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.

A community study of male androgenetic alopecia in Bishan, Singapore.

BACKGROUND: Androgenetic alopecia is the most common form of hair loss. It affects a large number of the local male population, with 1,812 men seeking treatment for hair loss at the sole dermatological tertiary referral centre in Singapore in 1994. The aim of this study was to assess the prevalence of male androgenetic alopecia in the community. METHODS: A questionnaire-based cross-sectional survey with a one-stage sampling method was conducted. Each male was diagnosed clinically and the severity graded according to the Norwood Criteria. The survey area was in Bishan East, a housing estate with 8,004 households. A total of 335 households were selected for the survey. RESULTS: The household response rate was 84%. Within these households, 254 out of 378 men participated in the study (67% response rate). The prevalence of androgenetic alopecia was found to be 63%. The prevalence of the condition increased with age, from 32% among young adults aged 17 to 26 years to 100% among those in their 80s. Proportionately more Indians (87%) were affected compared to Chinese (61%). 81% of the respondents with androgenetic alopecia did not seek help as they did not view it as a problem. Of those seeking treatment, 74% used non-medical methods of unproven effectiveness. CONCLUSION: There is a high prevalence of androgenetic alopecia in the community in Singapore. Age specific prevalence and racial differences correlate well with both Western and local studies respectively.

The effects of ethnicity on disease patterns in 472 Orientals with systemic lupus erythematosus.

OBJECTIVE: To determine the effects of ethnicity on disease manifestations in Oriental patients with systemic lupus erythematosus (SLE) and to describe the risk of developing renal or central nervous system (CNS) involvement with time. METHODS: A retrospective study of 472 patients with SLE seen at the only Rheumatology Unit in Singapore. The effect of ethnicity on selected disease manifestations at diagnosis was assessed after adjusting for demographic variables using multiple logistic regression. The probability of developing selected disease manifestations with time was determined using the Kaplan-Meier product limit method. RESULTS: At diagnosis, Malays had a higher risk of renal or CNS involvement than Chinese (OR 2.26, 95% CI 1.21 to 4.21, and OR 3.07, 95% CI 1.01 to 9.34, respectively), and Indians a lower risk of malar rash and a higher risk of oral ulcers than Chinese (OR 0.30, 95% CI 0.13 to 0.68, and OR 2.90, 95% CI 1.45 to 7.34, respectively). The prevalence of renal or CNS involvement in the entire cohort increased with time, reaching 75.6% (95% CI 66.1% to 85.0%) and 16.7% (95% CI 11.7% to 21.6%), respectively, after 18 years of disease. CONCLUSION: Ethnicity influenced disease manifestations at diagnosis in this cohort of Oriental patients with SLE. Renal or CNS involvement developed in previously unaffected patients up to 18 years after diagnosis, highlighting the need for continued vigilance in patients with lupus.

Clinical predictors of nephritis in systemic lupus erythematosus.

We identified clinical predictors of lupus nephritis presenting more than 6 months after the diagnosis of lupus in a cohort of 335 lupus patients. Almost 24% (80/335) of patients developed nephritis more than 6 months after the diagnosis of lupus. Using a Cox proportional hazards model, we found hypertension, thrombocytopaenia and leukopaenia to be associated with lupus nephritis presenting more than 6 months after diagnosis, with adjusted relative risks of 2.5 (95% CI 1.3 to 4.7), 4.3 (95% CI 1.7 to 10.8) and 3.2 (95% CI 1.7 to 6.2) respectively. In this cohort, hypertension, thrombocytopaenia and leukopaenia were associated with lupus nephritis presenting more than 6 months after the diagnosis of lupus.

Patterns of psoriatic arthritis in Orientals.

