• Study: Fluoridated Water
• Eradication Of Polio By 2005
• Prenatal Cocaine Exposure
• ACL Injuries (Anterior Cruciate Ligament In The Knee - A Common Sports Injury Affecting Many Female Athletes)

LONDON (AP) - The first examination of 50 years of research on the safety of adding fluoride to drinking water found no evidence of harm, and some experts said the findings should allay lingering fears it could cause cancer, osteoporosis or Down Syndrome.

The review, published this week in the British Medical Journal, involved 214 studies and was the most comprehensive since fluoridation was first introduced in the United States after World War II.

Fluoride opponents dismissed the research, saying it ignored some studies showing adverse effects, such as an increase in bone

"This is not the last word on fluoride,'' said Paul Connett, a professor of chemistry at St. Lawrence University in New York and a fluoridation opponent. "This is a superficial look and you've got to put this in the context that we can't control the dose. You have to test the fluoride level in people's bones."

The research was commissioned by the British government, which is contemplating a nationwide fluoridation program. As in many other countries, fluoride is added to the water in some British communities but not in others.

Worldwide, more than 360 million people live in areas with fluoridated water. In the United States, about 145 million people drink fluoridated water.

Fluoridation, which aims to reduce tooth decay, has been widely debated worldwide since its introduction. Fluoride is also found naturally in tea, fish and other foods, and is added to some tooth pastes.

The researchers, from the National Health Service Center for Reviews and Dissemination at the University of York in northern England,

Their analysis confirmed that fluoridation reduces tooth decay by about 15 percent, but found that it was also linked to dental fluorosis, or mottled teeth, about 48 percent of the time. In 12.5 percent of cases, mottling was moderate or severe, involving brown patches on the teeth. That is a cosmetic condition that can be rectified, said Paul Wilson, a lead researcher.

One of the most lingering suspicions has been that fluoridated water could make elderly people more likely to suffer bone fractures. At extremely high doses, fluoride can eat away at teeth and bones.

"The finding that long-term exposure to fluoridated water does not increase the risk of osteoporotic fractures among elderly people should alleviate remaining concerns about the safety of fluoridation," said Hannu Hausen, an epidemiologist and dental professor at the University of Oulu in Oulu, Finland, who was not connected with the research.

The fear of osteoporosis has never been based on strong evidence, Wilson said.

"There are some very vociferous groups on both sides that have polarized the debate," Wilson said. "But we've looked at 50 years of the best research and we've not been able to find any association with any harm."

Connett was not convinced, saying tooth decay has been declining since World War II in both fluoridated and non-fluoridated areas. Fluoridation programs aim for a trade-off of only a minor level of mottled teeth, he said, and the study shows that has not been achieved.

"They wanted no more than 10 percent dental fluorosis in the mild stage," he said. "This study shows they've got 48 percent, and 12.5 percent where it is 'aesthetically unpleasing.' The program is a total failure."

Connett also objected to considering mottled teeth a purely cosmetic problem, saying it could be an indicator of a toxic effect. He also said the analysis of bone fracture risk was not thorough enough.

"You want the benefit of fluoride? Brush your teeth and spit it out as soon as you can. Why put it in the drinking water?" Connett said.

According to the World Health Organization, skeletal fluorosis is observed when drinking water contains 36 milligrams of fluoride per liter of water. The WHO recommends about 1.5 mg per liter. In most communities, the concentration is about 1 mg per liter.

Wilson said the studies he examined tracked the effects of up to 4 mg per liter in drinking water. He said people living in a community with a fluoridation program and consuming fluoride from other sources would be getting no higher a dose than that.

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Heads of state, business leaders and celebrities endorsed the goal of worldwide eradication of polio by the year 2005, at a "Polio Summit" held at the United Nations on Wednesday.

"We will succeed. We will make history," said Dr. Gro Harlem Brundtland, director-general of the World Health Organization (WHO). She spoke on a panel with the actress Mia Farrow, who is a polio survivor; Ted Turner, vice-chair of Time-Warner, Inc.; Donna Shalala, US Secretary of Health and Human Services; and Carol Bellamy, executive director of the United Nations Children's Fund (UNICEF), among others.

