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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 14  |  Issue : 2  |  Page : 105-108

Assessment of homocysteine, Vitamin B12, and Zinc levels among patients with acute ischemic stroke in Northwestern Nigeria


1 Department of Chemical Pathology, ABUTH, Zaria, Nigeria
2 Department of Medicine, ABUTH, Zaria, Nigeria
3 Department of Radiology, ABUTH, Zaria, Nigeria
4 Department of Chemical Pathology, FMC, Bida, Nigeria

Date of Web Publication5-Oct-2017

Correspondence Address:
H M Suleiman
Department of Chemical Pathology, Ahmadu Bello University Teaching Hospital, Zaria
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njbcs.njbcs_49_16

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  Abstract 

Background: Stroke has been a global burden, with increasing morbidity and mortality. Several risk factors have been identified, which are the target of preventive strategies, they include hyperhomocysteinemia, hypovitaminosis B12, and low zinc levels. There is paucity of data on the biochemical risk factors in our environment which necessitated this study. Objective: To evaluate the serum levels of homocysteine, vitamin B12, and zinc in patients with acute ischemic stroke in Zaria. Patients and Methods: This is a case-control study conducted over 13 months in ABUTH Zaria. One hundred patients with clinical diagnosis of ischemic stroke diagnosed, confirmed by brain CT-scan and Siriraj stroke score of less than -1, and equal number of apparently healthy age, and sex-matched were recruited. Their fasting serum homocysteine and vitamin B12 were measured using enzyme-linked immunosorbent assay, while zinc was measured using direct colorimetric method. Stroke severity was determined using National Institute of Health Stroke Score (NIHSS), patients with NIHSS score of 1–4, 5–15, and 16–42 were classified as mild, moderate, and severe stroke respectively. Results: Mean serum homocysteine for patients was significantly higher than that of controls (P < 0.05) and mean serum zinc and vitamin B12significantly lower compared to that of controls (P < 0.05). There was no association between hyperhomocysteinemia, low vitaminB12, and low zinc concentrations with the severity of stroke using NHISS Score. Conclusion: Elevated serum homocysteine, low vitamin B12, and zinc were found to be significant risk factors associated with ischemic stroke.

Keywords: Homocysteine, Stroke, Vitamin B12, Zinc


How to cite this article:
Suleiman H M, Aliyu I S, Abubakar S A, Anaja P, El-Bashir JM, Adamu R, Ibrahim M Z, Mohammed A, Yusuf R, Manu M, Dogara A B. Assessment of homocysteine, Vitamin B12, and Zinc levels among patients with acute ischemic stroke in Northwestern Nigeria. Niger J Basic Clin Sci 2017;14:105-8

How to cite this URL:
Suleiman H M, Aliyu I S, Abubakar S A, Anaja P, El-Bashir JM, Adamu R, Ibrahim M Z, Mohammed A, Yusuf R, Manu M, Dogara A B. Assessment of homocysteine, Vitamin B12, and Zinc levels among patients with acute ischemic stroke in Northwestern Nigeria. Niger J Basic Clin Sci [serial online] 2017 [cited 2019 Jul 19];14:105-8. Available from: http://www.njbcs.net/text.asp?2017/14/2/105/216053


  Introduction Top


Stroke is defined as a clinical syndrome of sudden onset of rapidly developing symptoms or signs of focal and at times global loss of cerebral function, with symptoms lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin.[1]

The World Health Organization (WHO) estimated that cardiovascular disease and stroke will be the leading cause of death and disability world wide by 2020.[2] Stroke is one of the leading causes of death in any population, and its prevention is a key strategy in reducing the rate of mortality and morbidity.[3] It is the third commonest cause of death in Western industrialized countries.[4] The current prevalence of stroke in Nigeria is 1.14 per 1,000 while the 30-day case fatality rate is as high as 40%.[5]

Several risk factors for stroke have been identified, which are the target of both primary and secondary preventive strategies,[3] the risk factors include hypertension, diabetes mellitus, cardiac diseases, obesity, hypercholesterolemia, hypertriglyceridemia, sickle cell anemia, and cigarette smoking. Other emerging risk factors include low serum levels of zinc and vitamin B12 and hyperhomocysteinemia.

