Original Article

KC Teh, VTH Ong
Correspondence: Dr Teh Kong Chuan, teh_kong_chuan@ssc.gov.sg

ABSTRACT
Introduction This study was conducted on Singaporean males and females to determine the extent of involvement in sport, work-based and home-based physical activities, and other activities such as walking and stairclimbing.
Methods A Physical Activity Questionnaire was designed and data collected in conjunction with the Singapore National Sports Participation Survey 2001.
Results Three hundred and ten households with 605 respondents (287 males and 318 females) completed the questionnaire, representing a response rate of 81 percent. Males spent more time doing sports, work-based physical activity and walking and stairclimbing activities while females spent more time in housework. However, females spent more time (568 versus 410 minutes per week) on overall physical activity, mainly due to their heavier involvement in housework. Compared with a similar study in 1997, males and females were doing more sports activities and walking and stairclimbing activities, but had reduced involvement in work-based and home-based activities. Overall, respondents in 2001 were spending about 31 percent less time (457 versus 598 minutes per week) on physical activities than respondents in 1997. There was a reduction in physical activities among males from 476 minutes per week to 410 minutes per week, and a sharper drop among females from 904 minutes per week to 567 minutes per week.
Conclusion Singaporean males and females in 2001 are spending less time on overall physical activities. The trend towards a reduction in overall physical activities from 1997 to 2001 is cause for concern. Relevant organisations would, therefore, need to continue promoting sports and physical activities to the Singapore population.

Keywords: housework, physical activities, physical activity questionnaire, sports, walking
Singapore Med J 2004; 45(11): 517-519

W Kang, KH Tan
Correspondence: Dr Kang Wee, kangwee@kkh.com.sg

ABSTRACT
Introduction The aim of this study was to assess user acceptability and effectiveness of implant contraception in Singaporean women.
Methods A prospective study was carried out on 553 patients who received Norplant implant in our hospital from 1 January 1992 to 31 December 2000, and followed-up till 15 July 2003. The patients' profile, side-effects, satisfaction and continuation rate of Norplant implant were studied.
Results The mean age of the subjects was 29.4 (plus or minus 5.1) years. The mean parity was 2.1 (plus or minus 1) live births. More than one-half (55.2 percent) of the subjects had used other methods of contraception before. The main reason for them to switch to implant contraception was convenience (63.6 percent). Of the 516 users on follow-up, the common side-effects were menstrual irregularity (51 percent), secondary amenorrhoea (9.6 percent) and weight gain (15.7 percent). 29.3 percent of users did not experience any side-effect. There was only one contraceptive failure, which may be related to drug interaction. The Pearl Index was 0.054 per hundred women years. There was only one serious adverse event of a patient (0.2 percent) who developed severe hypertension requiring treatment. The continuation rate was 92.4 percent after one year, 80.8 percent after two years, 68.9 percent after three years and 58.5 percent after four years. The main reasons for early implant removal were side-effects and desire for future pregnancy. Re-insertion was carried out in 53.7 percent of users who had completed five years of Norplant contraception.
Conclusion This largest sub-dermal hormonal implant contraception study in multi-racial Singapore showed that Norplant contraception had a high degree of effectiveness with relatively high user satisfaction and continuation rate.

Keywords: contraceptive, hormonal implant, implant contraception, Norplant
Singapore Med J 2004; 45(10): 482-486

CCM Ng, WHC Han
Correspondence: Dr Christopher Ng Chee Mun, drchrisng@hotmail.com

