Age and gender distribution of study population.

Basic characteristics of patients referred for measurement of serum Cbl levels and included in the study (n = 818). Age is displayed with means and corresponding 95% confidence intervals. Sex is displayed as number and fractions (%) of males.
*P-values were obtained by one-way analysis of variance when testing for difference in mean age across Cbl levels groups. Cbl: cobalamin, vitamin B12; 95% CI: 95% confidence interval.