P C Ng

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (130)446.03 Total impact

  • Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2013; 19 Suppl 8:10-1.
  • Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2013; 19 Suppl 8:12-5.
  • Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2013; 19 Suppl 9:21-5.
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    ABSTRACT: 1. Human coronaviruses (HCoVs)were detected in 2.5% of 2982 local children hospitalised for acute respiratory infections in 2005 to 2007. 2. Using the 'pancoronavirus' reverse transcription-polymerase chain reaction assay, detection rates were 0.6% for HCoVNL63,1.2% for HCoV-OC43,0.5% for HCoV-HKU1, and 0.2% for HCoV-229E. Notably, HCoV-NL63 infections were significantly more common among children hospitalised in 2006/2007 (1.2%) than in 2005/2006 (0.3%).3. The peak season for HCoVNL63 infection was autumn(September to October). 4. HCoV-NL63 infection was associated with younger age,croup, febrile convulsion, and acute gastroenteritis. Such disease associations were not found with the other three HCoVs. 5. Most local HCoV-NL63 isolates were closely related to the prototype strain in Netherlands(NL496), but a few were phylogenetically distinct from the major cluster.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 02/2012; 18 Suppl 2:27-30.
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    ABSTRACT: 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. Cross-sectional study. Thirty-six randomly selected primary and secondary schools in Hong Kong. A total of 14 842 children and adolescents aged 6 to 18 years in Hong Kong during 2005/06. Creation of age-specific z-scores for height, weight, and body mass index relative to HK1993 and WHO2007 references. 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. 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.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 06/2011; 17(3):174-9.
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    ABSTRACT: The present study assessed the relationship between breakfast frequency and measures of obesity in Hong Kong Chinese children aged 9-18 years. A total of 11,570 children (50 % boys) underwent anthropometric measurements and completed a simple self-administered dietary behaviour questionnaire. Their parents completed a questionnaire providing demographic information. Breakfast frequency was assessed by a single question, 'How many days over the past week did you have breakfast?' Children were categorised into three groups: skippers (ate breakfast 0-2 times/week); semi-skippers (ate breakfast 3-4 times/week); non-skippers (ate breakfast 5-7 times/week), to assess all associated characteristics. Of the 3644 primary and 7926 secondary school students, 8 % (8·7 % of boys and 6·9 % of girls) and 14 % (14 % of boys and 15 % of girls), respectively, were breakfast skippers. The prevalence of obesity among breakfast skippers, semi-skippers and non-skippers was, respectively, 9·8, 10·6 and 3·8 % (P < 0·001) for primary school students and 3·9, 3·1 and 2·4 % (P < 0·001) for secondary school students. The 12 % of Hong Kong children aged 9-18 years who skipped breakfast had higher BMI, BMI z-scores and percentage of body fat (PBF) than their counterparts. The dose effects of breakfast frequency (unstandardised regression coefficient, P < 0·001) on BMI and PBF were, respectively, -0·125 kg/m2 and -0·219 % for boys and -0·165 kg/m2 and -0·353 % for girls, adjusting for physical activity per additional breakfast meal per week. Further study is recommended to elucidate whether regular breakfast consumption may have a role in the prevention of childhood obesity.
    The British journal of nutrition 05/2011; 106(5):742-51. DOI:10.1017/S0007114511000754 · 3.34 Impact Factor
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    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 02/2011; 17 Suppl 2:38-40.
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    ABSTRACT: The aim of this study was to determine the association between blood pressure and the frequency of structured physical training activity in Chinese adolescents. A total of 9558 students aged 11-18 years underwent anthropometric and blood pressure measurements in a cross-sectional growth study. Structured physical training activity was assessed by two simple self-administered questions and parents were asked to complete a questionnaire providing demographic information. Ninety per cent of eligible students participated in the study, of which 94% provided data on physical training frequency for final analysis. Of the boys, 22.6% and of the girls, 14.5% were physically active with extracurricular school exercise at least twice a week. Over half of the students did not regularly exercise except during physical education classes at school. Blood pressure had a positive correlation with body mass index (BMI). Both systolic blood pressure and diastolic blood pressure were substantially decreased with increased training frequency (P<0.05). Logistic regression adjusting for age, family history of hypertension, BMI and sleep duration showed that exercising two or more times a week had a negative relation with hypertension (odds ratio: 0.63, 95%CI 0.47-0.85). In conclusion, structured physical training activity of two or more times a week has a beneficial effect on blood pressure in Hong Kong children aged 11-18 years.
