Normative values of motor performance and their relationship with BMI status in Hong Kong preschoolers

This study aimed to establish sex- and age-specific reference values for motor performance (MP) in Hong Kong preschoolers aged 3-5 years old and examine the relationship between MP and BMI status. A cross-sectional study was conducted among 5579 preschoolers in Hong Kong. Three MP tests were administered, and height and weight information were collected. GAMLSS was used to compute the normative values of the motor tests. Boys outperformed girls in activities requiring muscle strength and power, while girls outperformed boys in activities requiring balance and coordination. The MP scores increased with age for both overarm beanbag throw and standing long jump for both sexes, while the one-leg balance scores showed larger differences between P50 and P95 in older preschoolers. Children with excessive weight performed worse in standing long jump and one-leg balance compared to their healthy weight peers. This study provides valuable information on the MP of preschoolers in Hong Kong, including sex- and age-specific reference values and the association between BMI status and MP scores. These findings can serve as a reference for future studies and clinical practice and highlight the importance of promoting motor skill development in preschoolers, particularly those who are overweight or obese.

The view of Hong Kong parents on secondary use of dried blood spots in newborn screening program

Background

Residual dried blood spots (rDBS) from newborn screening programmes represent a valuable resource for medical research, from basic sciences, through clinical to public health. In Hong Kong, there is no legislation for biobanking. Parents’ view on the retention and use of residual newborn blood samples could be cultural-specific and is important to consider for biobanking of rDBS.

Objective

To study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese parents.

Methods

A mixed-method approach was used to study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese parents of children 0–3 years or expecting parents through focus groups (8 groups; 33 participants) and a survey (n = 1012, 85% mothers) designed with insights obtained from the focus groups. We used framework analysis to summarise the themes as supportive factors, concerns and critical arguments for retention and secondary use of rDBS from focus group discussion. We used multiple logistic regression to assess factors associated with support for retention and secondary use of rDBS in the survey.

Results

Both in focus groups and survey, majority of parents were not aware of the potential secondary use of rDBS. Overall secondary use of rDBS in medical research was well accepted by a large proportion of Hong Kong parents, even if all potential future research could not be specified in a broad consent. However parents were concerned about potential risks of biobanking rDBS including leaking of data and mis-use of genetic information. Parents wanted to be asked for permission before rDBS are stored and mainly did not accept an “opt-out” approach. The survey showed that parents born in mainland China, compared to Hong Kong born parents, had lower awareness of newborn screening but higher support in biobanking rDBS. Higher education was associated with support in rDBS biobanking only among fathers.

Conclusion

Long-term storage and secondary use of rDBS from newborn screening for biomedical research and a broad consent for biobanking of rDBS are generally acceptable to Hong Kong parents given their autonomy is respected and their privacy is protected, highlighting the importance of an accountable governance and a transparent access policy for rDBS biobanks.

In utero exposure to gestational diabetes and adiposity: does breastfeeding make a difference?

BACKGROUND/OBJECTIVES

Short-term breastfeeding from mothers with gestational diabetes (GDM) may programme metabolism and increase offspring diabetes risk. We examined the association of in utero GDM exposure with adiposity from infancy to adolescence, and whether any association was modified by breastfeeding during early infancy.

METHODS

In the prospective Chinese birth cohort "Children of 1997" (n = 7342, 88% follow-up rate), generalised estimate equations with multiple imputation were used to assess associations of in utero GDM exposure with age- and sex-specific body mass index (BMI) z-score during infancy (3 and 9 months), childhood (2- < 8 years) and adolescence (8-16 years), adjusted for sex, parity, maternal age, birth place, preeclampisa, smoking, and family socio-economic position. We also tested whether the associations differed by mode of infant feeding (always formula-fed, mixed, always breastfed) during the first three months of life.

RESULTS

In utero GDM exposure (7.5%) was associated with a lower BMI z-score during infancy (-0.13, 95% confidence interval (CI) -0.22, -0.05) but higher BMI z-scores during childhood (0.14, 95% CI 0.03, 0.25) and adolescence (0.25 95% CI 0.11, 0.38). Breastfeeding for the first three months did not modify the association of in utero GDM status with subsequent BMI (all p values for interaction >0.4).

CONCLUSIONS

In utero GDM exposure was associated with greater adiposity during childhood and adolescence. Breastfeeding in early infancy from mothers with GDM was not associated with greater adiposity in children and thus should still be encouraged.

Self-reported waist circumference: a screening tool for classifying children with overweight/obesity and cardiometabolic risk factor clustering

OBJECTIVES

The objectives of this study were twofold - (i) to assess the agreement between self-reported waist circumference (SRWC) and assessor measured waist circumference (MWC) and (ii) to evaluate the diagnostic ability of SRWC for classifying (i) a clustering of cardiometabolic risk factors (CMRFs) and (ii) overweight/obese status in Hong Kong Chinese children aged 6-18 years.

METHODS

A cross-sectional study with cluster random sampling was conducted. A self-administrated questionnaire, which included demographic data, body weight, body height and waist circumference, was given to children to bring home for completion. Children were asked to return the questionnaire and fast themselves for at least 8 h on the day of the survey. Anthropometric measurements and blood pressure were taken by trained research staff and fasting blood samples were collected for measurements of fasting plasma glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol.

RESULTS

A total of 515 boys and 711 girls were included in the data analysis. Agreement between SRWC and MWC was assessed by intra-class correlation coefficient and it ranged from 0.77 to 0.87. The ability of sex-specific SRWC values to classify children with a clustering of CMRFs and overweight/obesity exhibited moderately high to high sensitivity and specificity, and the area under the receiver operating characteristics ranged from acceptable to excellent (from 0.76 to 0.84).

