Childhood BMI key to later CVD risk

November 7, 2007

Primary care physicians and pediatricians who do not measure childhood body mass index (BMI) are missing a prime opportunity to prevent cardiovascular disease later in life.

Primary care physicians and pediatricians who do not measure childhood body mass index (BMI) are missing a prime opportunity to prevent cardiovascular disease later in life.

That is the conclusion from a new Cincinnati Children's Hospital study that links earlier childhood weight gain with increased cardiovascular risk by age seven. The newly identified risk, BMI rebound age, describes the age at which a child's BMI reaches its lowest point before climbing toward adolescence and adulthood.

"The obesity epidemic of today's children will be the cardiovascular disease epidemic of 20 years from now," said Thomas Kimball, MD, director of echocardiography and of the Cardiovascular Imaging Core Research Laboratory at Cincinnati Children's Hospital Medical Center. "This study tells us that we need to educate pediatricians, primary care physicians, and parents that BMI matters even in young children."

In normal children, BMI climbs from birth through the first few years of life, Dr Kimball explained. BMI falls to its lowest between ages four and seven, then begins to climb as children grow and gain weight in preparation for adolescence.

Dr Kimball's group followed 308 three-year olds, measuring their height and weight every four months over four years. At age seven, each child was assessed for known cardiovascular risk factors. Each underwent an echocardiogram to check left ventricular mass and left atrial size. Standard laboratory tests measured systolic and diastolic blood pressure, serum insulin and leptin.The children were divided into three groups based on the age at BMI rebound:

  • Early BMI rebound age, below the 25th percentile
  • Middle BMI rebound age, between the 25th and 75th percentile
  • Late BMI rebound age, above the 75th percentile

The mean rebound age for children in the 25th percentile was 4.4 years for boys and 4.2 years for girls. In the 75th percentile, the mean rebound age was 6.6 years for boys and 6.6 years for girls.

For both boys and girls, an early BMI rebound age was positively associated with increased cardiovascular risk at age seven. Increased risk factors included higher BMI, higher systolic and diastolic blood pressure, higher serum insulin and leptin levels, higher left ventricular mass and higher left atrial size.

"Pediatricians don't need to measure BMI every four months, they just need to start measuring," Dr Kimball said. "Plump is not good when it comes to children's health."

Weight loss intervention is indicated if a child's BMI exceeds the 85th percentile for age, Dr Kimball continued.

"What you do for an overweight child is well known - diet and exercise," he said. "Intervention starts by recognizing the problem. You need to measure BMI for children just like you do for teens and adults to get a handle on their weight. The earlier in life you control weight, the healthier the person is for life."

The children are still being followed and assessed for changes to their cardiovascular risk and status. Dr Kimball said he expected elevated cardiovascular risk during childhood to translate into higher rates of cardiovascular disease in later years. Plans call for follow up to continue into the child cohort's adult years.