Clustering scheme for heterogeneity grouping of healthy adolescents based on a profile of serum biochemical variables

All 890 study subjects attended two serum biochemistry screenings at an interval 3.5 years, the first while they were aged between 14 to 17 years (mean 15.5 and standard deviation 0.7). Three mutually independent laboratory indices--hepatocellular damage, liver metabolism, and outer-liver measurement--were identified as physiological scales by principal component analysis on ten common serum biochemical tests. Existence of a subgroup for an entity of healthy adolescents were supported by sum-of-squares clustering analysis of these three-dimensional indices. The consistency between two time-point repeated screenings for each of the same subjects confirmed the practicability of clustering schemes. The resulting cluster pattern for each screening bore a relation to gender or hepatitis B surface antigen (HBsAg) classifications. These features are expected to provide insight into normal references with enhanced group homogeneity, and lead to an improved multivariate protocol that will aid in health monitoring of subgroups with high risk.