High insulin levels and abnormal liver-function tests found in obese preteens
May 2003 - Children are becoming obese as young as 3 years old, and obese 10-year-olds are showing abnormal liver function and abnormally high insulin levels, which may lead to type 2 diabetes, analysis of data from a group of children referred to University at Buffalo pediatric endocrinologists has shown.
Moreover, information and counseling on diet and exercise programs to treat the obesity had little effect in this group. Obese children who were followed for an average of two years after seeing a specialist gained even more weight, findings showed.
The results of the study were presented today (May 3) at the Pediatric Academic Societies meeting being held May 3-6 in Seattle.
"Childhood obesity not only affects a child's self esteem, it also is associated with multiple medical consequences," said Teresa Quattrin, M.D., UB associate professor of pediatrics and director of the study. "High insulin level is believed to be related to type 2 diabetes, formerly known as 'adult-onset diabetes.' In fact, the incidence of type 2 diabetes in children has risen significantly in recent years, along with high prevalence of obesity.
"Children at risk of obesity must be identified very early, even at the preschool level," she said. "Obese children often have obese parents, so an effective family-based multi-factor intervention program should begin as soon as obesity is diagnosed."
The purpose of the study, conducted by Quattrin and co-investigator Emily Liu, M.D., UB research assistant professor of pediatrics at Kaleida Health's Women's and Children's Hospital in Buffalo, was to identify characteristics of obese children who are referred to the hospital's pediatric endocrine specialists, determine the age of onset of obesity and analyze the results of treatment recommendations.
Statistics indicate between 16 and 33 percent of U.S. children and adolescents are obese, and childhood obesity is rising at an alarming rate. Compared to children of normal weight, overweight children are much more likely to become overweight adults, with all of the health problems associated with adult obesity. Because there are few treatment options, obese children often are referred to an endocrinologist.
To get a sense of what is happening with one group of obese children, the Buffalo researchers reviewed medical records of 385 children who were seen by endocrinologists at the hospital between 1984 and 2002. Girls accounted for 57.6 percent of the total group, which was 75 percent Caucasian, 17 percent African-American, 3 percent Hispanic and 2 percent "other."
Obesity was defined as having a body-mass index (BMI, a ratio of height squared to weight) at or above the 85th percentile for age for two years or more. The researchers also had information for some children on bone age, glucose and insulin levels, liver function tests and cholesterol. They obtained growth data from primary-care physicians to determine how old the children were when they hit the obesity mark.
At the initial visit, parents or caretakers received extensive counseling on diet and activity recommendations, along with written guidelines, and were advised to meet with a dietician.
Two-year follow-up data were available for 110 children. This data showed that during that period, BMI increased on average from 29.2 to 31.5. (Optimal BMI for children depends on the child's age; for adults the healthy range is 19-25.)
"Clearly referral to pediatric endocrinologists and dieticians is not effective in treating childhood obesity," said Liu. "An effective weight-loss program should not only focus on children, it should also include the parents and the school system. Obese children likely have obese parents. High-calorie school lunches may add to the problem."
Even though there may be a genetic predisposition for obesity, other factors play important roles, she said, including food available at home and school, environmental factors such as a watching TV, playing computer games, and lack of exercise, and the role model of parents.
Additional results showed that 86 percent of 177 children were obese before the age of six, and children were obese for an average of three years before they were referred to an endocrinologist. Abnormally high insulin levels were found in children as young as 4 years old, and eight of 43 children with abnormally high insulin levels were younger than 10. In addition, 13 percent of 147 children had abnormal liver-function tests.
"Our data show it is very important for obesity intervention to begin at the preschool level," Liu said. "It is also crucial to monitor all potential comorbidities in obese children, such as liver function and insulin levels, to prevent early onset of chronic disease. 'Fatty liver' is common in obesity, and the condition can lead to a disease called nonalcoholic steatohepatitis, which, in turn, can develop into cirrhosis. A high insulin level is associated with diabetes, especially in children with a family history of diabetes.
"Perhaps the epidemic of obesity can be stopped if we intervene very early with an intensive behavioral modification program," said Liu.
The research was supported in part by a summer student grant from the Lawson Wilkins Pediatric Endocrine Society to medical student Natalie Shaw and a Stransky Award from the Women and Children's Foundation.
Source: University of Buffalo