Child Health Survey 2005-2006: Surveillance and Epidemiology Branch Centre for Health Protection Department of Health pptx

The aim of the survey was to provide baseline data on the healthand well-being of children aged 14 and below in Hong Kong in order to strengthen the Government’sinformation base on the h

Child Health Survey

2005-2006

Commissioned by

Surveillance and Epidemiology Branch

Centre for Health Protection

Department of Health

December 2009

(English version updated in April 2010)

Copyright of this survey report is held by the Department of Health

Child Health Survey

2005-2006

Surveillance and Epidemiology Branch

Centre for Health Protection

Government of the Hong Kong Special Administrative Region, the People’s Republic of China Copyright 2009

Produced and published by

Surveillance and Epidemiology Branch, Centre for Health Protection,

Department of Health, Hong Kong Special Administrative Region

18/F Wu Chung House, 213 Queen’s Road East, Wan Chai, Hong Kong

Copies of this publication are available from the Centre for Health Protection website at:

http://www.chp.gov.hk

Investigation Team

Department of Paediatrics and Adolescent Medicine,

LKS Faculty of Medicine, The University of Hong Kong

Professor YL Lau, Doris Zimmern Professor in Community Child Health Professor L Low

Professor YF Cheung

Dr SL Lee

Mr Wilfred Wong

School of Public Health, LKS Faculty of Medicine,

The University of Hong Kong

Professor TH Lam, Sir Robert Kotewall Professor in Public Health Professor Gabriel M Leung

ADHD Attention Deficit Hyperactivity Disorder

AIDS Acquired Immunodeficiency Syndrome

CBCL Child Behaviour Checklist

CHQ Child Health Questionnaire

CHS Child Health Survey

COS Comprehensive Observation Service

CSSA Comprehensive Social Security Assistance

DSS Developmental Surveillance Scheme

ETS Environmental Tobacco Smoke

FHS Family Health Service

ISAAC International Study of Asthma and Allergies in

Childhood PHS Population Health Survey

YSR Youth Self Report

WHO World Health Organization

Notation

* Less than 0.05

General remarks

1 There may be a slight discrepancy between the sum of

individual items and the total in the tables owing to rounding.

2 Unless otherwise specified, figures presented in the tables are grossed up figures.

Characteristics of the Households and Study Population

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Executive Summary

The Department of Health commissioned the Department of Paediatrics and Adolescent Medicine and theSchool of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, to conduct theChild Health Survey (CHS) in 2005/2006 The aim of the survey was to provide baseline data on the healthand well-being of children aged 14 and below in Hong Kong in order to strengthen the Government’sinformation base on the health status of the child population and to support evidence-based decision making inhealth policy, resources allocation, and provision of health services and programmes

The fieldwork was carried out from September 2005 to August 2006, with the use of face-to-face interviewsand self-administered questionnaires Households were drawn from the Register of Quarters maintained bythe Census and Statistics Department by systematic replicated sampling The percentage of quarterssuccessfully enumerated (including those without children aged 14 and below) was 73.3% A total of 7 393land-based non-institutionalized children aged 14 and below in Hong Kong were enumerated, excluding thosewith non-Cantonese speaking parents and those living in area segments in non-built-up area The samplerepresented 884 300 children of the target population

The survey instrument was developed by the Department of Paediatrics and Adolescent Medicine and theSchool of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, in consultation withthe Department of Health and a group of experts Information was obtained from parent as proxy respondentfor children aged 10 and below and from both parent and children for children aged 11 to 14

The scope of the survey included the followings: 1) general and psychosocial health, 2) physical health, 3) dietand physical activities, 4) risk behaviours, 5) childhood injury and safety practices, 6) parenting, and 7)disease prevention and utilization of health care services

General and Psychosocial Health

The survey showed that 92.2% of children aged 0 to 5 and 91.9% of children aged 6 to 10 were rated to have

“excellent”, “very good”, or “good” general health status by their parents On the other hand, 82.9% ofchildren aged 11 to 14 rated their own general health as “excellent”, “very good” or “good”

The CHS also collected information on emotional and behavioural problems in children aged 6 to 11 by usingthe Child Behaviour Checklist (CBCL), and in those aged 12 to 14 by using both the CBCL and Youth SelfReport (YSR).

