|Year : 2014 | Volume
| Issue : 4 | Page : 241-245
How common is Vitamin B12 deficiency - A report on deficiency among healthy adults from a medical college in rural area of North-West India
Jagjit Singh Chahal1, Sunil Kumar Raina2, KK Sharma1, Navjot Kaur3
1 Department of Biochemistry, Dr. Rajendra Prasad Government Medical College, Tanda, Kangra, Himachal Pradesh, India
2 Department of Community Medicine, Dr. Rajendra Prasad Government Medical College, Tanda, Kangra, Himachal Pradesh, India
3 Department of Pathology, Dr. Rajendra Prasad Government Medical College, Tanda, Kangra, Himachal Pradesh, India
|Date of Submission||29-Apr-2014|
|Date of Acceptance||08-May-2014|
|Date of Web Publication||22-Aug-2014|
Sunil Kumar Raina
Community Medicine, Dr. Rajendra Prasad Government Medical College, Tanda, Kangra 176 001, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Vitamin B12 is an essential micronutrient that plays a fundamental role in cell division and in one carbon metabolism. Materials and Methods: This was an observational study carried out at among students and staff of a medical college facility located in a rural area of north-west India. Results: Mean serum vitamin B12 in both the groups of employees as well as students, was low (group I N 69: 241.56 ± 101.88 pg/ml; group II N 84: 217.98 ± 92.78 pg/ml). Using 200 pg/ml as threshold, 53.6% of total participants had low vitamin B12 concentration (66.6% of female students and 70.6% of female employees), while 16.3% of study population was severely deficient having serum vitamin B12 level below150 pg/ml. Conclusion: Our observation of high prevalence of sub-optimal vitamin B12 is consistent with findings drawn from scholarly literature and supplemented with those from our country too.
Keywords: Deficiency, North-West India, report, vitamin B12
|How to cite this article:|
Chahal JS, Raina SK, Sharma K K, Kaur N. How common is Vitamin B12 deficiency - A report on deficiency among healthy adults from a medical college in rural area of North-West India. Int J Nutr Pharmacol Neurol Dis 2014;4:241-5
|How to cite this URL:|
Chahal JS, Raina SK, Sharma K K, Kaur N. How common is Vitamin B12 deficiency - A report on deficiency among healthy adults from a medical college in rural area of North-West India. Int J Nutr Pharmacol Neurol Dis [serial online] 2014 [cited 2020 Aug 6];4:241-5. Available from: http://www.ijnpnd.com/text.asp?2014/4/4/241/139406
| Introduction|| |
Vitamin B12 is an essential micronutrient that plays a fundamental role in cell division and in one carbon metabolism. There are two major metabolic roles for vitamin B12: (a) synthesis of methionine from homocysteine; and (b) conversion of methylmalonyl coenzyme A to succinyl coenzyme A.  Folic acid plays five major metabolic roles in: (a) serine and glycine metabolism; (b) histidine catabolism; (c) thymidylate synthesis; (d) methionine synthesis; and (e) purine synthesis. A deficiency of either vitamin B12 or folate can lead to megaloblastic anemia. Folate and vitamin B12 metabolism is linked to the transfer of a methyl group from N5-methyltetrahydrofolate to cobalamin. In the absence of vitamin B12, folate is "trapped" and cannot be recycled back into the folate pool. Eventually this leads to a reduction in thymidylic acid synthesis that produces megaloblastic anemia. Further deficiencies of either folic acid or vitamin B12 or both, can lead to hyperhomocysteinemia, which is a risk factor for atherosclerosis. ,,
Serum vitamin B12 has usually seen to be lower among Indian toddlers and in adults, more so in vegetarians than in non-vegetarians. Low serum vitamin B12 may not be associated with any anemia or neurological complications. , But chronic vitamin B12 depletion (i. e., prolonged low intake or intestinal malabsorption) results in a state of negative vitamin B12 balance. The depletion process may take years to become clinically evident. Early and reliable diagnosis of deficiency is crucial, owing to the latent nature of the disorder and the resulting possible irreversible neurologic damage. ,
| Materials and methods|| |
This was an observational study carried out at a medical college facility located in a rural area of north-west India. The protocol and plan of study was accepted by the Scientific Advisory cum Protocol Review Committee and was subsequently approved by the Institutional Ethics Committee. Voluntarily willing students and employees were recruited for the study after obtaining informed written consent. A total of 153 study units were picked by stratified random sampling method from the sampling frame that comprised of all students and employees of the medical college.
