Danish National Birth Cohort

The Danish National
Birth Cohort
Marin Strøm, MSc, PhD
Post Doc & Scientific Secretary
Danish National Birth Cohort

The Danish National Birth Cohort (DNBC)
• a longitudinal conception-to-death study
• aims to investigate associations between early-life factors and
diseases in a life-course perspective
• holds data from several data sweeps during pregnancy and
early childhood, including an FFQ during pregnancy and
follow-up at child age 7 - as well as data from national
administrative registers
• Holds 2 blood samples from the mother taken during
pregnancy and 1 from the umbilical cord
• Currently (2010-14) collects data from the 11-year-old
participants as well as from their mothers in two separate
questionnaires and further follow up is underway
Danish National Birth Cohort

DNBC Sampling
All pregnant women in Denmark 1996-2002
100%
100%
Appr. 30% do not
receive an invitation
Appr. 60% receive an invitation
Appr. 40% choose
not to participate
Appr. 10% do not
fulfill inclusion criteria
Appr. 60% are enrolled in the study
Total: 101.042 participants
100%
1st interview: 92.892
92% of total
4th interview: 65.764
65% of total
FFQ: 70,183
69% of total
3rd interview: 70.296
70% of total
2nd interview: 87.802
87% of total
Danish National Birth Cohort

Data collections in the DNBC
120000
101042
100000
92892
87802
80000
%
%
92
86
%
70183
%
60000
70296
87
69
65764
60242
%
69
%
65
40000
%
62
22635
20000
%
50
Time
11
-y
ea
r
7ye
ar
4
In
t
3
In
t
2
In
t
Q
FF
.1
In
t
ed
ic
at
io
n
Pr
epr
eg
.M
en
ts
0
En
ro
lm
Number of responders
87249
Danish National Birth Cohort

Biological samples
100000
1,2
93000
90000
1
80000
Number of responders
71000
70000
61000
0,8
60000
50000
0,6
40000
0,4
30000
20000
0,2
10000
0
0
1st bloodsample
2nd bloodsample
Umbillical sample
Danish National Birth Cohort

Food Frequency Questionnaire during pregnancy
•
•
•
•
•
•
19 pages long
~300 food items
One month back in time (from gw25)
Fixed time categories
Fixed food item names
Food supplements
Ref: Olsen SF et al. Paed Perin Epi 2007
Danish National Birth Cohort

Access to data : www.dnbc.dk
Danish National Birth Cohort

Linkage to other sources
The DNBC is a national registry, owned by the Danish National Board of Health
Individual level linkage via population registries allow us to:
• follow the individual from birth to grave
• follow diseases through generations (gene/environment)
• follow millions of individuals
CPR-number
Birth characteristics
Diseases
Prescribed medication
Vaccinations
School performance
Family, place of living
Education, employment
Biological specimens
Danish National Birth Cohort

Ongoing data collection:
11 y child questionnaire
Self-reported exposure info on:
Self-reported outcome info on:
• Social relationships (family/peers)
• School environment
• Sleeping habits
• Eating habits (FFQ)
• Physical (in)activity
• Traffic safety
• Smoking and alcohol
• Dental hygiene
• Global health (SOCS)
• Sleeping disorders
• Eating disorders
• Musculoskeletal problems
• Child’s strengths and difficulties (SDQ)
• Depression, self-injuries (DAWBA)
• Psychotic symptoms/Schizophrenia (PLIKS)
• Puberty (Tanner stages)
Danish National Birth Cohort

Ongoing data collection:
11 y child questionnaire
Parent-reported exposure info on:
Parent-reported outcome info on:
• Organic food
• Vitamins/Dietary supplements
• Sun and sunscreen
• Medication/Vaccination
• Chlorine exposure
• Housing and indoor air pollution
• Hereditary factors (family disease history)
• Parental factors (alcohol, smoking,
anthropometrics, mental health)
• Asthma/Allergy/Eczema (ISAAC)
• Disabilities/Physical impairment
• Infections
• Diabetes/Celiac disease
• Vision and hearing impairment
• Enuresis
• Tics (DAWBA)
• Obesity (anthropometric measures)
Danish National Birth Cohort