OBJECTIVE: To determine the clinical features of psoriatic arthritis (PsA) in a multiethnic Oriental population and to study the effect of ethnicity on disease patterns. METHODS: A retrospective study of 80 patients with PsA seen at either a rheumatology or dermatology referral center. Patients and case records were reviewed and data abstracted according to a standard protocol. Eighty consecutive patients with psoriasis without PsA seen at the dermatology center were recruited as controls. RESULTS: Asymmetric polyarthritis developing in the 4th decade with an equal male to female ratio was the commonest pattern of arthritis among Chinese, Indians, and Malays. Clinically apparent lumbar spondylitis was significantly more common in Indians than Chinese (10/11 vs 11/20, respectively; p = 0.046), although the prevalence of lumbar spondylitis was similar in all ethnic groups. Eighty-nine percent of subjects required nonsteroidal antiinflammatory drugs and 51% required disease modifying antirheumatic drugs at some time for control of joint disease. PsA was significantly more common among Indians compared to the ethnic distribution of the Singapore population (p < 0.000001). Multiple logistic regression identified Indian ethnicity as a risk factor for the development of PsA (OR 2.39, 95% confidence interval 1.02 to 5.60). CONCLUSION: The commonest pattern of PsA in all ethnic groups was asymmetric polyarthritis. Ethnicity affected the development and presentation of PsA in our series: Indians with psoriasis had double the risk of developing PsA compared to Chinese with psoriasis, and lumbar spondylitis when present in Chinese subjects was asymptomatic in 45%, being detectable only on radiological examination.

Cumulative blood lead levels and neurobehavioral test performance.

The current scientific literature provides inadequate evidence to conclude whether or not cumulative exposure to or absorption of lead adversely affects performance in neurobehavioral tests in adults. One of reasons for this controversy is the lack of studies with good cumulative exposure to or dose of lead. The aims of this study are to compare the neurobehavioral test performances of a group of lead-exposed workers and a referent group, and to study the association of the neurobehavioral test performances with concurrent blood lead levels and cumulative blood lead levels. Fifty lead battery workers and 97 non-exposed (referent) workers from a vehicle maintenance workshop were evaluated on their neurobehavioral performance using the World Health Organization Neurobehavioral Core Test Battery (WHO-NCTB). The geometric mean concurrent blood lead (ConPb) of the exposed and referent groups were 37.1 (range 13.2-64.6) microg/100 ml and 6.1 (range 2.4-12.4) microg/100 ml, respectively. Cumulative blood lead (CumPb) was defined as area under the curve for the number of years each worker was exposed to lead (three workers previous blood lead results were not available). ConPb and CumPb were used to study the association with the neurobehavioral test results. The exposed group had significantly poorer manual dexterity, perceptual-motor speed, and motor steadiness compared with the referents. The standardized partial regression coefficients were higher for CumPb than ConPb for most of the neurobehavioral test results. In the group >35 years old, there were significantly stronger associations between CumPb and Digit Symbol and Trail Making Part A results than for ConPb which are tests of perceptual and motor skills. CumPb was a better predictor than ConPb of the effects of lead on neurobehavioral performances.

Maximal respiratory pressures in adult Chinese, Malays and Indians.

Maximal static inspiratory and expiratory mouth pressures (PI,max and PE,max, respectively) enable the noninvasive measurement of global respiratory muscle strength. The aim of this study was primarily to obtain normal values of PI,max and PE,max for adult Chinese, Malays and Indians and, secondarily, to study their effect on lung volumes in these subjects. Four hundred and fifty two healthy subjects (221 Chinese, 111 Malays, 120 Indians) were recruited. Measurements of PI,max from residual volume (RV), PE,max from total lung capacity (TLC) and forced vital capacity (FVC) were obtained in the seated position. There were significant ethnic differences in PI,max and PE,max measurements obtained in males, and FVC measurements in both males and females. Chinese males had higher PI,max values (mean (+/-SD) 88.7+/-32.5 cmH2O) and higher PE,max values (113.4+/-41.5) than Malay males (PI,max 74.0+/-22.7 cmH2O, PE,max 94.7+/-23.4 cmH2O). Chinese males had higher PE,max than Indian males (PI,max = 83.7+/-30.0 cmH2O, PE,max 98.4+/-29.2 cmH2O). There were no significant differences among Chinese females (PI,max 53.6+/-2.3 cmH2O, PE,max 68.3+/-24.0 cmH2O), Malay females (PI,max 50.7+/-18.3 cmH2O, PE,max 63.6+/-21.6 cmH2O) and Indian females (PI,max 50.0+/-15.2 cmH2O, PE,max 60.7+/-20.4 cmH2O). In both sexes, the Chinese had a higher FVC compared with Malays and Indians. After adjusting for age, height and weight, race was still a determinant for PE,max in males, and FVC in both sexes. The FVC only correlated weakly with PI,max and PE,max in both sexes. Ethnic differences in respiratory muscle strength, and lung volumes, occur among Asians. However, respiratory muscle strength does not explain the differences in lung volumes in healthy Asian subjects.

