A study on the prevalence of hepatitis B surface antigen among Chinese adult males in Singapore.

A study was conducted in Singapore on 8829 Chinese men aged 35 years or more to determine whether the prevalence of hepatitis B surface antigen (HBsAg) positivity is associated with the source from which the subjects were recruited, or with occupation as an indicator of socioeconomic status. The HBsAg prevalence rates were significantly different (p less than 0.0001) among the five source groups: 8.3% in healthy blood donors, 7.8 in other healthy subjects, 9.2 in non-hepatic outpatients, 10.3 in hospital non-hepatic patients who were not gravely ill, and 11.2 in hospital non-hepatic patients who were gravely ill. After statistical adjustment by multiple logistic regression for age and occupation, the odds ratio (using 'other healthy subjects' as the reference group) ranged from 0.98 (95% CL = 0.65-1.47) for healthy blood donors to 1.42 (95% CL = 0.95-2.12) for hospital non-hepatic patients who were gravely ill. The HBsAg prevalence rates were also significantly different (p less than 0.0001) among occupations: 8.5% in professional, technical and administrative personnel, 9.7 in clerical, sales and services personnel, 10.3 in agricultural and factory workers and unskilled labourers, and 10.5 among the unemployed and retired. After statistical adjustment for age and source groups, the odds ratio (using professional, technical and administrative subjects as the reference group) ranged from 1.07 (95% CL = 0.99-1.17) for the unemployed and retired subjects, to 1.19 (95% CL = 0.93-1.53) for agricultural and factory workers and unskilled labourers.