CONCLUSIONS

SRWC has good agreement with MWC and could be used as a screening tool to classify children with a clustering of CMRFs and overweight/obesity status in Hong Kong Chinese children.

Role of low-glycemic index diet in management of childhood obesity

Conventional dietary recommendation for obesity management is a low-fat energy-restricted diet, which however, only have modest and non-sustained effects on weight reduction. Alternative dietary interventions, including low-glycemic index (GI) diet, have been proposed. Glycemic index is a measure of blood glucose excursion per unit of carbohydrate. Foods with high GI are rapidly digested, absorbed and transformed into glucose. These processes cause accelerated and transient surges in blood glucose and insulin, earlier return of hunger sensation and excessive caloric intake. Conversely, low-GI diet decreases blood glucose and insulin excursion, promotes greater fat oxidation, decreases lipogenesis and increases satiety. Modern food-processing technology has produced many food products with high GI which may contribute to the burgeoning epidemic of obesity especially in children/adolescents. Epidemiological and clinical trials suggest a role for low-GI diet in the management of childhood obesity and associated cardio-metabolic risks although results are not always consistent. In this article, we shall review the physiological basis and current evidence for and against low-GI diet in obesity management, with particular focus in children and adolescents.

Implications of using World Health Organization growth reference (2007) for identifying growth problems in Hong Kong children aged 6 to 18 years

OBJECTIVE

To evaluate the implications of replacing Hong Kong's 1993 growth references (HK1993) with the World Health Organization's 2007 references (WHO2007) for children aged 6 to 18 years.

DESIGN

Cross-sectional study.

SETTING

Thirty-six randomly selected primary and secondary schools in Hong Kong.

PARTICIPANTS

A total of 14 842 children and adolescents aged 6 to 18 years in Hong Kong during 2005/06.

MAIN OUTCOME MEASURES

Creation of age-specific z-scores for height, weight, and body mass index relative to HK1993 and WHO2007 references.

RESULTS

Use of WHO2007 instead of HK1993 could classify an additional 1.4% children aged 6 to 10 years and 2.8% children aged 11 to 18 years as having a short stature. Using WHO2007, respective proportions that could be classified as underweight and obese increased by 3.5% and 2.1% among children aged 6 to 10 years, and 5.5% and 1.6% among children aged 11 to 18 years.

CONCLUSIONS

Use of WHO2007 could increase clinical workload and patient and parent anxiety by 'over-diagnosing' short stature and underweight. Although WHO2007 may have a role in international comparative research, retention of HK1993 would seem appropriate from a clinical perspective.

Factors associated with length of hospital stay in children with respiratory disease

OBJECTIVES

To explore factors associated with length of stay, and secondarily to explore the potential of enhanced diagnostics to address respiratory disease burden in children.

DESIGN

Prospective study.

SETTING

A university teaching hospital in Hong Kong.

PATIENTS

Data from 475 children with respiratory tract symptoms or fever admitted to Prince of Wales Hospital, Hong Kong from November 2005 to April 2007.

MAIN OUTCOME MEASURES

Aetiological diagnoses based on enhanced diagnostics and their association with clinical information.

RESULTS

Data from 469 subjects showed that major presentations were fever (84%), cough (72%), and runny nose (64%). The median length of stay was longest (3 days) for adenovirus, metapneumovirus and mycoplasma infections, while children with negative aetiological results had a median length of stay of 2 days. Fever duration during admission (P<0.001), the highest recorded temperature during admission (P < 0.001), use of antibiotics during admission (P<0.001), ear pain before admission (P = 0.019), and high white cell counts (P = 0.021) were associated with increased length of stay (univariate analysis). Identifying an aetiological agent did not affect length of stay. Comparison of children with a positive immunofluorescence test result (rapidly available) with those in whom the test was negative though a positive multiplex polymerase chain reaction ensued (result not available to clinicians) also showed no association with length of stay.

CONCLUSION

Although rapid enhanced diagnostics may not have a major influence on length of stay, these data form an integral part of enhanced sentinel surveillance systems.

Residues of persistent organic pollutants (POPs) in human milk in Hong Kong

Data on pesticide body load in the south China region are scarce. Here, we report the concentrations of 24 persistent organic pollutants (POPs), in 10 pools of human milk samples, collected at 2-6weeks postpartum from 238 primiparous women living in Hong Kong and south China, who participated in the 2002-2003 WHO exposure study. Residues were determined by gas chromatography with electron capture detector and confirmed by gas chromatography with mass spectrometry. The mean levels of alpha-HCH (mean 0.6ngg(-1) fat), beta-HCH (940ngg(-1) fat), gamma-HCH (1.8ngg(-1) fat), dieldrin (1.0ngg(-1) fat) and HCB (21.8ngg(-1) fat) were much lower than the 1985 estimates. Mean levels of alpha-HCH, gamma-HCH, dieldrin, cis-heptachlor-epoxide (0.7ngg(-1) fat), sum-chlordane (6.1ngg(-1) fat), trans-nonachlor (12.0ngg(-1) fat), BDE 47 (1.9ngg(-1) fat) and sum PBDE (3.4ngg(-1) fat) were comparable to the international median levels of the 15 other countries participating in the 2002-03 WHO exposure study. Hong Kong had the highest level of beta-HCH, possibly a residual effect of previous high exposures in the 1970s. Body loads of beta-HCH and chlordane were lower among mothers with younger age while mothers born in mainland China had lower levels of beta-HCH, cis-heptachlor-epoxide, oxy-chlordane and trans-nonachlor. Levels of toxaphene, endrin, endosulfan, bromcyclene and nitrofen were not detected in all or almost all of the milk pools. Continuous monitoring of POPs in human milk, especially beta-HCH, is needed for surveillance and interpretation of time trends, and for linkage to strict enforcement of agricultural regulations.