Study plan and procedure was explained to the recruited participants and they were then subjected to focused general physical examination after having been interviewed using a structured questionnaire. Clinical variables were taken by standardized anthropometric measurements on first day of contact only. Height was measured to the nearest 1.0 cm, without shoes on and with feet together, in Frankfurt's plane with measuring tape.  Weight was measured in light indoor clothes barefooted on adult weighing machine. The body mass index (BMI) was calculated as weight in kilogram divided by height in meter square.
Blood sample was collected by following standardized procedure for the collection of blood sample, when the enrolled subject (with empty stomach after overnight fasting) came to the department of Biochemistry next day after having got their clinical variables recorded the previous day.
Any adult (male and female aged from 18 to 62 years) voluntarily consenting student or employee of Dr. Rajendra Prasad Government Medical College Kangra at Tanda, district Kangra, Himachal Pradesh.
Subjects refusing to participate were excluded from the study. Also subjects who were taking methylcobalamin or vitamin B12 or have taken the same for more than 15 days during last 3 months, subjects who had received vitamin B12 as injectables during the last one year, those with chronic illness like tuberculosis, cancer or immunocompromised subjects, pregnant or lactating mothers, anyone who had either donated or received blood in last three months were excluded.
Principle of the procedure for the assay of vitamin B12
It is a solid phase, competitive chemiluminescent enzyme immunoassay. Vitamin B12 estimation involves a preliminary heat denaturation step. Vitamin B12 in the patient sample is released from carrier protein by incubation at 100 o C in the presence of dithiothreitol and potassium cyanide to inactivate vitamin B12- binding proteins even at extreme levels, as well as antibodies to intrinsic factor. After the heat denaturation step, the treated patient's sample and hog intrinsic factor are simultaneously introduced into an Immulite 1000 test unit (T U) containing a polystyrene bead coated with a vitamin B12 analog, and incubated for approximately 30 minutes at 37 o C with intermittent agitation. During this incubation, vitamin B12 in the treated sample competes with the vitamin B12 analog on the solid phase for a limited number of vitamin B12 binding sites on the purified intrinsic factor (endogenous vitamin B12 analog does not interfere, because the binder is free of R-protein). Alkaline phosphatase-labeled anti-hog intrinsic factor is introduced, and the T U is incubated for another cycle of 30 minutes. The unbound enzyme conjugate is washed off. 
| Results|| |
A total of 153 subjects comprising of 69 employees (group I) along with 84 students (group II) were enrolled in the study. Youth (18-25 years) constituted 54.91% of study population, whilst those who were older than 45 years constituted 12.42% of the total and the rest were aged between 26 and 45 years. The oldest participant was aged 56 years. The mean ± SD age of subjects in two groups of employees and students (group I N 69: 39.06 ± 8.51 years; group II N 84: 20.82 ± 2.93 years) had significant intergroup variability (P < 0.05) [Table 1]. Males comprised of 56.2% (N = 86) whereas females were 43.8% (N = 67) of the study population and this exhibited significant distribution variability within each group based upon occupation (P < 0.05). Male employees were three times the female employees while female students were more than one and a half times of male students [Table 2]. The proportion of vegetarian and non-vegetarian subjects in our study population was almost equal i. e., 49% and 51%, respectively. Non-vegetarianism was prevalent; more than two times amongst males in both the groups [Table 3]. Smokers constituted 12.43% of the enrolled participants in our study and all of them were males. The male employees comprised of more than 89% of total smokers enrolled [Table 4]. Participants categorized as alcohol users constituted 17.6% of the study population. All were males and barring one participant, belonged to the group of employees [Table 5]. It was observed that 13 (8.5%) participants were underweight (BMI < 18.5) and 109 (71.24%) participants were having normal weight (BMI 18.5-24.9) while 31 (20.26%) participants were categorized as overweight (BMI >25). Mean ± SD BMI of subjects in two groups of employees (group I) and students (group II) (group I N 69: 23.88 ± 2.94; group II N 84: 20.94 ± 2.33) exhibited significant intergroup variability in respect of their occupation and gender (P < 0.005 for both). One participant belonging to vegetarian group of female students had lowest BMI (16.00) whilst one having BMI of 33.00 belonged to the group of non-vegetarian male employees. Mean serum vitamin B12 in both the groups of employees as well as students, was low (group I N 69: 241.56 ± 101.88 pg/ml; group II N 84: 217.98 ± 92.78 pg/ml). Using 200 pg/ml as threshold 53.6% of the total participants had low vitamin B12 concentration (66.6% of female students and 70.6% of female employees), while 16.3% of study population was severely deficient having serum vitamin B12 level below150 pg/ml [Table 6]. On further analysis of data (student's t test), male participants were observed to possess higher serum vitamin B12 than that in their female counter parts (248.36 ± 98.72 vs 203.28 ± 90.16), which showed significant inter-group variability (P < 0.05), while it was not so based on occupation. Participants who had suboptimal serum vitamin B12 (less than 200 pg/ml) exhibited significant inter-group variability based on Chi-Square Test (P = 9.30, P = 0.026) [Table 6].
