Persistence of Pneumococcal Serotype 3 in Adult Pneumococcal Disease in Hong Kong.

The epidemiology of hospitalised pneumococcal disease in adults following the introduction of universal childhood pneumococcal immunisation in 2009 was assessed. Culture-confirmed Streptococcus pneumoniae (SP) from adults hospitalised between 2009 to 2017 were examined. The cases were categorised into invasive pneumococcal disease (IPD) and pneumonia (bacteraemic, non-bacteraemic, and that associated with other lung conditions). The isolates were serotyped and antimicrobial susceptibilities were determined by microbroth dilution. Patient characteristics, comorbidities, and outcomes were analysed. Seven hundred and seventy-four patients (mean age, 67.7 years, SD ± 15.6) were identified, and IPD was diagnosed in 110 (14.2%). The most prevalent serotype, 19F, was replaced by serotype 3 over time. Penicillin and cefotaxime non-susceptibilities were high at 54.1% and 39.5% (meningitis breakpoints), 19.9% and 25.5% (non-meningitis breakpoints), respectively. The overall 30-day mortality rate was 7.8% and 20.4% for IPD. Age ≥ 75 years (OR:4.6, CI:1.3-17.0, p < 0.02), presence of any complications (OR:4.1, CI:1.02-16.3, p < 0.05), pleural effusion (OR:6.7, CI:1.2-39.4, p < 0.03) and intensive care unit (ICU) admission (OR:9.0, CI:1.3-63.4, p < 0.03) were independent predictors of 30-day mortality. Pneumococcal disease by PCV 13 covered serotypes; in particular, 19F and 3 are still prominent in adults. Strengthening targeted adult vaccination may be necessary in order to reduce disease burden.

Validation of prediction equations for estimating resting energy expenditure in obese Chinese children.

OBJECTIVES: (1) To examine the validity of existing prediction equations (PREE) for estimating resting energy expenditure (REE) in obese Chinese children, (2) to correlate the measured REE (MREE) with anthropometric and biochemical parameters and (3) to derive a new PREE for local use. DESIGN: Cross-sectional study. SUBJECTS: 100 obese children (71 boys) were studied. MEASUREMENTS: All subjects underwent physical examination and anthropometric measurement. Upper and central body fat distribution was signified by centrality and conicity index respectively, and REE was measured by indirect calorimetry. Fat free mass (FFM) were measured by DEXA scan. Thirteen existing prediction equations for estimating REE were compared with MREE among these obese children. Fasting blood for glucose, lipid profile and insulin were obtained. RESULTS: The overall, male and female median MREEs were 7.1 mJ/d (IR 6.2-8.4), 7.3 mJ/d (IR 6.3-9.7) and 6.9 mJ/d (IR 5.6-8.1) respectively. No sex difference was noted in MREE (p=0.203). Most of the equations except Schofield equation underestimated REE of our children. By multiple linear regression, MREE was positively correlated with FFM (p<0.0001), conicity index (p<0.001) and centrality index (p=0.001). A new equation for estimating REE for local use was derived as: REE=(17.4*logFFM)+(11.4*conicity index)-(2.4*centrality index)-31.3. The mean difference of new PREE-MREE was -0.011 mJ/d (SD 1.51) with an interclass correlation coefficient of 0.91. CONCLUSION: None of the existing prediction equations were accurate in their estimation of REE, when applied to obese Chinese children. A new prediction equation has been derived for local use.

Body fat measured by bioelectrical impedance in Hong Kong Chinese children.