Three-year follow-up of serial nerve conduction among lead-exposed workers.

OBJECTIVES: The purpose of this study was to investigate the serial nerve conduction parameters of a group of lead-exposed workers and determine their correlation with the serial blood lead results over a three-year period. A "nonresponse" level (defined as no significant changes in the nerve conduction in response to changes in the blood lead level of each exposed worker observed over the period of study) was also determined for blood lead in respect to the peripheral nerves. METHODS: Seventy-two male workers from a lead battery manufacturing factory were followed at six-month intervals for three years. At each follow-up, the blood lead level was determined and nerve conduction tests (ulnar and median nerves) were conducted. A group of 82 unexposed subjects served as referents. RESULTS: Significant differences were observed for some of the mean values of the median nerve conduction parameters between the exposed and reference groups. The 28 exposed workers who completed the follow-up were divided into the following two blood lead categories: < 40 micrograms. 100 ml-1 (< 1.93 micromol.l-1 and > or = 40 micrograms. 100 ml-1 (> or = 1.93 micromol.l-1. In the latter, the median motor conduction velocity, median distal latency, median amplitude, ulnar motor conduction velocity, and ulnar amplitude were significantly correlated (adjusted for age and within-subject variation) with the blood lead levels, but not so in the former. CONCLUSIONS: According to the three-year serial results, the "nonresponse" level for blood lead with respect to the peripheral nerves would be < 40 micrograms.100 ml-1 (< 1.93 micromol. l-1).

Transcutaneous bilirubinometry in Chinese, Malay and Indian infants.

The objective of this study was to investigate the correlation of transcutaneous bilirubinometry (TcB) and plasma bilirubin concentrations in full-term Chinese, Malay and Indian infants. TcB was performed with the Minolta Airshields bilirubinometer on Chinese, Malay and Indian fullterm infants. The readings were taken on the chest (sternum) and forehead (glabella) when capillary blood was sampled for bilirubin determination. Five hundred and forty TcB indices in 253 Chinese infants, 282 in 169 Malay infants, and 182 in 120 Indian infants were obtained over the sternum and forehead. A good correlation between the TcB indices and the bilirubin concentrations was observed in Chinese, Malay and Indian infants: r = 0.78 (chest), r = 0.73 (forehead); r = 0.86 (chest), r = 0.84 (forehead); and r = 0.84 (chest), r = 0.82 (forehead). The correlation was just as good when the combined values were evaluated together: r = 0.80 (chest) r = 0.75 (forehead). In Chinese infants, correlation at values below 250 mumol l-1 was significantly better than that at values over 250 mumol l-1 r = 0.80 versus r = -0.20, p < 0.00001 (chest), and r = 0.74 versus r = 0.07, p < 0.00001 (forehead). However, a safer cut-off point clinically would be 200 mumol l-1, since only relatively few higher bilirubin values were encountered when TcB indices were below 200 mumol l-1. The same pattern was noticed with the other two groups, and the combined group. Thus, TcB provides a non-invasive, cost-effective screening method for significant neonatal jaundice, sparing infants and parents physical and emotional stress, and medical and nursing personnel extra work and inconvenience.

Cumulative concentrations of blood lead and postural stability.

