Association between vitamin B12 level and clinical peripheral neuropathy in type 2 diabetic patients on metformin therapy
Nouran Fakkar
Hammam Fakkar (1), Diaa Marzouk (1,2), Mohamed Farouk Allam (1), Mohamed
Mahmoud Fouad (3), Maram Maher Aboromia (4) Mohsen Gadallah (2)
1. Department of
Family Medicine, Faculty of Medicine, Ain Shams University, E11566, Cairo,
Abbasia, Egypt.
2. Department of
Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain
Shams University, Cairo, Egypt.
3 Department of Neurology,
Faculty of Medicine, Ain Shams University, Cairo, Egypt.
4. Department of
Internal Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
https://doi.org/10.1186/s41983-022-00483-9
Abstract
Background: Vitamin B12
malabsorption is one of the side efects of long-term metformin intake.
Prolonged vitamin B12 defciency can lead to irreversible nervous system damage.
So, the current study aimed to determine the association between serum vitamin
B12 level and clinical peripheral neuropathy among type 2 DM patients who are
on metformin in comparison to those not taking it. It is a cross-sectional
study that was conducted in Egypt and recruited 100 type 2 diabetic patients
who were divided into 2 groups: metformin treated, and non-metformin treated
(50 subjects per group). The collected data included personal history, medical
history, dietetic history that included frequency of eating food rich in
vitamin B12 and clinical peripheral neuropathy assessment by Toronto Clinical
Scoring System (TCSS). Blood samples were collected for assessment of HbA1c and
vitamin B12 level.
Results: Vitamin B12
defciency was present in 4% of metformin group and 2% of non-metformin group.
The mean value of vitamin B12 between metformin users (624.3±364.1 pg/ml) and
non-metformin users (991.0±489.9 pg/ml) showed a high signifcant diference, p
value<0.001. There was a signifcant diference between study groups regarding HbA1c level (p value=0.03). Peripheral neuropathy was signifcantly associated with HbA1c (p value=0.04) and female gender (p value=0.001). Conclusions: Vitamin B12 level was lower in type 2 diabetic patients on metformin compared to those on other oral anti-diabetic drugs, but without signifcant defciency. Peripheral neuropathy was signifcantly associated with poor glycemic control and female gender, but was not associated with vitamin B12 defciency. Keywords: Metformin, Peripheral neuropathy, Type 2 diabetes mellitus, Vitamin B12 defciency>
<0.001. There was a signifcant diference between study groups regarding
HbA1c level (p value=0.03). Peripheral neuropathy was signifcantly associated
with HbA1c (p value=0.04) and female gender (p value=0.001)
Conclusions: Vitamin B12
level was lower in type 2 diabetic patients on metformin compared to those on
other oral anti-diabetic drugs, but without signifcant defciency. Peripheral
neuropathy was signifcantly associated with poor glycemic control and female
gender, but was not associated with vitamin B12 defciency.
Keywords: Metformin, Peripheral neuropathy, Type 2 diabetes
mellitus, Vitamin B12 defciency.
The Egyptian Journal of Neurology, Psychiatry and Neurosurgery 2022;58:46.
https://ejnpn.springeropen.com/articles/10.1186/s41983-022-00483-9
