This month, Dr. Sydney Spiesel discusses whether to take a daily baby aspirin, the sudden deaths of young athletes, the spinach scare, and the link between sugar and behavioral problems in kids. (Click here and here for his last two columns.)
Daily baby aspirin: your stomach vs. your heart
Daily dose: Like many people my age (I get some senior discounts), I pop a daily baby aspirin tablet of 80 mg, or the equivalent of one-quarter of an adult tablet. I do it to reduce my risk of heart attack by 25 percent or 30 percent (check your heart attack risk at this site) and to possibly reduce my risk of colon cancer, but mainly because my personal physician thinks it's a good idea. Every once in a while, I wonder whether the benefits match the risks (this is a tough universe, you know). I had that thought a few weeks ago, when I encountered a friend, another doctor, at a party. His foot and lower leg were in a cast. He'd done something foolishly athletic and damaged a tendon, but the real problem, he said, was his daily baby aspirin. Because of its effects on blood clotting, the aspirin led to a lot of local bleeding and swelling.
New research: Now a new study points out that taking aspirin poses risks to the stomach and upper digestive track—specifically, of a higher probability of serious upper-gastrointestinal bleeding or perforation. This risk needs to be balanced against the potential benefit of heart-attack prevention. The authors are Sonia Hernández-Díaz of the Harvard School of Public Health and Luis García Rodríguez of the Spanish Center for Pharmacoepidemiological Investigation in Madrid. They made use of two large clinical databases: the UK's General Practice Research Database, which includes clinical information about roughly 3 million patients, and a similar Spanish database of more than a million patients.
Competing risks: The competing risks of heart and GI problems aren't uniform. Some people are at unusually high risk for heart attack, a risk much higher than that of GI bleeding or perforation. For that group, the optimal strategy is clear—take your aspirin. Conversely, the study identifies a group of patients whose risk of heart attack isn't especially high. For those people, the optimum strategy might well be to forego daily aspirin treatment. Factors known to affect the risk of heart attack include age, male gender, blood pressure, cigarette smoking, diabetes, cholesterol level, and previous diagnosis of cardiovascular disease. In the new study, increasing age, male gender, and ulcer history were risk factors for GI complications.
Findings: The researchers found that daily low-dose aspirin approximately doubles the risk for each of these factors. At the low-risk end of the spectrum—female patients under 60 years old, for instance—aspirin adds only a small amount of risk for GI bleeding or perforation. At the high end—male patients in their 80s with a complicated ulcer history—aspirin leads to 150 more cases of GI complications per 1000 people in the course of a year.
Conclusion: This number is vastly higher than the number of heart attacks the aspirin might be expected to prevent. It's probably a strong argument against using aspirin to prevent cardiovascular disease in high-GI-risk populations. In short, this study gives us a more rational way to plan preventive treatments for heart disease. Since I'm not in a high-risk group for GI problems, I'm going to keep taking my aspirin.
Problem: Like every pediatrician, I am regularly called on to clear youngsters for athletic participation. Many elements of the required physical exam are probably not worth much. But we all march through the ritual and then check the boxes on the form. More often from taking a good history than from the physical exam, we occasionally find something to worry about. But the exam isn't likely to identify the greatest danger: the possibility of sudden cardiovascular death.
Cause: Mostly, these deaths are due to an unrecognized structural defect in the heart, in particular cardiomyopathy. This condition has multiple causes, including congenital defects and high blood pressure (both of which place excess demand on the heart muscle) and certain viral infections (which diminish the heart's ability to respond to normal demands). Often a heart with cardiomyopathy develops an irritability that leads to abnormal rhythms. These, in turn, interfere with proper pumping functions—sometimes fatally.
New research: This week's Journal of the American Medical Association includes a study, conducted by a group of Italian physicians, including Drs. Domenico Corrado and Gaetano Thiene, of 40,000 athletes whose examinations included standard electrocardiograms. The use of ECGs as a screening tool for young athletes is not standard practice in the United States because of the expense. It is more common in Europe, and the study sought to determine the value of this practice.
Findings: At first glance, it looks as if the ECGs were quite valuable. Over the 26-year period of the study, the annual rate of sudden cardiovascular death in young athletes dropped by 89 percent compared with the risk before the study was begun. Two percent of athletes were disqualified from participating in sports. During the same period, the rate of sudden cardiovascular death among nonathletes remained essentially the same. This result would seem to be a slam-dunk, even in a country that favors soccer over basketball.
Caveat: But an accompanying editorial points out some problems. There was no control group—in other words, the study's results would have been much clearer if all the athletes had been given the same physical exam and then some were not given an ECG. In addition, the reported rates of sudden cardiovascular death were sort of funny. To be sure, the annual incidence of these deaths dropped from 3.6 per 100,000 person-years before the study began to 0.4 per 100,000 person-years at the end. But that reduction sounds less impressive when compared with the last reported annual rate in the United States, without ECGs: 0.44 per 100,000 person-years. In addition, and remarkably, there were no deaths among the 2 percent of athletes who failed the screening.