The survey showed that 0.7% and 0.9% of children aged 6 to 11 scored in the clinical range on theInternalizing and Externalizing Problems scales respectively The specific syndromes most frequentlyidentified in the clinical range were Withdrawn, Anxious/Depressed, Social Problems, Thought Problems, andAttention Problems, with a prevalence of 0.2% for each of these problems

In children aged 12 to 14, based on the CBCL, 0.8% and 1.0% scored in the clinical range on the Internalizingand Externalizing Problems scales respectively, while the corresponding prevalence was slightly higher whenusing the YSR at 1.0% and 2.1% respectively The specific syndromes most frequently identified in theclinical range by both the CBCL and YSR were Somatic Complaints and Delinquent Behaviour

Physical Health

The five most frequently reported acute health conditions encountered by children aged 14 and below in the 4weeks preceding the survey were common cold or influenza-like illness (29.6%), snoring (4.8%), persistentcough for more than 2 weeks (2.6%), diarrhoea (2.0%) and vomiting (1.9%) Except for children aged belowtwo, these five conditions were the most frequently reported problems across different age groups As forchildren aged below two, the five most frequently reported acute health conditions were common cold orinfluenza-like illness (24.4%), snoring (2.7%), persistent cough for more than 2 weeks (2.5%), diarrhoea(2.0%) and wheezy attack (1.7%)

The five most frequently reported chronic health conditions in children aged 14 and below were visualproblems (27.3%), allergic rhinitis (24.5%), eczema (12.4%), food allergy (5.1%) and asthma (4.1%) Theprevalence of visual problems, allergic rhinitis, and asthma generally increased with age, while that of eczemaand food allergy generally decreased with age

Based on the International Study of Asthma and Allergies in Childhood questionnaire, the three mostfrequently reported allergic conditions or symptoms ever had in children aged 14 and below were allergicrhinitis (24.5%), sneezing or a runny or blocked nose without a cold or flu (14.5%) and eczema (12.4%).

Allergic to food items was reported in 5.1% of children aged 0 to 14 In children reported to have food allergy,the five most frequently reported food items causing food allergy were seafood (38.4%), egg (16.8%), broadbean (13.0%), milk and dairy products (11.4%) and fruit (8.8%), while the five most frequently reported types

of allergic reaction were urticaria (30.5%), exacerbation of eczema (23.2%), anaphylaxis (14.9%), diarrhoea(11.9%) and facial edema (7.1%)

Pain is an under-recognized and under -treated health problem in children Overall, 2.9% of children aged 4 to

14 were reported to have experienced musculoskeletal pain in the 4 weeks preceding the survey

The prevalence of visual impairment in children aged 0 to 14 was 27.3% Among these children, the threemost frequently reported visual problems were short-sightedness (82.1%), astigmatism (35.8%) and long-sightedness (7.6%), while 83.2% of them were reported to use prescribed glasses or contact lenses

In children aged 0 to 5, the prevalence of developmental delay was 1.3%, and more than half of them (57.4%)had speech delay

Other childhood disabilities occurred with a prevalence of less than 1% included hearing impairment inchildren aged 0 to 14 (0.5%), stammering or stuttering in children 2 to 14 (0.6%), gross motor disability inchildren aged 6 to 14 (0.4%), fine motor disability in children aged 6 to 14 (0.4%) and mental handicap inchildren aged 6 to 14 (0.4%)

Diet and Physical Activities

The CHS collected information on diet and physical activities, including nutrition, eating behaviour,breastfeeding, weaning, physical activities and sedentary activities

A balanced diet is recommended in children aged 2 to 14 Overall, in children aged 2 to 14, 98.3% ate meat,95.7% ate eggs, 94.8% ate fish, 81.0% ate beans and 48.9% drank one or more cups of milk in the 7 dayspreceding the survey With regard to consumption of vegetables, 80.0% of children aged 2 to 14 ate less than

Diet high in sugar, salt or fat is undesirable The CHS explored the consumption of soft drink, fast food, friedfood and junk food by children Among children aged 2 to 14, 26.0% consumed at least one cup of soft drinkeach day, 26.7% consumed fast food for at least twice per week, 19.8% consumed fried food in main meals for

at least 3 times per week and 14.4% consumed junk food at least once a day

For consumption of health supplements, 22.5% of children aged 2 to 14 were reported to take vitaminsincluding fish oil and 4.3% were reported to take calorie supplement per week

With regard to eating habits and behaviours, majority (94.3%) of children aged 2 to 14 had 3 regular meals perday, 0.4% had 3 irregular meals per day, 3.7% omitted breakfast and 0.4% sometimes omitted breakfast.Moreover, about three-quarters (75.2%) of children aged 2 to 14 ate their meals while watching television for

5 days or more per week, 14.8% for 1 to 4 days per week, while 9.2% rarely or never took their meals whilewatching television

The World Health Organisation recommends exclusive breastfeeding for the first 6 months of life on apopulation basis The CHS included questions to assess breastfeeding practices in children aged 0 to 5.Overall, 45.5% of children aged 0 to 5 had ever been breastfed Among them, 28.3% had been exclusivelybreastfed for 6 months or more and the median duration of exclusive breastfeeding was 2.0 months Amongchildren who had ever been breastfed, 71.3% consumed infant formula milk, 47.0% consumed water orglucose water, 36.7% consumed cow’s milk and 36.3% consumed milk substitute before 6 months old Withregard to weaning, 7.4% of children aged 0 to 5 were given solid food regularly before 4 months old, 41.1%between 4 to 6 months old and 39.6% after 6 months old