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.

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.

Identification of viral and atypical bacterial pathogens in children hospitalized with acute respiratory infections in Hong Kong by multiplex PCR assays

Acute respiratory tract infection is a leading cause of hospital admission of children. This study used a broad capture, rapid and sensitive method (multiplex PCR assay) to detect 20 different respiratory pathogens including influenza A subtypes H1, H3, and H5; influenza B; parainfluenza types 1, 2, 3, and 4; respiratory syncytial virus (RSV) groups A and B; adenoviruses; human rhinoviruses; enteroviruses; human metapneumoviruses; human coronaviruses OC43, 229E, and SARS-CoV; Chlamydophila pneumoniae; Legionella pneumophila; and Mycoplasma pneumoniae; from respiratory specimens of 475 children hospitalized over a 12-month period for acute respiratory tract infections. The overall positive rate (47%) was about twice higher than previous reports based on conventional methods. Influenza A, parainfluenza and RSV accounted for 51%, and non-cultivable viruses accounted for 30% of positive cases. Influenza A peaked at March and June. Influenza B was detected in January, February, and April. Parainfluenza was prevalent throughout the year except from April to June. Most RSV infections were found between February and September. Adenovirus had multiple peaks, whereas rhinovirus and coronavirus OC43 were detected mainly in winter and early spring. RSV infection was associated with bronchiolitis, and parainfluenza was associated with croup; otherwise the clinical manifestations were largely nonspecific. In general, children infected with influenza A, adenovirus and mixed viruses had higher temperatures. In view of the increasing concern about unexpected outbreaks of severe viral infections, a rapid multiplex PCR assay is a valuable tool to enhance the management of hospitalized patients, and for the surveillance for viral infections circulating in the community.

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.

DDT levels in human milk in Hong Kong, 2001-02

High levels of p,p'-DDT were detected in Hong Kong breast milk sampled in 1976 and 1985. Monitoring DDT levels in human breast milk in this region is important to identify trends in exposure. As part of the 2002-03 WHO/EURO coordinated exposure study, the concentrations of DDT and its metabolites were determined in 10 pooled milk samples classified by geographic origin and dietary history, comprising milk samples from 238 primiparous mothers giving birth in Hong Kong. Analysis was performed by Gas Chromatography (GC) with electron capture detector and confirmed by GC/Mass Spectrometry. The sum-DDT concentration (range: 0.92-2.05 mg/kg fat) was age-dependent and indicated a decreasing trend since the 1970s. Mothers who recently came from mainland China had higher p,p'-DDT to p,p'-DDE ratios, suggesting a more recent exposure compared to women mainly residing in Hong Kong. The average Hong Kong sum-DDT level (1.50 mg/kg fat) was among the highest of the contemporary levels (range: 0.12-1.97 mg/kg fat; median: 0.40 mg/kg fat) in the 16 countries/regions participating in the 2002-03 WHO/EURO exposure study. This is probably due to the previous extensive DDT exposure and continuing use of DDT in agriculture in mainland China. Despite the apparent decrease of DDT body load over 30 years, the environmental health hazard from DDT contamination in the Pearl River Delta region remains a concern. Measures to eradicate illegal use of DDT in mainland China and regular food monitoring programs are needed in the region. Despite the presence of DDT and other persistent organic pollutants in human breast milk, breastfeeding should continue to be strongly supported for its life-long benefits to infants.

The effect of diet and strength training on obese children's physical self-concept

AIM

The aim of this study was to examine the effects of a 6-week diet and exercise program, with emphasis on strength training, on the physical self-concept, body composition, and physical fitness of young overweight and obese children.

METHODS

Eighty-two overweight and obese children aged 8-11 years were randomized into a diet-only or a diet-and-strength training group. Self-concept, body composition and physical fitness were measured before and after the 6-week study period using the Physical Self Description Questionnaires (PSDQ), dual-energy X-ray absorptiometry (DXA), and standard fitness tests. Dietary intake was assessed with a food frequency questionnaire. Total daily energy intake was significantly reduced in both groups with a trend of more reduction in the diet-only group.

RESULTS

Both groups developed greater confidence in strength. Those in the diet-and-strength training group also improved their endurance self-concept. Body Mass Index (BMI) decreased significantly in both groups. Lean mass increased significantly in both groups but significantly more in the diet-and-strength training group (+0.8 kg vs +0.3 kg, P<0.05). Handgrip, shuttle run, sit-up, and push-up were significantly improved in both groups, to a significantly greater extent in the diet-and-strength training group.

CONCLUSION

These findings confirm the 6-week program of either diet-only or diet-and-strength training improved overweight/obese children's self-perception of muscular strength and body composition. With the diet-and-strength training program, self-concept in endurance also improved and the gain in lean body mass was more than double that of the diet only group.

Rotavirus vaccination for Hong Kong children: an economic evaluation from the Hong Kong Government perspective

AIMS

To perform an economic analysis of government-funded universal rotavirus vaccination in Hong Kong from the government's perspective.

METHODS

A Markov model of costs and effects (disability averted) associated with universal vaccination was compared with no vaccination. In both strategies, newborns were studied until 5 years of age or until they died, using cost, probability and utility data from the literature. The potential cost savings and cost effectiveness of vaccination were calculated and their sensitivities to changes in vaccine and health care costs, presumed decline in vaccine efficacy over time, and the use of discounting and age weights were determined.

RESULTS

Depending on assumptions, the new rotavirus vaccines would be cost saving to the Hong Kong Government if they cost less than US$40-92 per course. Higher vaccine costs would quickly lead to an incremental cost-effectiveness ratio exceeding that of the gross national product per capita if the mortality rate of rotavirus gastroenteritis remained at zero.