There were more than 7,000 polio cases worldwide last year, but fewer than 2,000 have been identified so far this year, Dr. Brundtland said. Polio will still exist in 20 countries after 2000, primarily because poverty, war and isolation have made it so difficult to vaccinate the children in these countries. Most of the affected countries are in Africa, but they also include Iran, Turkey, India and Nepal. "No nation is truly free from polio unless every nation is free of polio, and finishing the job will not be easy," Shalala told the assembled dignitaries.

The effort will require sufficient vaccine stocks, thousands of volunteers, and about US billion, the speakers said.

WHO, Rotary International, UNICEF and the US Centers for Disease Control and Prevention (CDC) have formed a partnership to coordinate efforts. Government funding plus contributions from the Bill and Melinda Gates Foundation, the UNEFoundation chaired by Ted Turner, and other private contributors are expected to total million. This leaves a shortfall of million to be obtained from other sources. "I call on the private sector blessed with more wealth than they need to make a major contribution to this campaign and share in the joy," Turner said.

Shalala said that the United States will contribute at least million to the effort, in addition to technical assistance from the CDC and the Peace Corps. "It doesn't make any difference what happens in November, both Republicans and Democrats are committed to eliminating polio," Shalala told Reuters Health. "There's an increasing awareness that unless we stop disease in other places, we can't protect our own people."

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Any prenatal exposure to cocaine negatively affects childhood behavior and these effects appear to be gender-specific, Dr. Beth Nordstrom-Klee reported at the Society for Developmental and Behavioral Pediatrics meeting in Providence, Rhode Island.

Dr. Nordstrom-Klee and colleagues from Wayne State University, in Detroit, assessed behaviors in 200 six- to seven-year-old African American children with prenatal exposure to cocaine and 268 children of similar age and ethnicity with no prenatal cocaine exposure.

The Michigan team developed a Problem Behavior Scale, which includes hyperactivity-conduct and central-processing sub-scales, to assess the study group. The researchers also analyzed reports of teacher-assessed behaviors in the entire population.

Girls exposed to cocaine late in their mother's pregnancies were significantly more likely to exhibit delayed speech and language development compared with girls not exposed to cocaine. The findings show that cocaine-exposed girls did not differ significantly from controls on teacher assessment or problem behavior scales.

In boys with prenatal cocaine exposure, hyperactivity and aggression assessment scores were significantly higher than for boys in the non-exposed group, Dr. Nordstrom-Klee said in an interview with Reuters Health. She added that, compared with controls, boys exposed to cocaine late in their mother's pregnancies had "significantly higher total behavior problem and central-processing problem scores."

It is unclear whether the behavioral effects identified with prenatal cocaine exposure are due to the timing or the extent of the exposure. This study population will be reanalyzed for the effects of cocaine exposure when they reach 11 and 12 years of age, Dr. Nordstrom-Klee said.

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Hello patients,
Following is an article which will be of great interest to some of you, some interest to a few more and no interest to others. You'll have to decide which category you are in.

I wrote the article for an upcoming issue of GOAL magazine. It contains important new information about prevention of one of the most common serious injuries suffered by female athletes, particularly soccer, basketball and volleyball players. The information is also important for competitive male athletes and skiiers.

I've assisted on surgical repairs of too many of these. I'm happy to help but I'd rather not have to.

Best,
Michael Carlston, M.D.

Over the past 25 years there has been a wonderful rise in the number of females participating in competitive athletics. You can't turn on the television without seeing a cute ad with little girls playing soccer. Women of all ages are gaining respect and self esteem through their efforts in athletic competition. We have come a long way from the days when "ladies don't sweat, they glow". Women are now sweating with pride.

Unfortunately, this increased activity has been paralleled or exceeded by a rise in serious athletic injuries among women. The most common of these serious injuries involve the anterior cruciate ligament in the knee. Estimates are that 250,000 such injuries occur every year, most commonly among 15 - 25 year old females. Female athletes suffer ACL injuries at a rate two to ten times that of males, depending upon the sport. Female soccer players suffer ACL injuries approximately three times as often as males. Professional women basketball players suffer ACL tears at a rate 10 times that of their male counterparts. Fortunately, there is some good news mixed in with the bad. Early medical research indicates that certain training activities can prevent these serious injuries, both in female and male athletes.