The Education Bureau recommended time allocated for Physical Education lessons in Primary 1 to 6 andSecondary 1 to 3 should be 5% to 8% of the whole curriculum, i.e 2 to 3 sessions per week The CHSassessed the level of physical activities in children aged 4 to 14 In the 4 weeks preceding the survey, aboutthree-quarters (73.1%) of children aged 4 to 14 had participated in vigorous physical activities outside school

reported vigorous physical activities were running (44.8%), racket sports (33.6%) and basketball (21.8%).Among children reported to have engaged in vigorous physical activities in the 4 weeks preceding the survey,the median frequency of engagement was 2 days per week

Participation in moderate physical activities outside school hours in the 4 weeks preceding the survey wasreported in 67.9% of children aged 4 to 14 The three most commonly reported moderate physical activitieswere jogging (49.1%), housework (28.3%) and leisure cycling (20.2%) Among those children who hadengaged in moderate physical activities in the 4 weeks preceding the survey, the median frequency ofparticipation was 2 days per week

Physical inactivity in children in the 4 weeks preceding the survey was assessed Overall, 88.0% of childrenaged 0 to 14 had watched TV or video in the 4 weeks preceding the survey, with a median frequency of 7 daysper week and a median duration of 120 minutes per day Moreover, 70.3% of children aged 4 to 14 hadplayed video game or computer including access to internet in the 4 weeks preceding the survey, with amedian frequency of 5 days per week and a median duration of 60 minutes per day.

With regard to other sedentary activities, 65.7% of children aged 4 to 14, being more common in females(71.9%) than males (59.9%), were reported to have participated outside school hours in the 4 weeks precedingthe survey The three most common activities were arts and crafts (45.2%), singing (36.0%) and playingmusical instruments (27.2%) Among those engaged in sedentary activities in the 4 weeks preceding thesurvey, the median frequency of participation was 2 days per week

There was 89.3% of children aged 4 to 14 reporting that they had spent time on homework and reading forstudy or leisure in the 4 weeks preceding the survey with a median frequency of 5 days per week and a medianduration of 90 minutes per day, while 28.6% had spent time on after school tutorial with a median frequency

of 3 days per week and a median duration of 90 minutes per day

Risk Behaviours

Adolescents start to experiment health risk behaviours that are interrelated and may continue into adulthood.

The CHS collected self-reported information on smoking, exposure to environmental tobacco smoke reported

by parent, self-reported alcohol and drug use, dating and sexual experience, suicidal behaviour, related behaviour and gambling in children aged 11 to 14

violence-The pattern of smoking and the intention to quit smoking were explored Overall, 2.2% of children aged 11 to

14 reported that they had ever smoked Among them, 22.1% had their first cigarette at aged 10 or younger,while 60.1% had their first cigarette at aged 11 to 14; and about two-thirds (64.6%) had at least one of theirfriends smoked Current smoker, defined as smoking for at least one day in the 30 days preceding the survey,was reported in 0.8% of children aged 11 to 14 Among children who were current smokers, 34.7% had tried

to quit smoking in the 12 months preceding the survey

Adverse effects of exposure to environmental tobacco smoke on fetuses, infants and children were welldocumented Maternal exposure to second hand smoking during pregnancy was reported in 31.6%, while

Among children aged 11 to 14, 0.2% reported that they had ever taken psychotropic drugs and 0.2% reportedthat they had been sold or given psychotropic drugs in the 30 days preceding the survey.

With regard to dating, 8.0% of children aged 11 to 14 reported that they had ever dated Among them, 20.2%had their first date at aged 10 or younger; while about three-quarters (77.6%) had their first date at aged 11 to

14 Overall, 0.3% of children aged 11 to 14 reported that they had sexual experience

Regarding suicidal behaviours, 1.3% of children aged 11 to 14 reported that they had suicidal ideation in the

12 months preceding the survey, the prevalence being higher in female (1.6%) than male (0.9%) children.Overall, 1.0% of children aged 11 to 14 reported that they had attempted suicide in the 12 months precedingthe survey, with 0.6% having two or more attempts

Participation in fight in the 12 months preceding the survey was reported in 6.4% of children aged 11 to 14,being significantly more common in males (9.6%) than females (2.9%) Overall, 0.9% of children aged 11 to

14 reported that they had ever been invited or threatened to join triad society

Youth gambling is of growing concern Overall, 2.5% of children aged 11 to 14 reported that they hadparticipated in gambling activities involving money in the 12 months preceding the survey Among childrenaged 11 to 14, the five most common types of gambling activities reported were poker (1.5%), mahjong(1.2%), sports gambling (0.5%), internet gambling (0.2%) and horse-racing (0.1%)

