Figure 1.

Results of principal components factor analysis. (A and B) The factor structure of HbAA study subjects and the variability explained by the retained factors. Numbers in panel A show the factor loadings. (C to E) Influence of age and hemoglobin status on the factor scores for the three factors shown in panel A. The point and 95% confidence intervals are depicted as markers (diamonds for factor #1, filled squares for factor #2 and circles for factor #3) and error bars, respectively. The analysis is shown for all combinations of age categories and hemoglobin status. For each age category and factor the influence of hemoglobin was assessed by ANOVA (p values shown at the top). Also, the factor scores for HbAS and HbSS subjects were compared with those of HbAA subjects for each combination using Mann-Whitney test. *, Bonferroni-corrected p < 0.05; ϒ, Bonferroni-corrected p < 0.01.