Synergistic effect of apolipoprotein E polymorphisms and cigarette smoking on risk of ischemic stroke in young adults.

BACKGROUND AND PURPOSE: The effect of apolipoprotein E (APOE) polymorphisms on stroke risk may be influenced by the coexistence of modifiable predisposing conditions. We explored the interactions of APOE genotypes and conventional risk factors in a case-control study of young adults with cerebral infarct. METHODS: We analyzed 124 consecutive patients (age, 34.7+/-7.3 years) and 147 age- and sex-matched controls. APOE genotypes were determined by restriction fragment-length polymorphism analysis. RESULTS: The prevalence of the epsilon4 allele and epsilon34 genotype was slightly higher in cases than in controls (0.125 versus 0.071 and 0.242 versus 0.136, respectively). Carriers of the epsilon34 genotype and epsilon4 allele were associated with an increased risk of stroke on multivariate analysis compared with the epsilon33 genotype and non-epsilon4 carriers, respectively (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.10 to 4.76; and OR, 2.27; 95% CI, 1.13 to 4.56). ORs for stroke were 2.99 (95% CI, 1.64 to 5.45), 2.69 (95% CI, 1.25 to 5.77), and 5.39 (95% CI, 1.59 to 18.30) for smokers with the epsilon33 genotype, nonsmokers with the epsilon34 genotype, and smokers with the epsilon34 genotype, respectively, compared with nonsmokers with the epsilon33 genotype. Similar results were obtained when epsilon4 carriers and non-epsilon4 carriers were compared in the same interaction model. No significant interaction between APOE and hypertension was found. CONCLUSIONS: In young adults, the APOE epsilon4 allele and cigarette smoking act synergistically, increasing an individual's propensity to have a cerebral ischemic event. This finding may help in determining an individual's predisposition to stroke and more targeted preventive interventions.

Inherited thrombophilic disorders in young adults with ischemic stroke and patent foramen ovale.

BACKGROUND AND PURPOSE: The pathogenic link between patent foramen ovale (PFO) and stroke remains unknown in most cases. We investigated the association between inherited thrombophilic disorders and PFO-related strokes in a series of young adults in the setting of a case-control study. METHODS: We investigated 125 consecutive subjects (age, 34.7+/-7.3 years) with ischemic stroke and 149 age- and sex-matched control subjects. PFO was assessed in all patients with transcranial Doppler sonography with intravenous injection of agitated saline according to a standardized protocol. Genetic analyses for the factor V (FV)(G1691A) mutation, the prothrombin (PT)(G20210A) variant, and the TT677 genotype of methylenetetrahydrofolate reductase (MTHFR) were performed in all subjects. RESULTS: A pathogenic role of PFO was presumed in 36 patients (PFO+). Interatrial right-to-left shunt either was not detected or was considered unrelated to stroke occurrence in the remaining 89 patients (PFO-). The PT(G20210A) variant was more frequent in the PFO+ group compared with control subjects and the PFO- group (PFO+ versus control subjects, 11% versus 2%; 95% CI, 0.04 to 0.94; PFO+ versus PFO-, 11% versus 1.1%; 95% CI, 1.09 to 109; P=0.047). A similar distribution was observed for subjects carrying either the PT(G20210A) variant or the FV(G1691A) mutation (PFO+ versus control subjects, 19.4% versus 5.3%; 95% CI, 0.08 to 0.75; PFO+ versus PFO-, 19.4% versus 3.3%; 95% CI, 1.45 to 26.1; P=0.021). Combined thrombophilic defects were observed in 3 subjects of the PFO+ group, in 2 control subjects (8.3% versus 1.3%; 95% CI, 0.01 to 0.66; P=0.015), and in 0 subjects in the PFO- group. A trend toward a difference in the frequency of the FV(G1691A) mutation between PFO+ and control subjects was found after bivariate analysis (11% versus 3.3%; P=0.068) but not after multinomial logistic regression analysis. No significant association was found in the distribution of the TT MTHFR genotype in the 3 groups. CONCLUSIONS: In young adults, the PT(G20210A) variant and, to a lesser extent, the FV(G1691A) mutation may represent risk factors for PFO-related cerebral infarcts. A role of systemic thrombophilic disorders in the pathogenesis of this specific subtype of stroke may be hypothesized.

Jugular valve incompetence: a study using air contrast ultrasonography on a general population.

OBJECTIVE: Internal jugular valves are the only venous valves between the heart and the brain. Conditions such as coughing and other precipitating activities may result in retrograde cerebral venous flow because of the absence or presence of internal jugular valve incompetence, allowing brief transmission of high venous pressure and resulting in brain disturbance. Knowledge of these valves and their noninvasive evaluation might be useful in clinical practice. METHODS: We applied air contrast ultrasonographic venography to a large sample of healthy subjects (n = 125) to evaluate the ultrasonographic aspects of internal jugular valves and their competence. RESULTS: The valves were observed in 121 (96.8%) of 125 subjects and were present bilaterally in 107 (85.6%) and unilaterally in 14 (11.2%). In 4 subjects we did not detect the valves. Retrograde venous flow was present in 48 (38.4%) of 125 subjects. The frequency of internal jugular valve incompetence was significantly higher on the right side (36 [30.2%] of 119) than on the left (7 [6.4%] of 109; P < .0001). Retrograde venous flow due to incompetence of jugular valves was significantly more frequent at older ages (<50 years, 20%; and > or =50 years, 38.75%; P < .03) and was more frequent in men (33 [25%] of 132) than in women (10 [10.41%] of 96; P < .02). CONCLUSIONS: Air contrast ultrasonographic venography is a noninvasive method for evaluating internal jugular valves and identifying retrograde venous flow. This information may be useful in clinical and interventional care.