Homocysteine is derived from methionine by demethylation. It can also be metabolized to cysteine by transsulfuration, or remethylated using betaine or methyltetrahydrofolate. Thus, elevated plasma homocysteine can be due to deficiencies of vitamin B12, B6, or folate. High plasma homocysteine concentrations confer increased cardiovascular risk. Concentration of homocysteine increases with age, impaired renal function, hypothyroidism, and drugs like theophylline, levodopa, and methotrexate.

There has been an increasing evidence of the association between high levels of serum homocysteine concentration (hyperhomocysteinemia), homocystinuria, and cardiovascular diseases. Even mild to moderate cases of hyperhomocysteinemia or homocystinuria, there is significant increase in the risk of cardiovascular disease. Elevated plasma levels of homocysteine can be due to deficiencies of vitamins B12, B6, and folate. The role of vitamin B12 deficiency in hyperhomocysteinemia and the promotion of atherosclerosis is only recently being explored.[6] Undiagnosed vitamin B12 deficiency subjects are 2.6 times as likely to suffer a stroke.[7]

Zinc is one of the most abundant trace elements in the body, second only to iron, it mediates several vital physiological functions and is essential for maintaining a healthy immune system, and meeting metabolic demands. However, whether zinc exerts neuroprotective or neurotoxic effects during cerebral ischemia is still unclear.[8] Low serum zinc concentrations are associated with more severe strokes on admission.[8] Preclinical studies have extensively evaluated the role of zinc in cerebral ischemia and it is still unclear whether zinc is neurotoxic, neuroprotective, or both. As such, zinc, which is able to function both as a signaling mediator and neurotoxin, has been implicated in cerebral ischemia. While zinc was first supported to have a role in cerebral ischemia nearly 20 years ago, our understanding of how zinc mediates ischemic injury is still in its relative infancy.


  Patients and Methods Top


Patients

The study population was made of 100 ischemic stroke patients confirmed by brain CT-scan admitted in Ahmadu Bello University Teaching Hospital Zaria and 100 apparently healthy age and sex matched control. Serum homocysteine, vitamin B12, and zinc were measured in both cases and controls. All the patients were newly admitted and blood specimen taken within 72 hours of developing stroke. Diagnosis of acute ischemic stroke was made clinically, confirmed by CT-scan and Siriraj stroke score below -1. Informed consent for the study was obtained from all participants or their caregivers where the patients were unconscious or were not in a state to decide for themselves. All patients were not on any medication that would affect homocysteine levels, those with renal insufficiency, thyroid disease, leukemia, or psoriasis were also excluded from the study.

Approval was obtained from Ethical and Scientific committee of ABUTH Zaria before embarking on the study.

Methods

Fasting blood samples were obtained from the antecubital fossa of each subject after disinfecting it with methylated spirit and allowed to dry. A tourniquet was applied 10 cm above the cubital fossa 5 ml syringe and a 21 g needle was used to draw blood from anterior cubital vein. The blood was transferred into a plain bottle and allowed to stand for about 30 minutes for it to clot and retract. This was then centrifuged for 5 minutes at 10000 rpm. The serum was separated from the cells and transferred into plain (sample) bottles and then frozen at -20°C until the time for analysis. Serum homocysteine and vitamin B12 concentrations were measured using commercial enzyme-linked immunosorbent assay kits while zinc concentration was measured by colorimetric method.

Data was analyzed using SPSS 20.0. Serum homocysteine vitamin B12 and zinc categorical data was summarized as frequencies and percentages while continuous data were summarized as mean and standard deviation (SD). Student's t-test was used to analyze continuous normally distributed variables. P values less than 0.05 were considered significant.

