Individual Study / AYLS

AYLS - Arvo Ylppö Longitudinal Study

AYLS logo
Networks -
Datasets -
Variables -

The AYLS is the Finnish arm of the Bavarian-Finnish Longitudinal Study. The original participants in the AYLS study were 1535 infants admitted to neonatal wards in obstetric units or transferred to the Neonatal Intensive care unit, and 658 control infants born without evidence of neonatal illness in Uusimaa, Finland in 1985-1986. The original aim was to compare the outcomes of neonatal care in Finland and in Bavaria, Germany up to 56 months of age. An additional wave of follow up was carried out in adulthood at 24-26 years. The main aims of the AYLS adulthood longitudinal study are to understand long-term somatic, cognitive, behavioral and emotional consequences of early life adversities. Early-life adversities include pre-, peri- and postnatal life adversities. In addition, the aim is to reveal potential resilience factors.


Investigators Contacts
  • Katri Räikkönen
    University of Helsinki
  • Kati Heinonen
    University of Helsinki
  • Rachel Robinson
    University of Helsinki


Start Year
Follow Up Is Ongoing
Year of Most Recent Data Collection
New Data Collection planned?


Access to external researchers or third parties provided or foreseen.

Data (questionnaire-derived, measured...)
Other access

Supplementary Information

We have data from questionnaires, clinical examinations, etc as well as data on cortisol from saliva samples.

Study Design

Study design
Number of Data Collection Events
Number of very preterm (VPT) and/or very low birthweight (VLBW) births included in cohort (live & still births)

Marker Paper

1. Childhood Follow up: Heinonen K, Räikkönen K, Pesonen AK, Kajantie E, Andersson S, Eriksson JG, Niemelä A, Vartia T, Peltola J, Lano A. Prenatal and postnatal growth and cognitive abilities at 56 months of age: a longitudinal study of infants born at term. Pediatrics. 2008 May;121(5):e1325-33. doi: 10.1542/peds.2007-1172.

2. Adulthood follow-up: Heinonen K, Kajantie E, Pesonen AK, Lahti M, Pirkola S, Wolke D, Lano A, Sammallahti S, Lahti J, Andersson S, Eriksson JG, Raikkonen K. Common mental disorders in young adults born late-preterm. Psychol Med. 2016 Jul;46(10):2227-38. doi: 10.1017/S0033291716000830.

PUBMED 18450875



All hospitals in area of Uusimaa.
Selection Criteria
  • Finland
Geographical Area
VPT/VLBW Group Inclusion Criteria
All infants born alive and admitted to neonatal wards in obstetric units or transferred to the Neonatal Intensive care unit between 15 March 1985 and 14 March 1986 in the study area. No specific inclusion criteria related to gestational age or birth weight.
Control Group Inclusion Criteria
An infant born after every second hospitalized infant and without evidence of neonatal illness was identified from one of the three biggest maternity hospitals in the study area during the same period.
VPT/VLBW Group Exclusion Criteria
Control Group Exclusion Criteria
Data Collection Events
# Name Description Start End
0 Perinatal Assessment Perinatal data were collected on gestational age, maternal smoking during pregnancy, pregnancy complications, delivery and birth, infant sex, length, weight, head circumference, parental ... 1985-03 1986-03
1 5 Month Follow Up At 5 months of age, participants underwent an neurological and clinical assessment, measurement of length, weight, head circumference, and administration of the Griffiths Scale of Babies ... 1986 1986
2 20 Month Follow Up At 20 months of age, participants underwent a clinical and neurological examination to assess length, weight, head circumference, cerebral palsy, visual and hearing impairment. The Griffiths scale ... 1987 1987
3 56 Month Follow Up At 56 months, a clinical and neurological examination was carried out to assess height, weight, head circumference, neurological measurements, cerebral palsy, and visual and hearing impairment. ... 1991 1991
4 24-26 Year Follow Up At 25 years of age, a full clinical assessment was performed to assess weight, height, waist circumference, waist anteroposterior diameter, blood pressure, 24 hour ambulatory blood pressure, body ... 2009-11 2012-12