Distribution of plasma total homocysteine concentrations in the healthy Iranians

doi:10.1016/j.clinbiochem.2003.10.005

Clinical Biochemistry

Volume 37, Issue 2, February 2004, Pages 149-151

https://doi.org/10.1016/j.clinbiochem.2003.10.005 Get rights and content

Abstract

Objective: The distribution of plasma total homocysteine concentrations in a population of South West of Iran Shiraz is described to test for differences in homocysteine concentrations among gender and age groups and those levels reported in other populations.

Design and methods: Two hundred one healthy males and 201 healthy females aged >15 years from Shiraz, Iran, were randomly selected. Plasma total homocysteine concentrations were measured using high-performance liquid chromatography.

Results: The mean plasma homocysteine level was significantly higher in men (geometric mean, 7.3μmol/l) than in women (geometric mean, 6.3μmol/l, P < 0.001). The geometric mean levels for ages 15–25, 26–36, 37–47, and 48–58, 59–69, and 70–80 years, were 5.9, 5.4, 5.2, 6.7, 7.3, and 7.6 μmol/l in women and 7.5, 8.7, 5.9, 5.9,7.2, and 9.1 μmol/l in men, respectively.

Conclusions: The homocysteine distribution in a representative sample of people of southwest of Iran indicates age and gender differences, as is found in other populations.

Introduction

It is now well documented that elevation of total circulating homocysteine concentrations in a fasting state is associated with an increased risk of cardiovascular disease [1].

Factors such as age, gender, racial and ethnic differences, geographical variations, genetic, dietary, and other life style have showed to be determinants of plasma homocysteine concentrations. Total plasma homocysteine levels are higher in men than in women and at older ages [2], [3], and elevated fasting homocysteine concentrations are associated with lower circulating concentrations and intakes of folate and vitamin B12 [4]. From the studies in different populations around the world, it is now believed that metabolism of homocysteine may be race–ethnic dependent [5].

Although the distribution of plasma concentrations of homocysteine has been reported in some populations of America and Europe, there is little or no available information describing homocysteine concentrations in the healthy Iranians and relating gender and age to circulating homocysteine concentrations. In the present study, total homocysteine concentrations were measured in plasma from 402 healthy Iranians in Shiraz, South West of Iran. This study provides the first opportunity to describe distribution of total homocysteine concentrations in a sample of healthy Iranians.

Section snippets

Subjects and methods

Four hundred two persons (201 men and 201 women; age, 15–80 years old; mean, 67.3 ± 8.5 years) were selected from population-based group in all regions of Shiraz. From the telephone directory, the first three digits that represent an area in Shiraz region, 700 people were phoned for interview and sampling, 174 were not interested, and 124 did not meet the inclusion criteria. Thus, a total of 402 subjects were studied. Exclusion criteria for male and female participants include cardiomyopathy,

Results

Mean, geometric mean, 95% confidence intervals, ranges, and percentiles of plasma homocysteine level of all 402 samples of females and males are shown in Table 1. The mean plasma homocysteine level was significantly higher in men than in women (P < 0.001).

The overall geometric mean levels in both males and females for ages 15–25, 26–36, 37–47, and 48–58, 59–69, and 70–80 years were 6.7, 7.1, 5.6, 6.3, 7.3, and 8.4 μmol/l, respectively. Mean, geometric mean, 95% confidence intervals, and ranges

Discussion

This study presents the first reference information on total homocysteine concentrations in an Iranian population. Our results showed that total homocysteine concentrations increased across age groups and were higher in males than in females. The age and sex differences in total plasma homocysteine levels observed in this study are consistent with observations from published studies in large and small sample size of adult men and women in some reported populations [7], [8]. In this study total

Acknowledgements

We thank the Office of the Vice Chancellor for Research Affairs, Shiraz University of Medical Sciences for supporting this work under grant No. 79-1130.

References (10)

A.B. Guttormsen et al.
Kinetic basis of hyper homocysteinemia in patients with chronic renal failure
Kidney Int.
(1997)
O. Nygard et al.
Coffee consumption and plasma total homocysteine. The Hordaland homocysteine study
Am. J. Clin. Nutr.
(1997)
D.S. Wald et al.
Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis
BMJ
(2002)
J. Selhub et al.
Vitamin status and intake as primary determinants of homocysteinemia in the elderly
JAMA
(1993)
O. Nygard et al.
Plasma homocysteine and cardiovascular risk profile. The Hordaland homocysteine study
JAMA
(1995)

There are more references available in the full text version of this article.

