Kai Chow Choi

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

BackgroundCentral 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.MethodsCross 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.ResultsWC 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).ConclusionReference 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.

Screening diabetic patients for non-alcoholic fatty liver disease with controlled attenuation parameter and liver stiffness measurements: a prospective cohort study

Objective Type 2 diabetes is an important risk factor for non-alcoholic fatty liver disease (NAFLD), but current guidelines provide conflicting recommendations on whether diabetic patients should be screened for NAFLD. We therefore studied the strategy of screening diabetic patients by FibroScan. Design Liver fat and fibrosis were assessed by controlled attenuation parameter (CAP) and liver stiffness measurements (LSM) by FibroScan at a diabetic centre for patients from primary care and hospital clinics. Probe-specific LSM cut-offs were used to detect advanced fibrosis. Results Of 1918 patients examined, 1799 (93.8%) had valid CAP and 1884 (98.2%) had reliable LSM (1770 with the M probe and 114 with the XL probe). The proportion of patients with increased CAP and LSM was 72.8% (95% CI 70.7% to 74.8%) and 17.7% (95% CI 16.0% to 19.5%), respectively. By multivariable analysis, female gender, higher body mass index, triglycerides, fasting plasma glucose and alanine aminotransferase (ALT) and non-insulin use were associated with increased CAP. Longer duration of diabetes, higher body mass index, increased ALT and spot urine albumin:creatinine ratio and lower high-density lipoprotein-cholesterol were associated with increased LSM. Ninety-four patients (80% had increased LSM) underwent liver biopsy: 56% had steatohepatitis and 50% had F3-4 disease. Conclusions Diabetic patients have a high prevalence of NAFLD and advanced fibrosis. Those with obesity and dyslipidaemia are at particularly high risk and may be the target for liver assessment. Our data support screening for NAFLD and/or advanced fibrosis in patients with type 2 diabetes.

Widespread public misconception in the early phase of the H1N1 influenza epidemic

OBJECTIVES To investigate the community responses and preparedness for a possible epidemic of H1N1 influenza in Hong Kong shortly after an imported case was confirmed. METHODS A random sample of 550 Chinese adults in the Hong Kong general population was interviewed during May 7-9, 2009. RESULTS The public did not perceive a high likelihood of having a local H1N1 outbreak, nor did they regard H1N1 as a threatening disease. Frequent hand-washing (73.6%) and use of face-masks in case of flu symptoms (47.9%) were prevalent. The public approved of governmental policies including the quarantining of hotel guests, was not panicking and perceived a high self-efficacy of self-protection. However, misconceptions were prevalent and the public avoided visiting crowded places (9.3%), which many people wrongly believed was a government recommendation. CONCLUSION Although the public response demonstrated vigilance and preparedness there were signs of complacency. Clear communication, updated scientific information and transparency on government decision making are warranted. Data of the study provide a baseline for an ongoing surveillance program to help shape policy and provide information to the international community.

BMI and Waist Circumference in Predicting Cardiovascular Risk Factor Clustering in Chinese Adolescents

Objective: To derive the optimal BMI and waist circumference (WC) cut‐off values to predict clustering of cardiovascular risk factors in Hong Kong Chinese adolescents.

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 14 842 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 12 680 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.

Association between obesity and atopy in Chinese schoolchildren.

Background: Despite parallel increases in asthma and obesity prevalence, there is little data on obesity as a risk factor for atopy. The latter is an important phenotype in asthmatic patients. This study investigates the association between asthma traits, atopy and obesity-related markers in Chinese adolescents. Methods: 486 schoolchildren were recruited among participants of our population-based study on the epidemiology of obesity, and their allergy status was ascertained using a standardized questionnaire. Subjects’ anthropometry was recorded on-site, and fasting blood was collected for allergen-specific immunoglobulin E (IgE), lipids and systemic inflammatory biomarkers. Results: 98 (20.2%) subjects were classified as overweight or obese. Obesity status was not associated with asthma, allergic rhinitis or eczema (p > 0.25). Atopy was not associated with age-adjusted body mass index (BMI) or waist circumference. Atopy and presence of allergen-specific IgE did not differ between overweight or obese children and those with normal BMI (p > 0.25), although subgroup analysis suggested that cockroach sensitization was more common among males who were obese or overweight (p = 0.045). White cell count (WCC) was higher among atopic than nonatopic children (mean values 6.5 × 109/l vs. 6.2 × 109/l, p = 0.006). Logistic regression revealed WCC to be the only risk factor for atopy (OR 18.97, p = 0.004). Conclusions: Obesity is not associated with asthma or atopy in Chinese children. High WCC is an important risk factor for atopy in both males and females. Gender does not exert any consistent effect on the association between obesity and allergen sensitization in children.

