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Health Matters: How dangerous is lead?

Q. There has been a lot of news coverage of the problem of lead in the drinking water in Michigan. What are lead's health effects?

A. Childhood exposure to lead found in the pipes supplying drinking water in Flint, Mich., but also in paint, solder and gasoline (from which lead can be absorbed from motor vehicle emissions) can have important and recognizable negative effects on brain development as children grow into adulthood.

A recently reported study from New Zealand found a stepwise reduction in adult IQ as the level of lead detected in their blood as children increased. Not only was IQ lower for those with higher lead levels, but socioeconomic status was lower, as well. While the differences were small to be sure, they nevertheless are troubling, especially since the apparent effects of childhood lead exposure could be detected more than three decades later.

Although lead was removed from paint and gasoline years ago, it appears that its damaging effects may still be with us today. One troubling finding of the study was that intellectual decline appeared to be progressive following lead exposure, rather than regressing as one might expect after toxic exposure.

While it is possible to remove lead from the tissues of the body with a medicine that binds to it and then is eliminated in the urine, prevention by removing lead from the environment is a better option.

Q. I've heard that taking Vitamin D can reduce my risk of getting cancer. Should I take some?

A. It was almost 40 years ago that an association was noted between colon cancer deaths and sunlight — death rates were highest in geographic regions that had the least sunlight. Thus, it was suggested that this "sunlight effect" was related to Vitamin D.

Numerous clinical studies since then have suggested there might be something to the sunlight effect, but what was lacking was a definitive study. Well, one was just reported that, while not definitive, is informative. In a study of more than 2,000 older women over a four-year period, cancer was no less common in women given Vitamin D supplements than those given a sugar pill. One of the limitations of the study is that it was only performed in women, so we really don't know if the same result would have been found in men.

The bottom line is that a definitive study needed to answer the question of whether you should take supplemental Vitamin D has not yet been performed. The good news is that several ongoing clinical trials are studying this question, and the results of the largest trial are expected soon.

That should provide a definitive answer, since the trial is looking at almost 26,000 people and assessing whether supplemental Vitamin D really helps over a five-year period. Until then, the answer to your question whether you should take supplemental Vitamin D to prevent cancer is a solid "maybe."

Wynne is vice president for health affairs at UND, dean of the School of Medicine and Health Sciences, and a professor of medicine. He is a cardiologist by training. Submit a question to Health Matters at healthmatters@med.und.edu or Health Matters, 501 North Columbia Road, Stop 9037, Grand Forks, ND 58202-9037. Remember, no personal details, please.

The content of this column is for informational purposes only and does not substitute for professional medical advice or care. The information provided herein should not be used for diagnosing or treating a health problem or disease. If you have or suspect you may have a health problem, you should consult your health care provider. Never disregard professional medical advice or delay in seeking it because of something you have read in this column.

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