FRIDAY, Sept. 7 (HealthDay News) -- A little shyness in young children can be endearing. But new research suggests that preschoolers who are extremely socially reserved and withdrawn may be at risk for falling behind in math and reading when they start kindergarten.

The study, published online recently in the Journal of School Psychology, suggests that super-shy kids may be at more risk than their active, overactive and outgoing peers. Children showing shy and withdrawn behavior early in the school year began with lower academic skills than other students and showed the slowest gains in learning skills over time.

Shy kids may fall into the background of the average preschool classroom, making it more likely teachers will fail to identify their unique learning needs, said study author Rebecca Bulotsky-Shearer, an assistant professor of psychology at the University of Miami. "Engagement is important in learning, especially in early childhood education. If there is a child who needs that extra support and is being missed, it's easier to fall behind the others," she explained.

The research suggests that feeling withdrawn may trigger a cascade of learning problems in the preschooler. "There may be different learning trajectories for kids if they are shy," Bulotsky-Shearer said.

For some children, the shyness may be a sign of another problem causing the inability to get actively involved in classroom activities with other children. "Some shyness is unhealthy, creating a high degree of anxiety," she said.

The study looked at the social and academic progress of children aged 3 to 5 throughout the school year, following over 4,400 pre-kindergarten children in the Head Start program in a large northeastern urban school district. The majority of participants were black (71 percent), with the remaining children Hispanic (16 percent), white (7 percent) and Asian or other (5 percent).

Most children were from homes with an annual income below $15,000. The participants came from 268 mixed-age classrooms in 100 different centers. Teachers assessed the emotional and academic progress of each child three times during the school year. To assess the non-academic behavior, they used a six-point scale that ranged from well-adjusted to extremely socially and academically disengaged.

Older children and girls tended to be better adjusted in class, showed fewer behavioral problems and exhibited higher levels of language and math skills, the data showed.

The research has limitations, said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children's Medical Center of New York. "There's a chicken-and-the-egg phenomenon: If there are children who are academically weak, they may be inhibited in a learning situation and then seem shy."

Adesman also questioned whether the lack of ethnic and socio-economic diversity in the study makes the research less applicable to the population as a whole. Too, he wondered whether the mixed-age classroom, including kids just starting preschool and others ready for kindergarten, could be skewing the results.

"For example, some 3-year-olds have separation issues and may be anxious in a preschool setting," he said. "After all, even if you put a high school freshman in a class with seniors, the freshman is going to be a little withdrawn."

To help ensure all kids -- the shy and the not-so-shy -- get the attention they need, Bulotsky-Shearer recommended parents check in with teachers regularly to see how their children are doing, both academically and socially, especially when their kids are young. "Everybody should ask how their kid does within the group," she said.

Adesman encouraged parents to realize that many kids who are considered shy do just fine. "The greatest risk is in a very small number of children," he said. "Be aware that sometimes troublemakers will get the teacher's attention, but teachers and parents need to be mindful that some children suffer silently and there may be some risk of academic difficulty in kids with significant social withdrawal."

While the study found an association between extreme shyness and possible learning problems, it didn't demonstrate a definitive link.

More information

Learn more about child development   from the Center on the Developing Child at Harvard University.

THURSDAY, Sept. 6 (HealthDay News) -- Almost all toddlers in the United States are getting their recommended childhood vaccinations, despite some parents' concerns about giving so many shots to the very young in such a short period of time.

A new government report shows immunization rates for many routine vaccines in 2011 were 90 percent or more among kids aged 19 months to 35 months.

The breakdown: Coverage for the birth dose of hepatitis B increased from 64.1 percent in 2010 to 68.6 percent in 2011, coverage for the recommended two doses of hepatitis A vaccine increased from 49.7 percent to 52.2 percent in the same period, coverage for rotavirus vaccines increased from 59.2 percent to 67.3 percent and coverage for the full series of Haemophilus influenzae type b (Hib) vaccine increased from 66.8 percent to 80.4 percent.

Vaccination coverage remained above the Healthy People 2020 target of 90 percent for measles, mumps and rubella (91.6 percent); poliovirus (93.9 percent); varicella (90.8 percent); and hepatitis B (91.1 percent), according to the 2011 National Immunization Survey, reported in the Sept. 6 issue of Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention.

Healthy People is a government program that establishes 10-year national health objectives aimed at improving health for all Americans.

Vaccination coverage rates did not vary by race or ethnicity for the most part. White and black children living below the poverty level, however, had lower immunization rates than those living above the poverty level.