| Discussion of results|| |
The results of our study showed the high frequency of suboptimal serum vitamin B12 in our study population. A total of 82 participants which makes 53.60% of the enrolled subjects were having suboptimal level of vitamin B12. Of note was an observation that mean serum vitamin B12 level in younger age group (students) was lower than that in older group (employees). More of younger age group (58.34%) was in the suboptimal group, compared to older ones (47.82%). By fixing 200 pg/ml as threshold for serum level of vitamin B12 66.6% of female students and 70.6% of the enrolled female employees were deficient or having suboptimal level, which collectively made up to 53.60% of the study population. Out of this number (N = 82), there were a sizeable proportion (30.5%) of participants (N = 25) who had serum vitamin B12 even lower than 150 pg/ml.
This observation was consistent with findings drawn from scholarly literature and supplemented with those from our country too. Our results were similar to those of Refsum et al., who reported that 52% of the enrolled subjects from Asian Indians had low serum cobalamin.  The prevalence of vitamin B12 deficiency as found in our study (53.60%) was higher than that reported by Mahmoud et al., who found suboptimal serum vitamin B12 in 48.1% of seemingly healthy young adults in Jordan but they had used a cutoff value of 222 pg/ml, whereas we used 200 pg/ml as threshold.  We would like to add further that this very prevalence of subnormal vitamin B12 as observed by us was having a worldwide trend amongst Indians residing in India or abroad. Yajnik et al., got similar findings based upon their work in 2006 and they reported an overall prevalence of vitamin deficiency to the tune of 67% amongst rural and urban Indians from Pune.  Similar findings were replicated by retrospective chart review that was done in 2004 in respect of South Asians at a Toronto clinic done by Gupta et al., and they found vitamin B12 deficiency in 46% of the reviewed subjects.  [Table 7] provides a detail on the relative prevalence of vitamin B12 and folic acid deficiency ,,,,,,,,,,
Universality of occurrence of subnormal levels of vitamin B12 as in our study can also be authenticated by drawing inferences from the relatively older as well recent literature as exemplified by work done by Garcia-Casal et al., who reported 11.4% deficiency of vitamin B12 amongst general population and nearly six times accentuation of this deficiency in pregnant women (61.3%). 
Chandra et al., reported that the deficiency of vitamin B12 to the tune of 32.0%. They also documented good co-relation between serum levels of mothers and their suckling infants.  It was therefore necessary for our population especially young females to have normal serum vitamin B12 because 66.0% of them were seen to possess subnormal level of vitamin B12.
A recent communication by Bhardwaj et al., from our part of India, reported vitamin B12 deficiency to be prevalent in all the enrolled adolescents in their study. 
It is imperative to diagnose and correct vitamin B12 deficiency because of the devastating effect that this deficiency can have on the neural development even before serum vitamin B12 falls below cutoff serum levels. During deficiency methylmalonyl-CoA accumulates and is used instead of acetyl-CoA in the synthesis of fatty acids; this results in unstable myelin that degrades more readily. ,, On the other hand, megaloblastic anemia occurs quite late in the development of overt cobalamin deficiency. 
Traditional knowledge assumes vitamin B12 deficiency to be uncommon as this vital hematopoietic micronutrient is conserved efficiently by enterohepatic circulation, and only 0.05-0.2% of body stores is excreted daily. Therefore, fastidious vegetarians, who consume little vitamin B12 in their diet may take approximately 20 years to become depleted, provided they were either born with or have acquired sufficient stores. , Diet may be a major contributory factor to low levels of cobalamin. Though majority of our population (51.0%) was non-vegetarian, their diet contained animal proteins in the form of milk, occasional eggs and less frequently meat. Against this background, the higher prevalence of subnormal levels of vitamin B12 in our study may be ascribed to cooking practices in Indian households. Overcooking of food might have caused lesser availability of cobalamin to intestine for absorption. Secondly, it may also be due to small portion size of red meat consumption or due to diminished absorption of food and vitamin B12.
We do recommend annual biochemical screening of those who are at risk to develop vitamin B12 deficiency. Also, cobalamin supplementation on the lines of folic acid could be considered. Probably a key area to target is an increase in intake of milk, dairy products, and eggs amongst lacto-vegetarians and increase meat consumption among non-vegetarians. Also the fact that the plants contaminated with vitamin B12-producing bacteria through fertilization with manure may also be a source of vitamin B12, and so, in theory, "organically grown" leafy vegetables may have higher vitamin B12 concentrations than do leafy vegetables exposed to chemical fertilizers.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]