Definition of the study
NFBC85/86 is a longitudinal one-year birth cohort study from an unselected population. The original aim of the study was to describe and analyse the epidemiology of diseases, risk factors for pregnancy outcomes and school achievements. VERTAILU VUODEN -66 SYNTYMÄKOHORTTIIN?
Determination of the NFBC8586
Cases belonging to the survey were determined by the calculated term: the series comprised all the mothers in Finland's two northernmost provinces Oulu and Lapland with the calculated term falling between July 1, 1985 and June 30, 1986. In fact, a small percentage of the births occurred towards the end of June 1985 and begin of July 1986. The calculated term, as was customary at that time, was counted from the first day of the last menstrual period. The number of deliveries in the cohort was 9362, which was 99% of the deliveries taking place in the target period of the cohort.
Data collection
Data collection was started before the birth and it has been continued up to the
present. Mothers provided background information concerning their health and
family's social situation on structured self-completed questionnaires. The
questionnaire was given to all mothers on the first antenatal visit and they returned it by the 24th gestation
week. Obstetrical and birth data were coded from hospital records at the time
of delivery. A postal questionnaire concerning the health of the
child and the sociodemographic background was mailed to parents when children
were 7 years old. At the same
time, information on the child's health was supplemented from hospital records.
Data on learning difficulties and behavioural problems was collected at the age
of eight. Child's teacher and parents received postal questionnaire when children
were completing their first year in the primary school.
The latest extensive data collection concerned health and well-being of adolescents and it
was carried out when children were at the age of 16. This included postal questionnaires
to adolescents and parents. Adolescents were also invited to clinical examinations.
Tässä pitäisi kai kertoa myös se,että tietoja täydennetty sairauskertomuksista ym. rekistereistä.
| Number of children born by gender, no of foetals and status |
| Fetal | All | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Singletons | Twins | Triplets | ||||||||||||
| Gender | All | Gender | All | Gender | All | Gender | All | |||||||
| Boys | Girls | Not known | Boys | Girls | Boys | Girls | Boys | Girls | Not known | |||||
| N | N | N | N | N | N | N | N | N | N | N | N | N | N | |
| Birth status | 25 | 18 | 1 | 44 | 1 | 2 | 3 | . | . | . | 26 | 20 | 1 | 47 |
| Still born | ||||||||||||||
| Live born | 4726 | 4477 | . | 9203 | 136 | 87 | 223 | 3 | 3 | 6 | 4865 | 4567 | . | 9432 |
| All | 4751 | 4495 | 1 | 9247 | 137 | 89 | 226 | 3 | 3 | 6 | 4891 | 4587 | 1 | 9479 |
| Mothers | Deliveries |
| 9362 | 9362 |
|
Questionnaire
|
Target population, children alive and adress known |
Number of participated
|
Participation%
|
| 7 y, Health study, postal questionnaire to parents |
9327
|
8416
|
90
|
| 8 y, Learning difficulties, postal questionnaire to parents |
9298
|
8370
|
90
|
| 8 y, Learning difficulties, postal questionnaire to teachers |
9298
|
8525
|
92
|
| 16y, Health and wellbeing of adolescents, postal questionires to parents |
9215
|
6985
|
76
|
| 16y, Health and wellbeing of adolescents, postal questionires to adolescents |
9215
|
7344
|
80
|
| 16y, Health and wellbeing of adolescents, clinical examination |
9215
|
6798
|
74
|
Person in charge
Marjo-Riitta Järvelin, Professor