MONDAY, Nov. 5 (HealthDay News) -- While the connection between a child's weight and the amount of sleep that child gets may not be immediately apparent, new research has found a strong correlation between the two.

Sixth-graders who averaged less than 8.5 hours of sleep a night had a 23 percent rate of obesity, while their well-rested peers who averaged more than 9.25 hours of sleep had an obesity rate of just 12 percent, according to a new study.

"We found that children who got less sleep were more likely to be obese," said the study's lead author, Dr. Julie Lumeng, an assistant research scientist at the University of Michigan Center for Human Growth and Development.

Lumeng said that even after compensating for other factors, such as the home environment, the link between less sleep and heavier weight was still apparent.

The study results are published in the November issue of the journal Pediatrics.

Lumeng said there are three likely reasons why sleep might affect weight. First, if children don't get enough sleep at night, they'll be less likely to run around and get exercise during the day. Second, when kids are tired, they're more irritable and may reach for junk food to help regulate their mood. And, finally, what Lumeng called a "hot area for future research" is the possible connection between sleep and fat metabolism. She said there have been studies done with adults that have shown that a lack of sleep may disrupt the secretion of hormones involved in appetite and metabolism, such as leptin and insulin.

The new study included 785 children who were in third grade at the start of the trial. Most were white -- 81 percent -- and half were female.

Parents were interviewed about their children's sleep habits when the youngsters were in third grade and then again when they were in sixth grade. The researchers also measured height and weight. Obesity was defined as having a body mass index (BMI, a ratio of weight to height) higher than the 95th percentile for age and gender, according to Lumeng. Eighteen percent of the children were obese in sixth grade.

The researchers also took into account maternal education, race, the quality of the home environment and parenting skills to see if those factors affected a child's weight.

No matter what a child weighed in third grade, too little sleep correlated with being obese in sixth grade. And, short sleep duration in sixth grade also correlated with excess weight in sixth grade, according to the study.

Third-graders who got less than nine hours and 45 minutes of sleep a night had an obesity prevalence of about 20 percent, while those who got more than nine hours and 45 minutes of sleep had obesity rates of about 12 percent, Lumeng said.

Those who were short-changing sleep in third grade had 40 percent higher odds of being obese in sixth grade, and sixth-graders who weren't getting enough sleep were 20 percent more likely to be obese, compared to their well-rested counterparts.

Lumeng said the researchers weren't able to find a statistical association between quality of sleep and obesity. But, she said that without a lab-based sleep study, it's difficult to objectively assess the quality of sleep, so there may be an association that this study wasn't able to uncover.

Dr. Stephen Sheldon, director of the Sleep Medicine Center at Children's Memorial Hospital in Chicago, said he would've liked to see sleep studies so the researchers could have known more about the quality of sleep these children were getting, such as how much REM sleep did they get and how fragmented was the sleep?

But, he said, the bottom line is that "pediatricians and parents really need to start paying closer attention to sleep-wake habits. In this society, we put a premium on being awake, and that premium may hurt us in the long run. Sleep may be as important as food to our health and well-being," said Sheldon, who's also a professor of pediatrics at the Northwestern University Feinberg School of Medicine.

Both Lumeng and Sheldon recommended trying to keep a consistent sleep schedule. Bedtimes and wake times are both important -- for children and adults. Sheldon said it's usually OK to vary your sleep times a little bit on the weekend, about an hour or so, but, he cautioned, "Letting you child sleep till noon or mid-afternoon is inviting trouble."

Lumeng also recommended that children not have a TV in their bedroom, because it can make it more difficult to fall asleep.

More information

To read more about the connection between overweight and sleep, visit the National Sleep Foundation  .

WEDNESDAY, Nov. 14 (HealthDay News) -- Breast-feeding in the first three months of life appears to help shield children from developing food allergies.

That's just one of a number of findings on food allergies scheduled to be presented this week at the annual meeting of the American College of Allergy, Asthma and Immunology in Dallas.

Research has determined a possible role for food allergy prevention strategies in high-risk children, including maternal food avoidance in pregnancy, breast-feeding, maternal food avoidance while breast-feeding, use of hypoallergenic formulas, delayed introduction of allergenic foods and probiotics, noted one expert.

"A review of 18 studies demonstrates a significant protective effect of exclusive breast-feeding for at least three months for children with high risk for atopy (genetic tendency to develop allergic diseases) against the development of atopic dermatitis and early childhood asthma-like symptoms," Dr. Robert Wood, international health director for pediatric allergy and immunology at Johns Hopkins School of Medicine, said in a prepared statement.

He offered a number of recommendations for children at high risk of allergic diseases:

• Women should avoid peanuts and tree nuts during pregnancy and while breast-feeding.
• Mothers should supplement breast-feeding with a hypoallergenic formula (extensively or partially hydrolyzed).
• Delay feeding these children solid foods until they're six months old.
• Delay introduction of milk and egg until age 1 and peanut and tree nuts until age 3.
• Start early intervention when signs of food allergy appear (secondary prevention).

In a planned presentation about allergies and dietary restrictions, another expert noted that a person may have an allergy to one member of a food family, but may be able to eat other members of the same food family.

For example, one study on nine common fish found cross-reactivity and allergenicity were highest among cod, salmon and pollack and lowest among halibut, flounder, tuna and mackerel. Another study on edible nuts found cross-reactivity was strong among walnut, pecan and hazelnut; moderate among cashew, pistachio, Brazil nut and almond; and extremely low between peanut and tree nuts.

"You may be allergic to a particular part of a food, but not to another part," Dr. Sami Bahna, chief of allergy and immunology at Louisiana State University in Shreveport, said in a prepared statement.