    Journal of human hypertension 10/2010; 24(10):646-51. DOI:10.1038/jhh.2009.117 · 2.69 Impact Factor
  • Hong Kong Journal of Occupational Therapy 12/2009; 19(2). DOI:10.1016/S1569-1861(10)70017-6 · 0.65 Impact Factor
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    ABSTRACT: To re-examine the prevalence of group B Streptococcus colonisation in our antenatal population, and identify demographic factors associated with carriage. Prospective observational study. A tertiary obstetrics unit in Hong Kong. A total of 1002 pregnant women were recruited at the booking clinic in a tertiary obstetrics unit in Hong Kong. High and low vaginal swabs and rectal swabs were taken for group B Streptococcus culture. Demographic data and delivery outcomes of the recruits were analysed. The prevalence of group B Streptococcus colonisation in our antenatal population was 10.4%. The majority of carriers were identified by low vaginal swabs (78%), while high vaginal swabs and rectal swabs only identified 31% and 30% of the carriers, respectively. Professional women yielded a higher carrier rate than housewives (21% vs 10%, P=0.03). There was no increase in preterm delivery rate in group B Streptococcus carriers. We noted a dramatic increase in the prevalence of group B Streptococcus colonisation in the Hong Kong pregnant population at their booking visit. Professional women had a higher colonisation rate compared to other groups.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2009; 15(6):414-9.
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    ABSTRACT: The natural history of mild childhood obstructive sleep apnoea (OSA) was examined and factors associated with disease progression were identified. Subjects were recruited from an epidemiological study which examined the prevalence of OSA in Chinese children aged 6-13 years. The first 56 consecutive children identified with mild OSA (apnoea-hypopnoea index 1-5) were invited for a repeat assessment 2 years after the diagnosis. 45 children participated in the follow-up study, in 13 of whom (29%) the OSA was found to have worsened. Compared with those in whom OSA had not worsened, the worsened OSA group had a greater increase in waist circumference, a higher prevalence of large tonsils (occupying > or =50% of the airway) at both baseline and follow-up, and a higher prevalence of habitual snoring at both baseline and follow-up. The presence of large tonsils had a positive predictive value of 53% and a negative predictive value of 83% for worsening OSA over a 2-year period. Multivariate linear regression analysis showed that the change in obstructive apnoea-hypopnoea index was associated with age at baseline (beta (SE) = -0.92 (0.34), p = 0.009), gender (male = 1; female = 0) (beta (SE) = 4.69 (1.29), p<0.001), presence of large tonsils at baseline (beta (SE) = 4.36 (1.24), p = 0.001), change in waist circumference (beta (SE) = 0.30 (0.09), p = 0.002) and persistently large tonsils (beta (SE) = 5.69 (1.36), p<0.001) over the 2-year period. Mild OSA in the majority of children does not resolve spontaneously. Subjects with tonsillar hypertrophy, especially boys, should be closely monitored to allow early detection of worsening OSA. Weight control should be stressed in the management of childhood OSA.
    Thorax 09/2009; 65(1):27-31. DOI:10.1136/thx.2009.120220 · 8.56 Impact Factor
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    ABSTRACT: Atopic eczema (AE) is characterized by reduced skin hydration (SH) and impaired integrity of the skin. Proper emollient usage is an important facet of AE management and patients are encouraged to use emollients liberally. To evaluate whether the amount of emollient and skin cleanser used correlates with eczema severity, SH or transepidermal water loss (TEWL), and whether liberal usage alters disease severity, SH and TEWL. We studied SH and TEWL at three common measurement sites on the forearm (antecubital flexure, 20 mm below the antecubital flexure, mid-forearm) and determined the SCORing Atopic Dermatitis (SCORAD) score, Nottingham Eczema Severity Score (NESS), Children's Dermatology Life Quality Index (CDLQI) and the amount of emollient and cleanser usage over a 2-week period in consecutive new patients seen at the paediatric skin clinic of a teaching hospital. In total, 48 subjects and 19 controls were recruited. Patients with AE had significantly higher TEWL and lower SH in the studied sites. Emollient and cleanser usage was significantly higher (P = 0.001 and P = 0.041, respectively) in patients with AE than in controls. The amount of emollient usage was correlated with NESS, SCORAD, CDLQI, TEWL and mid-forearm SH. No such correlation was found with cleanser usage. Regardless of SCORAD, prescribing 130 g/m(2)/week of emollient met the requirement of 95.8% of patients, and 73 g/m(2)/week met that of 85.4%; for the cleanser, prescribing 136 g/m(2)/week met the requirement of 91.7% of patients. Although skin dryness and SH were improved, there was no significant improvement in SCORAD or TEWL after 2 weeks. In terms of global acceptability of treatment, three-quarters of patients with AE and controls rated the combination of cream and cleanser as 'good' or 'very good'. Adequate amounts of emollient and bathing cleanser should be prescribed to patients with AE. These amounts can be conveniently estimated based on body surface area instead of the less readily available tools for disease severity, degree of SH or skin integrity. However, liberal usage of emollients and bathing cleanser alone does not seem to alter disease severity or TEWL within 2 weeks, implying that additional treatments are necessary to manage AE.
    Clinical and Experimental Dermatology 07/2009; 35(1):22-6. DOI:10.1111/j.1365-2230.2009.03341.x · 1.23 Impact Factor
  • Case Reports 02/2009; 2009:bcr2007136903. DOI:10.1136/bcr.2007.136903
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    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 10/2008; 14(5 Suppl):11-4.