OBJECTIVE: To study the association in a group of battery manufacturing workers between computerised postural sway parameters and present concentrations of blood lead (PPb), index of cumulative blood lead years (CBI), and cumulative blood lead at different years of exposure (CPbYs). METHODS: Postural stability was investigated with a computerised postural sway measurement system in 60 workers exposed to lead with exposure duration of 84 (range 3-366) months and in 60 control subjects. An index of CBIs in 55 workers (previous blood lead results of five workers were not available) and CPbYs were computed for each worker by calculating the area under the curve of concentrations of blood lead against time. RESULTS: The mean (SD) PPb was 36.0 (11.7) (range 6.4 to 64.5) micrograms/dl for the exposed workers and 6.3 (2.4) (range 3.1-10.9) micrograms/dl for the 14 randomly selected control subjects. Significant differences between groups for the postural sway parameters obtained when the eyes were closed were found for length of sway path (L); mean velocity of the centre of pressure along its path (Vel); area included within the path of the centre of pressure (Ao); 95% confidence elliptical area (Ae). The Romberg ratio (the relation between eyes closed and open) for the Vel, L, Ao, and Ae of the exposed group were also significantly different from those of the controls. The postural sway parameters (eyes closed) were not significantly correlated with PPb or CBI. However, the cumulative blood lead for the past two years before the postural sway assessment, CPbY2, was significantly correlated with all the postural sway parameters. CONCLUSION: The study showed that workers exposed to lead had significantly poorer postural stability than a control group. Lead may affect certain parts of the somatosensory system resulting in postural instability when the visual input is cut off. The CPbY2 was significantly positively correlated with most of the postural sway parameters. Effects of lead on postural stability may be related to recent increases in blood lead concentration among the exposed workers rather than to cumulative body burden.

Cumulative blood lead levels and nerve conduction parameters.

Most studies on the effects of lead on the peripheral nerves used "current' blood lead levels of the workers and infer the nerve conduction's findings to it. This practice is not ideal as the toxicity of lead on the peripheral nerves occurs over a period of time. Seventy-two workers in a lead battery manufacturing factory and 82 referents were studied with the aim of (1) correlating the nerve conduction parameters of the median and ulnar nerves of the dominant forearms with the blood cumulative lead-years (BPbCum) results; (2) determining a "noeffect' cumulative dose of lead on the peripheral nerves. The mean BPb for the exposed and referent were 36.9 micrograms/100ml and 10.5 micrograms/100ml, respectively. The mean BPbCum was 136.8 (range = 6.7-1087.0)micrograms-year/100ml. Significant differences were found in the adjusted (for age, ethnical groups, smoking and drinking habits by ANCOVA) means median sensory conduction velocity, motor conduction veloclty, distal latency and amplitude between the exposed and referent groups. But for the ulnar nerve only, distal latency was significantly different. With the BPbCum groups, dose response relations are noted in both the nerve conduction parameters of the median and ulnar nerves. There were no significant differences for the ulnar and median nerves conduction parameters between BPbCum < 40 micrograms-year/100ml group and referent. Based on the study's findings, it would suggest that a maintained blood lead level of less than 40micrograms/100ml for one year may not have significant effects on the median and ulnar nerves.

Chili--protective factor against peptic ulcer?

The aim of the present study was to determine the frequency and amount of chili taken by peptic ulcer patients and control subjects. One hundred three Chinese patients with peptic ulcer and 87 control patients were interviewed using a standard questionnaire. Those subjects who deliberately avoided chili use because of symptoms or advice from friends or medical practitioners were excluded. The median number of times of chili use per month was eight in the ulcer group (25-75% quartiles 1-30) compared to 24 (8-56) in the control group (P < 0.001). The median amount of chili used per month was 312 units (25-75% quartiles 38-899) in the ulcer group compared to 834 units (274-1892) in the control group (P < 0.001). The odds ratio of having peptic ulcer disease, adjusted for age, sex, analgesic use, and smoking by multiple logistic regression, was 0.47 (95% confidence intervals: 0.25-0.89) for subjects who had a higher intake of chili both in terms of frequency as well as amount used compared to those who took less chili. Our data support the hypothesis that chili use has a protective effect against peptic ulcer disease.

Symptoms, lung function, and diurnal variation in peak expiratory flow rate among female solderers in the electronics industry.

