Daily Dose of DrGreene

Preventing Asthma

Asthma is the leading serious chronic illness in children. More than 6 million children suffer from asthma in the United States alone. Steps parents take before their baby’s birth and during the first year of life appear remarkably effective at preventing childhood asthma, even among those kids otherwise most likely to get it. The Canadian Childhood Asthma Primary Prevention Study has now followed hundreds of babies out to 7 years of age. The results appear in the July 2005 Journal of Allergy and Clinical Immunology. All of the babies in the study were at high risk of developing asthma because of their close family members with asthma and allergies. For half of the babies in the study, the parents received detailed coaching for decreasing asthma risk. Researchers instructed parents to reduce dust mite exposure by using hypoallergenic covers on parents’ and babies’ mattresses, by weekly hot water washing of all bedding, and by benzyl benzoate cleaning of carpets and upholstery before birth and at 4 and 8 months old. Parents were encouraged to eliminate tobacco smoke exposure to their babies. They were encouraged to avoid pets (I’m not sure whether this helped or hurt). They were also encouraged to breastfeed for at least 4 months, and preferably throughout the first year. If formula was used at any time, it was to be a partially hydrolyzed, hypoallergenic formula. And introduction of solid foods was to be delayed until at least 6 months of age. This sounds like a lot of work and expense – but perhaps less work and expense than caring for a child with asthma. Parents were variably successful at carrying out the interventions. Nevertheless, those kids in the coaching group for the first year were a dramatic 56 percent less likely to have asthma at age 7 than their otherwise matched peers. Developing asthma depends on a combination of genetic tendencies and environmental triggers. Lifestyle changes can make a big difference!

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Alan Greene MD FAAP
Reviewed by Alan Greene MD FAAP December 2005

Preschool French Fries and Breast Cancer

The more servings of French fries that women had eaten way back when they were preschoolers, the more likely they were to develop breast cancer as adults, according to a Harvard study in the August 10, 2005 online International Journal of Cancer. We know that diet and cancer are often linked, and that changes in pre-pubertal breasts could lead to later cancer. This study was based on data spanning over forty years from the Nurses’ Health Study, which follows thousands of nurses over time. The mothers of the nurses were asked to describe their preschool. Out of 30 foods analyzed, French fries were the only food linked to higher breast cancer rates (whole milk during the preschool years was linked to a slightly lower than average rate). For every weekly serving of fries the adult risk of breast cancer rose 27 percent! Even though high fat diets have been associated with increased breast cancer risk, in this study the French fry effect is not just the fat. Other high fat foods such as hot dogs and ice cream were not associated with the increased risk. While this one study is not enough to prove that fries cause cancer, it is consistent with cancer concerns arising from the acrylamide in fries. A survey of the American diet found that for today’s toddlers, French fries are the number one ‘vegetable’ consumed. Fries are the most common side item in kids’ meals. And they are even a top seller in school cafeterias. Breast cancer strikes more than 200,000 women in the U.S. each year.

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Alan Greene MD FAAP
Reviewed by Alan Greene MD FAAP December 2005

Walking to School

One finding from an August 2005 study of kids walking to school was predictable; another was rather surprising. In this study, published online August 17, 2005 in the British Medical Journal, four classes of 30 students each were recruited to wear devices that measured their amounts of healthy moderate-to-vigorous physical activity (MVPA) throughout the day (except when showering, bathing, or swimming). As expected, those that walk to and from school had significantly more total physical activity than those that traveled by car or bus. In fact, 100% of the walkers met the recommended average of at least 60 minutes of MVPA each day. Surprisingly, though, the walkers got more exercise even when the walk itself was not counted! In particular, those that walked to school tended also to get more exercise during the morning break, during the lunch break, throughout the school day, and outside of school. Even those who walked just one way each school day enjoyed significant benefits during every time period measured over those that rode in cars or buses. The students in this study were all 13 or 14 years old. Previous research has produced similar results in 10-year-old children. In 5-year-olds, the benefits beyond the walk itself are not clear. Getting active seems to encourage getting active – perhaps all the more so as kids grow up.

Alan Greene MD FAAP
Reviewed by Alan Greene MD FAAP December 2005

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Overweight: Not Just Skin Deep

More than a third of overweight kids, age 2 through 18, already have elevated blood pressure, according to a study of 497 kids that appears in the August 2005 Pediatrics. About half of the kids with high blood pressure were already in trouble with their cholesterol levels. Strikingly, more than a quarter of overweight kids who still had normal blood pressure already had abnormal cholesterol levels. And many of these kids already have elevated insulin levels, setting them up for increasing weight problems and for type 2 diabetes. Children with a body mass index (BMI) greater than or equal to the 95th percentile for their gender and age are considered to be overweight. There are more overweight kids every year. I recommend that parents learn the BMI of their children and where it fits on the growth curves. The immediate take home message of this study is that if your children are at or above the 95th percentile, it is wise to check their blood pressures, and to check their cholesterol panels even if the blood pressure is normal. But the bigger message is that our society would be wise to promote healthy weight in kids. And parents would be wise to take action, even if society doesn’t.

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Alan Greene MD FAAP
Reviewed by Alan Greene MD FAAP December 2005

Cars: Hotter Than You Think

Kids (and pets) left alone in cars have died from heat stroke on days as cool as 70 degrees Fahrenheit. How can this be? We all know that on hot August afternoons the inside of cars can become unbearably hot. But researchers at Stanford University School of Medicine have shown that parked cars can heat just as quickly on mild days – even if the windows are cracked open. Their study, published in the July 2005 Pediatrics, documented that on sunny days, even if the temperature is a relatively cool 72 degrees, the inside temperature of the car will reach 117 degrees within 60 minutes of turning the car off (and will top 108 degrees within 30 minutes!). Leaving the windows open 1.5 inches made no difference in the final temperature or the rate of rise. Cooling the car with an air conditioner before parking made no difference in the final temperature, but did delay the peak by 8 minutes. On hot days, the rate of rise is the same, but dangerous temperatures can be reached within 5 minutes of closing the car doors, even if the windows are cracked. Overall, when the outside temperature was anywhere between 72 and 96 degrees, the inside temperature rose by an average of 32 degrees in the first 30 minutes.

The results of this can be devastating. First comes heat stress, the discomfort and strain from being left in the hot car. Next, heat exhaustion, where the children or pets can’t get rid of their extra heat and their body temperatures begins to rise. Heat exhaustion often includes intense thirst, anxiety, weakness, headache, nausea, dizziness, and fainting. Finally, there is heat stroke when the body temperature tops 104 degrees, with no way to get rid of the excess heat (unlike fevers of 104 degrees). For half of those with heat stroke, it results in delirium, convulsions, coma, and death. Even with heat warnings, children die from heat stroke in parked cars every year. It can happen even if the temperature on the other side of the car window is a balmy 72 degrees. Laws regarding leaving young children unattended in cars exist in 9 of the United States. Regardless of the law where you live, preventing heat stroke is straightforward: don’t leave young children or pets unattended in the car. Even for a few minutes.

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Alan Greene MD FAAP
Reviewed by Alan Greene MD FAAP December 2005