Interview with Dr. John Colquhoun (1998)

John Colquhoun, BDS, PhD 1924 - 1999

A dentist and historian, John Coquhoun lived in Auckland, New Zealand while pursuing a career as a researcher, dental practitioner and public health official. He graduated from the University of Otago in New Zealand in 1948 with a Bachelor of Dental Surgery degree and received his diploma for education in Sydney. After 7 years service in the national School of Dental Service, as a teacher and administrator, he entered private practice. In 1971, he became Principal Dental Officer for the Auckland Health District. During this period he carried out research in both dentistry and Auckland social history.

Until 1980, Colquhoun was a keen advocate of water fluoridation. In that year, he was sent on a world study tour by the New Zealand Department of Health for the purpose of investigating recent research into fluoridation. Upon his return he was appointed to the post of Chairman of the Fluoridation Promotion Committee of the New Zealand Dental Health Foundation.

After returning from his study tour, Dr. Colquhoun reported the new discovery (for 1980) that dental decay was declining in "western" counties, with or without fluoridation, and that the differences between decay rates in fluoridated versus non-fluoridated locations were much less than had been claimed would occur.

Nonetheless, like many of his professional colleagues of the day, Colquhoun was very reluctant to admit that fluoridation was a failure. He advocated, and his superiors agreed to a new approach based on the belief that fluoridation still provided a marginal benefit. Colquhoun felt he was reinforced in that belief by his superiors' claim that new statistics, collected for all New Zealand School Dental Service patients (98% of the childhood population) revealed such a benefit.

He was shocked to discover, when the statistics were sent to him, that they revealed no such benefit. In fact, in most Health Districts the percentage of children who were "caries-free" was higher in the non-fluoridated areas of New Zealand.

Colquhoun disagreed sharply with his superiors' action in circulating a document, "overview of fluoridation statistics," which omitted the Health District statistical information on fluoride and "disgracefully doctored" the remaining statistics, claiming that a marginal benefit existed.

When, in addition, he discovered that dental fluorosis prevalence (a sign of fluoride toxicity) was much higher than expected in fluoridated areas, Colquhoun publicly changed his stance on fluoridation in 1983.

Dr. Colquhoun continued his research, which contributed to the earning of a Doctor of Philosophy degree in 1987, and was appointed to the post-doctoral position of Honorary
Research Fellow of the University of Auckland. In 1992 he became editor of the Journal of the International Society for Fluoride Research (Fluoride), a position which provided a good overview of fluoride research in different academic disciplines.

Dr. Colquhoun passed away peacefully in his home on March 23rd, 1999 at the age of 75, remaining intellectually active almost until his final moments.