The purpose was to determine if solderers had increased diurnal variation (DV) in peak expiratory flow rate (PEFR) and chronic impairment of lung function. A cross-sectional study of 150 female operators doing manual soldering using flux-cored (rosin-based) solder wire and 52 administrative staff from two electronics factories was carried out. They answered a questionnaire, had their forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC) measured and their 3-hourly PEFR monitored for 5 working days. The DV in PEFR was the difference in the daily maximum and minimum PEFR expressed as a percentage of the maximum. Six solderers with smoking history were excluded from the analysis. Solderers had a significantly higher prevalence of work-related eye (14.6%) and nose (10.4%) irritation. The prevalence of cough, breathlessness, and wheezing was low. There was no overt case of occupational asthma. The DV in PEFR of 6.0% was not increased. The analysis of FEV1 and FVC was restricted to Chinese only (101 solderers and 51 controls): these were not significantly different. Solderers with 5 or more years of exposure had a significantly lower FEV1/FVC (%) of 88.4% after adjustment for age. In conclusion, solderers with 5 or more years of exposure may have a mild obstructive effect apart from smoking, asthma, or age.

Occupational health through primary health care clinics in Singapore.

The training of primary health care workers in occupational health is important for the provision of occupational health care to the workforce. In Singapore, over 400 Designated Factory Doctors, mostly general practitioners, have been trained. Occupational health is also incorporated in the training of family medicine trainees. Referral centres for cases of suspected work-related diseases are also available. Two specialist occupational health clinics function within Government polyclinics serving the large working population in Singapore. One such clinic operates every Wednesday morning at the Jurong Polyclinic. In the last four years, 485 patients with work-related complaints were seen. There were 268 cases (55%) of occupational skin disease, 74 patients (15%) with respiratory complaints, 38 patients (8%) with acute toxic exposures and 36 patients (7%) with musculoskeletal complaints. Three hundred and forty-nine of the referrals (72%) came from the Jurong Polyclinic doctors, with small numbers from other polyclinics and neighbouring private practitioners. The experience gained in conducting this clinic demonstrated that significant numbers of diseases seen at the polyclinic are work-related in varying degrees. Hence, there is a need for the further development of occupational health care delivery within the primary health care system. This can be achieved by improving occupational health training for all primary health care workers, providing an occupational health resource person at primary health care centres, and raising the awareness of such referral facilities in occupational medicine.

A study of needle-stick injuries among house officers in a major hospital.

House officers (HO) undergoing housemanship in the departments of Surgery, Medicine and Orthopaedics in a major hospital were studied with regard to the incidence and causes of needle-stick injuries via a self-administered recall questionnaire. A response rate of 79% (44 out of 56 HOs) was obtained, of which 35 HOs had completed 2 months of housemanship and 9 had completed 8 months. A total of 171 needle-stick injuries (1.2 per HO-month) were reported with 6 HOs never sustaining an injury. The more experienced HOs had less injuries than the less experienced HOs with an incidence rate of 4.65 (95% confidence interval of 4.08-8.87). Resheathing was the commonest reported cause of injury (45% of 113 described cases). Forty-three HOs (90%) reported that they frequently resheathed used needles before disposal. Most HOs (61%) felt that they were at nil to moderate risk of contracting an infectious disease from a needle-stick injury. A system of reporting and policies on management of infected personnel may be needed to monitor this health hazard.

Skin disorders among hand solderers in the electronics industry.