Prevalence of preventive behaviors and associated factors during early phase of the H1N1 influenza epidemic

Background The community plays an important role in controlling influenza A/H1N1. There is a dearth of data investigating adoption of preventive behaviors in the initial phase of the A/H1N1 pandemic. Methods Three round of random, population-based, anonymous telephone survey were conducted in Hong Kong during the pre-community outbreak phase (May 7 to June 6, 2009) of the influenza A/H1N1 pandemic in Hong Kong (n = 999). Results Respectively, 46.65%, 88.75%, and 21.5% washed hands more than 10 times/day, wore face masks when having influenza-like illness (ILI), and wore face masks regularly in public areas. Perceptions related to bodily damages, efficacy of frequent handwashing, nonavailability of effective vaccines, high chance of having a large scale local outbreak, and mental distress because of influenza A/H1N1 were associated with frequent handwashing (odds ratio [OR], 1.46 to 2.15). Perceived vaccine availability was associated with face mask use when having ILI (OR, 1.60). Perceived fatality, efficacy of wearing face masks, and mental distress because of influenza A/H1N1 were associated with face mask use in public areas (OR, 1.53 to 2.52). Conclusion Preventive behaviors were prevalently adopted by the public and were associated with cognitive and affective factors. Prevention efforts should take public perceptions into account, and emerging infectious diseases provide good chances for promoting hygiene.

The influence of knowledge and perception of the risk of cervical cancer on screening behavior in mainland Chinese women

Theories of health behavior and empirical research highlight the risk perception as a significant factor for people adopting cancer screening. However, screening uptakes and risk perception of cervical cancer in mainland Chinese women remains unknown.

Prevalence of influenza vaccination and associated factors among pregnant women in Hong Kong.

A total of 568 pregnant women in Hong Kong were interviewed. Of them, 85.4% had heard of influenza vaccine, 21.3% had ever been vaccinated, 3.9% self-reported receiving influenza vaccination (IV) in the 2005/2006 flu season, and 33% were inclined toward receiving IV in the coming year. Multivariate analysis showed that those who had been recommended by health care professionals to receive IV during pregnancy were more likely than others to have received IV. Other variables related to the Health Belief Model were significantly associated with having ever been vaccinated or inclined toward receiving IV in the coming year.

Association between Physical Activity and Cardiovascular Risk in Chinese Youth Independent of Age and Pubertal Stage

BackgroundChildhood and adolescence are critical periods of habit formation with substantial tracking of lifestyle and cardiovascular risk into adulthood. There are various guidelines on recommended levels of physical activity in youth of school-age. Despite the epidemic of obesity and diabetes in China, there is a paucity of data in this regard in Chinese youth. We examined the association of self-reported level of physical activity and cardiovascular risk in Hong Kong Chinese youth of school-age.MethodsThis was a cross-sectional study conducted in 2007-8 in a school setting with 2119 Hong Kong Chinese youth aged 6-20 years. Physical activity level was assessed using a validated questionnaire, CUHK-PARCY (The Chinese University of Hong Kong: Physical Activity Rating for Children and Youth). A summary risk score comprising of waist circumference, blood pressure, fasting plasma glucose and lipids was constructed to quantify cardiovascular risk.ResultsIn this cohort, 21.5% reported high level of physical activity with boys being more active than girls (32.1% versus 14.1%, p < 0.001). Regression analysis showed physical activity level, sex and pubertal stage were independently associated with cardiovascular risk score.ConclusionSelf-reported level of physical activity is associated with cardiovascular risk factors in Chinese youth after adjusting for sex and pubertal stage.