History

The Estonian Children Personality Behaviour and Health Study (ECPBHS) is a prospective longitudinal multidistsiplinary study initiated in 1998 by Maarike Harro (1960-2006) and Jaanus Harro. ECPBHS was incorporated from original European Youth Heart Study (EYHS) in Estonia initiated in 1998, which was initially designed for studying different cardiovascular health factors. So, initially narrower study of EYHS, now called ECPBHS, has significantly broadened and seeks answers to the questions regarding the development of both mental and physical health in general. To accomplish that, we have examined health complaints; risky behaviour including alcohol, tobacco and drugs use; nutrition; physical activity; socioeconomic background; stressful life events; family and peer relations; anxiety; personality; impulsivity; blood pressure and heart rate; body composition; biological markers.

In brief, all schools of Tartu County, Estonia, that agreed to participate (54 of the total of 56) were included into the sampling using the probability proportional to the number of students of the respective age groups in the school, and 25 schools were selected. In 1998/99, all children from grades 3 (the younger cohort) and 9 (the older cohort) were invited to participate. The age of children was selected on the basis of sexual maturation. As puberty is a time with rapid changes in many bodily functions, and as the start and speed of pubertal development is individual, two groups of children, 9-years old (just before the puberty) and 15-years old (at the end of the puberty) were chosen. A written informed consent was received from 79.1% (n=1176) of the invited subjects and their parents. The number of subjects participating in first wave was 583 in the younger cohort, age 9.6 (SD=0.5) years, and 593 in the older cohort, age 15.6 (SD=0.6) years. Follow-up studies of the younger cohort took place in 2004/2005 (n=483, mean age 15.3 (SD=0.7)), in 2007/2008 (n=454, mean age 18.3 (SD=0.5)) and in 2014/2015 when participants were 25-years-old (n=441). Follow-up studies of the older cohort were carried out in 2001/2002 (n=479, including 62 additional subjects, mean age 18.4 (SD=0.9)), in 2008/2009 (n=541, mean age 24.7 (SD=0.7)) and in 2016/2018 when participants were 33-years-old (n=504). The overview of the follow-ups of the two cohorts is given here (Study Waves).

All the studies were approved by the Tartu University Ethics Review Committee on Human Research.