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    ABSTRACT: Quality of life (QoL) is impaired in children with atopic dermatitis (AD) but the various aspects of QoL may not be equally affected. Aim. To evaluate if age and gender affect some aspects of QoL in children with AD. The Children's Dermatology Life Quality Index (CDLQI) was used for all children with AD seen at a paediatric dermatology clinic over a 3-year period. Disease severity was assessed using the SCORing Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS) tools. We reviewed CDLQI in 133 children (70 male and 63 female; age range 5-16 years) with AD. Itch, sleep disturbance, treatment and swimming/sports were the four aspects of QoL issues that were most commonly affected, in 50%, 47%, 38% and 29% of patients, respectively. Problems with interpersonal issues (friendship, school/holidays, and teasing/bullying) occurred in only a minority of children (<or= 10%). Girls had more problems with issues of clothes and shoes than did boys (OR = 2.86, 95% CI 1.05-8.00; P = 0.038). Significant itch and sleep disturbance affected both genders similarly but were generally more common in children <or= 10 years (itch: OR = 2.31, 95% CI 1.04-5.14; P = 0.039; and sleep: OR = 2.31, 95% CI 1.05-5.13; P = 0.037). Not all aspects of QoL are affected equally in children with AD. The disease seems to affect personal domains of itch and sleep more than the interpersonal issues. Age and gender are relevant factors in QoL, with the issue of clothes/shoes being more troublesome for girls. itch and sleep disturbance seem to be a problem mainly in younger children.
    Clinical and Experimental Dermatology 09/2008; 33(6):705-9. DOI:10.1111/j.1365-2230.2008.02853.x · 1.23 Impact Factor
  • Archives of Disease in Childhood - Fetal and Neonatal Edition 08/2008; 93(4):F304. DOI:10.1136/adc.2007.136903 · 3.86 Impact Factor
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    ABSTRACT: High-dose systemic dexamethasone is effective in facilitating extubation of ventilated infants with bronchopulmonary dysplasia. Although the suppression and recovery of pituitary-adrenal response had been assessed after corticosteroid treatment in very low birth weight infants, its effect on hypothalamic function has not been longitudinally monitored. This study was designed to assess the longitudinal hypothalamic response before, during and 4 weeks after a 3-week dose-tapering course of systemic dexamethasone treatment. Twenty very low birth weight infants had blood collected for corticotropin-releasing hormone, ACTH and cortisol measurements immediately before starting dexamethasone (week 0), after receiving the maximum dose of treatment (week 1), at the end of the 3-week course (week 3) and 4 weeks after stopping corticosteroids (week 7). All circulating hormone concentrations were significantly suppressed during the treatment period at week 1 and week 3 compared with pretreatment concentrations at week 0 (p < 0.001). The recovery of pituitary function started early soon after week 1, whereas that of hypothalamus and adrenal functions started after the end of the dexamethasone course. Plasma ACTH concentration at week 7 had returned to the pretreatment level, but plasma corticotropin-releasing hormone (p < 0.05) and serum cortisol (p < 0.001) concentrations remained significantly suppressed. Partial recovery of hypothalamic and adrenal function was observed at week 7 (62 vs. 36% of their pretreatment levels, respectively). Our findings suggest that the hypothalamic function is suppressed during systemic corticosteroid treatment but partial recovery occurs 4 weeks after stopping therapy. Even in preterm infants, the hypothalamic-pituitary-adrenal axis behaves in a similar manner as in adult subjects and the pituitary function recovers earlier than that of hypothalamus and adrenals.
    Neonatology 07/2008; 94(3):170-5. DOI:10.1159/000143396 · 2.37 Impact Factor
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    ABSTRACT: Childhood obstructive sleep apnoea (OSA) is increasingly being recognised. Its effects on blood pressure (BP) elevation and hypertension are still controversial. To evaluate the association between OSA and ambulatory BP in children. Children aged 6-13 years from randomly selected schools were invited to undergo overnight sleep study and ambulatory BP monitoring after completing a validated OSA questionnaire. OSA was diagnosed if the obstructive apnoea-hypopnoea index (AHI) was >1, and normal controls had AHI <1 and snoring <3 nights per week. Children with OSA were subdivided into a mild group (AHI 1-5) and moderate to severe group (AHI >5). 306 subjects had valid sleep and daytime BP data. Children with OSA had significantly higher BP than normal healthy children during both sleep and wakefulness. BP levels increased with the severity of OSA, and children with moderate to severe disease (AHI >5) were at significantly higher risk for nocturnal systolic (OR 3.9 (95% CI 1.4 to 10.5)) and diastolic (OR 3.3 (95% CI 1.4 to 8.1)) hypertension. Multiple linear regression revealed a significant association between oxygen desaturation index and AHI with daytime and nocturnal BP, respectively, independent of obesity. OSA was associated with elevated daytime and nocturnal BP, and is an independent predictor of nocturnal hypertension. This has important clinical implications as childhood elevated BP predicts future cardiovascular risks. Future studies should examine the effect of therapy for OSA on changes in BP.
    Thorax 04/2008; 63(9):803-9. DOI:10.1136/thx.2007.091132 · 8.56 Impact Factor