Spirometric recordings of 1098 Malaysian children who were free of respiratory symptoms were examined by least square regression analysis of log-transformed lung function data. Ethnic differences were observed in FVC, FEV1, and FEF25-75 independent of father's education, exposure to passive smoking, wood stove, kerosene stove and mosquito repellents, family history of chest illness and history of allergy, after adjusting for standing height, age and sex. Exposure to kerosene stove was significantly associated with reduced FVC and FEV1 indicating that environmental factors may impair lung function in symptomless children. Prediction equations were derived for each ethnic group and sex. Comparison with data from the literature showed that Malaysian children had lower lung function values than Caucasian children. Generally, Chinese children had higher FEV1, FVC and FEF25-75 than Malay and Indian children. Indian children consistently had the lowest lung function values. Since these ethnic differences were independent of environmental and other host factors, anthropometric variations could be an explanation.
In a cross-sectional study of 7-12 year-old primary school children in Kuala Lumpur city, lung function was assessed by spirometric and peak expiratory flow measurements. Spirometric and peak expiratory flow measurements were successfully performed in 1,214 and 1,414 children, respectively. As expected, the main predictors of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), and peak expiratory flow rate (PEFR) were standing height, weight, age, and sex. In addition, lung function values of Chinese and Malays were generally higher than those of Indians. In multiple regression models which included host and environmental factors, asthma was associated with significant decreases in FEV1, FEF25-75, and PEFR. However, family history of chest illness, history of allergies, low paternal education, and hospitalization during the neonatal period were not independent predictors of lung function. Children sharing rooms with adult smokers had significantly lower levels of FEF25-75. Exposures to wood or kerosene stoves were, but to mosquito repellents were not, associated with decreased lung function.
The effects of indoor environmental factors on respiratory illness were studied in 15017-12 year old school children in Kuala Lumpur. Exposure to mosquito coil smoke for at least three nights a week was independently associated with asthma and persistent wheeze. Passive smoking, defined as sharing a bedroom with an adult smoker, was independently associated with a chest illness in the past year. No relationships were found between exposure to kerosene stoves, wood stoves, fumigation mat mosquito repellents or aerosol insecticides and respiratory illness. Host factors predictive of at least one respiratory outcome included family history of chest illness, history of allergy, male sex, hospitalization in the neonatal period and low paternal education. With 95% confidence, avoidance of regular exposure to mosquito coil smoke and passive smoking could reduce the prevalences of persistent wheeze, asthma and chest illness by up to 29%. Measurements of lung function confirmed the validity of questions pertaining to wheezing and asthma in the study questionnaire.
Prediction equations for peak expiratory flow rate (PEFR) of Malay, Chinese and Indian children were obtained by analysing 1020 PEFR recordings of children free of respiratory symptoms and illnesses. Boys had significantly higher PEFR than girls. For both sexes the highest levels of PEFR were observed in Malays and the lowest in Indians. The differences between Malay and Chinese boys were not statistically significant but the levels of PEFR for Malay and Chinese boys were significantly higher than those for Indian boys. In girls the differences among the ethnic groups were not statistically significant. Although ethnic differences were observed in boys these differences might not be clinically important. A common prediction equation for each sex should be both practical and accurate. When compared with predicted levels for white American and Australian children the predicted levels of PEFR of Malaysian children were found to be lower; these differences could be clinically important and the use of standards for Western children when assessing Malaysian children might not be appropriate.
To investigate the role of serum C-reactive protein (CRP) in the diagnosis of typhoid fever, we studied 227 febrile Malaysian children hospitalized during a 12-month period. The children were: culture-positive for Salmonella typhi (Group 1; n = 108); culture-negative but with typical clinical features of typhoid fever (Group 2; n = 60); or had non-typhoidal illness (Group 3; n = 59). Group 1 children had the highest serum CRP concentrations (geometric mean [SD range]; 43 [12-150] mg/l vs. 26 [8-85] mg/l in Group 2 and 21 [4-110] mg/l in Group 3; p < 0.001). In regression analysis, age, patient group and fever duration were independently associated with serum CRP (p < 0.05) but gender was not. In Group 1 patients, there was a significant positive association between serum CRP and Widal O and H agglutinin titres. In receiver-operator characteristic (ROC) analysis of serum CRP for Groups 1 and 2 combined, compared with Group 3, the area under the curve (AUC) was 0.65. These data show that the serum CRP is highest in culture-positive children with enteric fever and reflects the immune response to the infection in this group. Nevertheless, serum CRP had relatively low sensitivity and specificity for confirmed or clinically diagnosed typhoid fever (68 and 58 per cent, respectively at 'cut-off' concentration 30.0 mg/l), and an AUC value only moderately above that associated with no predictive power (0.5). Although of limited use as a primary diagnostic test, a raised serum CRP may still have a place as one of a range of features that facilitate assessment of a febrile child in a typhoid-endemic area.