What is an ACL?
The ACL (anterior cruciate ligament) is a short ligament inside the knee connecting upper leg bone (femur) with the larger lower leg bone (tibia). It looks much like a very thick piece of white ribbon with its thin shiny fibers. The ACL maintains knee stability by preventing these bones from moving too far away from each other, either forward or to the side. It can be strained, partially or completely torn. In approximately 1/3 of cases the ACL is completely torn. An intact ACL is very important to knee function in competitive sports like soccer that require a lot of sudden stops, starts and changes of direction. Although athletes who have a torn ACL can sometimes continue to play their sports, their physical ability is markedly reduced because of the instability of that knee. They just can't do the things they used to do. In addition, because of this instability, athletes who have torn an ACL are much more likely to experience another, potentially disabling knee injury. An athlete with a torn ACL must choose between quitting her sport, continuing to play with less ability and the threat of another injury that might permanently disable her or having major surgery hoping to repair the knee. So, tearing an ACL is a serious problem.

Just how serious?
We know that ACL injuries are one of the main causes of permanent sports disability. We have new surgical techniques which are much better than a decade ago, when an ACL injury meant the certain end of sports careers for even highly trained and motivated athletes. Unfortunately, these welcome improvements don't erase the problem. The sad fact is that nearly one third of high level competitive female soccer players sustaining ACL injuries give up the sport because of poor function or fear of re-injury. It is even worse for less committed athletes.

How common is the problem?
ACL injuries are more common among female athletes than male athletes, up to eight times as common in some studies. In descending order, ACL injuries are most common in gymnasts, soccer, basketball and volleyball players. A survey of NCAA athletes from 1989-93 found that female soccer players suffered ACL injuries at a rate three times that of males. ACL injury rates are so high in college female soccer players that they translate (staggeringly) into nearly one ACL injury for every women's NCAA soccer team every year. The only group of college athletes with a greater risk was female gymnasts. The high risk gymnasts face is easy to understand if one imagines a female gymnast with her hyperflexible joints flying through the air at high speeds and then coming to a dead stop with straight legs, as the form of gymnastics requires. It is distressing that female soccer players are so close behind their risk level.

The rate of ACL injuries increases with the level of competition. The highest rates are among the highest level female athletes. However, even among high school athletes, ACL injuries are the most common serious knee injury with approximately 20,000 occurring every year in the United States.

How do ACL injuries occur?
As you might imagine, a thin fibrous band inside a very small space surrounded by constantly moving bones is vulnerable to getting pinched or torn. In a way, it is a small miracle of design that ACLs don't tear every time we bend and turn. Although injuring an ACL seems simple, the specifics of why one player gets injured at a particular time become much more complex and confusing. Probably the easiest way to understand ACL injuries is to divide them into two types of injury. The first type is ACL injuries occurring as a result of contact with another player and the second is those that don't.

Contact ACL injuries occur when a player is hit from behind or on the outside of the knee. They are one reason referees should not hesitate to pull out a card when fouls of this nature occur. It doesn't just look bad and hurt, it can end a players career. ACL injuries from contact occur at a similar frequency in male and female soccer players.

Non-contact ACL injuries result from sudden changes in direction, particularly while slowing down at the same time, and from landing on a straight knee. Either of these movements can shear the ligament practically instantaneously if performed the wrong way at the wrong time.

Non-contact ACL injuries are the reason for the massive difference in ACL injury rates between male and female soccer players. Nearly 80% of ACL injuries in females occur without contact, while non-contact ACL injuries represent a minority of injuries in males. Some studies have shown as much as a four-fold difference in non-contact ACL injury rates between females and males.

One of the factors believed to increase non-contact ACL injuries is the interaction between soccer shoes and the playing surface. In other words, cleats getting caught in the turf and poorly maintained fields can contribute to these injuries. Indoor soccer has a significantly higher rate of ACL injuries than outdoor soccer. It may be that the tendency of artificial turf to grab onto the shoes could lead to ACL injuries. In that case, the newer indoor surfaces, which appear not to catch players' shoes so easily, may be safer surfaces for indoor play. More research is needed for definitive answers to these questions.