Childhood Injury and Safety Practices

Injury is a significant health problem in children The CHS collected information on prevalence and commontypes of injury in children, as well as the injury prevention behaviours

The prevalence of injury that needed medical advice or treatment in the 12 months preceding the survey inchildren aged 0 to 14 was 4.4%, being higher in male (5.4%) than female (3.2%) children In childrenreported to have injuries that needed medical advice or treatment in the 12 months preceding the survey, thethree commonest types were fall injury (31.6%), sports-related injury (29.3%) and bicycle-related injury(8.5%) In these children, the average number of injuries in the 12 months preceding the survey was 1.9, withthose aged 11 to 14 had the highest average number of 2.3

Among children aged 0 to 14 who had ever ridden a bicycle, only 2.6% reported always or for most of thetime wearing a helmet when riding a bicycle.

Among children aged 0 to 10, the prevalence of never being left alone at home or being cared for by elderchildren aged below 16 was 64.0%

In more than 80% of children aged 0 to 5, their parents reported the adoption of the following safety practices:keeping sharp objects like knives and scissors out of reach of children or in a locked cabinet (86.2%), keepingmedicines out of reach of children or in a locked cabinet (85.5%), keeping matches or fire lighter out of reach

of children or in a locked cabinet (82.0%), setting up window guards or other barriers (81.8%), keepingthermal flasks or electric dispensing pot out of reach of children (80.9%), and keeping cleaning agents likedetergents and bleach out of reach of children or in a locked cabinet (80.3%)

On the other hand, only about half to two-thirds of children aged 0 to 5 had their parents adopting thefollowing safety practices: lowering the temperature of water heater (68.8%), covering electrical sockets toavoid insertion of fingers or other objects (59.5%), and applying padding around sharp edges like dining tablecorners (54.8%)

In children aged 0 to 1, 78.8% of children had parents reported not leaving children alone in a bed withoutrailing or on a sofa, and 46.1% had parents set up baby gates for stairs or doors to kitchen and toilets

Parenting

Families provide support for children and influence their life-style behaviours Parents and primary carers ofchildren hence play an important role in the child health status The CHS collected information on parents,primary carers, parenting and parental participation in children’s activities

Mother was the primary carer in about three-quarters (75.5%) of children aged 0 to 14, helpers in 10.6%,father in 6.9% and grandparents in 5.9% Both father and mother were married in 94.6% and both parentswere born in Hong Kong in 53.3% of children aged 0 to 14

Overall, more than 80% of children aged 0 to 14 had fathers (82.9%) and mothers (84.1%) completedsecondary or tertiary education Slightly less than half of children aged 0 to 14 had both father and mother

The disciplinary action most frequently adopted by parents in children aged 0 to 5 was explanation to childrenwhy their behaviour was inappropriate (75.0%) while the least frequently adopted one was spanking (23.6%).Raising voice or yelling to discipline children was reported by parents in about half (50.5%) of children aged 0

to 5, giving time-out (i.e making children refrain from whatever activities they were participating in) inslightly more than one-third (36.9%) and taking away toys in 26.1%

Concerning parental participation in children’s activities, about two-thirds (67.1%) of children aged 0 to 14engaged in outdoor activities together with either parent, slightly less than half (46.2%) read with either parentand about one-third (32.1%) engaged in leisure activities with either parent in a week

Disease Prevention and Utilization of Health Care Services

The CHS collected information on the adoption of disease preventive practices, which include physical anddevelopmental checkups, immunization, as well as utilization of health care services

About half (46.5%) of children aged 0 to 14 had regular physical checkup in the 12 months preceding thesurvey in the absence of any symptom or discomfort Among these children, the majority (88.5%) attendedthe public sector service

In children aged 0 to 5, slightly more than one-third (36.8%) had regular developmental checkup in theabsence of suspected developmental problems in the 12 months preceding the survey Among these children,about three-quarters (77.5%) attended the public sector service

With regard to immunization, 93.6% of children aged 0 to 14 had received vaccinations according to therecommended immunization schedule Among all children aged 0 to 14, the majority (92.7%) attended thepublic sector service, while 3.5% attended the private sector for vaccination Moreover, 16.5% of childrenaged 0 to 14 received vaccines other than those in the recommended immunization schedule in the 12 months

chickenpox (28.2%) and hepatitis A (6.0%) at the time of the survey

Most (90.8%) of the children aged 0 to 14 usually consulted western medicine practitioners only, 7.5%consulted both western and Chinese medicine practitioners and 1.4% consulted Chinese medicine practitionersonly when they were sick Among those who consulted western medicine practitioners only or both westernand Chinese medicine practitioners, about two-thirds (68.6%) visited western medical practitioners in privateclinics, while 13.3% attended the public clinics

About one-third (36.0%) of children aged 0 to 14 had experienced symptoms in the 4 weeks preceding thesurvey Among these children, about two-thirds (66.1%) visited private general practitioners’ clinics, 12.5%

visited doctors or family physicians in public clinics or hospitals including staff clinics, and 6.0% did not havemedical consultation and just ignored it.

