City-Funded Study Knocks Fluoride Data
By Nina Kim
February 2, 2000
ESCONDIDO -- A controversial report commissioned by the City Council has concluded that a state-funded water-fluoridation study is seriously flawed and does not provide conclusive evidence that fluoridated drinking water helps prevent cavities.
The $5,000 report by a Tennessee-based company, Senes Oak Ridge, was commissioned by the council in September, largely to counter a state mandate that most cities fluoridate their water. The report, by Senes Oak Ridge researcher Kathleen Thiessen, was delivered to city officials yesterday.
Thiessen's report contends that data from a 1993-94 study by the California Dental Health Foundation does [not] support its conclusion that fluoridation of public water supplies is beneficial, in part because the state study did not take into account other ways children can ingest fluoride.
"A potentially significant source of uncertainty for his study is the actual fluoride intake by each individual child," Thiessen wrote. "Other major factors influencing the amount of fluoride in the diets of individuals have not been addressed."
The principal researcher for the $620,000 state study, Howard Pollick, acknowledged last night that Thiessen's conclusions had some merit, but said they were somewhat biased.
"She has been asked by the people who she is contracted with to answer certain specific questions that I don't think she's able to answer with any certainty based upon the available evidence that she had before her," said Pollick, a professor of dental health at the University of California San Francisco.
Pollick said Thiessen did not contact him or the California Dental Health Foundation in conducting her analysis.
"I think if she wanted to delve further into this, that's what she should have done," he said. "I don't feel we have anything to hide here."
The state study, called the Oral Needs Assessment, was conducted by the dental foundation with money from the California Department of Health Services, Maternal and Child Branch, and the California Wellness Foundation. It assessed the dental health of 6,600 school-age children over two years in 10 geographic areas with fluoridated water, unfluoridated water and in rural communities.
Fluoride opponents contend the state study was the principal evidence used by the Legislature in passing a 1995 law requiring all water systems with more than 10,000 connections to fluoridate as soon as money was available to pay for it.
Thiessen did not conduct any research of her own, but reviewed data from the Oral Needs Assessment study. Her report praises the "obvious care and thoroughness" of the state research, and says her report is not offering any conclusions about the pros and cons of water fluoridation.
Her analysis, however, contends that the state research failed to take into account that children often can get fluoride through bottled water, toothpaste, soft drinks, juices, tea and some seafoods, and therefore no conclusions can be drawn from it about the benefits of fluoridating public water supplies.
Also, Thiessen found that economic background or the presence of dental sealants, which also can affect tooth decay, were not considered factors in the state study.
In March, council members Keith Beier, Jerry Kaufman, and Marie Waldron voted to ban the use of fluoride in Escondido water, despite the state mandate to add it as a cavity-fighting measure. Mayor Lori Holt Pfeiler and June Rady were opposed.
In September, on the same 3-2 vote, the council approved a contract with Senes Oak Ridge to review the 6-year-old state study.
Pfeiler and Rady questioned the objectivity of Thiessen and Senes Oak Ridge after learning that she has written letters to the House Science Committee and to a Florida school board questioning the use of fluoride in drinking water.
Yesterday, Rady said that not all scientific studies are perfect, and there are hundreds of other studies that have attested to the health benefits of water fluoridation.
"What have people of Escondido received for the $5,000 spent on this study?" Rady asked. "Why are the residents of Escondido paying for a study for anti-fluoride supporters, who are trying to disprove something science has proven again and again for the last 50 years?"
Other council members could
not be reached for comment.
Staff writer Kim Peterson contributed
to this report.