Reference intervals for plasma homocysteine by the AxSYM immunoassay after collection in fluoride tubes

Relationship between homocysteine levels and post-stroke cognitive impairment in female and male population: from a prospective multicenter study

Background and Objectives:

To investigate the relationship between homocysteine levels and post-stroke cognitive impairment (PSCI) in Chinese female and male populations with minor acute ischemic stroke or transient ischemic attack.

Materials and methods:

A total of 1070 participants with clinically confirmed acute minor ischemic stroke or transient ischemic attack and baseline homocysteine information from a nationwide multicenter prospective registry study in China were included in this study. Of these, 919 patients had cognitive assessments at 3-month follow-ups and 584 participants had cognitive assessments at 12-month follow-ups. The incidence of PSCI was defined as a Montreal Cognitive Assessment score ≤22. The differences in homocysteine levels and the incidence of PSCI were compared between female and male populations. Relationships between homocysteine levels and the incidence of PSCI in female and male populations were analyzed using multiple logistic regression, respectively.

Results:

Females had lower baseline homocysteine levels than males. Compared to males, females had lower education levels, lower rates of smoking and alcohol intake, and higher rates of diabetes and hypertension. No relationship was observed between elevated homocysteine level and 3-month PSCI incidence in either females or males. After adjusting the confounders, elevated baseline homocysteine significantly increased the 12-month PSCI risk (odds ratio 3.28, 95% confidence interval 1.47–7.34, P = 0.004) in females, but not in males (odds ratio 0.86, 95% confidence interval 0.49–1.49, P = 0.586).

Conclusion:

Elevated homocysteine levels increased the 12-month PSCI risk in females, but not in males with minor acute ischemic stroke or transient ischemic attack.

Homocysteine and cognition: A systematic review of 111 studies

BACKGROUND

Elevated plasma homocysteine ​​(Hcy) levels have been associated with cognitive dysfunction in a wide range of conditions. The aim of this review is to establish which cognitive domains and populations are the most affected.

METHODS

We systematically review the literature and consider all articles that showed any relationship between plasma Hcy levels and scores achieved on cognitive performance tests in both, the general population and patients suffering from central nervous system disorders and other diseases. When effect sizes were available and combinable, several meta-analyses were performed.

RESULTS

We found 111 pertinent articles. There were 24 cohort studies, 18 randomized trials, 21 case-control studies, and 48 cross-sectional studies. This review reveals a positive trend between cognitive decline and increased plasma Hcy concentrations in general population and in patients with cognitive impairments. Results from the meta-analyses also confirm this trend. Treatment with vitamin supplementation fails to show a reduction in cognitive decline.

DISCUSSION

Further investigations are warranted to clarify this relationship. Earlier detection of the elevated Hcy levels may be an effective intervention to prevent cognitive impairment and dementia.

Elevated second trimester serum homocysteine levels in women with gestational diabetes mellitus

OBJECTIVE

Our aim was to investigate the association between total serum homocysteine, vitamin B12 and folate levels in pregnant women with gestational diabetes mellitus (GDM), glucose intolerance and compare them with those of glucose tolerant pregnant women.

MATERIALS AND METHODS

Serum homocysteine, vitamin B12 and serum folate levels were prospectively measured in a total of 223 pregnant women who were grouped according to their status of glucose tolerance as gestational diabetes (abnormal 1-h and 3-h glucose tolerance test; n = 30), glucose intolerant (abnormal 1-h, but normal 3-h glucose tolerance test; n = 46) or normal controls (normal 1-h glucose test; n = 147).

RESULTS

Mean serum homocysteine concentration of women in gestational diabetes, glucose intolerants and normal controls at 24-28 weeks of gestation was 9.0 +/- 3.1, 8.1 +/- 2.5 and 7.4 +/- 1.6 micromol/l, respectively. The only statistically difference in homocysteine levels was observed between women with gestational diabetes and normal controls (P < 0.01). However, no difference was observed for vitamin B12 and folate levels.

CONCLUSION

Second trimester serum homocysteine concentrations are higher among women with GDM, as compared to normal controls.

Analytical and clinical evaluation of the Bayer ADVIA Centaur homocysteine assay

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in the United States. Elevations in homocysteine (Hcy) have been associated with increased risk of acute coronary syndrome, stroke and peripheral vascular disease. Increased utilization of Hcy as a risk marker has prompted the need for high throughput methods that are simple to use and analytically accurate and precise.

METHODS

We report the performance characteristics of the automated Bayer ADVIA Centaur chemiluminescent Hcy assay. Centaur Hcy is based on a three-step procedure: (1) reduction of Hcy disulfides to free Hcy, (2) enzymatic conversion of free Hcy to S-adenosyl Hcy (SAH) and (3) quantitation of SAH in a competitive immunoassay (labeled anti-SAH antibody: magnetic particles coupled with SAH).

RESULTS

Total assay precision ranged from 3.5% to 6.8% at 4.9-62 micromol/Hcy; linearity undiluted from 0 to 65 micromol/l, up to 650 micromol/l with automatic dilution. Method comparisons with fluorescent polarization immunoassay and high-performance liquid chromatography (HPLC) gave linear regression equations with slopes between 0.95 and 1.0. Measurement of Hcy concentrations in apparently healthy populations yielded middle 95th percentile of 9.7 micromol/l, consistent with epidemiologic studies suggesting that 9-10 micromol/l represents the lower threshold of a population at risk of CVD.

CONCLUSIONS

The Centaur Hcy assay is a sensitive and precise assay for the measurement of Hcy.