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Studies from Centers for Disease Control and Prevention further understanding of life sciences. go to web site cdc growth charts

Biotech Week March 24, 2010 New investigation results, ‘Characterizing extreme values of body mass index-for-age by using the 2000 Centers for Disease Control and Prevention growth charts,’ are detailed in a study published in The American Journal of Clinical Nutrition. “The 2000 Centers for Disease Control and Prevention (CDC) growth charts included lambda-mu-sigma (LMS) parameters intended to calculate smoothed percentiles from only the 3^rd to the 97^th percentile. The objective was to evaluate different approaches to describing more extreme values of body mass index (BMI)-for-age by using simple functions of the CDC growth charts,” investigators in the United States report (see also Life Sciences).

“Empirical data for the 99^th and the 1^st percentiles of BMI-for-age were calculated from the data set used to construct the growth charts and were compared with estimates extrapolated from the CDC-supplied LMS parameters and to various functions of other smoothed percentiles. A set of reestimated LMS parameters that incorporated a smoothed 99^th percentile were also evaluated. Extreme percentiles extrapolated from the CDC-supplied LMS parameters did not match well to the empirical data for the 99^th percentile. A better fit to the empirical data was obtained by using 120% of the smoothed 95^th percentile. The empirical first percentile was reasonably well approximated by extrapolations from the LMS values. The reestimated LMS parameters had several drawbacks and no clear advantages. Several approximations can be used to describe extreme high values of BMI-for-age with the use of the CDC growth charts. Extrapolation from the CDC-supplied LMS parameters does not provide a good fit to the empirical 99^th percentile values. Simple approximations to high values as percentages of the existing smoothed percentiles have some practical advantages over imputation of very high percentiles,” wrote K.M. Flegal and colleagues, Centers for Disease Control and Prevention. site cdc growth charts

The researchers concluded: “The expression of high BMI values as a percentage of the 95^th percentile can provide a flexible approach to describing and tracking heavier children.” Flegal and colleagues published their study in The American Journal of Clinical Nutrition (Characterizing extreme values of body mass index-for-age by using the 2000 Centers for Disease Control and Prevention growth charts. The American Journal of Clinical Nutrition, 2009;90(5):1314 – 20).

For additional information, contact K.M. Flegal, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, MD 20782 USA.