Hepatitis B Seroprevalence Study 1999.

Hepatitis B is a disease of public health importance in Singapore. A study was conducted in 1999 to estimate the overall and gender-, age- and ethnic-specific prevalence of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and antibody to hepatitis B surface antigen in the Singapore population. A cross-sectional sample of the Singapore population constituting 4,698 Singapore residents aged 18-69 years was surveyed. This was the first time a large-scale study has been conducted to assess the hepatitis B seroprevalence rates in the Singapore population. The overall prevalence of the HBsAg in the general population was estimated to be about 4%. About 13% of the HBsAg carriers were also HBeAg positive. Only about 40% of the population had immunity to hepatitis B virus either through immunisation or from previous exposure to the virus. There was still a large proportion (60%) of the population who had no immunity, especially the younger age group of 18-29 years where only 28% had immunity. There is a need to strengthen the hepatitis B immunisation programme to reach out to those who have no immunity, especially the young adults.

Obstructive sleep apnea syndrome in obese Singapore children.

We set out to determine the prevalence of obstructive sleep apnea syndrome (OSAS) among obese Singapore school children and identify risk factors for OSAS. This study was designed as a prospective study in three phases. Parents completed a questionnaire with regards to sleep and daytime symptoms in Phase 1. Children suspected to have OSAS based on the questionnaire and all with a percent ideal body weight (IBW) >/=180 were called for clinic visits in Phase 2. All whose percent IBW >/=180 and those in whom the physicians strongly suspected OSAS were subjected to a polysomnogram in phase 3. The children were recruited from the School Health Nutritional Clinic for obese children. The investigations were carried out at Tan Tock Seng Hospital. In all, 3,671 children were screened with the questionnaire. Of these, 146 were selected to undergo polysomnography. Twenty-six had abnormal sleep studies with apnea/hypoxia indices (AHIs) >5/hr. The significant clinical feature which correlated with OSAS was sleep sitting up (P = 0.005). The risk is higher in morbidly obese (IBW >/=180), with a prevalence of 13.3% (8/60), than in less obese children (IBW <180). One in eight (12.5%) of these children was asymptomatic and would have been missed based on the questionnaire. Presence of adenotonsillar hypertrophy led to increased risk of OSAS. The prevalence of OSAS was 0.7% (26/3,671) among the obese schoolchildren in Singapore, which is similar to the prevalence reported by others. Using discriminant analysis, the estimated prevalence increased to 5.7%. In the morbidly obese (IBW >/=180), the prevalence rate is higher at 13.3%.