Changes and variability in high levels of low-density lipoprotein cholesterol among children

A 2008 report from the American Academy of Pediatrics recommended both population and individual approaches (including pharmacologic interventions) for adolescents who had low-density lipoprotein (LDL) cholesterol levels above various cutoff points (130, 160, and 190 mg/dL). However, the tracking and variability of these very high levels have not been investigated.

A total of 6827 subjects underwent multiple LDL cholesterol determinations in childhood and adulthood in the Bogalusa Heart Study. The total number of determinations was 26748, and the median interval between examinations was 3 years.

Correlations between initial and subsequent LDL cholesterol levels ranged from r approximately 0.8 for measurements made within the same year to r approximately 0.5 for periods of > or = 20 years. Most children who had very high LDL cholesterol levels, however, had substantially lower levels at the next examination. LDL cholesterol levels between 160 and 189 mg/dL (n = 201) decreased, on average, by 21 mg/dL at the next examination, whereas levels of > or = 190 mg/dL (n = 44) decreased by 34 mg/dL. In contrast, the mean increase for LDL cholesterol levels of <70 mg/dL was 13 mg/dL. These changes were equal to those expected on the basis of regression to the mean.

There can be large changes in extreme levels of LDL cholesterol because of regression to the mean, and practitioners should be aware that very high levels may decrease substantially in the absence of any intervention.