Hospital admission in the 12 months preceding the survey was reported in 2.2% of children aged 0 to 14 Theprevalence of hospital admission decreased with increasing age from 6.3% in children aged 0 to 1 to 0.8% inthose aged 11 to 14 There was a higher prevalence of hospital admission in male (3.1%) than female (1.4%)children Among these children, 65.3% were admitted to hospitals under Hospital Authority only, 24.6% toprivate hospitals only, and 6.5% to both types of hospitals As for the number of times of hospital admission,74.0% were admitted once, 17.2% were admitted twice and 4.0% were admitted three times or more

Regarding follow up for special health problems in children aged 0 to 14, 2.5% consulted doctors regularly forphysical problems, 0.5% consulted physiotherapist, occupational therapist or speech therapist regularly formotor or speech problems and 0.2% consulted mental health professionals for mental problems

The majority (98.7%) of children aged 0 to 14 had parents reported that they did not consider their childrenbeing failed to be treated properly or delayed in receiving treatment The median satisfaction score of healthcare services of the private sector was 80 and that of the public sector was 65, with 0 being the lowest and 100being the highest level of satisfaction

For health insurance coverage, 41.2% of children aged 0 to 14 were covered by one or more of the following:medical insurance coverage provided by parents’ current employer, family medical insurance policy andchild’s personal medical insurance policy

Conclusion

This survey revealed that our children population aged 0 to 14 had generally enjoyed good health prior to thestudy period Nevertheless, there were areas that required improvement, including short-sightedness, eatingbehaviour, activity level and risk taking behaviours

This survey has provided a rich body of information on a number of health issues concerning the childpopulation in Hong Kong The results should have significant reference value and served as baselineinformation for subsequent surveys As such, the population based child health survey should be conducted

Chapter 1

Background and Methods

This Chapter provides the background of the population-based Child Health Survey (CHS) The objectives ofthe study, methods used, fieldwork involved, survey instruments used to collect data, quality control measures,confidentiality and the statistical analyses are also described

information to the Population Health Survey (PHS) conducted in 2003/04 to give a comprehensiveinformation base of the population health by including baseline data on the health and well-being of children

in Hong Kong This is the first of population health survey ever conducted in children aged 14 and below inHong Kong and is carried out by the Department of Paediatrics and Adolescent Medicine and the School ofPublic Health of the Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU)

The objectives of this survey are to strengthen the Government’s information base to assess the health status

of the child population and to support evidence-based decision-making in health policy, resource allocation,and provision of health services and programmes

The scope of the survey includes the following:

 To measure the physical, mental/psychological health status of the child population;

 To collect data related to the demographic variation in health;

 To collect data on risk factors of important causes of morbidity and disability;

 To collect data on health behaviours and practices of the child population;

 To collect data on the prevalence and/or incidence of important diseases and health conditions specific

to the child population;

 To collect data on the utilization of health services among the child population;

 To identify and differentiate the health needs between subgroups of the child population; namely

1.2 Sample Selection

The study design was a population-based cross-sectional survey with the use of face-to-face interviews andself-administered questionnaires It aimed to cover land-based non-institutionalized children aged 14 andbelow in Hong Kong Owing to operational consideration, children whose parents could not speak Cantoneseand those living in area segments in non-built-up areas were not covered in the survey

The sample of households was drawn from the Register of Quarters maintained by the Census and StatisticsDepartment Systematic replicated sampling was applied to select quarters from the Register of Quarters Allhouseholds in the selected quarters were visited in order to determine if there were children aged 14 and belowliving in the quarters Households with children aged 14 and below were selected for the interview and theinterview covered all children aged 14 and below in the sampled households Information was obtained fromeither parent as proxy respondent for children aged 10 and below, and from both parent and children for aged

11 to 14 A total of 7 393 children were enumerated in the survey

1.3.1 Data collection

Fieldwork of the survey was carried out from September 2005 to August 2006 Face-to-face interviews witheither parent were conducted by well-trained interviewers using structured questionnaire in Chinese After theface-to-face interviews, parents would complete self-administered questionnaires in Chinese which includedInternational Study of Asthma and Allergies in Childhood (ISAAC)1 questionnaire, Child Behaviour Checklist(CBCL)2,3and Child Health Questionnaire (CHQ)4 A separate face-to-face interview and a self-administeredquestionnaire in Chinese on potential sensitive topics including quality of life, psychological assessment andrisk behaviours was conducted for each child aged 11 to 14 except for those who were mentally handicapped.The survey also collected physical measurements from the children sampled