CONCLUSIONS

Based on 2002 demographic, cost and morbidity data and reasonable uncertainty estimates of these variables, a universal rotavirus vaccination programme paid for by the Hong Kong Government is cost neutral at a per course vaccine cost of US$40-92. For a fixed vaccine cost, the potential savings and cost effectiveness of the vaccine increase with higher estimated health care costs and vice versa.

Agreement between breast milk dioxin levels by CALUX bioassay and chemical analysis in a population survey in Hong Kong

Chemically-activated luciferase gene expression (CALUX) bioassay and gas chromatography/mass spectrometry (GC/MS) are used to determine dioxin levels in food and humans. Valid measures of the agreement between the two methods would improve interpretation of bioassay results. Paired breast milk samples from 250 mothers, as 11 pooled samples, were analysed by GC/MS for total WHO-TEQ (7 polychlorinated dibenzo-para-dioxins, 10 polychlorinated dibenzofurans and 12 dioxin-like polychlorinated biphenyls) and as individual samples by CALUX. Mean difference between total WHO-TEQ (weighted by TEF system derived in 1997) and mean CALUX-TEQ in each pool was 1.6 pg/g fat (95% CI: 0.7, 2.4), indicating a statistically significant overestimation of CALUX-TEQ compared to WHO-TEQ, probably due to the presence of Ah-receptor agonists. CALUX estimated toxicity of 13 pg/g fat was greater than the WHO-TEQ by 0.9, 3.1 and 0.3 pg/g fat for mothers from Hong Kong, mainland China and overseas territories, respectively. When the 2005 TEF system was applied, a reduction of 14-26% in the WHO-TEQ and a larger but less disperse discrepancy between WHO-TEQ and CALUX-TEQ (3.9 pg/g fat, 95% CI: 3.5, 4.4) were observed. Our study suggested that the mothers' place of residence explained the discrepancy between CALUX-TEQ and WHO-TEQ and should be considered in inter-country comparisons for CALUX-TEQ. For regulatory purposes bioassays for detecting quantitative dioxin contents in any setting must be combined with adequate extraction, clean-up and validation with WHO-TEQs. The larger difference between the two measurements after using the new TEF system warrants further investigation.

Evaluation of a peer counselling programme to sustain breastfeeding practice in Hong Kong

Background

Peer counselling is reported to increase breastfeeding rates. We evaluated an intervention consisting of mainly telephone contact peer counselling programme on breastfeeding duration and exclusivity.

Methods

Peer counsellors (PCs) were mothers who had successfully breastfed and had received formal training. Following a postnatal visit, they provided scheduled telephone consultations (Days 1, 4, 7, Weeks 2, 4, 8, and Month 4) to PC group mothers (n = 100) who continued breastfeeding their infants after discharge. Control group mothers (n = 100) received routine care.

Results

After adjusting for mothers' previous breastfeeding experiences, mothers' working status and breastfeeding problems, no statistical differences in mothers' feeding methods (exclusive, almost exclusive or predominant breastfeeding) were noted at the three follow-up times for intervention and control mothers respectively (Day 5: 37%/38%, 46%/53%, 57%/63%; Month 3: 10%/9%, 17%/23%, 20%/26%; Month 6: 2%/1%, 18%/18%, 18%/19%). All differences between the groups were not significant. Also, there was no evidence to suggest that PC intervention prolonged breastfeeding duration.

Conclusion

The lack of effect of our PC intervention may reflect the low baseline breastfeeding rate and low value placed on breastfeeding in our population, the type of PC intervention or group allocation biases.

Trial registration

ISRCTN93605280.

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.

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.

Demographic and lifestyle factors associated with dioxin-like activity (CALUX-TEQ) in human breast milk in Hong Kong

Maternal exposure to dioxins and related compounds before conception may affect the health of the fetus. To identify factors affecting dioxin body load in Hong Kong, in 2002, total dioxin-like activity was estimated in 250 individual milk samples at 2-6 weeks postpartum, from a representative group of primiparous mothers, aged 18-42 years (mean 29 +/- 5 years), by a chemically activated luciferase expression (CALUX) bioassay. Associations between the CALUX-TEQ and 20 socio-demographic and dietary variables were examined separately in mothers younger than 30 years (n = 114) and 30 years or older (n = 119), by multiple linear regression analysis. CALUX-TEQ (mean 14.5 +/- 5.8 pg/g fat) significantly increased by 0.4-0.5 pg/g fat for every year of the mother's age. Mothers born in Guangdong province of China had a significantly higher CALUX-TEQ. Higher seafood consumption (older mothers; p = 0.07) and having a female baby (younger mothers; p = 0.002) were associated with a higher maternal CALUX-TEQ level. Age was the strongest factor affecting human dioxin levels in Hong Kong. Birthplace and residence are important indicators of variations in exposure to environmental pollution in the Asia Pacific region. Temporal trends in body loads of dioxins remain to be established and continuous monitoring of dioxins in humans and foods is necessary as a precautionary approach to guide environmental control measures and prevent exposure to infants.

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.

Ultrastructural assessment of Plasmodium falciparum in age-fractionated thalassaemic erythrocytes

Culture of Plasmodium falciparum in age-fractionated thalassaemic red blood cells (RBC) has shown evidence of parasite damage on light microscopy in older cells during the third culture cycle (96-144 h). In this report, parasites growing in thalassaemic trait and normal RBC were examined ultrastructurally from 96 to 144 h. All parasite stages in old thalassaemic RBC showed evidence of damage worsening with culture duration. There were cytoplasmic alterations with ribosomal damage, and parasite cytoplasm became increasingly loose and grainy, with multiple fissures. Discontinuity of the nuclear membrane with an abnormal nucleolus was seen at l20 h. Cytosomes remained normal, but damage to the food vacuole and shrunken disintegrating parasites were observed at 144 h. These changes are compatible with cellular degeneration and developmental retardation and would account for the schizont maturation arrest and reduced reinvasion rates previously reported. Increased free radicals associated with thalassaemic erythrocytes would explain these changes, further supporting the role for oxidant stress in the protective mechanism.

