Fractions of Total Plasma Homocysteine in Patients with Ischemic Stroke Before the Age of 55 Years

Hyperhomocysteinemia independently associated with the risk of hypertension: a cross-sectional study from rural China

This study was designed to investigate the current prevalence of hyperhomocysteinemia (Hhcy) and its association with hypertension in rural adults of Northeast China. A cross-sectional study was performed in subjects aged⩾35 years in a general Chinese population. Demographic data, laboratory examination of traditional cardiovascular risk factors and self-reported information on lifestyle factors, such as physical activities, current smoking and drinking status, dietary habits and familial factors were collected by trained personnel. A total of 7130 participants (3317 men and 3813 women) were included in this study and the mean Hhcy level of the whole population was 17.39±12.34 mmol l(-1), which was 20.99±14.83 mmol l(-1) in males and 14.19±8.51 mmol l(-1) in females, respectively. Prevalence of Hhcy in total population was 41.3%. Stratified by gender, the prevalence of Hhcy was higher in males than in females (59.0 vs 25.8%, P<0.05). After adjustment for conventional risk factors including age, salt intake, smoking, body mass index, diabetes, dyslipidemia, activity time and family history, multiple logistic regression analysis showed that Hhcy was independently associated with the risk of hypertension in males (odds ratio (OR)=1.501, 95% confidence interval (CI): 1.012-2.227; P<0.001), but not in females in this population (OR=1.182; 95% CI, 0.993-1.407; P=0.060). In conclusion, a high prevalence of Hhcy in the general adult population of rural northeast China was detected and Hhcy may be a risk factor for hypertension, particularly in males.

Interaction of homocysteine and conventional predisposing factors on risk of ischaemic stroke in young people: consistency in phenotype-disease analysis and genotype-disease analysis

BACKGROUND AND OBJECTIVES

Whether the association between mild hyperhomocysteinaemia and ischaemic stroke is the consequence of a predisposing genetic background or is due to the confounding influence of established predisposing factors remains to be determined.

METHODS

Plasma total homocysteine (tHcy) concentration and the distribution of the C677T genotypes of the methylenetetrahydrofolate reductase gene (MTHFR) were compared in 174 consecutive patients with stroke aged <45 years and 155 age and sex-matched controls. The effect of conventional risk factors on the relationship between phenotype-disease and genotype-disease was analysed by two-way and three-way interaction analysis and by the classification and regression trees (CART) model.

RESULTS

tHcy concentrations were markedly higher in patients with ischaemic stroke (median 11.9 micromol/l, range 2.0-94.0) than in controls (median 9.8 micromol/l, range 4.7-49.6). An increased risk was also associated with the TT677 genotype (odds ratio (OR) 1.98; 95% confidence interval (CI) 1.04 to 3.78) and with the T allele (1.40; 95% 1.03 to 1.92) of the MTHFR gene. A differential effect of Hcy levels on risk of stroke was observed according to the distribution of environmental-behavioural risk factors, with a stronger influence in the subcategory of people with hypertension and smokers (OR 24.8; 95% CI 3.15 to 196). A comparable environmental-dependent TT677 MTHFR genotype-stroke association was observed in the genotype-disease analysis.

CONCLUSIONS

A consistency of phenotype-disease analysis and genotype-disease analysis is indicated by analysing specific subcategories of patients, defined by the distribution of established risk factors. The assumption that the Hcy-stroke relationship is unlikely due to a reverse-causality bias is indirectly supported by our data.