Cited by (17)

Determinants of hyperhomocysteinemia in healthy and hypertensive subjects: A population-based study and systematic review
2017, Clinical Nutrition
Citation Excerpt :
The main characteristics of the included studies are shown in Tables 3 and 4. Subjects were ethnically diverse, and the studies were conducted in North America [23–28], Europe [8,29–62], Asia [9,63–87], Africa [88,89], and Australia [90]. The correlates of Hcy were shown in Table 4.
Hyperhomocysteinemia (HHcy) is known to increase the risk of many diseases. Factors influencing HHcy in healthy and hypertensive subjects remain under-researched.
A large population-based study was conducted in 60 communities from Shenzhen, China. Responses to standardized questions on lifestyle factors and blood samples were collected from all participants after a 12-h overnight fast. Multiple linear and multivariate logistic regressions were used to explore risk factors for HHcy. Results were then compared to those from a systematic review of English-language articles listed in Pubmed, EBSCOhost, Web of Science, Embase and Cochrane libraries that investigated HHcy risk factors in healthy and hypertensive subjects.
A total of 1586 healthy (Male/Female = 642/944) and 5935 hypertensive subjects (Male/Female = 2928/3007) participated in our population-based study. In logistic regression analyses, age, BMI and creatinine (Cr) were risk factors, while being female, fruit intake and physical activity were protective factors for HHcy in healthy subjects. In hypertensive subjects, seven [age, smoking, salt intake, systolic blood pressure (SBP), uric acid, triglycerides (TG), and Cr] and four [female, fruit intake, total cholesterol (TC), and glucose] factors were associated with higher and lower HHcy respectively. The review of 71 studies revealed that potential risk factors for Hcy included nutritional, physiologic, lifestyle habits, ethnicity, genetics, interactions between gene–environment, gene–gene, gene–nutritional, environment–environment, nutritional–nutritional.
Our study indicates the potential importance of increasing folic acid and vitamin B supplementation, daily fruit and vegetable intake, regular exercise and refraining from tobacco smoking and alcohol consumption as preventive strategies for Hcy.
Association between the MTHFR C677T polymorphism, blood folate and vitamin B12 deficiency, and elevated serum total homocysteine in healthy individuals in Yunnan Province, China
2017, Journal of the Chinese Medical Association
Citation Excerpt :
Thus, dietary folate deficiency and drugs that interfere with folate metabolism may lead to Hcy accumulation and the consequent cellular efflux of Hcy.36 In our study, the mean serum tHcy concentration was notably higher than previously reported concentrations.37–41 We speculate that this difference may have resulted from the unique cooking and dietary habits among people in Yunnan Province.
An increased serum total homocysteine (tHcy) concentration is typically associated with genetic defects involved in Hcy metabolism or related nutritional deficiencies. In this study, the combined effects of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and folate and vitamin B12 deficiency on serum total Hcy (tHcy) levels were evaluated in a healthy Chinese population in Yunnan Province, China.
The MTHFR C677T polymorphism was genotyped in 330 volunteers (164 men and 166 women) using polymerase chain reaction-restriction fragment length polymorphism analysis. Folate, vitamin B12, and tHcy concentrations were determined by corpuscle immune chemiluminescence assays. The tHcy concentration was determined using an enzymatic assay.
Significant negative correlations (p < 0.001) were observed between the serum levels of tHcy and folate (r = −0.252) and vitamin B12 (r = −0.243). Men had significantly higher serum tHcy concentrations than women (p < 0.001). Individuals with the MTHFR TT genotype had significantly higher serum tHcy concentrations than individuals with the CC and CT genotypes (p < 0.001). The folate level of red blood cells was significantly increased in individuals with the TT genotype than in individuals with the CC genotype (p < 0.05). Moreover, in the low vitamin group, the serum tHcy level was significantly correlated with the levels of folate (r = −0.334, p = 0.001) and vitamin B12 (r = −0.212, p = 0.046).
The MTHFR C677T polymorphism, folate deficiency, and B12 deficiency were significantly associated with elevated serum tHcy levels. Among these three factors, folate deficiency had the greatest contribution to the serum tHcy concentration, followed by (in order of decreasing effect) MTHFR C677T and vitamin B12 deficiency. Thus, folic acid and vitamin B12 supplementation could help prevent diseases associated with tHcy accumulation, especially in individuals with the MTHFR 677TT genotype.
Clinical risk factors and association of hyperhomocysteinemia with diabetic retinopathy in Iranian type 2 diabetes patients. A cross-sectional study from Shiraz, Southern Iran
2008, Diabetes and Metabolic Syndrome: Clinical Research and Reviews
Citation Excerpt :
Hyperhomocysteinemia was defined in males with plasma tHcy levels of >15 μmol/l and in females with plasma tHcy levels of >12. These values represent the cut-off values determined from the upper limit of the reference range of plasma tHcy in males and females determined in our laboratory [21]. Diabetic duration was defined as the duration from the first diagnosis of type 2 diabetes to the time of the blood sampling.