Chemicals and equipment

The chemicals and kits used for measurements of serum homocysteine, vitamin B12, and zinc were procured from Wkea Medical Supplies Corporation, Changchum China, Diagonostic Automation/Cortez Diagnostics USA, and Labkit, Chemlex S.A. Barcelona Spain, respectively.

Hettich Universal 32 centrifuge (Germany) was used to spin the blood specimen. Manufactured by DJB Labcare Ltd 20, Howard Way Interchange Business Park, Newport Pagnell, Buckinghamshire, MK16 9QS, England.

Beckman Coulter DU-20 general purpose ultraviolent/visible spectrophotometer was used for measuring absorbance of zinc. Manufactured by Beckman Coulter South Africa Pty Ltd.

Bio Rad PR-5100, Vamed Engineering Nigeria Limited, L10000-ZR-002, Micro plate reader.

Quality control

Quality control material was obtained from pooled sera for homocysteine and vitamin B12. Commercially prepared quality control materials (normal and pathological) bought from labkit chemlex sa. pol. ind. spain were used for Zinc. All assays were done in duplicates. Coefficient of variation was calculated from mean and SD obtained as shown below:

  • Serum homocysteine intra assay: SD-0.1, CV-6.75%, and inter assay SD-0.03, CV-1.59%
  • Serum vitamin B12 intra assay: SD-17.6, CV-3.6%, and inter assay SD 46.7, CV-10.6%
  • Serum zinc intra assay: SD-4.6, CV-2.27%, and inter assay SD 0.9, CV-0.45%.



  Results Top


The mean age ± SD of the patients and controls were similar 59 ± 14.08 vs 59 ± 14.09 years respectively (P > 0.05), the male:female ratio was 1.6:1 in both stroke patients and controls. Ninety one per cent of the patients had hypertension while 8% had diabetes mellitus and 1% had sickle cell anemia. Both systolic and diastolic blood pressures were significantly higher among the cases (156 ± 32 mmHg vs 120 ± 20 mmHg) and controls (94 ± 20 mmHg vs 76 ± 7 mmHg) respectively (P < 0.0001) see [Table 1].
Table 1: Clinical and demographic characteristics of study population

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Pattern of serum homocysteine, vitamin B12, and zinc concentrations of patients and controls were shown in [Table 2]. Stroke patients had higher serum homocysteine and lower vitamin B12, and zinc levels than the corresponding controls (P < 0.05).
Table 2: Comparison of admission homocysteine, vitamin B12 and zinc (mean±SD) based on different modifying risk factors

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History of hypertension, age, and sex had no influence on serum concentrations of homocysteine, vitamin B12 and zinc among the stroke patients; however, the mean serum homocysteine levels of diabetic stroke patients was significantly higher than that of non-diabetic stroke patients (P = 0.024) as shown in [Table 2].

Fifteen per cent of the patients had severe stroke and majority (74%) had moderate stroke. Serum levels of homocysteine, vitamin B12, and zinc were similar in patients with mild, moderate, and severe strokes (P > 0.05) see [Table 3].
Table 3: Admission serum homocysteine vitamin B12 and zinc (mean±SD) based on stroke severity

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  Discussion Top


Prevalence of stroke increases with age worldwide. Various studies in Nigeria reported mean age of cerebrovascular accident (CVA) of above 55 years. The mean age of 59 years in this study was similar 60.58 years as reported in Benin,[9] 56.4 years in Maiduguri.[10] and 58.8 years in Borno.[11] More males were affected in this study, with male female ratio of 1.6:1. This agrees with the findings of 1.65:1 in Maiduguri,[10] 1.3:1 in Benin and Lagos,[12] and 1.3:1 in Sokoto.[13] The most likely explanation for this is that women had higher high density lipoprotein cholesterol than males and therefore less likely to develop atherosclerosis. Also, the male – female ratio of hypertension among diabetic Africans was 1.68:1.[14] This agrees with our findings above.