Meal glycaemic load of normal-weight and overweight Hong Kong children

OBJECTIVE

To describe the pattern of meal glycaemic load of children in Hong Kong and to determine whether the meal glycaemic load is associated with childhood overweight.

METHOD

Dietary records (3-day) of 316 Hong Kong children aged 6-7 years were collected. Glycaemic load was calculated from the estimated weight (WT), carbohydrate content (%CHO) and glycaemic index (GI) of each food taken using the equation: (% CHO x GI x WT/100). The meal glycaemic load was then the sum of the glycaemic loads of all food taken in each meal. Logistic regression analyses were used to compare the average meal glycaemic load (of breakfast, lunch and dinner) and other dietary parameters between overweight children and normal-weight children.

RESULTS

Breakfast, lunch, dinner and snacks provided, respectively, 17, 29, 29 and 25% of the total glycaemic load in a day. White rice (excluding congee (rice porridge) and glutinous rice) contributed almost half of the total glycaemic load. Adjusted logistic regression showed that the meal glycaemic load was not significantly associated with childhood overweight after adjusting for parental obesity, birth weight, sleeping duration, mean energy intake and paternal smoking.

CONCLUSION

Meal glycaemic load calculated from current diet was not an independent factor associated with childhood overweight in children aged 6-7 years. Our data suggested that modifying the type of rice/staple consumed and choosing low-GI snacks could have a major influence on the total meal glycaemic load of young Hong Kong children.

International Child Care Practices study: breastfeeding and pacifier use

Although the Baby-Friendly Hospital Initiative advises that no pacifiers be given to breastfeeding infants, both breastfeeding and pacifier use may protect against sudden infant death syndrome. The International Child Care Practice Study data set on child care practices associated with sudden infant death syndrome risk from 21 centers in 17 countries was used to describe infant-feeding practices and pacifier use and assess factors associated with breastfeeding. At approximately 3 months of age, rates of breastfeeding only (4%-80%) and pacifier use(12.5%-71%) varied between centers. Pacifier use was negatively associated with breastfeeding, and a dose-response effect was noted. Other negative (multiple birth, smoking by mother) and positive (intention to breastfeed, bed sharing, mothers' education) associations with breastfeeding only were identified. Although causality should not be inferred, these associations are consistent with previous studies. Advice on pacifiers should include potential benefits as well as risks.

A case-control study of SARS versus community acquired pneumonia

The clinical, laboratory, and radiological features at presentation of 16 children (<12 years) with severe acute respiratory syndrome (SARS) and pneumonia were compared with 32 age matched patients with community acquired pneumonia for determination of predictive factors that could allow early differentiation of the two conditions. A definitive contact history was the most important predictor for SARS. Raised serum lactate dehydrogenase concentration in the presence of low neutrophil count and serum creatine phosphokinase level at presentation also indicated an increased likelihood of SARS-coronavirus infection in young children.

Review of children hospitalised for ingestion and poisoning at a tertiary centre

INTRODUCTION

The main aim of this study is to determine the pattern of referrals of poisoning to a tertiary university hospital. The information will be used for poison prevention programme planning, and for educating and awareness promoting to the public.

MATERIALS AND METHODS

All patients (under 21 years of age) admitted to the paediatric wards between January 1997 and December 2002 with a discharge diagnosis indicating unintentional (UP) or intentional poisoning (IP) were identified through the computerised discharge information.

RESULTS

Sixty males and 98 females accounted for 161 admissions over the 6-year period. Their mean (standard deviation, SD) age was 8.2 (6.2) years. Sixty per cent of admissions involved UP. Females accounted for 47% of the UP but 86% of the IP [odds ratio of females for IP, 7.05; 95% confidence interval (CI) 2.95 to 17.28]. When compared with UP, IP patients were significantly older [mean (SD): 14.9 (1.7) versus 3.6 (3.3) years]. In 70% of the admissions, the patients ingested a single substance. Tablets and pills, especially in the IP adolescents, were more commonly ingested than syrups. The spectrum of substances ingested was vast but paracetamol, cough or cold medicines, and common adult household medications and agents accounted for the majority of medications ingested. The substances ingested were obtained at home in 81 cases (50%) and as over-the-counter medication in 33 (20%). The majority (92%) of patients presented within 24 hours of ingestion. On admission, 63% of UP and 45% of the IP were asymptomatic. No active treatment was required in 65% of patients. In IP, nearly 30% of IP who ingested paracetamol had toxic levels and received N-acteyl cysteine. A history of previous poisoning was more common and subsequent follow-up was offered to 74%.

CONCLUSION

Young boys were more at risk of unintentional ingestion whereas adolescent girls were more likely to ingest medications as a gesture of suicide. Paracetamol is a frequently ingested medicinal for which an antidote is available.

Bone mineral density and calcium metabolism of Hong Kong Chinese postpartum women—a 1-y longitudinal study

OBJECTIVE

This paper reports longitudinal changes in bone mineral density (BMD), calcium homeostasis and dietary calcium intake in a group of Hong Kong breastfeeding women during the first year postpartum.

DESIGN AND SUBJECTS

Nine mothers who breastfed exclusively or almost exclusively for at least 3 months and 14 formula feeding mothers aged 20-40 y were interviewed after delivery, 2 and 6 weeks, 3, 6 and 12 months postpartum. BMD at L2-L4 lumbar spine (LS), trochanter (Tro) and femoral neck (FN), serum intact parathyroid hormone (iPTH), serum bone-specific alkaline phosphatase (b-ALP), urinary deoxypyridinoline (Dpd), serum and urinary calcium (Ca) and phosphorus (P) and dietary intake of macronutrients were assessed.