The identification and quantitation of factors that are associated with the risk of retinopathy in diabetic patients is essential to be identified in different populations. Data exist for the risk factors associated with the prevalence and incidence of diabetic retinopathy in our population is limited. In this study, we assessed the association of risk factors including hyperhomocysteinemia with retinopathy in Iranian patients with type 2 diabetes.
In a cross-sectional study, the association of biometric and biochemical characteristics of two hundred and fifty four established type 2 diabetic patients with or without retinopathy were investigated. Patients were classified by funduscopic examination and angiographic results into normal, non-proliferative and proliferative retinopathy.
Multiple logistic regression analysis showed that the risk of all type of retinopathy was significantly and independently associated with a longer duration of diabetes, hypertension and hyperhomocysteinemia. Subjects with hyperhomocysteinemia had more than 2.7-, 2.5-, and 2.5-fold risk of all type of retinopathy, non-proliferative and proliferative retinopathy, respectively, compared with the subjects with normal plasma tHcy when adjusted for other risk factors.
We conclude that longer duration of diabetes, hypertension and hyperhomocysteinemia are independent risk factors associated with retinopathy in type 2 diabetes in our population.
Total plasma homocysteine values among elderly subjects: Findings from the Maracaibo Aging Study
2006, Clinical Biochemistry
The present study generated baseline data for total homocysteine (tHcy) in elderly Caribbeans of Hispanic ancestry, residing in Venezuela, their country of origin.
2106 participants in the Maracaibo Aging Study (MAS), older than 55 years, underwent standardized clinical and laboratory assessments, including measurement of plasma tHcy levels, folate, and vitamin B12 in fasting samples.
tHcy concentration in the healthy, normative group ranged from 4.1 to 31.8 μmol/L, with a median of 11.5 ± 4.7 μmol/L. tHcy level increased with age, was significantly higher in men than in women, and exhibited inverse correlations with folate and vitamin B12.
tHcy levels of the MAS participants were generally higher than levels previously reported for community-dwelling elderly populations from other countries. The normative centile curves for tHcy can be used in disease risk analysis for this population, and possibly for other Hispanic populations residing in the Caribbean.
Methylenetetrahydrofolate reductase gene polymorphisms in essential hypertension: Relation with the development of hypertensive end-stage renal disease
2005, American Journal of Hypertension
The pathogenesis of hypertensive nephropathy is multifactoral and in addition to BP, other factors contribute to the development of this renal pathology and its progression to end-stage renal disease. These include genetic predisposition and increased pleasure level of homocysteine-intermediate protein catabolism product known to induce kidney injury. The 677C → T polymorphism in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene is associated with elevated homocysteine level in the general population, and therefore it has been hypothesized to be a risk factor for the development of renal failure in the course of essential hypertension.
In this case-control, cross-sectional study the frequency of the MTHFR 677C → T and the 1298A → C polymorphism was compared between patients with hypertension-related chronic renal failure (n = 90), patients with essential hypertension without kidney injury (n = 90), and healthy individuals (n = 90) who were matched for age and gender. In addition, the influence of these polymorphisms on homocysteine concentration in individuals with essential hypertension was examined.
The frequency of the MTHFR 677 TT genotype did not differ between groups (4.5%, 12.3%, and 11.1%, respectively). Patients with hypertension and the 677TT genotype showed significantly higher homocysteine levels as compared to individuals having CC and CT. In the multivariate correlation analysis the MTHFR 677TT genotype (P < .01; β = 0.27), age (P < .001; β = 0.33), and body mass index (P < .01; β = 0.3) were independent predictors for total homocysteine level.
Plasma homocysteine levels in individuals with essential hypertension is affected by the MTHFR 677C → T polymorphism. However, we did not prove the hypothesis that MTHFR 677C → T influences the risk of development of renal failure in the course of hypertension.
Folate and vitamin B<inf>12</inf> status and their relation to hematological indices in healthy adults of Iranians: Azar cohort study
2019, Nutrition and Health

View all citing articles on Scopus

View full text

Distribution of plasma total homocysteine concentrations in the healthy Iranians

Abstract

Introduction

Section snippets

Subjects and methods

Results

Discussion

Acknowledgements

Kidney Int.

Am. J. Clin. Nutr.

Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis

BMJ

Vitamin status and intake as primary determinants of homocysteinemia in the elderly

JAMA

Plasma homocysteine and cardiovascular risk profile. The Hordaland homocysteine study

JAMA