Why are women at greater risk?
This question could stump "Who Wants to be a Millionaire" winners. Faced with an epidemic of serious injuries with long-term consequences, we have been trying to understand what can be done to prevent ACL injuries. Many answers have been proposed and probably all of them play some part.

Angle of knee:  Because women's hips are wider, the upper leg bone comes down to the knee at a sharper angle, placing additional stress on the ACL

Anatomy of the notch inside the knee:  Some people have smaller spaces inside the knee, but whether there is a difference between males and females is controversial.

Hormonal variations:  Estrogen makes ligaments looser. One small study found a higher rate of ACL tears around mid-cycle (days 10-14) when estrogen levels peak.

Loose ligaments:  Women generally have looser ligaments, possibly increasing ACL risk.

Weaker hamstrings: The smart money is riding on this theory as the most important factor. The big leg muscles, the quads in the front of the thigh and the hamstrings in the back, also help stabilize the knee. When the stress is too great these muscles can't counteract the force. If the stress then exceeds the strength of the ligament, it suddenly tears. Men have stronger hamstrings than women. Men use their stronger hamstrings when they land from a jump. This appears to be an important preventive factor because recent studies of a training program, which markedly reduced the rate of ACL injuries, also showed considerable improvement in hamstring strength and knee stability.

The point of all this guesswork about "why" is to help us learn how to prevent ACL injuries. It looks like we are getting there.

How to prevent ACL injuries
The first study of any size to show a reduction in ACL injury rates was conducted with 600 Italian male semi-professional soccer players. They found that proprioceptive training reduced ACL injury rates by over 700%. Proprioception is the ability to locate the extremities in space without looking. Although it may be surprising, loss of proprioception is an extremely common cause of re-injury following knee and ankle injury. The athlete slightly mis-steps and sprains an ankle or knee, even though the joint is strong. These soccer players spent 20 minutes a day (2-6 days a week) of balance training during 4-6 weeks of preseason. They would balance on a balance board for 2-5 minutes on each leg four times a day. During the season they did this three times every week.

Although they used fancier and much more expensive equipment, you can make an adequate balance board by purchasing a 12" round of plywood and gluing 1/2 of a softball to the middle of it. If you've seen the Ajax youth training videos you'll remember their players practicing by standing on such a board while juggling a soccer ball inside a net (to save the furniture).

The biggest and best studies were recently conducted here in the USA by Hewitt on female athletes, including soccer players. Their intervention utilized a six week preseason program of muscles, nerves and coordination, owing much to plyometric jump training. They taught subjects to work on technically perfect jumping landing quietly with a toe to heel rock and bent knees. They also taught the subjects to recoil instantly, preparing for the next jump using images like "straight as an arrow", "light as a feather", "recoil like a spring" and "be a shock absorber." Trained study participants had a rate of ACL injury 3.6 times less than controls. They also found average increases in hamstring strength of 44% and jump height by 1.5 inches. One subject increased her vertical jump by six inches!

Last year I used Hewitt's techniques with my U-10 Class I girls team. I was very interested to observe that the non-dominant leg of each girl would shake on landing. This shaking is a sign of weakness and one of the technical failures Hewitt's group teaches to avoid. You can learn more about Hewitt's program by purchasing their Cincinnati Sportsmetrics video (contact Cincinnati Sportsmedicine Research and Education Foundation).

Another recent study suggests that simply encouraging basketball players to come to a stop over three steps (perhaps too restrictive in soccer) and to keep the knees bent when turning can reduce knee injuries in female athletes.

The bottom line is:

• ACL injuries are a big problem
• ACL injuries are a bigger problem for females
• ACL injuries are preventable
• Every serious female soccer player (of ANY age) should Practice proprioceptive training (a good idea for competitive male soccer players as well)
• Strengthen hamstrings by Jump training and/or leg curls
• Avoid turning and landing with straight legs

These measures can help prevent serious injury and will almost certainly improve performance to boot. Sorry about the pun. I just couldn't resist.

Best,
Michael Carlston

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