Esther Entin, M.D. is a Board Certified pediatrician and Clinical Associate Professor of Family Medicine at Brown University's Warren Alpert School of Medicine.

When health care providers want to help their patients remain healthy, they look for ways to screen them for potentially dangerous conditions even before the patient develops symptoms. If a patient is identified as being at risk by screening, he or she may have further tests. If the results are definitive, preventative treatment will be recommended. Screening tests are most useful when they are applied to a select group of patients who are most likely to have the troubling condition, rather than screening everyone. They are less useful when they identify too many people who, on further evaluation, actually don't have the condition. Deciding which patients to screen is the key to effective testing and physicians look for the characteristics of a patient's personal health or health history that increase the likelihood that a test will be helpful.

Screening tests are only recommended when there is an available treatment for the condition or when knowing that the patient is at risk will change their medical care and follow−up.

The American Academy of Pediatrics recommends both dietary and medication treatment for overweight children with abnormal total cholesterol and low density lipoproteins.

Abnormal Lipids From Childhood to Adulthood
Abnormal blood lipids (cholesterol, high and low density lipoproteins and triglycerides) are associated with coronary artery disease in adults, and adults are routinely screened for their blood levels as part of preventative care. It is known is that abnormal lipid levels in childhood often persist into adulthood and that plaques and abnormalities associated with atherosclerosis can be seen in the cells lining the coronary arteries in adolescents and young adults. Overweight and obese children and adolescents have an increased risk of abnormal lipids, but universal lipid screening for children and adolescents remains controversial. The U.S. Preventive Services Task Force stated that there is not enough evidence to decide whether screening children and adolescents is or isn't useful. However, the American Academy of Pediatrics and the American Heart Association recommend targeted screening on specific groups of children and teens who are thought to be at increased risk.

The American Academy of Pediatrics (AAP) revised their lipid screening guidelines in 2008 in response to the rise in overweight and obesity among U.S. children and adolescents. They recommended that a targeted population of children and adolescents should be screened for abnormal total cholesterol, high− (HDL) and low− (LDL) density lipoproteins and triglycerides, starting as early as two years of age and no later than ten years. The American Heart Association has a similar recommendation.

Currently, the AAP guidelines for screening pediatric patients for abnormal lipids consider whether the child’s parents have elevated cholesterol or early cardiovascular disease (occurring before 55 years in men and before 65 years in women) as well as whether the child has a personal history of high blood pressure, diabetes, smoking or overweight or obesity.

Children whose Body Mass Index (BMI) is between the 85 and 95 percentile for their age and sex are considered overweight, and those whose BMI is greater than 95 percentile for age and sex are considered obese. The AAP uses the 85 percentile or greater as a threshold for starting lipid screening.

Not Such a Useful Screening Tool
A recent study published in the August issue of Archives of Pediatric and Adolescent Medicine has raised concerns that the AAP weight screening guidelines are not accurately predicting the group of children and adolescents who are most likely to be helped by the test. Using information on blood lipid levels and body mass index obtained by the National Health and Nutrition Examination Survey (NHANES) the researchers looked at 9338 children, ages 3−18 years. By looking at the lipid values for these children and teens at a variety of BMI measurements, they were able to determine whether the measurement would have been helpful in identifying the children whose lipids were likely to be abnormal. They found that if they used the AAP body mass index recommendations for screening, they would have missed a significant number of children with elevated total cholesterol and decreased LDL which the AAP recommends be considered for treatment with medication. The BMI was somewhat more helpful for abnormal HDL and triglycerides, which are treated with dietary management, just as one would with any overweight or obese pediatric patient.

They found that the BMI is not an effective way to identify those children and adolescents who would benefit from screening for abnormal lipids because it is least accurate for the group that might most benefit from medication as well as dietary management. As a result they concluded that a BMI− based screening test that misses as many as half of children and adolescents with the problem isn't useful.

What Parents Should Take Away From This Controversy
Despite, or really, because of these unresolved issues, the researchers are concerned about overweight and obesity in the pediatric population, and the likelihood that lipid abnormalities that are present early in life will likely have some negative impact on cardiovascular health down the line. They recommend a population−wide preventive strategy that emphasizes a low saturated fat and low cholesterol diet starting in infancy. Studies have demonstrated that such a diet is beneficial to serum cholesterol values and coronary artery function later in childhood and does not have negative consequences on physical growth, achievement of developmental milestones and age appropriate thinking and reasoning skills, or normal onset of puberty. They call on the American Academy of Pediatrics to adopt a general dietary policy to prevent cardiovascular disease in the entire pediatric population.

It is far easier to prevent a child from becoming overweight than getting an overweight child to lose weight. Adopting a healthy diet and exercise program early in life, decreasing time spent sitting indoors, and reinforcing healthy food choices are critical if parents want to positively impact their children's health throughout their life. Parents may wish to discuss their children's diet with their primary care provider, or they may want to request a referral to a nutritionist to determine the saturated fat and cholesterol sources in their family's daily diet and learn how to reduce them. If parents are concerned that their child is at risk for abnormal blood lipids, they should ask their child's doctor whether a blood test would be helpful.