OBJECTIVE: To establish reference standards for percentage body fat measured in Hong Kong Chinese children, by methods involving bioelectrical impedance analysis. DESIGN: Cross-sectional study. SETTING: Thirty-six randomly selected primary and secondary schools and a teaching hospital in Hong Kong. PARTICIPANTS: A total of 14 842 students randomly selected from the schools and two additional small convenience samples of subjects. MAIN OUTCOME MEASURES: Percentage body fat was measured with the Tanita Body Composition Analyzer (Model no. BF-522) and percentile curves were constructed using the LMS method. In one separate small sample of children, repeatability of the percentage body fat measurement was assessed at different times of the day by BF-522 bioelectrical impedance analysis. In another sample, assessment was by the BF-522 and two other models (BC-418 and BF-401) consecutively to test the agreement of percentage body fat values obtained by the three different models. RESULTS. The percentage body fat values and percentile curves are presented. From the age of 6 to 18 years, the percentage body fat remained fairly stable in boys, but increased steadily in girls. The mean difference in percentage body fat measured with BF-522 at different times of the day was around 1% (95% limits of agreement: -4% to +8%). The mean differences in readings obtained from the BC-418 and BF-522 devices were -3.5% and 1% in boys and girls, respectively. The 95% limits of agreement were particularly wide in boys (-15% to 8%). CONCLUSIONS: Reference values for percentage body fat of Chinese children and adolescents are provided. Caution needs to be exercised however, given that readings obtained at different times of the day vary and data obtained by different makes and models of bioelectrical impedance analysis machines may not be interchangeable.

Secular changes in height, weight and body mass index in Hong Kong Children.

BACKGROUND: Large population growth surveys of children and adolescents aged 6 to 18 y were undertaken in Hong Kong in 1963 and 1993. The global epidemic of obesity is a major public health concern. To monitor the impact of this epidemic in Hong Kong children and to identify secular changes in growth, a further growth survey was undertaken in 2005/6. METHODS: Cross-sectional height and weight measurements of 14,842 children and adolescents aged 6 to 18 y from Hong Kong's 18 districts were obtained during the 2005/6 school year. Percentile curves were constructed using LMS method and sex-specific percentile values of weight-for-age, height-for-age, and BMI-for-age were compared with those data from 1963 and 1993. RESULTS: Secular changes in height, weight and BMI were noted between 1963 and 1993 and between 1993 and 2005/6. In the latter period, greater changes were observed at younger ages, and particularly in boys. On an annual basis, the 1993-2005/6 changes were less than those during 1963-1993. Using the International Obesity Task Force cut-offs, 16.7% of children were overweight or obese in 2005/6, which was a 5.1% increase since 1993. CONCLUSION: These data provide policy-makers with further evidence of the secular changes in child growth and the increasing obesity epidemic among Hong Kong children.

Waist circumference and waist-to-height ratio of Hong Kong Chinese children.

BACKGROUND: Central body fat is a better predictor than overall body fat for cardiovascular (CV) risk factors in both adults and children. Waist circumference (WC) has been used as a proxy measure of central body fat. Children at high CV risk may be identified by WC measurements. Waist-to-height ratio (WHTR) has been proposed as an alternative, conveniently age-independent measure of CV risk although WHTR percentiles have not been reported. We aim to provide age- and sex-specific reference values for WC and WHTR in Hong Kong Chinese children. METHODS: Cross sectional study in a large representative sample of 14,842 children aged 6 to 18 years in 2005/6. Sex-specific descriptive statistics for whole-year age groups and smoothed percentile curves of WC and WHTR were derived and presented. RESULTS: WC increased with age, although less after age 14 years in girls. WHTR decreased with age (particularly up to age 14). WHTR correlated less closely than WC with BMI (r = 0.65, 0.59 cf. 0.93, 0.91, for boys and girls respectively). CONCLUSION: Reference values and percentile curves for WC and WHRT of Chinese children and adolescents are provided. Both WC and WHTR are age dependent. Since the use of WHRT does not obviate the need for age-related reference standards, simple WC measurement is a more convenient method for central fat estimation than WHRT.

Smoking pattern during pregnancy in Hong Kong Chinese.

