Effects of fluoride in public drinking water in New Zealand
Speaker discusses research linking oral health outcomes to fluoride
Fluoridation in public drinking water is a contentious topic in the United States and abroad. It merits continuous research, according to an expert in oral health longitudinal research.
Drinking water is exposed to many contaminates, like naturally occurring bacteria, animal waste, chemical runoff from farms and other toxins. That’s why routinely collecting water quality data is critical to the safety of public drinking water.
Jonathan Broadbent, B.D.S., Ph.D., PGDipComDent, an oral sciences professor in dental public health at the University of Otago in Dunedin, New Zealand, spoke about fluoride and other research as the featured speaker during the annual Toni Eigner-Barry Endowed Lectureship series. His topic, “Longitudinal research and community water fluoridation” was presented on Feb. 3 to members of the School of Dentistry in the Robertson Life Sciences Building. Longitudinal research is when the same group of people are studied over an extended period.
Health effects
Fluoride was introduced to the public drinking water in Hastings, New Zealand, in 1957 and expanded throughout the country in the 1960s. Studies that followed showed a decline in tooth decay in areas where fluoride was added, Broadbent said.
A chart from a May 15, 2014, study, titled “Community Water Fluoridation and Intelligence: Prospective Study in New Zealand,” by Jonathan Broadbent, et al., that appeared in the American Journal of Public Health. The results: “No clear differences in IQ because of fluoride exposure were noted.”
Today, about 58% of the population in New Zealand has fluorinated public drinking water.
In comparison, the U.S. began adding fluoride to water in 1945 and 63% of the population has access to fluorinated water, according to Centers for Disease Control 2022 data.
Broadbent talked about a development study that began in 1972 by tracking 1,000 newborns. Today, 90% of the cohort are still alive. It is one of the few such studies that includes a comprehensive oral examination, he noted.
The Dunedin Multidisciplinary Health and Development Study has examined the effects of oral health care, childhood cavities as a risk factor for aging and the association of oral hygiene and the oral microbiome within oral health.
His research has elicited opposing opinions and stirred emotions in New Zealand and around the globe. Broadbent says he’s been harassed and threatened for publishing his findings and participating in advocacy work.
Today, the researcher focuses solely on the health effects of fluoridation and avoids public opinion venues.
“We shouldn’t be dismissive of potential concerns (about fluoride),” he said. “We must continue to research to determine the right levels of fluoride in the water.”
Photos, left to right,
A chart from a May 15, 2014, study, titled “Community Water Fluoridation and Intelligence: Prospective Study in New Zealand,” by Jonathan Broadbent, et al., that appeared in the American Journal of Public Health. The results: “No clear differences in IQ because of fluoride exposure were noted.”
Jonathan Broadbent, B.D.S. Ph.D., PGDipComDent, oral sciences professor in dental public health at the University of Otago in New Zealand, talks about his research to members of the School of Dentistry on Feb. 3.
National Toxicology Program from the U. S. Department of Health and Human Services report on fluoride use and IQ. “The NPT found no evidence that fluoride exposure had adverse effects on adult cognition.”
Story by Rhonda Morin, APR
Photos by Patrick Lee