Another expert said doctors need to consider food allergy as a potential cause of gastrointestinal or dermatological symptoms in patients.

"The eosinophilic gastrointestinal disorders (EGID) which may affect the esophagus, stomach, colon and rectum are mostly chronic and recurrent disorders that adversely impact quality of life for patients and families," Dr. Amal Assa'ad, director of the Food Allergy & Eosinophilic Disorders Clinic at Cincinnati Children's Medical Center, said in a prepared statement.

"Patients with EGID have a high rate of sensitization to food and environmental allergens, and many of them have a high rate of clinical symptoms with various food ingestions. A subset of patients respond to removal of major food allergens from their diet," Assa'ad said.

"EGID management often requires multiple specialists, including the primary physician, allergy and immunology, gastroenterology, nutrition and psychology," she noted.

More information

The U.S. National Institute of Allergy and Infectious Diseases has more about food allergy.

MONDAY, Nov. 5 (HealthDay News) -- Doctors may be overprescribing anti-reflux medications to infants, new research suggests.

The study found that fewer than one in five babies given anti-reflux medications, which work by lowering levels of stomach acid, actually had elevated acid levels. That means four out of five infants included in the study likely didn't need anti-reflux medications, and may have simply been experiencing normal infant regurgitation commonly referred to as "spitting up."

"In the absence of red flags, such as a child who is not gaining weight, has feeding problems or a learned aversion to food, a chronic cough or recurrent respiratory problems or apnea, regurgitation may not require medication," said study author Dr. Vikram Khoshoo, a pediatric gastroenterologist at the Pediatric Specialty Center at West Jefferson Medical Center in New Orleans.

"Regurgitation won't improve with anti-reflux medications. Acid suppression will improve irritability and feeding problems, but it won't change spitting up. As long as the child is gaining weight and happy, and has no recurrent red flags, regurgitation is a laundry problem, not a medical problem," Khoshoo said.

The findings are published in the November issue of Pediatrics.

Reflux is common in infants. In fact, more than half experience reflux symptoms during the first three months of life, according to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms of reflux include spitting up, vomiting, coughing, feeding difficulty and irritability.

Khoshoo and his colleagues reported that back in 1998 and 1999, infants with regurgitation made up about 14 percent of their referrals, and about 40 percent of those babies were already on anti-reflux medication or on special easier-to-digest formula. But by 2006 to 2007, infants with regurgitation accounted for 23 percent of their referrals, and 90 percent were already on medications or special formula.

"We felt it was unlikely that the incidence had increased so suddenly," Khoshoo said.

To measure whether or not these infants' symptoms were caused by acid reflux, the researchers conducted pH studies on 44 babies with persistent regurgitation. The average age of the babies was 18 weeks.

To complete a pH study, doctors must thread a wire down the nose and leave it in place for 24 hours, Khoshoo said, so it's not a test that would be practical to do on every child with regurgitation.

Of the 44 babies tested, only eight showed elevated pH levels, meaning they had excess levels of stomach acid, and anti-reflux medications would be indicated in these cases. However, 42 of the babies were already on such medications, meaning that many were taking a medication they didn't need.

While these medications are generally considered safe, Khoshoo said there is some concern that they may affect calcium metabolism, and they've been associated with osteoporosis in older people who take them for long periods of time.Because infants are building new bones, this potential side effect is even more concerning, Khoshoo added.

Dr. David Keljo is a pediatric gastroenterologist and director of the Inflammatory Bowel Disease Center at Children's Hospital of Pittsburgh. He said, "Reflux in babies is a tough issue, and I think the concerns in this study are well-raised. Babies may be cranky from reflux or from something else. The vast majority will outgrow their reflux whether we do anything or not."

Both Khoshoo and Keljo said these medications are probably overprescribed because parents want to do something, anything to try to stop their babies' regurgitation and irritability.

Khoshoo said that taking care not to overfeed your infant and making sure he or she is positioned so that their bodies are at least somewhat upright after eating will help to lessen reflux symptoms. Another critical thing parents can do, he said, is make sure that children aren't exposed to secondhand smoke, which can increase reflux symptoms.

Keljo said there are certain signs that indicate your baby should be evaluated by a specialist. If your child throws up blood, a substance that looks like coffee grounds, or if there's green in the vomit, your child should be seen right away. Also, if your child isn't gaining weight or is even losing weight, if you can hear significant choking sounds, if there's a chronic cough or hoarseness that accompanies regurgitation, your child should see a gastroenterologist, he said.

More information

To learn more about acid reflux in babies, visit the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.

FRIDAY, Oct. 19 (HealthDay News) -- Not only is secondhand smoke a threat to teen health, it can also affect their school test scores, a new study finds.

Researchers at Temple University found that 16- and 18-year-olds exposed to secondhand smoke at home were 30 percent less likely to pass standardized tests than their peers.

They reached this conclusion after analyzing data from thousands of mothers and children in the United Kingdom, and factoring in other known risk factors, such as socioeconomic status, gender and smoking by teens.

The study was published in the Journal of Adolescent Health.

The findings add to a growing body of evidence that secondhand smoke affects children's academic performance, as well as their health, the researchers said.

"It's important that we help smoking parents learn how to reduce their children's exposure to secondhand smoke, a goal that can be achieved without requiring the parent to immediately quit smoking, although that's the ultimate goal for the health of the entire family," study author Bradley Collins, an assistant professor of public health and director of the Health Behavior Research Clinic at Temple, said in a prepared statement.

This study did not answer why secondhand smoke affects teen's test scores. Previous studies have suggested a link between prenatal exposure to cigarette smoke and increased risk of cognitive and academic problems, learning disabilities and impulsivity in children.

More information

The American Lung Association has more about secondhand smoke and children  .