Federal investigators and Harvard University officials
are probing whether a Harvard professor buried research
suggesting a link between fluoridated tap water and bone
cancer in adolescent boys.
The National Institute of Environmental Health Sciences
(NIEHS), which funded Chester Douglass's $1.3 million study,
and the university are investigating why the Harvard School
of Dental Medicine epidemiologist told federal officials
he found no significant correlation between fluoridated
water and osteosarcoma, a rare form of bone cancer. Douglass,
who serves as editor in chief for the industry-funded Colgate
Oral Care Report, supervised research for a 2001 doctoral
thesis that concluded boys exposed to fluoridated water
at a young age were more likely to get the cancer.
The Environmental Working Group, an advocacy organization,
urged federal officials late last month to explore whether
Douglass had skewed his 2004 report to the institute to
play down possible risks associated with fluoridation.
The practice of fluoridating tap water -- which more than
170 million Americans drink -- has inspired controversy
for years, but the majority of federal and state officials
back it as a highly effective way to prevent tooth decay.
The Centers for Disease Control and Prevention has ranked
fluoridation as one of the top 10 health achievements of
the 20th century, and numerous studies have shown that fluoridation
prevents tooth decay. The National Cancer Institute states
on its Web site: "Many studies, in both humans and animals,
have shown no association between fluoridated water and
risk for cancer."
Douglass reported last year that the odds of having osteosarcoma
after drinking fluoridated water was "not statistically
different" from the risk after drinking non-fluoridated
water. But in 2001, Douglass's doctoral student, Elise Bassin,
published a thesis using his data that concluded: "Among
males, exposure to fluoride at or above the target level
was associated with an increased risk of developing osteosarcoma.
The association was most apparent between ages 5-10, with
a peak at six to eight years of age."
Bassin's thesis work is considered the most rigorous human
study to date on a possible connection between fluoridation
and osteosarcoma, a rare but lethal form of cancer that
affects males nearly twice as often as females. Patients
with the cancer live an average of three years after diagnosis.
In 1990, an animal study by the National Toxicology Program
found "equivocal evidence" of a link between fluoridated
water and cancer in male rats. And more than a decade ago,
a New Jersey Department of Health survey found that young
males in fluoridated communities had a higher rate of osteosarcoma
than those in non-fluoridated communities.
"Fluoride safety is a major public health issue, and a
Harvard professor potentially falsifying public research
results has huge public health implications," said Richard
Wiles, senior vice president of the Environmental Working
Group. He added that Douglass's role in editing a newsletter
funded by Colgate-Palmolive Co. "creates the appearance
of a conflict of interest."
Douglass, who has taught at Harvard since 1978 and has
edited the Colgate quarterly since 1997, referred inquires
to the university's press office. Harvard Medical School
spokesman John Lacey said the school "takes all allegations
of misconduct seriously and has a standard system for reviewing
allegations of research impropriety. The school is assembling
an inquiry committee to review the questions raised concerning
the reporting of this work."
Douglass has not edited for the newsletter articles on
the possible connection between fluoridation and cancer
and has not testified publicly on the issue, Lacey added.
The institute issued a statement similar to Harvard's,
saying the NIEHS "takes allegations of misconduct very seriously"
and is reviewing the matter.
Bassin could not be reached.
Some public health experts, including Richard Clapp, an
expert in the environmental causes of cancer at Boston University's
School of Public Health, think Bassin's study should prompt
additional research. Researchers suspect a possible connection
because half of ingested fluoride is deposited in bones,
and fluoride stimulates growth in the end of bones, where
osteosarcoma occurs. The Environmental Protection Agency
has commissioned a National Academy of Sciences study to
examine the safety of fluoridation. A report is due next
"It's important, and it needs to be followed up," Clapp
said of Bassin's work. "There's a legitimate biological
rationale for focusing on young boys."