ABSTRACT
Introduction This study compares the efficacy of abdominal and vaginal routes in correcting severe uterovaginal or vault prolapses by examining their primary surgical outcomes.
Methods A retrospective study was conducted on operations performed from March 1998 to December 2001. The classifications of uterovaginal prolapse and vault prolapse were based on the Halfway system. It involved 177 women with at least grade 4 uterovaginal prolapse or grade 3 vault prolapse, and had undergone vaginal sacrospinous ligament fixation or abdominal sacrocolpopexy. The subjects were divided into two groups: 113 women who had an abdominal sacrocolpopexy and 64 women who had a vaginal sacrospinous ligament fixation. The primary surgical outcome measures was classified as cured, improved or failure according to our definition at their last follow-up.
Results The abdominal sacrocolpopexy group had significantly greater intra-operative blood loss, operating time, haematuria, longer postoperative catheterisation and hospitalisation. Vaginal sacrospinous ligament fixation had more suture erosion. 95.6 percent of women with abdominal sacrocolpopexy were cured compared to 79.7 percent with vaginal sacrospinous ligament fixation. Five (4.4 percent) patients in the abdominal sacrocolpopexy group and six (9.4 percent) in the vaginal sacrospinous ligament fixation group defaulted their six-month follow-up with a mean follow-up of 18.1 months (range 0.9-48.1 months) and 13.2 months (range 1.1-29.1 months), respectively.
Conclusion Abdominal sacrocolpopexy is more effective in correcting severe uterovaginal or vault prolapses but it is associated with higher intra- and post-operative morbidity compared to vaginal sacrospinous ligament fixation. Vaginal sacrospinous ligament fixation is preferred in patients with medical disorders.

Keywords: abdominal sacrocolpopexy, uterovaginal prolapse, vaginal sacrospinous ligament fixation, vault prolapse
Singapore Med J 2004; 45(10): 475-481

WW Woo, KA Lim, H Yang, XY Lim, F Liew, YS Lee, SM Saw
Correspondence: Dr S M Saw, cofsawsm@nus.edu.sg

ABSTRACT
Introduction Refractive errors are becoming more of a problem in many societies, with prevalence rates of myopia in many Asian urban countries reaching epidemic proportions. This study aims to determine the prevalence rates of various refractive errors in Singapore medical students.
Methods 157 second year medical students (aged 19-23 years) in Singapore were examined. Refractive error measurements were determined using a stand-alone autorefractor. Additional demographical data was obtained via questionnaires filled in by the students.
Results The prevalence rate of myopia in Singapore medical students was 89.8 percent (Spherical equivalence (SE) at least -0.50 D). Hyperopia was present in 1.3 percent (SE more than +0.50 D) of the participants and the overall astigmatism prevalence rate was 82.2 percent (Cylinder at least 0.50 D).
Conclusion Prevalence rates of myopia and astigmatism in second year Singapore medical students are one of the highest in the world.

Keywords: astigmatism, epidemiology, myopia, prevalence rates
Singapore Med J 2004; 45(10): 470-474

HC Zow, AAL Hsu, PCT Eng
Correspondence: Ms Huey-Chin Zow, gm3zhc@sgh.com.sg

ABSTRACT
Introduction The National Health Survey in Singapore reported that the prevalence of smoking had decreased from 20 percent in 1984 to 15 percent in 1998. This may be due to the efforts of smoking cessation education established island-wide. In this study, we review the efficacy of the Singapore General Hospital smoking cessation programme and examine the efficacy of different treatment modalities.
Methods We studied the immediate quit rate and point prevalence abstinence rates at six and 12 months in our telephone survey. Subjects were patients who attended our programme from June 1999 to December 2002. Pharmacotherapeutic aids utilised with counselling sessions were individualised.
Results The study populations for outpatient and inpatient arms were 394 patients and 425 patients, respectively. In the outpatient programme, mean age was 46 years (range of 12 to 80 years), and the ratio between males and females was 8.6. The outpatient immediate quit rate was 33 percent, and the six and 12 month quit rates were both 36 percent. However, in the inpatient programme, mean age was 65 years (range of 15 to 93 years), and the ratio between males and females was 4.9. The six and 12 month quit rates of the inpatient arms were 30 percent and 32 percent, respectively. Although there is no statistically significant difference in the different treatment modalities, the immediate quit rates for bupropion only and counselling only were relatively higher (36 percent and 41 percent, respectively). These were sustained at more than 35 percent at six and 12 months follow-up. We achieved comparable efficacy compared to published data. Counselling, as a sole therapy, can be effective in a select patient group. One-time inpatient counselling achieved a quit rate (32 percent at 12 months) far superior to previously-reported self-quit rate (3 percent and 8 percent at 12 months).
Conclusion We strongly recommend that all inpatients who are smokers to be routinely referred for counselling.

