Poor oral health in childhood linked to higher incidence of cardiovascular disease in adulthood

A tooth cavity and bleeding gums is a common scenario among Danish children – and one that researchers now connect to health problems long after the last baby tooth has left the mouth.

Children who have multiple tooth cavities or suffer from severe gingivitis show a markedly higher incidence of stroke, heart attack and coronary artery disease as adults. That's the conclusion of a new study by researchers at the University of Copenhagen.

The researchers analyzed data from 568,000 children born in the 1960s and 70s from the Danish Health Authority's National Child Odontology Registry and compared them with data on cardiovascular diseases in the National Patient Register up to 2018, when the children had reached adulthood.

By examining these extensive datasets, the researchers identified several striking patterns. Children with numerous tooth cavities had up to a 45% higher incidence of cardiovascular disease in adulthood compared to children with few tooth cavities. For children with severe gingivitis, the incidence was up to 41% higher. The figures vary by sex, but the trend is clear for both groups. At the same time, the incidence seemed to increase as dental problems worsen throughout childhood.

Inflammation is a possible explanation

So, what explains the link between dental disease and cardiovascular disease? The researchers cannot say for certain based on this study, as they did not investigate the causes but merely identified statistical correlations. One theory, however, points to inflammation.

We suspect that exposure to high levels of inflammation in the form of gum disease and dental caries already in childhood may influence how the body later responds to inflammation."

Nikoline Nygaard, postdoctoral researcher, University of Copenhagen's Department of Odontology and one of the study's authors

This theory is supported by several other studies that have found an association between periodontitis and cardiovascular disease. The World Heart Federation has issued a consensus report  stating that strong evidence exists that periodontitis increases the risk of cardiovascular disease. The report suggests that bacteria from gum disease may trigger systemic inflammation elsewhere in the body, accelerating atherosclerosis cardiovascular disease.

In another study, Nygaard and her colleagues also examined the relationship between oral health and type 2 diabetes and found a similar pattern. Children with severe gum disease had up to 87% higher incidence of type 2 diabetes, while those with multiple tooth cavities had 19% higher incidence.

Lifestyle as a key factor

Lifestyle is likely to have a significant impact on the increased incidence of cardiovascular disease and type 2 diabetes, and therefore the researchers adjusted their data for educational level. In general, a higher level of education is associated with healthier and longer lives.

"We cannot rule out that lifestyle plays an important role. But even after adjusting for educational level, the incidence of cardiovascular disease is still quite marked," says Nikoline Nygaard.

Don't forget the toothbrush

Although the study cannot establish causality, it may still point to a significant potential for prevention. This is especially relevant given that childhood dental caries is one of the most widespread diseases globally – and both dental caries and gum disease can be prevented relatively easily with thorough tooth brushing.

"In Denmark, 20 per cent of children and young people account for 80 per cent of all registered dental disease. If we can identify markers indicating who is at higher risk of various diseases later in life, we can tailor preventive efforts to those groups. And that could have long-term health benefits well into adulthood," says Merete Markvart, associate professor at the Department of Odontology at the University of Copenhagen and co-author of the study.

She points out that gingivitis is generally under-researched, despite its high prevalence among children and adolescents. Thus, she would encourage making registration of gingivitis mandatory in the National Child Odontology Register, the same way tooth cavities are registered.

"It's not that you can solve cardiovascular disease by treating children's teeth. But if we target our efforts towards specific groups, you can nudge many people in the right direction simply by improving their oral health," says Merete Markvart.

About the study

The researchers used data from the National Child Odontology Register (SCOR) on all children born between 1963 and 1972 who had at least two SCOR registrations – a total of 568,778 individuals. These were compared with National Patient Register data from 1995–2018 on cardiovascular disease, during which time the same individuals were aged between 30 and 56.

The study is a cohort study, in which a well-defined group is followed over time to examine how a particular exposure (in this case, poor oral health) affects the incidence of disease.

The results were adjusted for the participants' educational level, which had a clear effect on disease incidence. The researchers also adjusted for the occurrence of type 2 diabetes, as this is a known risk factor for cardiovascular disease.

The study only examines correlations between oral health and cardiovascular disease and cannot determine causality – meaning it cannot show whether the dental problems directly caused the cardiovascular diseases or whether other factors played a role.