Present studies showed predominance of hypertension as a major risk factor for CVA which is similar to what was reported by other studies.[10],[11],[12]

Present study demonstrated an association between raised plasma homocysteine and acute ischemic stroke. Similar results were obtained by Alkali et. al. in Maiguduri.[11] Hyperhomocystinaemia observed in patients in this study is a well documented risk factor for artherosclerosis and CVA and may be as a result of hypovitaminosis B12. In addition to nutritional factors, genetic variability may be another important determinant of plasma homocysteine levels. Thus, variability in the prevalence of genetic mutations of the enzyme methylene tetrahydrofolate reductase and varied practices between countries regarding fortification of dietary flour with folic acid and dietary intake of vitamin B12 could explain the hyperhomocysteinemia. In this study, we found that the means of serum vitamin B12 in cases was significantly lower than that of their age-matched controls from the same population, this is in agreement to the findings in Iran where homocysteine was higher among stroke patients and also in contrast to the same study where vitamin B12 was comparatively similar among the cases and controls.[13] This can be explained by the fact that vitamin B12 is more adequate among the Iranian general population than Nigeria.[15]

This study demonstrated an association between low zinc levels and stroke,[8] reported similar findings in Michigan among the 224 stroke patients he analyzed. Preclinical studies have extensively evaluated the role of zinc in cerebral ischemia, though the mechanism is still unclear,[16] but he suggested that low zinc levels may be in fact a risk factor for stroke.

The current study demonstrated similar levels of plasma homocysteine, vitamin B12, and zinc among both males and females patients with CVA. This is contrary to the findings of Nura et al.[11] in Maiduguri who reported higher homocysteine among the male patients than females. Better socioeconomic status in north-west Nigeria compare with north east may be responsible for that. Probably dietary vitamin B12 status was higher in north-western Nigeria.

The present study reported that homocysteine, zinc, and vitamin B12 in the acute phase of stroke were not associated with stroke severity; this agrees with Archittbhatt et al.[8], Perini et al.[17], and Haapaniemi, et al.[18] was the first to relate zinc with severity of stroke.


  Conclusion Top


We can conclude that elevated serum homocysteine level, low serum vitamin B12, and zinc might be an independent risk factor for ischemic stroke. However, because this study was a case control one, we could not rule out the possibility of acute phase response being responsible for the elevation of serum Hcy level in acute stroke patients. More prospective and population based studies are needed to define whether elevated homocysteine level, low vitamin B12, and zinc is an independent risk factor for cerebrovascular diseases or stroke by itself or the reverse. Early management of hyperhomocysteinemia, low vitamin B12, and zinc may be an effective way of decreasing the incidence of stroke in our environment. Vitamin B12 and zinc supplements may be beneficial to the patients at risk.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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Amu E, Ogunrin O, Danesi M. Re-appraisal of risk factors for stroke in Nigerian Africans-A prospective case-control study. African Journal of Neurological Sciences 2005;24:20-7.  Back to cited text no. 9
    
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Ducorps M, Bauduceau B, Mayaudon H, Sonnet E, Groussin L, Castagne C. Prévalence de l'hypertensionartérielledansune population de diabétiquesafricains. Arch Mal Coeur Vaiss 1996;89:1069-73.  Back to cited text no. 14
    
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Munshi A, Babu S, Kaul S, Shafi G, Rajeshwar K, Alladi S, et al. Depletion of serum zinc in ischemic stroke patients. Methods Find Exp Clin Pharmacol 2009;32:433-6.  Back to cited text no. 16
    
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Perini F, Galloni E, Bolgan I, Bader G, Ruffini R, Arzenton E, et al. Elevated plasma homocysteine in acute stroke was not associated with severity and outcome: Stronger association with small artery disease. Neurol Sci 2005;26:310-8.  Back to cited text no. 17
    
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    Tables

  [Table 1], [Table 2], [Table 3]



 

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