Do we need large population studies?

A new article in JAMA Pediatrics discusses the importance of large birth cohorts, such as the Norwegian Mother and Child Cohort Study (MoBa) and the Danish National Birth Cohort (BSIG) while noting why the US and Britain have tried to launch similar birth cohorts, but failed due to economic and more practical reasons.

In the US and UK they argue, it is simply too difficult to collect data about the mother, father and children, and it is very expensive. When the US survey - the National Children's Study - was shelved, it had already cost 1.3 billion US dollars even though it had been planned and tested on a small scale for over 15 years. The authors argue that many of the important diseases that affect children would have been impossible to research without epidemiological data (biological data and questionnaire data) from these studies. These data include birth defects, childhood cancers, type 1 diabetes and autism in children.

Increased knowledge about disease

Thanks to these studies, we now know more about the significance that infections in mother and child have for development in utero and after birth. We also understand better the role that pollutants and diet play for child development, and the role genes play in the development of disease.

MOBA is a so-called prospective health study. This means they gather data from the mother, father and child when they are healthy. If illness should occur in the future, scientists can go back to the data and look for causal factors. This requires large surveys of more than 100,000 people. In MoBa, 114,500 children, 95,000 mothers and 75,000 fathers participate. BSIG and MoBa have so far published more than 800 research papers. According to the authors, the most important discoveries relate to understandings about how chronic diseases in the mother during pregnancy affects the baby, and how the mother's intake of folic acid before and during pregnancy can prevent autism.

When it comes to research on cancer and type 1 diabetes in children, even MoBa and BSIG are too small. These studies have therefore collaborated with several other cohorts, including large cohorts from Asia, to obtain a better basis for research. One important collaboration is called The International Childhood Cancer Cohort Consortium (I4C).

Genetic causes

The authors argue that we now need large population studies more than ever before. They point to the importance that these studies have for finding genetic causes of disease and for investigating exposure to infectious diseases.

The authors conclude that although the United States and Britain have failed in setting up large birth cohorts, these countries can still play an important role in facilitating global collaboration between cohorts, such as the pediatric cancer initiative I4C.

So the US may be important, such as for funding through the National Institutes of Health (NIH), even if the country can't actively participate because our costs for academia are too high.