Too much caffeine may raise blood pressure in black teens.
* THE QUESTION The typical teenager consumes a growing amount of caffeine from soft drinks, coffee, tea or chocolate. Might this contribute to the rising blood pressure readings among American youth?
* THIS STUDY called for 159 white and black teenagers to eat for three days from a list of low-sodium food and drinks containing varying amounts of caffeine. The researchers calculated the amount of caffeine each person consumed and measured the participants' blood pressure at the end of the experiment. Among the white teens, caffeine consumption seemed unrelated to blood pressure. But among the black teens, the 11 who took in the most caffeine (equal to about four 12-ounce cans of soda daily) had an average systolic, or top-number, blood pressure of 119, about 13 points higher than that of the 70 black teens whose diets contained less caffeine or none at all.
* WHO MAY BE AFFECTED BY THESE FINDINGS? Black teenagers. Hypertension occurs more often and at an earlier age among blacks than among members of other racial groups in the United States.
* CAVEATS This study was small and not randomized. Also, the study did not account for lifestyle factors such as exercise, smoking and other food choices that may have affected blood pressure.
* BOTTOM LINE Black teenagers may want to monitor the amount of caffeine in their diet.
* FIND THIS STUDY May issue of the Archives of Pediatrics and Adolescent Medicine; abstract available online at www.archpediatrics.com.
* LEARN MORE ABOUT blood pressure concerns for teenagers at http://kidshealth.org/teen and at www.americanheart.org (search for "blood pressure").
Early surgery to unclog arteries may produce beneficial results.
* THE QUESTION When a carotid artery -- a blood vessel in the neck that carries blood to the head -- becomes clogged, the likelihood of stroke increases. But carotid endarterectomy, the surgery to open such a narrowed blood vessel, is also risky. Does one risk outweigh the other?
* THIS STUDY randomly assigned 3,120 people with a partially blocked carotid artery either to have surgery as soon as possible or to have surgery deferred until it became medically imperative. People in both groups continued to take whatever medication their doctors had prescribed, often anti-platelet or lipid-lowering drugs. After five years, 12 percent of the people younger than 75 whose surgery had been deferred had had a stroke, compared with 6 percent of those who had the surgery right away. About half the strokes were fatal or disabling.
* WHO MAY BE AFFECTED BY THESE FINDINGS? Anyone diagnosed with a clogged carotid artery.
* CAVEATS Long-term benefits of early endarterectomy have not been determined. The study warns that operations performed by less-experienced surgeons or on less-than-ideal candidates for the surgery may not yield the same results.
* BOTTOM LINE People with a clogged carotid artery may want to ask their doctor about having surgery before it becomes urgent to do so.
* FIND THIS STUDY May 8 issue of The Lancet; abstract available online at www.thelancet.com.
* LEARN MORE ABOUT strokes at www.strokeassociation.org and www.ninds.nih.gov.
Early overexposure to the sun may lead to vision loss later.
* THE QUESTION Age-related macular degeneration (ARMD) usually develops after age 50. Does exposure to sunlight years earlier contribute to this common cause of vision loss?
* THIS STUDY compared the vision quality of 2,764 people aged 43 to 86. Their replies to questionnaires showed that those who had regularly been in the sun more than five hours a day during their teens, thirties and at the start of the 10-year study were more than twice as likely to have developed ARMD symptoms as people exposed to less than two hours of sun a day. Also, among the participants who spent more than five hours a day in the sun during their teens and thirties, those who often wore hats and sunglasses had a 50 percent lower risk of developing signs of deteriorating vision than those who did not take these protective measures.
* WHO MAY BE AFFECTED BY THESE FINDINGS? Anyone who spends significant amounts of time outdoors.
* CAVEATS Participants' recall of their sun exposure years earlier might be inaccurate.
* BOTTOM LINE Even at a young age, people might want to limit their exposure to the sun.
* FIND THIS STUDY May issue of the Archives of Ophthalmology; abstract available online at www.archophthalmol.com.
* LEARN MORE ABOUT macular degeneration at www.mayoclinic.com and www.nei.nih.gov.
-- Linda Searing