Does this study seem reasonable? Women aren't affected.

Since, it's just an association, causality doesn't seem to be
established.

At website: http://www.foxnews.com/story/0,2933,190977,00.html
Friday, April 07, 2006
By Daniel J. DeNoon

Boys who drink fluoridated water have an increased risk of a deadly
bone cancer, a new study suggests.

Elise Bassin, DDS, completed the study in 2001 for her doctoral
dissertation at Harvard, where she now is clinical instructor in oral
health policy and epidemiology. The study finally was published in the
May issue of Cancer Causes and Control.

Bassin and colleagues' major finding: Boys who grew up in communities
that added at least moderate levels of fluoride to their water got bone
cancer -- osteosarcoma -- more often than boys who drank water with
little or no fluoride.

The risk peaked for boys who drank more highly fluoridated water
between the ages of 6 and 8 years -- a time at which children undergo a
major growth spurt. By the time they were 20, these boys got bone
cancer 5.46 times more often than boys with the lowest consumption. No
effect was seen for girls.

Unexpected Results

In a prepared statement provided to WebMD, Bassin says she "was
surprised by the results."

"Having a background in dentistry and dental public health, [I] was
taught that fluoride at recommended levels is safe and effective for
the prevention of dental [cavities]," Bassin says in the statement.
"All of [our analyses] were consistent in finding an association
between fluoride levels in drinking water and an increased risk of
osteosarcoma for males diagnosed before age 20, but not consistently
for girls."

It's not surprising that Bassin found a risk for boys but not for
girls. Osteosarcoma is about 50% more common in males than in females.
And boys tend to have more fluoride in their bones than girls.

Caution About Study

However, a commentary accompanying Bassin's article warns to take her
findings with a grain of salt. Ironically, it is from Harvard professor
Chester W. Douglass, DMD, PhD. Douglass led Bassin's PhD committee,
which approved of the study when it was presented as her doctoral
dissertation.

Douglass warns that the Bassin study is based only on a subset of
people exposed to fluoridated water. Preliminary results from the
entire population of exposed individuals, Douglass writes, show no link
between bone cancer and water fluoridation.

But Bassin specifically looked at the subgroup of people most likely to
be affected by fluoridation: children. She limited her analysis to
people who got bone cancer by age 20. That's because most cases of
osteosarcoma occur either during the teen years or after middle age.

Fluoride collects in the bones. And it's particularly likely to
accumulate in the bones during periods of rapid bone growth. So Bassin
looked at fluoride exposures during childhood for 103 under-20
osteosarcoma patients and compared them with 215 matched people without
bone cancer. Her study took into account how much fluoride was in the
water in the communities where children actually lived and the history
of municipal, well water, or bottled water use.

The Environmental Working Group, a nonprofit watchdog organization,
says water fluoridation should stop until further research can refute
or confirm Bassin's findings. Tim Kropp, PhD, is a senior scientist at
EWG.

"About 65 percent of the U.S. water supply has added fluoride," Kropp
tells WebMD. "With evidence this strong, it only makes sense to act on
it. Right now, it makes the most sense to put fluoride in toothpaste,
and not into our water. It's not like this is a huge contaminant that
will cost billions of dollars to fix. We can just stop adding it to our
water it if we want to."

According to the American Cancer Society, every year some 900 Americans
-- 400 of them children and teens -- get osteosarcoma.

By Daniel J. DeNoon, reviewed by Louise Chang, MD

SOURCES: Bassin, E.B. Cancer Causes and Control, May 2006; vol 17: pp
421-428. Douglass, C.W. and Joshipura, K. Cancer Causes and Control,
May 2006; vol 17: pp 481-482. Elise Bassin, DDS, prepared statement,
provided by the Harvard University press office. Tim Kropp, PhD, senior
scientist, Environmental Working Group, Washington, D.C.