three spirograms were used to compute the mean transit time (MTT). Through multiple linear regression analysis, age was the only factor that was significantly associated with MTT. The regression coefficients for age of smoking and non-smoking fire-fighters were nearly equal (0.011 and 0.010 seconds per year respectively). When 28 pairs of smoking and non-smoking fire-fighters were matched for age, duration of service, ethnicity and job groups, their average MTT were not significantly different. An increasing age-adjusted mean MTT was seen among the non-smoking fire-fighters with job groups requiring greater exposure to fire-fighting. Normal smokers had been shown to have a much greater regression coefficient for age on MTT when compared to normal nonsmokers. When compared with this study, the regression equation for MTT of non-smoking fire-fighters differed markedly from that of normal non-smokers and approached that of normal smokers. Coupled with the 'dose-response' relationship shown in the non-smoking fire-fighters, this study provides evidence of pulmonary dysfunction in fire-fighters. This pulmonary dysfunction may be localised in the small airways.

Adult↗
PubMed1986

Blood cholinesterase levels among agricultural workers in four Asian countries.

In this study whole blood cholinesterase activities were determined (tintometric method) of agricultural pesticide users exposed to organophosphorus compounds in Indonesia, Malaysia, Sri Lanka and Thailand. Analysis of the data demonstrated a universal relationship between cholinesterase levels and the time between the last exposure to organophosphorus compounds and the day of blood collection for cholinesterase determination. It is suggested that it takes approximately 5 days before whole blood cholinesterase levels revert to their normal values. No relationship between whole blood cholinesterase levels and the sex of pesticide users was demonstrated except in Sri Lanka where female sprayers had lower values. It is suggested that these lower values are associated with the anaemic status of female agricultural workers. No relationship between whole blood cholinesterase level and age was demonstrated. The measurement of pre-exposure cholinesterase values is essential for comparison of values after pesticide application.

Adult↗
PubMed1986

Neuropsychological studies on lead workers in Singapore.

The neuropsychological performance of a group of 49 workers occupationally exposed to lead was compared with a matched control group of 36 non-exposed workers. The psychometric measurements were composed of tests covering a broad range of different neuropsychological functions, particular emphasis being given to perceptual motor ability and attention concentration functioning. A questionnaire to assess subjective symptoms in mood, sleep disturbance, poor concentration and forgetfulness, somatic complaints, and social passivity was also included in the battery of tests. Compared with the controls, the performance of the lead workers was found to be significantly poorer for digit symbol, Bourdon-Wiersma, trail making test (part A), Santa Ana test, flicker fusion, and simple reaction time. In terms of subjective symptoms the exposed group also reported significantly more complaints of anxiety and depressed mood, poor concentration and forgetfulness, and other somatic complaints. These differences were observed among lead workers with a mean blood lead value of 2.35 mumol/l (SD 0.7).

Adult↗
PubMed1985

Dermatitis in small-scale metal industries.

A survey in 21 small metal factories in Singapore revealed that 6.6% of 751 workers (530 male, 221 female) had a skin disorder on their hands and arms. Dermatitis accounted for 4.5% (34 cases) and follicular rashes for 1% (8 cases). Positive patch tests were found in 23% (8 cases) of those with dermatitis and in 9.8% (21 workers) of a control group without any skin problem. Dermatitis was found to be associated with exposure to solvents. Simultaneous analysis of various exposure/risk factors by multiple logistic regression indicated a significant effect of combined exposure to oils and solvents (interaction). Being over 35 years of age was also a significant risk factor, whereas the rôle of contact allergy, detected by patch testing, was less pronounced.

Adolescent↗
PubMed1985

Concentrations of lead in maternal blood, cord blood, and breast milk.

Lead concentrations in maternal blood, umbilical cord blood, and breast milk from 114 women who were not occupationally exposed to lead were determined by graphite atomic absorption spectrophotometry. The mean concentrations of lead in maternal blood, umbilical cord blood and breast milk were 0.7, 0.55, and 0.23 mumol/l, respectively. A significant correlation was observed between maternal and umbilical cord blood (r = 0.63). A lower correlation was noted between maternal blood and breast milk (r = 0.29). These results suggest that lead freely crosses the placental barrier from mother to fetus and the transfer of this heavy metal from maternal tissues to breast milk is possible, but the metabolic mechanisms are more complicated. In addition, a longitudinal study was conducted of concentrations of lead in breast milk in nine lactating women. Results suggested no significant change in the content of lead in breast milk during early lactation.

Female↗
PubMed1985

Neurophysiological studies on workers exposed to lead.

Nerve conduction and somatosensory evoked potential studies were undertaken on 46 workers exposed to a combination of organic and inorganic lead. In addition electroencephalograms were carried out on 20 of the workers; the results were compared with those obtained for workers not exposed to lead. The workers exposed to lead had a mean blood lead concentration of 2.35 mumol/l (48.7 micrograms/100 ml), whereas the concentration for workers not exposed to lead was 0.76 mumol/l (15.8 micrograms/100 ml). The mean maximum motor conduction velocities of the median and the posterior tibial nerves were significantly lower in the workers exposed to lead than in the controls. Similarly, the distal latency for these two nerves was significantly prolonged for the workers exposed to lead. No significant differences for the two groups of workers were seen in the nerve conduction and distal latency measurements of the median (sensory) and the sural nerves. The EEG studies of the 20 workers exposed to lead showed no abnormalities. The somatosensory evoked potential of the median (sensory) and posterior tibial nerves were significantly prolonged when measured at the negative and positive deflections. The results suggest that, in addition to nerve conduction velocities, somatosensory evoked potential and distal latency are suitable measurements to detect subclinical neurological damage among workers exposed to lead. As these changes were seen at blood lead concentrations of 2.35 mumol/l (48.7 micrograms/100 ml) there may be a need for more stringent monitoring of workers exposed to lead.

Electroencephalography↗