Current status in the 11-year follow-up
• The 11-year follow-up was launched in July 2010
• To the end of 2014 invitations are sent to approx. 350
families every week
• In case of no-reply reminders are sent out 4 and 8
weeks after the invitation
• effort to increase participation: win quick-reply prizes
when answering within 4 weeks after invitation
Danish National Birth Cohort

An ongoing substudy of the DNBC
AHEAD GDM study
A study of long-term HEAlth after the Development of
Gestational Diabetes Mellitus
Collaboration between
Rigshospitalet (Allan Vaag, Louise G Grunnet and others)
Statens Serum Institut (Sjúrdur F Olsen and others)
Harvard School of Public Health (Frank Hu and others)
NIH / NICHD (Cuilin Zhang and others)
Danish National Birth Cohort

AHEAD GDM study: Objectives
• To describe the association between mother’s GDM and child’s risk
for developing T2D and metabolic disorders
– influence of specific dietary components during pregnancy on the risk
for developing T2D in the child
– influence of physical activity during pregnancy on the propensity for
developing T2D in the child
– underlying epigenetic mechanisms that may mediate effects of maternal
factors (GDM, diet, physical activity) on T2D propensity in the offspring
Danish National Birth Cohort

Study subjects
• ~1500 children to GDM and control mothers (aged 9-15 years)
recruited from DNBC
Aarhus
Copenhagen
Smaller sites/mobile clinic
Danish National Birth Cohort

Clinical examination
Children
• Anthropometry: weight, height, waist, hip, head circumference
• Blood pressure and heart rate
• Fasting blood samples (glucose, insulin, C-peptide, incretin, leptin,
adiponectine)
• DEXA scanning
• Urine sample
• Online questionnaire (diet, physical activity)
Mothers
• Weight, height, waist, hip, blood pressure and heart rate
• OGTT (fasting blood samples and DNA, PAX genes)
• DEXA scanning
• Urine (endocrine disrupting chemicals) and toenail samples (trace metals
incl magnesium, chromium)
• Online questionnaire and FFQ
Danish National Birth Cohort

Further follow up of DNBC children
•
Puberty study
–
–
–
–
–
•
FFQ14
–
–
–
–
•
Launched few weeks ago
Aim: investigate reasons for early puberty
~20000 children invited to fill in Q on puberty stage
Repeated every 6 mo
Web based, focused Q
Will be launched Jan 2013
Assess diet & physical activity in teenagers 14y
All DNBC children asked to fill in Q
Web based, built on GUTS  adapted to DK
Planned: FFQ in mothers
Danish National Birth Cohort

Thank you for your
attention!
www.dnbc.dk
Danish National Birth Cohort

Danish National Birth Cohort

Danish National Birth Cohort

Danish National Birth Cohort

Clinical examination
Standardization
3 days prior to visit
-
No hard physical activity
No alcohol consumption
The day before the examination
All participants will be asked to eat a small meal at 8 PM
Following the small meal: Not eat, drink and smoke
On the day of visit
Transport to the hospital by car or public transport – no bicycle
No steps – take the elevator
Danish National Birth Cohort

Enrolment plan
RH
Esbjerg
Århus
Næstved (20-21)
October
RH
Esbjerg ( 16.11)
Århus
Nykøbing F/Nakskov
(10-11)
Odense
November
RH
Odense
(114 total)
Århus
Holbæk
(4 days)
December
RH
Århus
Herning
(136 cases
total)
Aalborg
(121 total)
January
Århus
Herning
Aalborg
Thisted
(32 total)
February
Århus
Herning
Aalborg
Follow up
March
Bornholm(9 total)
Follow up
April
Danish National Birth Cohort

København
Århus
Næstved
Esbjerg Odense
The rest
Total
# GDM
335
211
121
201
114
311
1293
already invited
333
211
121
199
0
0
864
Not invited yet
0
0
0
0
114
310
424
Dead or alive
abroad
2
0
0
2
0
1
5
Danish National Birth Cohort

København
Århus
Næstved
Esbjerg
Total
Completed
160
33
45
0
206
Have made
appointment
18
32
9
24
83
Contact later
19
5
8
3
35
Declined to
participate
65
40
23
9
137
Appointment
deleted
7
2
3
0
No contact yet
64
99
33
163
PRELIMINARY PARTICIPATION RATES:
CPH: 178/(160+18+19+65+7)268= 68%
Århus: 58%
Næstved: 61%
359
%
48%
10,6%