Associate Professor Jonathan Broadbent
Associate Professor Jonathan Broadbent

10 October 2019

A study showing a clear long-term association between a child’s upbringing and the state of their teeth as a middle-aged adult has seen Otago dentist Associate Professor Jonathan Broadbent awarded the Health Research Council of New Zealand (HRC) Liley Medal at the Royal Society Te Apārangi Research Honours in Auckland.

Dr Broadbent, head of preventive and restorative dentistry at Otago University, led the study to help explain how socioeconomic inequalities in dental health arise, using 40 years of data following participants from the world-renowned Dunedin Multidisciplinary Study.

The main paper1 from the study, which was the most-read article in the Journal of Dental Research in 2016, showed that parents’ socioeconomic status and beliefs about how to keep teeth healthy strongly influenced their children’s beliefs and health behaviours growing up. These factors were also associated with substantial differences in untreated tooth decay and tooth loss by the time their children reached their 30s.

HRC Chief Executive Professor Kath McPherson says the paper reveals just how critical childhood is for determining our future dental health, and that ongoing exposure to socioeconomic disadvantage increases our risk of worsening oral health as we age.

“Jonathan and his colleagues have been able to explore and model the pathways to poor oral health from birth to adulthood thanks to the invaluable and unique data accumulated through the Dunedin Study, which the HRC has supported for more than 40 years,” says Professor McPherson.

“The high-quality evidence provided in this paper hammers home the need to tackle intergenerational socioeconomic disadvantage if we are going to meet our goal of improving the health of all New Zealanders.”

Dr Broadbent says the association between socioeconomic status and dental health is probably stronger in dentistry than any other area of health.

“I believe dentistry is a case study of what happens when we commercialise healthcare. Dental problems are serious health conditions and cause pain, embarrassment and worry, but most dental treatment is provided as a user-pays service. This doesn’t make sense since those who are least able to afford care are also those who need it the most,” says Dr Broadbent.

The research shows a striking inequality in dental treatment.

“Up to age 18, the study members that needed care mostly got it, but once access to state-funded dental care ended, the socioeconomic gap widened at an increasing rate as the study members aged,” says Dr Broadbent.

“In this paper, we traced the explanation back to their childhood. Those whose parents held inaccurate beliefs about what is good for the teeth grew up to also be less likely to believe in the importance of brushing, avoiding too much sugar, and visiting the dentist. They ended up with more teeth extracted or with untreated decay.”

Dr Broadbent says he is fortunate to work with an excellent team of researchers using high-quality data.

“I’m extremely grateful to my colleagues and to the study participants. I hope that by being acknowledged with such a prestigious award the findings will get the attention of health policymakers. I’d like this paper to get people thinking about the way we provide dental health care, particularly to adults, for whom the social divide in dental care is greatest.”

Dr Broadbent is an investigator on a HRC-funded programme ($5 million) led by Dunedin Study Director Professor Richie Poulton considering why some people age faster or slower than their age-peers. He is also working on a HRC-funded project ($1.2 million) using the Dunedin Study data to investigate dental health changes from childhood to age 45 years, including the interrelationship between oral health and other aspects of health such as heart health and quality of life.

1 Broadbent JM, Zeng J, Foster Page LA, Baker SR, Ramrakha, Thomson WM. Oral health-related beliefs, behaviours, and outcomes through the life course. Journal of Dental Research 95: 808­­–813 (2016).