Full-time solderers (n = 150) and non-soldering administrative staff (n = 52) were interviewed and examined to determine the prevalence of work-related rashes, to assess their acne status and to measure their forehead skin sebum levels with a Sebumeter. The period prevalence rates (of ever having a work-related skin rash since working as a solderer) for the 82 solderers using multicored solder wire and for the 68 workers using liquid flux were 19.5 per cent and 10.3 per cent respectively. Among the liquid flux solderers, 29 used cotton gloves. The prevalence rate of work-related skin rashes was 3.4 per cent in this group, compared to 15.4 per cent among the 39 ungloved workers. A similar finding was noted among the multicored solder wire users (9 per cent of the 11 gloved workers and 21 per cent of the 71 ungloved workers). On examination, six solderers (all ungloved multicored flux users) had work-related dermatitis of the hands or fore-arms. The point prevalence rate of work-related dermatitis among all solderers was 4 per cent. For non-occupational dermatitis, the point prevalence rate was 2.7 per cent among the solderers and 4 per cent among the administrative staff. The point prevalence and severity of acne among the 150 solderers were the same as those of the 52 administrative workers who were of a similar age and sex distribution. Forehead skin sebum levels, after adjusting for possible confounding factors such as age, atopic status and time elapsed since the last face wash, were also similar in the two groups of employees.(ABSTRACT TRUNCATED AT 250 WORDS)

Outcome of patients with cervical spondylotic myelopathy seen at a rehabilitation centre.

A retrospective study was conducted on 21 patients with cervical spondylotic myelopathy to study the clinical characteristics of these patients and the influence of surgery and rehabilitation on their outcome. All the patients were 50 years and above, with a mean age of 63.6 years. The most common presenting feature was weakness of all the limbs. Neckache was not a prominent finding. Although only 2 patients complained of bladder disturbance, 6 other patients were found to have bladder dysfunction after urodynamic assessment. Clinical outcome after surgery was 50% improved, 28% unchanged and 22% worsened. Fifty percent of the patients with voiding problems recovered after bladder training. Rehabilitation was significant in assisting in the recovery of patients after surgery. One patient had a disabling stroke 4 days after cervical surgery while another died of urinary tract infection while undergoing rehabilitation.

A study of needle stick injuries among medical undergraduates.

A study was conducted to determine the incidence and causes of needlestick injuries among 158 medical undergraduates who had completed their first clinical year. A response rate of 97.5% (154 out of 158 students) was obtained, of which 54 students (35.1%) reported at least one needlestick injury. The commonest cause of injury was during the process of venepuncture (27%), followed by uncapping of needles (22.2%) and recapping of used needles (19.8%). The highest incidence of injury occurred during a medical posting (33/154 students), followed by surgical posting (14/154 students) and elementary clinics (9/154 students). Formal training on handling of used needles was reported by only 15-23% of the students in the various postings. The awareness of risk of contracting diseases from needlestick injuries was high (84.4%).

Purification and characterization of a higher-molecular-mass form of protein phosphotyrosine phosphatase (PTP 1B) from placental membranes.

Purification of a major placental membrane protein phosphotyrosine phosphatase (PTP-I) through the use of a nonhydrolysable phosphotyrosine analogue affinity ligand has enabled identification of the enzyme as a single polypeptide of at least 46 kDa. This phosphatase specifically dephosphorylates phosphotyrosine-containing substrates, including the src peptide, the epidermal-growth-factor receptor tyrosine kinase and the non-receptor tyrosine kinase p56lck. The p56lck can be dephosphorylated by PTP-I at two tyrosine residues (Tyr-394 and Tyr-505), which are differentially phosphorylated in vitro and in vivo and have been suggested to modulate kinase activity. The activity of PTP-I towards these substrates indicates a possible function of regulation of cellular tyrosine phosphorylation pathways at the level of growth-factor receptor and/or oncogene/proto-oncogene tyrosine kinases. Kinetic analyses show that PTP-I exhibits a Km value of about 2 microM with either src peptide or reduced, carboxyamidomethylated and maleylated (RCM)-lysozyme as substrate, and is inhibited in a mixed competitive manner by the polyanions heparin and poly(Glu4,Tyr1). Sequencing of PTP-I peptides reveals almost complete identity with sequences within the N-terminal half of the 37 kDa non-receptor tyrosine phosphatase 1B. However, the size and amino acid composition of PTP-I are similar to that of a higher-molecular-mass form of PTP 1B predicted from cDNA cloning. These results suggest that the 37 kDa PTP 1B is a proteolysed form of PTP-I, and provide evidence that a larger form of PTP 1B exists in vivo, at least in association with placental membranes.