BACKGROUND: While the prevalence of young female smokers is rising among the Hong Kong Chinese population, data on their smoking pattern during pregnancy are limited. AIMS: To investigate the smoking habit of Hong Kong Chinese women and their partners during pregnancy. METHODS: Postal questionnaires were sent to 479 couples to explore their smoking patterns during pregnancy at one to two years after the index delivery. RESULTS: Questionnaires were completed by 247 subjects. Among 117 women who were ever-smokers, 26% had stopped smoking before the index pregnancy, while 60% stopped and 14% reduced smoking during the pregnancy. Most women stopped smoking in the first trimester (93%) and prior to the first antenatal visit (79%). Those who used to smoke fewer cigarettes before pregnancy were more likely to stop smoking during pregnancy but women with a history of recreational drug use were more likely to continue smoking during pregnancy. The post-partum smoking relapse rate was 59% in women who had stopped smoking before or during their pregnancy. Only 2.6% of the partners who were ever-smokers stopped smoking before the pregnancy while smoking habits remained unchanged in 52%. CONCLUSIONS: Approximately one-fifth of an unselected sample of Hong Kong mothers had a history of smoking prior to pregnancy. Pregnancy is an opportune time to implement smoking intervention programs for female smokers and their partners with an emphasis on the maintenance of post-partum smoking abstinence.

Oscillometrically measured blood pressure in Hong Kong Chinese children and associations with anthropometric parameters.

BACKGROUND: Oscillometric devices are increasingly used to measure blood pressure (BP). Reference data are limited and have not used devices validated against sphygmomanometric measurements on which current standards are based. BP standards for Chinese children have been based on sphygmomanometry and have not provided height-related or weight-related BP percentiles. METHODS: BP was measured in 14842 Hong Kong Chinese schoolchildren aged 6-18 years randomly selected from 36 schools in the 18 Hong Kong districts, using a validated oscillometric device (Datascope Accutorr Plus). Height, weight, heart rate and waist circumference were measured. Percentiles for systolic BP and diastolic BP by sex, age, height and weight were generated. Features associated with systolic BP and diastolic BP in 12680 children were analysed by univariate and multivariate analysis. RESULTS: Reference BP standards by sex, age, weight and height are presented. BP was associated (in descending order of strength) with weight > height > age > waist circumference > body mass index, and weakly with heart rate (which added considerable influence on multivariate analysis). BP increases similarly with age, height (which can normalize for variations in growth) and weight (which is associated most strongly with BP). BP was associated also with family history of high BP and (inversely) with sleep duration. CONCLUSIONS: The study provides oscillometrically measured BP standards for Chinese children, with age-related and sex-related height-specific and weight-specific percentiles. Implications of the findings are discussed. Screening by sex-specific BP-height percentile charts, and then if high, reference to the BP-sex-age-weight table, is suggested.

Assessing disease burden of respiratory disorders in Hong Kong children with hospital discharge data and linked laboratory data.

OBJECTIVES: To describe the pattern of respiratory disorders in the Hong Kong paediatric population admitted to government hospitals, and to assess the reliability of the diagnoses by linkage with laboratory data. METHODS: Discharge diagnoses for all admissions are recorded in a central computerised database, the Clinical Management System. These data were analysed for the inclusive period July 1997 to June 1999. Virology laboratory results from a single hospital were linked to the Clinical Management System diagnostic codes to examine discrepancies in coding specific viral aetiologies. RESULTS: A primary diagnosis of a respiratory disorder was noted in 37.5% (upper respiratory 30.1%, tonsillitis/pharyngitis 10.5%, croup/laryngitis 2.3%, acute otitis media 2.7%, bronchitis/chest infection 2.6%, bronchiolitis 10.2%, pneumonia 20.9%, influenza 4%, asthma and allergic rhinitis 16.5%), and a primary or secondary diagnosis in 42.5% of children younger than 15 years. The incidence rates of respiratory illness coded as bronchiolitis and influenza were respectively estimated to be 887-979 and 222-381 per 100,000 children under 5 years and 3551-3949 and 415-528 per 100,000 children under the age of 1 year. The percentage of respiratory-associated admissions varied significantly by hospital and detailed analysis of data at one hospital highlighted important discrepancies between discharge diagnosis and laboratory results. CONCLUSIONS: These passive surveillance data provide general estimates of the disease burden for respiratory disorders in Hong Kong children. Active surveillance studies are required to provide more accurate estimates of the disease burden. Consideration should be given to enhance the Clinical Management System by routinely linking all laboratory data with discharge diagnosis information, by establishing sentinel surveillance hospitals and by assessing new strategies to standardise coding.

Insulin and obstructive sleep apnea in obese Chinese children.

