Published 3.12.2020
Writer: Tomi Laitinen
 

In the 1960s, it was realized that, in international comparison, mortality due to various cardiovascular diseases was statistically at a very high level in Finland – especially among men. The statistics were corroborated by the Seven Countries Study (SCS) initiated in the 1950s, which investigated the associations between diet, blood cholesterol levels and coronary heart disease mortality in middle-aged men in different countries. The seven countries chosen for the SCS included Japan and three Mediterranean countries with low rates of heart diseases, and Finland, the Netherlands and the United States, where the incidence of coronary artery disease (CAD) was high. An essential finding of the study was the clear correlation between dietary saturated (‘hard’) fat, serum cholesterol level and CAD. Among the seven countries, the highest CAD mortality was found in Finland. The study revealed that both the saturated fat intake and serum cholesterol levels were the highest among men living in Eastern Finland. In contrast, men living in the island of Crete in Greece consumed similar amounts of fat as men in Finland, but CAD was rarely found among them. The main difference concerned the type of fat. While the Cretans used vegetable oils, mostly olive oil, the sources of fat for men in Finland included butter, fatty milk and pork fat.

In the 1970s, as a result of the findings of the Seven Countries Study, researchers in Finland began to focus on the cardiovascular disease risk factors, especially within the extensive North Karelia Project. The aim of the North Karelia Project was to have an impact on the high cholesterol and blood pressure levels in general population by encouraging people to assume healthier eating habits and to cease smoking.

 

Do cardiovascular diseases have their roots in childhood?

Earlier, it was surprisingly found that young symptom-free US soldiers who were killed during the Korean and Vietnam Wars had clear atherosclerotic changes in their arteries. In fact, similar findings had been made already during First World War. In their study of a Finnish population sample in the 1970s, Erkki Pesonen and co-workers observed coronary artery wall thickening in younger than one-year-old infants. In 1975, Hans Åkerblom and Kauko Kouvalainen asked an important question in the Finnish Medical Journal (Suomen Lääkärilehti): “Could cardiovascular diseases be prevented already in childhood?” Since then, major population studies, such as the Bogalusa Heart Study in the USA, have shown that almost all teenagers have early atherosclerotic changes in their coronary arteries and abdominal aorta. Advanced and worrisome fibrous plaques are also found in some teenagers and young adults. The current understanding is that CAD could best be prevented by avoiding the development of risk factors already in childhood and adolescence.

 

Should children’s cholesterol levels be screened?

Recommendations have been issued during the past decades to promote cardiovascular health in children. They have primarily encouraged people to pay attention to their lifestyle: a healthy diet, sufficient physical activity and no smoking. Recently, however, some international recommendations – especially in the USA – have suggested that blood cholesterol levels should be screened routinely for all children. This is a highly debated matter since scientific evidence for the benefits, or the possible harms, of such screening is lacking.

The research project funded by the Sakari Alhopuro Foundation utilises large prospective studies conducted in Finland, Australia and the USA. Ranging from childhood to adulthood, the studies seek to determine at which stages of our lifecycle and in what ways blood cholesterol levels are associated with early changes indicative of CAD and the risk of cardiovascular events, such as a heart attack. The extensive research data provides us with a unique opportunity to investigate these research questions through different study materials. Moreover, the generalisability of the findings can be ensured by combining these materials. The research results will add to our knowledge regarding the question as to whether or not we should routinely screen the cholesterol levels in children. The research results will also help us determine the optimal age for possible screening. Thus, the findings may significantly contribute to the development and targeting of measures to prevent CAD morbidity – starting from childhood.

 

 

Tomi Laitinen, MD, PhD, is a physician who also serves as a Senior Scientist at the Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku. Laitinen earned his PhD in 2015 from the University of Turku and his dissertation concerned the association between cardiovascular health in childhood and early vascular changes. In 2019, he worked as a post-doc researcher at the Murdoch Children’s Research Institute in Melbourne, Australia. Research collaboration with the Australian parties is continuing along with the present project supported by the Sakari Alhopuro Foundation.

 

 

Further reading:

Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents; National Heart, Lung, and Blood Institute. Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: summary report. Pediatrics 2011;128:S213-56
Pahkala K, Niinikoski K, Raitakari O. Sydän- ja verisuonisairauksien ehkäisy lapsuudesta alkaen. Lääketieteellinen aikakauskirja Duodecim. 2014;130(8):778-84