Conclusion: Including an ECG in the sports physical would likely identify some kids who would be better off not playing competitive sports. But I wish this study gave us the information we need to judge whether a routine ECG for all aspiring athletes is cost effective. There is a limit to the resources we can devote to medicine, and if we require universal ECGs for young athletes, we may well reduce other medical services that have a greater impact on quality of life and health.
Cause: The cause of the outbreak of food poisoning from spinach in September is E. coli, in particular the O157:H7 type of the germ. It's not entirely clear why O157:H7 is capable of causing such terrible illness—most strains of E. coli are completely harmless. But it probably has to do with the capacity of this strain to produce verotoxin, the poisonous product of the dysentery germ, along with a substance that breaks down red blood cells and a material that helps the germs to stick to the wall of the bowel. Also important: O157:H7 is unusual in its ability to tolerate acid conditions.
History: This germ and the disease it causes were first described during a major outbreak in 1982 involving ground beef. Epidemics have also been associated with contaminated salad greens and nonpasteurized fruit juices—especially apple juice. Infections caused by E. coli O157:H7 are almost always the result of eating food contaminated by cow poop, even in trace amounts. Why have these E. coli outbreaks only been seen since 1982? I think the cause can be traced to an unintended consequence of changing practices in beef production.
New diet: Cattle raised for beef used to roam grasslands or eat a diet of relatively low nutritional density, often hay-based. Then, farmers began to feed cattle a diet richer in calories and protein, often made of corn or wheat. This feeding resulted in more efficient beef production. And the slaughtered cattle had a smaller volume of intestinal contents, which would be less likely to contaminate beef in the slaughterhouse.
Acid changes: But something else happens when you feed cattle these nutritionally concentrated diets. The bacteria present in the cow's rumen (its first stomach) produce an excess amount of acid byproducts of food digestion. That environment selects for bacteria that are exceptionally tolerant of acid conditions—including the O157:H7 E. coli strain. These acid-tolerant bacteria aren't deterred by the acidity of our stomachs, which usually protects us against disease. Evidence for my theory also comes from the first juice-associated outbreaks. Public health officials had assumed that apple juice would be safe to drink, given that its pH is very low. Yet the low pH of the apple juice failed to deactivate the contaminating E. coli in these outbreaks.
Conclusion: Preventing these E. coli outbreaks is hard. Slaughterhouses need to be extremely careful to maintain high standards of cleanliness, as do production facilities for salad. Fruit juices should be pasteurized and hamburgers thoroughly cooked. Recent research suggests that new feeding practices for cattle might also help a lot.
Sugar connection: Many parents who come to my office are convinced that sugar in kids' diets makes them crazy, or at least hyperactive. Since sugar doesn't affect me that way, I've always been skeptical. But am I wrong?
New study: A recent paper by Lars Lien and co-workers at the University of Oslo considers the association between sugared soft-drink consumption and hyperactivity, mental distress, and conduct problems in Norwegian adolescents. The authors found a fertile location for their research in Oslo, since Norway has the highest worldwide rate of soft-drink consumption: a per-person average of 30 gallons, or 25 pounds of sugar for every man, woman, child, and infant from soft drinks alone. (What is it about Scandinavians and their beverages?) The new study compares the soft-drink habits of more than 5,000 Norwegian teens with measurements of their mental distress (these pretty much overlapped with symptoms of depression) and with a coarse measurement of their conduct problems and of hyperactivity. A weakness: The assessment of psychological problems was based on questionnaires filled out by the teens.
Findings: The authors found that the teens' self-reported hyperactivity scores were directly proportional to the weekly consumption of soft drinks. Depressionlike mental-distress scores similarly climbed, especially for girls, as the weekly consumption of soft drinks increased. (An anomaly: Kids who drank no soft drinks reported, on average, more distress than those who drank a small amount.) Self-reported conduct problems also rose with increasing soft drink consumption (except again for a high result for boys who drank no soft drinks).
Caveat: The study merely reports an association between sugar-laced soft drinks and teen behavior. But the authors infer causality, claiming that the sugar was responsible for the behavioral problems. This study, more than most, doesn't justify that inference. In the first place, we have no idea how honest the kids were in self-reporting. Also, maybe depressive thoughts push kids to reach for the comfort of the soft-drink bottle and not the other way around. Maybe "hyperactive" kids have a drive to sip something, and soft drinks are easily available. Maybe kids fattened by excess sugar consumption are depressed about being heavy. Maybe the soft-drink-eschewing boys with the conduct problems are drinking harder stuff instead. In short, the possibilities are endless, and this study really tells us nothing about causation.
Conclusion: But if this study doesn't convince me that sugar in a diet has psychological effects, an earlier one is more persuasive. A 1995 paper by William Tamborlane and his colleagues at the Yale University School of Medicine reported a difference in the way the bodies of children and adults handled an oral dose of sugar. Both groups release a splash of insulin that pushes the blood sugar down to approximately the same level. In children only, the drop in blood sugar stimulates the release of a slug of epinephrine, a hormone, which, in turn, led to symptoms of hypoglycemia (shakiness and sweatiness) and a decrease in cognitive function. So, maybe there is something to the notion that sugar can lead to behavioral change or decreased attention, at least in kids.