Less than 1 percent of toddlers had received no vaccines at all, the report found.

Although national vaccination coverage is at or near targeted levels for most vaccines, vaccination coverage did vary by state in 2011, with the largest variations seen in the birth dose of hepatitis B vaccine and for vaccinations of hepatitis A and rotavirus.

The report also noted that 15 states have measles immunization coverage rates that do not yet meet the Healthy People 2020 goal of 90 percent. Low vaccination rates for extremely infectious diseases such as measles is a cause for concern, CDC officials said.

The agency urged parents, public health officials and community leaders not to be complacent about the importance of childhood vaccinations. Everyone needs to do what they can to help make sure the shots are given as recommended.

More information

The American Academy of Family Physicians has more about childhood vaccines  .

THURSDAY, Sept. 6 (HealthDay News) -- Six-month-old babies closely monitor their parents to determine if something is funny, and this appears to help them develop a sense of humor, a small study suggests.

For the study, U.S. researchers studied 30 babies in their homes when they were 6 months old and 1 year old. Initially, the babies watched their parent react to two ordinary events in which a researcher read a picture book and showed a small red foam ball to the babies.

The two events were then changed to be absurd. The researcher bounced the open picture book on her head while she said "Zoop! Zoop!" and then put the foam ball on her nose while she poked at it and said "Beep! Beep!"

During this odd behavior by the researcher, the parents were told to either point and laugh at the researcher or to just stare without expression.

The 6-month-old babies stared longer at the absurd events than they did at the normal events, but their reactions to the events did not depend on their parents' responses. However, the babies did watch their parents closely when they laughed.

By the time they were 1 year old, the babies laughed at the absurd events even if their parents remained expressionless.

The combination of paying close attention to absurd events and to others laughing at those events when they are 6 months old may explain how babies develop the sense of humor they have when they're a year old, the researchers suggested.

The study was scheduled for presentation Sept. 6 at a British Psychological Society meeting in Glasgow, Scotland.

"Humor might seem like a frivolous topic, but it provides a vehicle for understanding infant development, in this case the development of social referencing. This study shows that 6-month-olds pay attention to 'unsolicited emotional advice' from parents during ambiguous situations that might be funny," study author Gina Mireault, of Johnson State College in Johnson, Vt., said in a society news release.

"Our findings suggest that 6-month-olds are starting to see parents as a source of emotional information, and this is likely to be an important step on the way to being able to obtain emotional advice from parents when this is needed, which we know infants do at 8 months. By 12 months, infants seem to have had just enough life experience to make up their own minds -- at least about what is absurdly funny," Mireault explained.

The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.

More information

The American Academy of Pediatrics outlines the ages and stages of a child's growth and development  .

SATURDAY, Sept. 1 (HealthDay News) -- Packing nutritious and fun school lunches can help children achieve and maintain a healthy weight.

Here are some tips for parents from Dr. William Gillespie, a pediatrician and chief medical officer at New York City-based EmblemHealth.

• Give your children a choice. If they get to decide what's in their lunch, they're more likely to eat it. Just make sure their choices are all healthy, such as apples, bananas, carrots or celery.
• Add dip to make vegetables more fun for kids. A quick dip can be made with plain non-fat yogurt and garlic powder (or any other seasoning your child likes).
• Make mini-kabobs by cubing low-sodium deli chicken or turkey and low-fat cheese. Place the cubes on pretzel sticks. You can also use grape tomatoes and green grapes.
• Use whole-wheat bread instead of white bread. Whole-wheat pita or tortillas are other healthy options. Let your child make a "face" on their sandwich with ingredients such as hummus, low-fat cream cheese and cut-up vegetables.

Presentation makes a difference in how much food appeals to kids, Gillespie noted. Children are more likely to eat things in smaller, bite-size pieces or slices. Slice sandwiches into four squares. Cut up an apple or create a fruit cup with pieces of different melons.

When it comes to warm foods in a thermos, try a healthy macaroni and cheese with whole-wheat pasta and some small broccoli florets. A three-bean chili with carrots and zucchini is another healthy option.

Make sure your child's lunch includes a good source of calcium, such as yogurt, smoothies, low-fat string cheese or low-fat milk.

Water is a better choice than sugary drinks such as juices and sodas. If your child likes something crunchy, give them baked chips, low-fat popcorn or whole-grain crackers.

Ask if your child's school has restrictions on what students are allowed to bring for lunch. For example, many schools don't allow peanut butter. Remember to use an ice pack to keep cold foods cold.

More information

The American Academy of Pediatrics has more about childhood nutrition  .