OBJECTIVE: In adults, obstructive sleep apnea (OSA) is associated with insulin resistance and dyslipidemia. We aimed to establish correlation between OSA, serum lipid profile, and insulin levels in obese snoring children. METHODS: Consecutive obese children with habitual snoring were recruited. They underwent physical examination, overnight polysomnography (PSG), and metabolic studies. OSA was diagnosed if apnea hypopnea index (AHI) > 1.0, and cases were considered to have moderate to severe OSA if AHI > 10. RESULTS: Ninety-four obese subjects with habitual snoring were studied. Seventy-three subjects were male and the median age of the studied group was 12.0 years (IQR 9.7-13.9). None of the subjects had active cardiopulmonary disease, and the BMI values of our subjects were >95th percentile using local reference charts. Sixty subjects had OSA, 47 being mild, and 13 being moderate to severe OSA. Multiple logistic regression analysis revealed that saturation nadir and insulin levels were significantly associated with OSA. CONCLUSION: OSA is prevalent among obese children with habitual snoring and insulin is independently associated with the condition. Its role in the cardiovascular complications of childhood sleep apnea is worthy of further exploration.

Breast milk dioxins in Hong Kong and Pearl River Delta.

There are no previous reports from South China on chemically determined polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) in human breast milk expressed as World Health Organization (WHO) toxic equivalents (TEQs). In a 2002-2003 WHO exposure study, 13 pools of breast milk comprising samples from 316 primiparous women in Hong Kong in 2002 were analyzed by gas chromatography/mass spectrometry for 29 PCDD/F and dioxin-like PCB congeners. Total WHO-TEQs ranged from 8.97 to 16.7 pg/g fat (weighted mean, 12.9 pg; weighted median, 13.4 pg). Variations in TEQs included positive associations with age (R2 = 0.73, p < 0.0005), higher consumption of dairy products and seafood, and lower TEQs in overseas mothers and ever-smokers. Congener profiles indicated geographic specificity of exposure in Hong Kong, mainland China, and overseas Asian countries, including higher proportions of PCB-TEQs (overseas) and PCDF-TEQs (mainland China). The median TEQs of PCDD/Fs (8.69 pg/g fat) and PCBs (4.73 pg/g fat) in Hong Kong were highest among the five Asian Pacific countries but lower than the levels for at least half of the European countries that participated in the WHO study. However, future international studies should incorporate mother's age in the design of the pooling strategy to allow standardization by other exposure factors and valid comparisons among different countries. The findings allow support for the WHO breast-feeding advisory. Trends in human dioxin levels in the region cannot yet be determined, and rigorous controls are needed to reduce emissions of dioxins and human exposure in mainland China.

Gender disparity in paediatric hospital admissions.

INTRODUCTION: To determine the magnitude of gender difference in paediatric hospital admissions. MATERIALS AND METHODS: We reviewed discharge data of general medical paediatric admissions to a university teaching hospital in Hong Kong from 1984 to 2000. Based on ICD-9 codes, 9 broad categories of disease with related sub-categories were used, namely respiratory, gastrointestinal, neurological, renal, cardiac, haematological/oncological, neonatal, miscellaneous and social. Data on patients admitted to the haematological, oncological and neonatal wards were excluded from this analysis. RESULTS: There were 92,332 patients admitted to the general paediatric wards. The 7 leading causes for admission accounted for 62% of all admissions: gastroenteritis (14%), upper respiratory tract infections (12%), asthma/wheezy bronchitis (10%), pneumonia (10%), bronchiolitis (6%), febrile convulsions (7%) and other convulsions (4%). Across almost all categories, there was a consistent excess of males (59.1% of all admissions). The male excess was even more pronounced for urinary tract infections (72%) and nephrotic syndrome (80%). The main sub-categories without this male predominance were accidents, accidental ingestion and social admissions (50% males), failure to thrive (49% males), acyanotic congenital heart disease (48%), endocrine (42%), auto-immune conditions (30%) and attempted suicide (19%). CONCLUSIONS: Although male vulnerability to illness has long been recognised, the consistency and magnitude of these gender differentials in admissions was impressive. More vigorous exploration of the underlying mechanisms responsible for this phenomenon is warranted.