To optimize the response rate, a multi-wave, multi-contact approach was adopted Notification letters weresent to all sampled households at least one week preceding the household visits The objectives of the surveywere clearly explained and assurance of data confidentiality was underscored in the letters A telephonehotline was set up to address enquiries about the survey from the households and for the respondents to makeappointment for interview When a refusal case was encountered, the fieldwork managers would reassigndifferent interviewers, accompany the interviewer to make a second attempt or even take over the case Eachhousehold was contacted for a minimum of 5 times at different times of the day and different days of the week,and a maximum of 15 times, to minimize and rectify non-contact

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1.3.2 Data coding, data entry and data cleaning

The completed questionnaires were manually edited for completeness and internal consistency Errors foundwere immediately referred back to the interviewers for follow up actions The data were then coded and inputinto the computer for processing Validation rules were drawn to ensure proper entry of data, appropriateskipping of questions, and consistency of the answers provided In addition, a computer validation programwas developed to detect errors that might be overlooked during manual editing stage

The survey instrument was developed by the Department of Paediatrics and Adolescent Medicine and School

of Public Health, HKU in consultation with Department of Health and a panel / group of experts The surveyincluded questions used in PHS, three validated questionnaires including CHQ, CBCL and ISAAC, and newquestions developed specifically for this survey

The CHQ was developed in the United States for measurement of physical and psychosocial well-being ofchildren aged 5 and older It consists of the child form (CF) and the parent form (PF) To assess the physicaland psychosocial well-being of children aged 6 to 10, parents were asked to complete the validated Chineseversion of the CHQ-parent form (PF) 50, which consisted of 50 items and based on which 12 multi-dimensional health concepts were scored Each of the concepts was scored from 0 to 100 Higher scoresindicate better perceived health or psychosocial well-being To assess the physical and psychosocial well-being of children aged 11 to 14, the children were asked to complete the validated Chinese version of theCHQ-child form (CF) 87, which consists of 87 items and based on which 11 multi-dimensional healthconcepts were scored The concepts were similarly scored from 0 to 100, and higher scores indicate betterperceived health or psychosocial well-being

The CBCL is the assessment of child behaviour CBCL allows us to obtain standardized ratings of diverseaspects of behavioural, emotional, and social functioning

The Chinese version of the ISAAC questionnaire is to assess the prevalence of asthma and related allergies

The questions of the survey were formulated based on the review of both local and overseas questionnaires

Part I Household questions, parental and primary carer’s characteristics

3 Primary carer’s characteristics

○ age, gender, relationship with child, etc of primary carer

Part II Questions on the personal health, lifestyles, practices and behaviours

o prevalence of acute and chronic conditions

o prevalence of specific illnesses including asthma and related allergies, food allergies and pain

o physical activity and sedentary behaviour

o exposure to environmental tobacco smoke (in-utero and current)

o youth risk behaviour including smoking, substance abuse, sexuality

5 Access and utilization of health services

o access to health care

o types of health services with frequency

o usage of mental health care and alternative health care

To test the applicability of the questionnaires and the fieldwork procedures, two pilot surveys covering a total

of 78 selected children were conducted in April/May and June 2005 After the first pilot survey, thequestionnaire was modified and the logistics arrangement was determined The length of the interview wasretested in the second survey

1.7 Quality Control Measures

Quality control measures were taken to ensure the credibility and reliability of the data The measuresencompassed the recruitment of experienced interviewers to conduct face-to-face household surveys, theprovision of proper training to interviewers, monitoring of the interviewing process by fieldwork managers,independent checking of at least 10% of the completed cases by a separate brief interview, selected on arandom basis, editing and checking of the completeness and consistency of the data and validation of thecollected data Through a reporting system from the field managers, the progress of the survey and the result

of quality control could be closely monitored The result of independent checking showed that the fieldsurvey was of high quality All non-contact cases and non-response cases were followed up by at least 5 times,made at different times of the day and different days of the week

Before the interview took place, a notification letter was sent to the parents/guardians at least one week beforethe start of the fieldwork, explaining the purposes of the survey and reassuring the respondents that datacollected in the survey would be kept strictly confidential Explanation letter, information sheet and consentform were prepared A telephone hotline and a contact person were included in the notification letter toenable the respondents to clarify any questions they might have about the survey, or to make appointment forthe interview Parental consent was obtained before the interview

All completed survey questionnaires were regarded as confidential documents All survey data were keptstrictly confidential Due care in handling the records was exercised to avoid possible loss and leakage ofinformation No individual names or personal identifiers would appear in publications and reports and onlyaggregate data would be presented All questionnaires would be destroyed within three months after thecompletion of the survey