RESULTS

Compared to the formula feeding group, BMD assessed at LS, Tro and FN decreased significantly in the breastfeeding group over the first 6 months, with rebound to approximate baseline values at 12 months for the latter two sites. Serum iPTH increased in both groups, whereas serum b-ALP was consistently higher in the breastfeeders. Urinary Ca and P excretion decreased early postpartum in both groups, but the breastfeeders had higher excretion at 3 and 6 months. Breastfeeding mothers consumed significantly more Ca than the formula feeding mothers in the early postpartum.

CONCLUSIONS

Increased calcium requirement during early lactation is affected through mobilisation of bone and renal calcium conservation. Bone mineral loss during lactation is temporary. Further studies are warranted to investigate the effects of diet and other hormonal factors on the calcium homeostasis during lactation.

Hepatic steatosis in obese Chinese children

OBJECTIVES

THE AIMS OF OUR STUDY WERE

(1) to determine the prevalence of asymptomatic hepatic steatosis and presumed nonalcoholic steatohepatitis, in our local population of obese Chinese children referred for medical assessment; and (2) to assess the correlation between severity of ultrasonographic hepatic steatosis and degree of obesity, insulin resistance and serum biochemical abnormalities.

DESIGN

Cross-sectional study.

METHODS

In total, 84 obese children, 25 girls and 59 boys with median age and body mass index (BMI) of 12.0 years (interquartile range (IR): 9.5-14.0) and 30.3 kg/m(2) (IR: 27.1-33.4), respectively, referred for medical assessment were studied. All subjects underwent physical examination, anthropometric and dual energy X-ray absorptiometry (DEXA) scan measurements and real-time ultrasonographic (US) examination of the liver. Fasting blood samples were collected for the measurement of liver function, hepatitis status, levels of serum glucose and insulin and lipid profile. Degree of fatty infiltration of the liver was graded according to ultrasonic appearance of liver echotexture, liver-diaphragm differentiation in echo amplitude, hepatic echo penetration and clarity of hepatic blood vessels.

RESULTS

All recruited subjects had no history of alcohol abuse and tests for Hepatitis B or C virus were negative. Thorough examination showed all of them to be in general good health without signs of chronic liver disease. Hepatic steatosis identified by defined ultrasonic appearances was diagnosed in 65 subjects (77%); 17 girls and 48 boys. The severity of fatty liver was positively related to anthropometric measurements including BMI, waist and hip circumference, subscapular skinfold thickness; insulin resistance markers [QUICKI and homeostasis model assessment (HOMA)], and hypertriglyceridaemia. Multvariate ordinal regression analysis showed that BMI and raised alanine aminotransferase (ALT) were positively associated with fatty liver. Combination of hepatic steatosis with raised ALT (presumptive NASH) was found in 19 subjects (24%). This group of patients had significantly higher waist hip ratio and conicity index compared to those with isolated hepatic steatosis. Boys with presumed NASH were also found to have significantly higher insulin resistance.

CONCLUSION

Nonalcoholic fatty liver disease (NAFLD) was common among our cohort of obese children referred for medical assessment. The prevalence of simple steatosis and presumed NASH was 77 and 24%, respectively. The severity of US steatosis was positively correlated with BMI, raised ALT, insulin resistance and hypertryglyceridaemia. Ultrasonography being noninvasive and readily available could be used for the monitoring of the progression of hepatic steatosis. Further longitudinal studies are required to determine the natural disease progression and the role of insulin resistance and other factors in the pathophysiology of NAFLD.

Rolling over in infants: age, ethnicity, and cultural differences

A preliminary cross-sectional study of 72 Hong Kong Chinese infants suggested that these infants learn to roll from supine-to-prone before rolling from prone-to-supine i.e. the opposite to teaching in most western texts. Three-hundred and sixty mothers were recruited postpartum and asked to record, on a chart, information related to the developmental milestone of rolling over for their infants (49% male) during the next 9 months. Telephone reminders were given at 4 and 8 months and, by the end of the study, information had been obtained from 240 mothers (67% of original sample, 51% male infants). Mean ages of rolling over were 5.1 months (SD1.5) for supine-to-prone and 5.7 months (SD1.3) for prone-to-supine. Age of rolling over from supine-to-prone was not influenced by usual sleep position, infant's sex, mother's intention to breastfeed infant, number of siblings, marital status, main daytime caregiver, or feeding method over 9 months. Hong Kong Chinese infants roll from supine-to-prone before they roll from prone-to-supine.

Towards an integrated approach to lung health in adolescents in developing countries

The World Health Organization strategies, Integrated Management of Childhood Illness and Practical Approach to Lung health provide assessment and management guidelines for health workers in developing countries. We reviewed issues important to lung health in adolescents to highlight whether differences in factors such as adolescent behaviour have consequences for the development of case management guidelines, to form a bridge between guidelines for younger children and for adults and to make suggestions for further study. Pneumonia, asthma and tuberculosis are the leading lung health problems in adolescents. As countries industrialise, the importance of asthma mortality and morbidity increases as that of pneumonia and pulmonary tuberculosis decreases. Guidelines for managing pneumonia and asthma in children and adults in developing and developed countries should be adaptable for use in adolescents in developing countries, although more information is needed on predictors of severity such as respiratory rate cut-offs, level of fever, hypotension, malnutrition and level of consciousness. The effectiveness of low-cost treatment for asthma should be explored further. HIV and the global resurgence of tuberculosis pose significant challenges for improving adolescent lung health, and prevention of smoking initiation during adolescence is a priority goal of any integrated approach to improving lung health.

