The Oslo Health Study (HUBRO) – The Youth part (UNGHUBRO)
Aims, materials and methods
By Anne Johanne Søgaard and Tove Eide, Norwegian Institute of Public HealthBackground
The National Health Screening Services (SHUS) has for many years conducted systematic
health screening surveys among adults in all of the Norway’s counties with the exception ofOslo. These data have been used by the county municipalities for planning health-related
activities. Until 2001, only data on aggregate level has been used to describe the state of heathamong adults in Oslo. The report “Oslohelsa” (1) was such an overview of the heath status inOslo, documenting large contrasts for a number of illnesses and health conditions within thecity.
In order to obtain identifiable data on individual level the Oslo Health Study (HUBRO) wasconducted in 2000-2001 (2). To gain more knowledge about the health of children andadolescents, 15-16 year olds were also invited. This study was named the youth part ofHUBRO (UNGHUBRO).
In 1996 the Norwegian Institute for Research on Adolescence, Welfare and Aging (NOVA)
had carried out a survey of 11,425 youth aged 14-17 years in Oslo (3). Their data was,however, anonymous and the focus was more on well-being than on health and illness. Thus
the health authorities wanted more information that could contribute to improved healthservices for youth in Oslo.
The other aims of UNGHUBRO were to investigate whether or not there were large
geographic, ethnic and social differences in health and illness also among youth, in addition todifferences in factors that can influence health and illness later in life.
HUBRO was a collaborative project between Oslo Municipality, the University of Oslo andthe SHUS (now the Norwegian Institute of Public Health). A separate description of thematerials and methods has been written for the adult part of HUBRO (2). In addition, ananalysis of non-responders (4) and an evaluation of the effect of sending reminders to nonresponders (5) have been published.
The aims of the health survey among youth were to:• Investigate what is important for the health and well-being of youth• Provide a better basis for designing health services for youth• Obtain more knowledge about the causes of illness and health
The invited sample
All students attending the 10th grade in Oslo during the school years 1999/2000 and2000/2001 were invited to participate in the health screening survey. A total of 8,435 students
were enrolled. Not all of the students received the invitation because some had moved after
the student information was collected and before the survey was conducted. More information
concerning the number of invited participants, the special schools that did not participate orparticipated partially, a discussion of the number of participants, etc. can be found in a
separate report (6). A total of 8,316 students received an invitation to participate in the study.
The number of invited boys and girls distributed between the 2 classes is presented in Table 1.
Questionnaires
A group including representatives from the National Institute of Public Health, the Universityof Oslo, the Norwegian School of Sport Sciences, Oslo Municipality and SHUS designed thequestionnaires. It was emphasized that the questions should be validated and preferably usedin previous youth surveys. Two 4-page questionnaires (named U and U/T) were designed. Allquestions on questionnaire U/T were suggested and paid by associated researchers. They hadprojects presented for and accepted by the board of HUBRO. A summary of supplementary
projects, questionnaires, letter of invitation, etc is available on the HUBRO website (7).
Questionnaires included questions concerning health, physical activity, smoking, intoxicants,
use of medicines, sexual behaviour and contraception, food and drink, education and plans forthe future, adolescence and sense of belonging. There was also a focus on strong and weaksides, concerns, the situation at school, culture and contact, relationship to family and friends,
mourning and war experiences (7, 8).
Approval
The study was submitted to the Regional Committee for Ethics in Medical Research andapproved by the Data Inspectorate of Norway. Additional concession has been granted for thelinkage of data between UNGHUBRO and Statistics Norway concerning parents’ educationand income.
The Data Inspectorate of Norway accepted that the informed consent form could be signed by
the student under the condition that the youth was 16 years of age by the day of the study andthat the parents/guardians were informed about the study. When these criteria were not met
the parents were contacted and asked to provide a separate informed consent form.
The authority to grant permission to perform the survey in the schools in Oslo was delegatedto the management of each school. Following a recommendation from SHUS, the Director ofSchools in Oslo sent a letter to all schools. In the letter the Department of School
Administration and the City Council of Oslo Municipality emphasized the importance of thestudy and stated that the participation of all schools with 10th grade students was important.
Thereafter SHUS contacted all schools and arranged to have a contact person designated forthe project at each school. Contact persons from the Department of School Administrationand SHUS were also designated.
Plans and information
In contrast to the adult part of HUBRO that also included collection of biological material, theyouth study consisted solely of questionnaires that were conducted at all public and private
high schools in Oslo.
Pilot study
A pilot study was conducted among 64 students in two 10th grade classes in one municipality
in a different county than Oslo. The pilot study was conducted according to the design thatwas planned for the questionnaire study in the Oslo Municipality. Results from the pilot study
indicated that it was necessary to improve some of the questions.
Contact with different institutions
A letter was sent to all public health centres in the city districts and information meetings withschool health services were held before the study commenced. The study was described andresearchers provided information concerning additional studies at these meetings.
Contact with the Red Cross was established and information concerning the possibility ofcontacting the Child and Youth Information Telephone Service was included in theinformation brochure that was sent to the homes of all students.

