The Northern Finland Birth Cohort study originated in the 1960s at the initiative of paediatrician Paula Rantakallio. The reason for the study was concern about the high morbidity and mortality rates of both mothers and newborns.
The original goal of the study was to find factors affecting low birth weight and premature birth as well as to learn to understand how these affected morbidity later on. This was the start of the NFBC1966 study in which more than 12,000 mothers living in Northern Finland with a due date in 1966 were selected. It corresponded to more than 96 percent of the births in the provinces of Oulu and Finnish Lapland.
The children were followed-up already before they were born and the follow-up resumed 10-year intervals. Most recently the people involved in NFBC1966 underwent extensive examinations as they turned 46. More than 250,000 biological samples were collected in a period of two years. Questionnaires were also used to study factors such as social background, lifestyles, and medication. Participants in the follow-up study had spinal and dental x-rays taken, for example.
Now that information has been collected from the same individuals, it is possible to compare what changes have occurred in their states of health as they grow older. One example of results worth mentioning is a study connected with smoking.
When comparisons were made when the subjects were 31 and 46 years old, one observation was that smokers used public health care services more frequently than non-smokers did. Especially, smokers were significantly more likely to use mental health services. Lifestyle choices had started to create differences.
Difference between generations
A new study following pregnancy and child development began at the University of Oulu in 1985. Nearly 9,400 mothers from Northern Finland were included.
This year, as the children turn 33, the participants in the NFBC1986 study will again be taken under closer examination.
The time points of the two cohorts were chosen so that the difference between the generations can be found. It is interesting to study how the health of people about 30 years of age differs when comparing groups of people born 20 years apart. In that period of time our awareness of factors affecting health has grown considerably. Many technological advances have brought changes to working methods and recreational activities.
But even greater upheavals have come in the past ten years. How do the health and well-being of those born into the age of mobile phones and computers differ when compared to those born in 1966 and 1986? With that in mind, many researchers have entertained the thought that it would be important to launch a third birth cohort.
Extensive research material
Samples collected from the birth cohorts, the results of various measurements, questionnaires, and information obtained from national registers, such as the use of medicines, form a unique research material. Its goal is to promote health and well-being in the population.
"More than 20 research groups at the University of Oulu are working with the cohort data”, says Minna Männikkö, research director in the Northern Finland Birth Cohorts.
Plenty of research publications and doctoral dissertations have been written as a result. "Cohort material has been utilised in more than 1,300 publications", Männikkö mentions. It is used both in Finland and in international cooperative projects.
Genetic studies of the birth cohort have helped in the understanding of the mechanisms that lead to the onset of disease. The impact of smoking while pregnant on the low birth weight of children has been shown. Vitamin D supplements given in the first years of life were seen to have a role in the onset of diabetes in children. Those who exercise actively have significantly fewer risk factors for cardiovascular diseases. In addition, it has been possible to look for connections between oral health and cardiac events. These are just a few examples of results obtained with the help of the cohort material.
It is clear that long-term population follow-up studies such as the Northern Finland Birth Cohorts are needed. They do not exclusively involve those who are afflicted by a particular disease. Instead, a large sampling of a certain age group is taken, which is then followed from cradle to grave.
Adequate resourcing is a challenge for these kinds of studies. Each time point, when questionnaires are sent to the cohort members or when they participate in various clinical studies, requires a major effort. A large number of people are involved in the planning of the follow-up studies. "The questions in the surveys must be planned carefully so the answers can also be utilised in further studies", Männikkö points out.
Financial contributions are also significant. "Depending on how extensive the clinical studies are, large amounts of money are needed for each time point”, Männikkö explains. For instance, nearly four million euros were needed for the extensive follow-up on the health of the 46-year-olds.
"It's not easy to find financiers that will fund the collection phase. However, there is often willingness to fund research that is done on the already collected data”, Männikkö observes. The search for funding starts already 2-3 years before invitations to take part in the study are sent.
This year the invitations to participate are sent to members of NFBC1986. They will be asked to answer questions regarding their health and well-being. This time the survey will be conducted online.
The health of those born in 1966 has been studied from the foetal stage. This has provided enough research material to fill up several metres of shelf space. Photo: Marika Kaakinen.
Text: Maarit Jokela
Last updated: 26.3.2018