Surveillance of childhood diarrhoeal disease in Hong Kong, using standardized hospital discharge data

Discharge information for all Hong Kong government hospitals, which is routinely collected through the Clinical Management System (CMS), was used to assess the relative importance of all causes of diarrhoeal illness and to address the issue of under-diagnosis of rotavirus by linking discharge diagnostic codes with actual laboratory results for one hospital. Of all children less than 5 years of age hospitalized in Hong Kong in the 2-year period July 1997 to June 1999, 12,257 (11%) were discharged with a primary diarrhoea diagnosis (74% coded as non-specified, 10.4% as rotavirus, 11% as Salmonella and 5% as other viral or bacterial). Linked laboratory and discharge data for one hospital demonstrated that 15% (n = 1522) of all admissions had a primary diarrhoea diagnosis and that 40% of these had a specimen sent for rotavirus testing, of which 37% were positive. However, 46% (67/145) of children with a diagnosis of rotavirus infection had no virology result, and 69% (172/248) of positive rotavirus results were in children with no diagnosis indicating rotavirus infection. Modification of the CMS to routinely combine existing computerized laboratory data with the CMS discharge diagnoses and to develop mechanisms to enhance reliability of discharge diagnosis coding could produce a powerful resource for disease surveillance, auditing and for monitoring the impact of future vaccination and other prevention programmes.

First report from the Asian Rotavirus Surveillance Network

Rotavirus remains the most common cause of severe, dehydrating diarrhea among children worldwide. Several rotavirus vaccines are under development. Decisions about new vaccine introduction will require reliable data on disease impact. The Asian Rotavirus Surveillance Network, begun in 2000 to facilitate collection of these data, is a regional collaboration of 36 hospitals in nine countries or areas that conduct surveillance for rotavirus hospitalizations using a uniform World Health Organization protocol. We summarize the Network's organization and experience from August 2001 through July 2002. During this period, 45% of acute diarrheal hospitalizations among children 0–5 years were attributable to rotavirus, higher than previous estimates. Rotavirus was detected in all sites year-round. This network is a novel, regional approach to surveillance for vaccine-preventable diseases. Such a network should provide increased visibility and advocacy, enable more efficient data collection, facilitate training, and serve as the paradigm for rotavirus surveillance activities in other regions.

Infection control for SARS in a tertiary paediatric centre in Hong Kong

Severe acute respiratory syndrome (SARS) is an emerging infectious disease. After the appearance of an index patient in Hong Kong in February 2003, SARS outbreaks occurred rapidly in hospitals and spread to the community. The aim of this retrospective study is to evaluate the effectiveness of a triage policy and risk-stratified infection control measures in preventing nosocomial SARS infection among paediatric healthcare workers (HCWs) at the Prince of Wales Hospital, a general hospital to which children with SARS are referred in Hong Kong. The acute paediatric wards were stratified into three areas: (1) ultra high-risk area, (2) high-risk area and (3) moderate-risk area according to different risk levels of nosocomial SARS transmission. The implementation of different levels of infection control precautions was guided by this risk stratification strategy. Between 13 March and 23 June, 38 patients with probable and suspected SARS, 90 patients with non-SARS pneumonia, and 510 patients without pneumonia were admitted into our unit. All probable SARS cases were isolated in negative-pressure rooms. Twenty-six HCWs worked in the ultra high-risk area caring for SARS patients and 88 HCWs managed non-SARS patients in other ward areas. None of the HCWs developed clinical features suggestive of SARS. In addition, there was no nosocomial spread of SARS-associated coronavirus to other patients or visitors during this period. In conclusion, stringent infection control precautions, appropriate triage and prompt isolation of potential SARS patients may have contributed to a lack of nosocomial spread and HCW acquisition of SARS in our unit.

Breast milk substitutes in Hong Kong

OBJECTIVE

In 1981 the World Health Assembly (WHA) adopted the International Code of Marketing of Breast Milk Substitutes (the Code) to support breastfeeding. Despite improving trends, Hong Kong has low rates of breastfeeding compared to other developed countries.

METHODS

We surveyed companies marketing breast milk substitutes in Hong Kong to determine self-reported adherence to the Code. Companies were informed that individual responses would not be published and seven of nine companies responded to the questionnaire.

RESULTS

The majority of respondents promoted infant and follow-on formula in hospitals and provided free supplies of infant formula to hospitals. Follow-on formula and weaning foods were promoted in shops and to the general public and free samples were given to mothers reflecting a belief that, despite WHA resolutions, follow-on formula is not a breast milk substitute.

CONCLUSIONS

Transnational companies should follow the Code and subsequent WHA resolutions equally in all countries.

Risk factors for childhood overweight in 6- to 7-y-old Hong Kong children

OBJECTIVE

To identify risk factors for overweight in Hong Kong children aged 6-7 y.

DESIGN

Case-control study.

SETTING

Student Health Service Centres, Hong Kong.

SUBJECTS

A total of 343 Hong Kong Chinese children aged 6-7 y old categorised into three groups, an overweight group (> or =92 nd centile for BMI), a normal middle-weight group (45th-55th centile for BMI) and a normal low-weight group (< or =8th centile for BMI).

MEASUREMENTS

Subjects and their parents/caregivers were interviewed at home. Data on lifestyle habits, dietary habits, family structure and demographic background were collected by questionnaire. A 3-day dietary record was administrated by the parents/caregivers to assess dietary intake of the children.