Keywords: bupropion, counselling, nicotine dependence, pharmacotherapy, smoking cessation
Singapore Med J 2004; 45(9): 430-434

SS Rana, R Singhal, RK Gupta, D Sharma, P Kar
Correspondence: Prof Premasis Kar, premashish_kar@rediffmail.com

ABSTRACT
Introduction The recombinant hepatitis B vaccine, at a conventional dose of 20 microgrammes, is highly effective in a majority of the population. Recent studies have reported that a 10-microgramme dose is as effective as the conventional dose, especially in young adolescents. This study compares the effect of two different doses of recombinant hepatitis B vaccine (Enivac HB) in healthy adolescents.
Methods Ninety-two adolescents were randomised into two equal groups to receive either 10 microgrammes (group 1) or 20 microgrammes (group 2) of vaccine using the vaccination schedule of 0, one and six months. Blood samples were collected at 30, 60, 90, 180 and 210 days to detect anti-HBs antibodies. At each interval, geometric mean titres were calculated for seroconverted subjects.
Results After the initial doses of the vaccine, greater proportion of subjects receiving the higher dose seroconverted. However, at six months, all subjects who received the low dose seroconverted, as did those who received the conventional dose. Furthermore, there were significant differences in the anti-HBs geometric mean titres for seroconverters at 180 days (218.27 versus 111.43) and 210 days (345.14 versus 133.35). The difference in the overall reactogenicity for the two dose levels was not remarkable, although the higher dose produced more local symptoms.
Conclusion 10-microgramme recombinant vaccine can be used in routine immunisation in healthy adolescents. If quick immunisation is needed, as in high-risk groups, the conventional dose should be administered, as it results in earlier seroconversion with higher anti-HBs geometric mean titres.

Keywords: hepatitis B, immunisation, low-dose hepatitis vaccine, recombinant vaccine, vaccination
Singapore Med J 2004; 45(9): 427-429

CT Wai, B Mak, W Chua, SG Lim
Correspondence: Dr Chun-Tao Wai, waict@nuh.com.sg

ABSTRACT
Introduction Carriers of hepatitis B virus (HBV) are at risk of developing long-term complications. Regular surveillance helps detect treatable chronic hepatitis, cirrhosis and liver cancer, and is recommended by practice guidelines in the United States, Europe and Singapore. However, there have been few studies evaluating the follow-up of HBV carriers. This study seeks to determine the proportion of HBV carriers on regular follow-up in Singapore and the impact on hepatitis B disease.
Methods An advertisement was taken in local newspapers advertising for free screening to HBV carriers. 387 persons answered the advertisement. The screening comprised history-taking, physical examination, blood tests (liver panel, alphafoetoprotein, hepatitis B surface antigen (Ag) and hepatitis B eAg) and ultrasonography of liver. Further evaluation was conducted if the screening results were abnormal.
Results Of the 387 HBV carriers, 346 (89 percent) were male and 375 (97 percent) were Chinese. Their mean age was 39 years (range 20-60 years) and 36 percent were positive for HBeAg. 247 (64 percent) were not on regular screening over the past 12 months. 19 (5.4 percent) patients were diagnosed to have complications, namely: 13 had HBeAg-positive chronic hepatitis, two had HBeAg-negative chronic hepatitis, one had early liver cancer who recovered well after a curative resection and three had compensated cirrhosis.
Conclusion Our screening programme diagnosed 5.4 percent of complications among 387 asymptomatic HBV carriers. However, 64 percent of the study subjects were not screened regularly and may pose an important public health threat if they develop long-term complications. Further studies are needed to evaluate and improve patient compliance for screening.

Keywords: chronic hepatitis B, hepatitis, hepatocellular carcinoma
Singapore Med J 2004; 45(9): 423-426

MEH Ong, PHY Ang, YH Chan, S Yap
Correspondence: Dr Ong Eng Hock Marcus, mftjong@yahoo.com