Contact with the schools
There was extensive contact with all of the schools in the municipality prior to the youth
study. The contact person was preferably the teacher in charge with responsibility for the 10th
grade class or the guidance counsellor at the school. The school was asked to provide
information concerning the number of classes, to send over class lists and if the study could
be conducted collectively or separately for each class. Furthermore, the schools were asked if
there were problems with language or need for translation etc., about the possibility ofreceiving help from language teachers specializing in mother tongues, reading and writing
difficulties among students, special problems that might warrant attention, travel plans,contact dates and a suggested date on which the study could be performed. The date on which
the study was to be performed was confirmed by letter.
The school contact person was responsible for sending the information to the school/students.
The contact person was also to ensure that the students were in the classroom at the time ofthe study. One teacher was also to be present in the classroom while the questionnaires werebeing completed but had otherwise no responsibilities in connection to the study.
Information to parents/guardians
Parents/guardians received via post an information brochure describing the youth study. The
brochure included information concerning why and how the study would be conducted, about
the topics addressed in the questionnaire, the voluntary nature of the study and how the results
would be used.
Execution of the study in the school
Oslo is the Norwegian municipality with the greatest concentration of foreign students who do
not have Norwegian as their mother tongue, and some of these students have difficulty
understanding all Norwegian words. However, it was decided that the forms should betranslated to English only and used as an aid when needed. Answers to the questions should
be written on the Norwegian questionnaire. Individual students with writing/reading
difficulties received extra help from a SHUS fieldworker or a language teacher. The person
providing assistance could not see the student’s answers.
The first part of UNGHUBRO was conducted during March 22 to June 21, 2000 and February
8-19, 2001. This is the busiest time of the year for 10th graders due to the final exams for highschool students. The study was conducted during the spring semester due to the age of thestudents. Students who, for example, participated in the school year 1999/2000 should intheory have passed their 15th birthday before December 31, 1999. Therefore the best chanceof including as many students as possible who were 15 years of age or older, and thus able toprovide informed consent themselves, was during the spring semester.
A total of 8 University-students were employed to conduct the study and assist in the classes,
4 in 2000 and 4 in 2001. These students received instruction with emphasis on proper conduct
before they visited the schools (see Protocol section B (8)). A list was prepared with“standard” explanations for words and concepts that school students had previously notunderstood. In this way all students who asked received the same answer regardless of theschool they attended or the assistant present during the study.
The participating students were given instruction in the classes according to accepted
procedures prior to the study. They were informed about the background of the study, why thestudy was important and how the answers would be used. It was especially important to
inform the students that all information collected was anonymous and that the researchers
would not be able to identify any of the participants. Two consecutive school hours were set
aside for the study.
It was arranged with the school authorities that students not wishing to participate in the study
should do regular school assignments during while the study was being performed.
Reminders
Questionnaires, informed consent forms and two addressed/stamped envelopes, one for thecompleted questionnaire and one for the consent form, were left at schools where students
were not present during the time at which the study was performed. In this was it was notpossible to connect the student providing consent with the completed questionnaire. A
separate instruction was prepared for teachers responsible for these students. Students who did
not return the completed questionnaire during the course of the school year were contacted byletter sent to their home. They were encouraged to answer the enclosed questionnaire and sign
the enclosed informed consent form, and return the completed forms in the respective
enclosed envelopes.
Data entry and analysis
Informed consent forms were registered separately. A separate list of codes was prepared for
injuries, contraception, birth control pills, mourning and “other physical activities”. Countryof birth was registered according to Statistic Norway standards and classification ofoccupation was based on ISCO-88. A database was designed for the registration of medicines
based on the ATC codes in the Norwegian Medicines Agency catalogue, WONCA standards
and ICPC codes. The forms were manually punched. Double punching was performed for 200forms, including both U and U/T forms, selected arbitrarily. In relation to the total number ofvariable values double punched (366 variables and 197 forms), incorrect registration wasbetween 0.1-0.3% (9).
Following the completion of the data file from UNGHUBRO, this information was linked toadditional information obtained from the Statistics Norway concerning parents’ highest
completed education, collective income and assessed income tax at the time the answer wasprovided by the responder. All personal identifiers were removed from the research file.
Participants
Sixty two schools participated in 2000 and 60 schools participated in 2001. A summary of theschools that participated/did not participate and why some schools did not participate ispresented in a separate report (6). A total of 7,343 (88.3%) of the 8,316 students who received
the invitation to participate in the study answered at least one question on one of thequestionnaires. A summary of the number of participants and the percent of boys and girls
distributed among the 2 years is presented in Table 1.
Information after the study
A health profile for children and youth in Oslo commissioned by the Oslo Municipality wasprepared following the completion of the study (10). A brochure entitled “How are you?”including some of the results from UNGHUBRO was prepared in 2002 (11). This brochure
was distributed to the classes that participated in the study, to 10th grade students in 2002, toschools and health stations in the city districts.

