K. C. Choi

Waist circumference and body mass index in Chinese children: cutoff values for predicting cardiovascular risk factors

Background:Body mass index (BMI) and waist circumference (WC) correlate with cardiovascular (CV) risk factors in childhood which track into adulthood. WC provides a measure of central obesity, which has been specifically associated with CV risk factors. Reference standards for WC, and for WC and BMI risk threshold values are not established in Chinese children.Objectives:To construct reference percentile charts of WC, establish relationships between WC, BMI and other risk factors, and propose WC and BMI threshold values predictive of CV risk factors in Hong Kong ethnic Chinese children.Methods:Weight, height, waist and hip circumference were measured in 2593 (52% boys, 47% girls) randomly sampled Hong Kong school children aged 6–12 years. In 958 of these and 97 additional overweight children (n=1055), the relationships between WC, BMI, waist/hip and waist/height ratio and six age-adjusted CV risk factors (>85% percentile levels of blood pressure (BP), fasting triglycerides, low-density lipoprotein (LDL) cholesterol, glucose and insulin levels, and <15% percentile levels of high-density lipoprotein (HDL) cholesterol) were studied. Receiver-operating characteristic analysis was employed to derive optimal age-adjusted sex-specific WC and BMI thresholds for predicting these measures of risk.Results:WC percentiles were constructed. WC correlated slightly more than BMI with CV risk factors and most strongly with insulin and systolic BP, but poorly or not with LDL and glucose. Optimal WC and BMI risk thresholds for predicting four of these six CV risk factors were ca. the 85th percentiles (sensitivities ∼0.8, specificities ∼0.87) with age-specific cutoff values in girls/boys from ∼57/58 to ∼71/76 cm and 17/18 to 22/23 kg/m2.Conclusion:These are the first set of WC reference data for Chinese children. WC risk cutoff values are proposed which, despite a smaller waist in Chinese children, are similar to those reported for American children. WC percentiles may reflect population risk.

Acceptability of A/H1N1 vaccination during pandemic phase of influenza A/H1N1 in Hong Kong: population based cross sectional survey.

Objective To investigate the intention of the Hong Kong general population to take up vaccination against influenza A/H1N1. Setting Cross sectional population based anonymous survey. Participants Random sample of 301 adults interviewed by telephone (response rate 80%). Main outcome measure Intention to take up vaccination against influenza A/H1N1 under five hypothetical scenarios: vaccination is free; vaccination per dosage costs less than

Associations of sleep duration with obesity and serum lipid profile in children and adolescents.

HK100 (£8; €9;

Factors in association with acceptability of A/H1N1 vaccination during the influenza A/H1N1 pandemic phase in the Hong Kong general population

13),

Associations between stigmatization toward HIV-related vulnerable groups and similar attitudes toward people living with HIV/AIDS: Branches of the same tree?

HK101-200, or more than

Perceived discrimination, social support, and perceived stress among people living with HIV/AIDS in China

HK200; and no data are available on the efficacy and safety of the vaccine. Results 45% (n=135) of the participants reported that they would be highly likely take up vaccination if it was free. When vaccination incurred a cost, however, the prevalence of uptake decreased: 36% (n=108) would take up vaccination if it cost less than

Prevalence and associated factors of depression among people living with HIV in two cities in China.

HK100, 24% (n=72) if it cost

Higher exercise frequency associated with lower blood pressure in Hong Kong adolescents: a population-based study

HK101-200, and 15% (n=45) if it cost more than

Oscillometric 24-h ambulatory blood pressure reference values in Hong Kong Chinese children and adolescents

HK200; and in absence of proved efficacy and safety decreased to 5% (n=14). Moreover, 32% (n=95) considered universal A/H1N1 vaccination unnecessary. Overall, 39% (n=117) of participants believed that A/H1N1 vaccination would prevent the virus being contracted; 63% (n=189) erroneously believed that efficacy of the vaccine had been confirmed by clinical trials, and 16% (n=49) believed that it is necessary for everyone in Hong Kong to take up vaccination against influenza A/H1N1. Conclusions The uptake of vaccination against influenza A/H1N1 by the general population of Hong Kong is unlikely to be high and would be sensitive to personal cost. Evidence about safety and efficacy is critical in determining the prevalence of uptake of vaccination.

Changes in knowledge, perceptions, preventive behaviours and psychological responses in the pre-community outbreak phase of the H1N1 epidemic

INTRODUCTION The association between sleep duration, obesity, and serum lipid profile in the youth population is under-explored. OBJECTIVE To evaluate the association between sleep duration, obesity and serum lipid profile in the youth population. METHODS We conducted a cross-sectional population-based study with students recruited from primary and secondary schools in Hong Kong. Anthropometric measurements, fasting lipid profiles and validated questionnaires on sleep duration were performed. A subgroup (n=138) was randomly selected for both questionnaires and actigraphy to assess the agreement between subjective and objective measurements of sleep duration. RESULTS We studied 2053 healthy children and adolescents aged 6-20 years. Their mean ages were 13.0±3.3 (boys) and 13.6±3.3 (girls) years. The average sleep duration during schooldays, weekends, and long holidays was 8.0±1.1, 9.6±1.2, and 9.8±1.2h in boys and 7.7±1.1, 9.9±1.2, and 10.1±1.2h in girls, respectively. Using logistic regression, age, and pubertal stage were associated with obesity in secondary school students, whereas male gender and short sleep duration were associated with obesity in primary school children. In secondary school children, those with long sleep duration, as compared to those with short sleep duration, were significantly associated with reduced risk to have high TC and LDL-C levels after adjustment for age, gender, BMI, and pubertal stage. There was no significant association between sleep duration and lipid levels in primary school children. CONCLUSION Reduced sleep duration was associated with obesity and atherogenic dyslipidemia in young school children in Hong Kong.