ABSTRACT
Introduction In the year 2002, the Society for Emergency Medicine in Singapore Chapter of Paramedics organised the first emergency medical services (EMS) day, to educate the public about basic emergency response skills and to increase public awareness of the local EMS System.
Methods This was an observational, cross-sectional study. A survey was conducted to find out about the knowledge and attitudes of the public and paramedic volunteer instructors towards the local EMS System.
Results Two hundred and six (81.4 percent) out of 253 members of the public and 70 paramedics (100 percent) responded. For the public, the majority were females (86 percent), mean age (standard deviation [sd]) was 15.9 (7.9) years, range 11.0 to 67.0 years. For the paramedics, mean (sd) age was 26.6 (3.8) years. 61.9 percent were females. The public showed good knowledge of the emergency ambulance number and the indications for calling an ambulance. Public expectations of ambulance response times were significantly shorter than paramedics. They were also less comfortable with ambulance crews performing advanced life support interventions compared with the paramedics.
Conclusion Continuing efforts should be made to increase public awareness of the EMS system as well as to manage public expectations regarding response times and the roles of paramedics. EMS day represents one such opportunity.

Keywords: ambulance, cardiopulmonary resuscitation, emergency medical services, paramedics
Singapore Med J 2004; 45(9): 419-422

P Karki, JA Ansari, S Bhandary, S Koirala
Correspondence: Prof Prahlad Karki, prahladkarki@hotmail.com

ABSTRACT
Introduction To study the extent, frequency and pathogenesis of the cardiac and electrocardiographical manifestations of acute organophosphate poisoning.
Methods 37 adult patients admitted over a three-year period with a diagnosis of acute organophosphate or carbamate poisoning were studied prospectively. The clinical features and electrocardiographical finding were recorded.
Results Cardiac complications developed in 23 patients (62.2 percent). These were: non-cardiogenic pulmonary oedema in eight cases (21.6 percent), electrocardiographical abnormalities including prolonged Q-Tc interval in 14 cases (37.8 percent), ST-T changes in 11 cases (29.7 percent), and conduction defects in two cases (5.4 percent). Sinus tachycardia occurred in 15 patients (40.5 percent) and sinus bradycardia in seven patients (18.9 percent). Hypertension developed in five patients (13.5 percent) and hypotension in four patients (10.8 percent). Five patients (13.5 percent) needed respiratory support because of respiratory depression of which two patients developed intermediate syndrome. Out of 14 patients with prolonged Q-Tc interval, only one had polymorphic ventricular tachycardia of the torsade de pointes type. Two patients died from non-cardiogenic pulmonary oedema and one from ventricular fibrillation, giving a hospital mortality of 8.1 percent.
Conclusion Cardiac complications usually occur during the first hour after exposure. Hypoxemia, electrolyte derangements and acidosis are major predisposing factors for the development of these complications. Intensive supportive treatment, meticulous respiratory care and administration of atropine in adequate doses vary early in the course of the illness will reduce the mortality.

Keywords: carbamate poisoning, cardiotoxicity, electrocardiographical abnormalities, insecticides, organophosphates
Singapore Med J 2004; 45(8): 385-389

ACC Poh, M Lin, HS Teh, AGS Tan
Correspondence: Dr A C C Poh; shirodka@yahoo.co.uk

ABSTRACT
Introduction To study the role of contrast-enhanced computed tomography (CT) of the abdomen and pelvis in the evaluation of patients with clinically-suspected but equivocal acute appendicitis.
Methods The medical records of 206 consecutive patients who had CT of the abdomen and pelvis for equivocal signs and symptoms of acute appendicitis were reviewed. 7 mm collimated axial sections from the diaphragm to the iliac crest and 5mm collimated sections of the pelvis with intravenous and oral contrast were obtained. The criteria used to diagnose acute appendicitis were: (a) a thickened appendix of more than 7 mm or (b) inflammatory changes in the periappendiceal fat. The CT findings were correlated with the histological diagnosis at appendectomy. If the CT findings were negative for acute appendicitis and surgery not performed, the results were correlated with other corroborating diagnostic investigations or clinical follow-up.
Results A total of 206 patients were scanned, of which 39 were excluded due to lack of any follow-up. Of the final 167 that were studied, there were 36 true positives, 127 true negatives, 4 false negatives and no false positives, resulting in a sensitivity of 93.9 percent, specificity of 100 percent and accuracy of 98.5 percent.
Conclusion We have found CT to be a safe, reliable and accurate modality in the diagnosis of acute appendicitis in patients with equivocal presentation.

Keywords: acute abdomen, acute appendicitis, computed tomography
Singapore Med J 2004; 45(8): 379-384