Acknowledgement
Many thanks to Carol Holm-Hansen for the translation of this manuscript.

References
1. Rognerud M, Stensvold I. Oslohelsa. Utredning om helse, miljø og sosial ulikhet i bydelene 1998
(In Norwegian). Oslo: Oslo kommune, Ullevål Universitetssykehus, 1998.
2. Søgaard AJ, Selmer R. The Oslo Health Study. Objectives, material and methods. Oslo: NorwegianInstitute of Public Health, 2004. http://www.fhi.no/prosjektweb/hubro
3. Bakken A. Ungdomstid i storbyen. Rapport 7/98. (In Norwegian). Oslo: Norsk institutt forforskning om oppvekst, velferd og aldring (NOVA), 1998.
http://www.isaf.no/~aba.nova/littuio96artikler.htm
4. Søgaard AJ, Selmer R, Bjertness E, Thelle D. The Oslo Health Study. The impact of self-selection
in a large, poulation-based survey. Int J Equity Health 2004; 3:3. Online:
http://www.equityhealthj.com/content/3/1/3.
5. Selmer R, Søgaard AJ, Bjertness E, Thelle D. The Oslo Health Study. Reminding the nonresponders – effects on prevalence estimates. Nor J Epidemiol 2003;13:89-94.
6. Haugstvedt Y. Materiale og metode, UNGHUBRO kohorten. Rapport. (In Norwegian). Oslo:
Statens helseundersøkelser 2002.
7. Helseundersøkelsen i Oslo. Nasjonalt folkehelseinstitutt.
http://www.fhi.no/tema/helseundersokelse/oslo/index.html
8. Helseundersøkelsen i Oslo. Protokol B – Ungdom. (In Norwegian). Oslo: Nasjonalt
folkehelseinstitutt, 2004.
9. Sagatun Å. Fysisk aktivitet og psykososial helse, en tverrsnittsstudie blant 15-16 åringer i Oslo.
Hovedoppgave. (In Norwegian). Oslo: Norges Idrettshøgskole 2003.
10. Grøtvedt L, Gimmestad A. Helseprofil for Oslo – Barn og unge. (In Norwegian). Oslo: Nasjonalt
folkehelseinstitutt, Oslo kommune, program for storbyrettet forskning, juli 2002.
http://www.fhi.no/tema/helseundersokelse/oslo/
11. ”Hvordan har du det”. Folder med noen resultater fra ungdomsdelen av HUBRO. (In Norwegian)
http://www.fhi.no/dav/2828A9BD4CAA447980D402C0E5025B55.pdf

Table 1.
UNGHUBRO
Girls

Number invitedBoys Unknown
*All

Girls

Number participating
Boys Unknown
All
*

2000
2052
2030
114093
1828
1689
93526
2001
2027
2163
2742171867
1923
213811
Unknown *6666Total
4079
4193
4483163695
3612
367343*
Gender and year of participation was not registered for some participants due to a mistake

GirlsParticipant %Boys Unknown

All*89,192,1

83,288,990,686,181,877,8
100,0
81,8

86,1
90,4
100,088,3