The survey was approved by the Ethics Committee of the Department of Health

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1.11 Statistical Analysis

The analyses reported were based on responses from 7 393 children obtained in the survey This represented

884 300 children of the target population Unless otherwise specified, all analyses were based on weighteddata

The survey sample was weighted to adjust for differences in response rates observed in different types ofhousing Post-stratification weights were used to adjust for the differences between the age and sex structure

of the survey estimates and the estimates of the target children The latter was estimates of children aged 14and below from General Household Survey during the fourth quarter of 2005 to the second quarter in 2006compiled by the Census and Statistics Department, and was adjusted to exclude children of non-Cantonesespeaking parents and those living in area segments in non-built-up areas Fifteen one-year age groups wereemployed in compiling post-stratification weights Data were analysed using SAS Version 9.2 and SPSSVersion 15.0 that took into account the clustering sample design of the survey

1 The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee Worldwidevariation in prevalence of symptoms of asthma, allergic rhinoconjunnctivitis, and atopic eczema: ISAAC.Lancet 1998; 351:1225-1232

2 Achenbach TM and Rescorla LA Manual for the ASEBA Pre-school Forms & Profiles (for ages 1½ – 5).Burlington VT Univeristy of Vermount, Research Center for Children, Youth, & Families, 2000

3 Achenbach TM and Rescorla LA Manual for the ASEBA School-Age Forms & Profiles (for ages 6 – 18).Burlington VT Univeristy of Vermount, Research Center for Children, Youth, & Families, 2001

4 Landgraf JM, Abetz L, Ware JE The CHQ: User's Manua Boston, MA: HealthAct, 1999

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Chapter 2

Representativeness of Sample and Characteristics of

the Households and Study Population

This chapter describes the sample representativeness, along with a portrayal of the characteristics of thehouseholds as well as the study population

A total of 30 000 quarters were selected from the Register of Quarters prior to the commencement of thefieldwork On completion of fieldwork in August 2006, the number of valid quarters (i.e with domestichouseholds residing in) was 26 373 Among these valid quarters, the percentage of quarters successfullyenumerated (including those without children aged 14 and below) was 73.3% (or 19 342) with refusal rate of17.3% (4 570 out of 26 373) and non-contact rate of 9.3% (2 461 out of 26 373) 4 975 households werefound to have children aged 14 and below residing there A total of 7 393 children aged 14 and below livingthere were enumerated The sample representativeness, characteristics of the households and the studypopulation are described in sections 2.2, 2.3 and 2.4 respectively

2.2 Sample Representativeness

2.2.1 Type of housing

There was a significant over-representation of children living in public rental housing and subsi dized salesflats and a significant under-representation of children living in private permanent housing in the sample

under-representation in private permanent housing was not unexpected It was generally more difficult to obtainpermission to enter private housing estates to contact the households and to convince them to participate in thesurvey Hence, the sample data were weighted to adjust for the differential response rates in different types ofhousing

Table 2.2.1 Sample representativeness on type of housing

Effect Size

0.36

0.36

0.36

0.36

0.36

C&SD denotes Census and Statistics Department.

Effect size indicates the degree of difference It has three levels – 0.1 for ‘small’, 0.3 for ‘medium’and 0.5 for ‘large’.1

2.2.2 Gender and age

Females were slightly under-represented, making up 48.1% of the sample It compared with 48.5% of studypopulation based on the estimates compiled by the Census and Statistics Department Conversely, males wereslightly over-represented, making up 51.9% of the sample, and compared with 51.5% of the study population(Table 2.2.2) Weightings were introduced to adjust for the difference between the study population and theage-sex profile of the data after adjustment by type of housing After weighting, the age and sex distributionreflected that of the study population during the survey period

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Table 2.2.2 Sample representativeness on age by gender

Effect Size

No of children % No of children % No of children % No of children

('000) %

No of children ('000) %

No of children ('000) %

No of children ('000) %

No of children ('000) %

No of children ('000) %

C&SD denotes Census and Statistics Department.

Figures in brackets refer to the proportions by gender.