RESULTS

Logistic regression analyses (overweight group compared with middle-weight plus low-weight groups) showed that childhood overweight was significantly associated with parental obesity (BMI > or =25 kg/m(2), Asian reference) (paternal: OR=2.66, 95% CI=1.51-4.70; maternal: 5.07, 2.62-9.79) but not parental overweight (BMI=23-25 kg/m(2)). After adjustment for parental obesity, the odds ratio for childhood overweight was increased by birth weight (<3.0 kg as reference, 3.0-3.5 kg: 2.13, 1.18-3.84; > or =3.5 kg: 4.89, 2.49-9.60) and decreased by sleeping duration (<9 h/day as reference, 9-11 h/day: 0.54, 0.30-0.97; > or =11 h/day: 0.31, 0.11-0.87). Childhood overweight was also significantly associated with higher energy consumption (2.62, 1.20-5.74) and having a father who was a current smoker (2.08, 1.25-3.46).

CONCLUSIONS

Although healthy diet and regular exercise will remain the cornerstones of obesity management in children, our data support the view that education about maintaining a healthy weight could be introduced much earlier in those families with high-risk children, as indicated by high parental BMI or high birth weight. The utility and practicality of such an approach should be carefully evaluated before becoming part of any public health policy. Further study of the role of short sleeping duration and parental smoking on childhood obesity development is warranted.

Unusual neurological presentation of neuroblastoma

Acute cerebellar ataxia and opsomyoclonus are presenting signs of occult neuroblastoma for a substantial proportion of paediatric patients. Cerebellar ataxia may be due to antibodies against the neuroblastoma cross-reacting with cerebellar tissue. This report is of a 26-month-old boy who presented with encephalitis-like features of ataxia, seizures, decreased consciousness, and involuntary movements. Magnetic resonance imaging of the brain and spine were normal 2 weeks after presentation. The child did not have the classical signs of opsoclonus or myoclonus at any stage of the disease but was found to have occult neuroblastoma. The late demyelinating changes seen on magnetic resonance imaging of the brain support an immunological basis for the paraneoplastic manifestations of occult neuroblastoma in this child. Occult neuroblastoma should be considered as one of the differential diagnoses for children presenting with persisting encephalitis-like features in the presence of normal neuroimaging findings.

The effects of obesity on pulmonary function

AIMS

(1) To determine the predominant pulmonary function abnormality in our population of obese children; and (2) to assess the correlation between the severity of lung function impairment and the degree of obesity as assessed by dual energy x ray absorptiometry (DEXA).

METHODS

Sixty four obese patients underwent physical examination, standardised pulmonary function tests (spirometry, lung volumes, and single breath diffusion capacity for carbon monoxide), and DEXA scan measurements. The trunk and subtotal (total - head) body fat mass were used as surrogate index of body adiposity.

RESULTS

Sixteen girls and 48 boys with median age and body mass index (BMI) of 12 years (interquartile range (IQR): 10-14) and 30.1 kg/m2 (IQR: 27.2-32.8) respectively were studied. None of the patients had clinical evidence of cardiopulmonary disease. Reduction in functional residual capacity (median FRC 93% predicted, IQR: 68.5-116.5%) and impairment of diffusion capacity (median DLco 83.5% predicted, IQR: 70.0-100.7%) were the most common abnormalities in our cohort, being observed in 30 (46%) and 21 (33%) patients respectively. Obstructive ventilatory impairment was found in three patients. There was significant negative correlation between the degree of reduction of FRC but not DLco with DEXA scan measurements, but such a relation was not found when BMI was used as the indicator of obesity.

CONCLUSION

Reduction in FRC and diffusion impairment were the commonest abnormalities found in our cohort of obese patients. Reduction in static lung volume was correlated with the degree of obesity.

Comparison of dioxin and PCB concentrations in human breast milk samples from Hong Kong and the Netherlands

The adverse effects of dioxins and polychlorinated biphenyls (PCBs) on human health are of increasing concern. These lipophilic compounds are concentrated through the food chain and are present in human milk. This study compares PCB levels in human milk samples from Hong Kong and Dutch mothers. Ten breast milk samples from Hong Kong and 10 from the Netherlands were collected during home visits between 2 and 6 weeks postpartum. Total toxic equivalence (TEQ) of dioxin and PCBs were determined using the DR-CALUX(R) bioassay. The total dioxin and PCB levels in breast milk samples for Hong Kong ranged from 3.1 to 29.9 pg TEQ g(-1) lipid and for the Netherlands from 8.9 to 89.5 pg TEQ g(-1) lipid. Despite Hong Kong's high degree of industrialization, the levels of dioxin and PCBs were fourfold lower in the Hong Kong than in the Dutch samples. This may be due to a lower dietary intake of dioxins and PCBs in Hong Kong because of lower background levels of these contaminants or to different food habits.

[Sleeping position to prevent sudden infant death syndrome in Latin-american and Caribbean hospitals]

Background The prone sleeping position for sleeping has been identified as the principal risk factor for sudden infant death syndrome (SIDS).ObjectiveThe aim of this study was to determine the prevalence of different sleeping positions and other risk factors for SIDS and to identify the advice given to parents in several maternity units in Latin America and the Caribbean through a specially-designed questionnaire.MethodsDescriptive cross-sectional study based in hospitals. All the countries in Latin America and the Caribbean were contacted through the Pan American Health Organization and responses were obtained from 16 countries.ResultsTwo hundred thirteen hospitals answered the survey. The preferred sleeping position for healthy infants was prone in 8.5 % of the hospitals, side in 48.8 %, and supine in 25.2 %. In 17.5 % of the hospitals no position was preferred or the answers were inconsistent.Concerning the recommendations given to parents on the best position for their infants at home, 25.7 % recommended the supine position, 7.6 % the prone position, 59.0 % the side position while 7.6 % made no recommendations.ConclusionsThe results of this study show that in the hospitals surveyed there is a policy of not placing healthy neonates in the prone position. However, the most frequent position was the side, which is not advisable as it increases the risk of SIDS. To reduce in the incidence of SIDS, campaigns to increase the use of the supine position should be carried out in hospitals and among the general public.