High frequency of suboptimal serum vitamin B12 level in adults in Jordan

To assess the prevalence of functional vitamin B12 deficiency status in an adult Jordanian seemingly healthy population.

We carried out this study in the Department of Physiology, Faculty of Medicine, Jordanian University of Science and Technology, Jordan from September 2004 to January 2005. We included a randomly selected sample of 216 healthy adult volunteers (male 124, female 92, aged 19-50 years) from north Jordan. We carried out the measurement of hematological variables by Micros 60-OT Analyzer. We measured the serum vitamin B12 by microparticle enzyme immunoassay and serum folate by ion-capture assay on an AxSYM Analyzer.

We found suboptimal (<222 pg/ml) serum levels of vitamin B12 in 104 (48.1%) (male 64, female 40) subjects. The mean serum vitamin B12 level of male in all volunteers was 238.8 +/- 97.3 pg/ml, not significantly different (p=0.24) from that of female (261.8 +/- 101.6 pg/ml). The mean serum values of vitamin B12 of male in the suboptimal group (168.3 +/- 36.4 pg/ml; range 90-221) were not significantly different from that of female (178.2 +/- 27.5 pg/ml; range 113-217) (p=0.31). Of the suboptimal group, 30 subjects (28.8%) had hyper-segmented neutrophils, 38 subjects (36.5%) had low mean corpuscular volume and 8 subjects (7.7%) had sub-optimal serum folate levels.

This study revealed that there was a high frequency of suboptimal serum vitamin B12 level, which is an early sign of negative B12 balance.