Effect size indicates the degree of difference It has three levels – 0.1 for ‘small’, 0.3 for ‘medium’and 0.5 for ‘large’.1

2.2.3 Distribution of households

The household distribution by District Council district in the survey was compared with the annual statistics

percentages of households on Hong Kong Island, in Kowloon and in the New Territories were 12.0%, 27.1%and 60.9% respectively in the survey sample Households with children aged 14 and below in the NewTerritories were over-represented while those from Hong Kong Island were under-represented In the CHS,Age

Table 2.2.3 Sample representativeness on household distribution by District Council district

C&SD Effect Size

No of households %

Households with children aged 14 and below

0.25

Hong Kong Island

Households with children aged 14 and below

0.25

Hong Kong Island

Households with children aged 14 and below

0.25

Hong Kong Island

Households with children aged 14 and below

0.25

Hong Kong Island

Effect size indicates the degree of difference It has three levels – 0.1 for ‘small’, 0.3 for ‘medium’and 0.5 for ‘large’.1

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2.3 Characteristics of the Households

The majority (99.8%) of the households did not share their quarters with other households (Table 2.3a) Thecharacteristics of the households surveyed are tabulated in Table 2.3b The most frequent number of membersper household was 4 (41.6%) The form of tenure were mainly owned (61.3%) or rented by the sole tenant(38.1%) Most households either lived in 40 to less than 60 square metres (38.7%) or in below 40 squaremetres (27.2%) of living quarter (Table 2.3b)

Table 2.3a Number of households per quarters in CHS

Base: All households with children aged 14 and below

Number of households in quarters

Table 2.3b Characteristics of households

2.4 Characteristics of the Study Population

2.4.1 Study population

The key characteristics of the study population are highlighted below Readers are advised to note that allestimates contained in this report are subject to sampling and non-sampling error For those estimates whichare based on only small number of sample observations, the sampling error may be relatively large and should

be interpreted with caution

A total of 7 393 children aged 14 and below were enumerated in the survey, representing a study population of

884 300 children The largest proportions of children were in the 13-year age group, at 8.9% and 9.5% forfemales and males respectively The median age of the study population was 9.1 (Table 2.4.1)

Table 2.4.1 Number of children aged 0 to 14 by age and gender

2.4.2 Place of birth

Nearly 90% of the children were born in Hong Kong The next common place of birth was Guangdongprovince (6.6%), followed by other provinces in China (1.8%) and only 0.2% was born in Macau Regardingthe relation between place of birth and age group, the vast majority (95.6%) of the young children aged 0 to 5were born in Hong Kong while comparatively larger share of children in the elder age group of 11 to 14 wereborn outside Hong Kong (13.2%) (Table 2.4.2)

Table 2.4.2 Place of birth in children aged 0 to 14 by age group

2.4.3 Age at immigration to Hong Kong

A total of 90 100 children were born outside Hong Kong, representing 10.2% of children aged 0 to 14 Most

of them first resided in Hong Kong at a young age before 6 years old (29.3%) However, readers are advised

to interpret the findings with care as over half of the children did not report their age immigrated to HongKong (Table 2.4.3)

Table 2.4.3 Age at immigration to Hong Kong by gender

2.4.4 Gestational age and birth weight at delivery

Analyzed by gestational age, 5.7% of the children were born pre-term (less than 37 weeks of gestation) and88.7% were born at gestation of 37 weeks or more (Table 2.4.4a)

Table 2.4.4a Gestational age in children aged 0 to 14 by gender

The mean, median and mode birth weight of the children were 3.09 kg, 3.20 kg and 3.20 kg respectively.Regarding the relationship between parent-reported birth weight and gender, only 0.5% of female children and0.7% of male children were born with very low birth weight (less than 1.5 kg) 36.1% of female children and35.1% of male children had birth weight of 3 kg to less than 3.5 kg 2.6% of female children and 3.6% ofmale children had a birth weight of 4 kg and above The median birth weight for male children (3.20 kg) wasmarginally higher than that of females (3.10 kg) (Table 2.4.4b).

Table 2.4.4b Parent-reported birth weight in children aged 0 to 14 by gender

0.01 3.07

3.10

0.01

3.10 3.20

0.01 3.07

3.10

0.01

3.10 3.20

0.01

Base: All children aged 0 to 14

2.4.5 Educational attainment

Children aged 2 to 14 were enquired on the current educational attainment, including playgroups Among theyoung children aged 2 to 5, the vast majority (85.2%) were studying either in playgroups or pre-school centres(including kindergartens) Analyzed by gender, a marginally higher proportion (85.9%) was observed in maleyoung children than in female counterparts (84.5%) Males also had a lower rate of not yet started schoolbecause of young age, at 11.0% as against 12.7% in females counterpart Some 2.7% of females and 2.9% ofmales were not enrolled in school for other reasons which were not specified (Table 2.4.5)

Among the children aged 6 to 10, the vast majority (96.2%) were studying at primary level of general localschools The corresponding proportions in females and males were 96.7% and 95.7% respectively As forchildren aged 11 to 14, 66.0% were studying at secondary level of general local school while 33.4% werestudying at primary level of general local schools (Table 2.4.5)

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Table 2.4.5 Current educational attainment in children aged 2 to 14 by age group and gender

Base: Children aged 2 to 14

Notes: “Pre-school ” refers to nursery and kindergarten K1-K3.

“Others” refers to special school, integrated programme in child care centre and international school.