This prospective case–control study included 199 consecutive patients with saccular intracranial aneurysms (SIA) (103 females and 96 males, mean age: 43.2 years) and 194 control subjects–blood donors at the regional blood transfusion center (86 females, 108 males, mean age: 38.4 years). This was the maximal number that could be achieved. No formal power calculation was done. Clinical characteristics of patients with SIA and controls are presented in Table . We consecutively recruited patients with SIA admitted to our regional neurosurgical center and control subject from 2003 to 2006. Aneurysms were verified by conventional cerebral angiography. 36 (18.1%) patients had multiple aneurysms. 22 patients (11%) had unruptured aneurysms. 177 patients (89%) had subarachnoid heamorrhages. 190 patients were operated of whom 177 had clipping and 13 coiling.
Clinical characteristics of patients with SIA and controls
Inclusion criteria for patients with SIA:
1. The patient had at least one saccular intracranial aneurysm confirmed by cerebral angiography
2. The patient lived in Yekaterinburg or in the Urals region.
3. The patient agreed to conduct additional examinations.
Exclusion criteria for patients with SIA
1. The patient had fusiform, traumatic or mycotic aneurysm.
2. Patients who were unable to give a coherent headache history.
3. The patient had contraindications to additional methods of investigation.
4. The patient refused further examination.
Inclusion criteria for the control group:
1. The patient had no history of stroke, intracranial haemorrhage or other serious neurological and somatic disease, or hereditary connective tissue diseases.
2. The patient had no first degree relatives with intracranial aneurysms, or inherited connective tissue diseases.
3. The patient’s age and sex were matched to patients with SIA.
4. The patient agreed to additional examinations.
We did not perform MR-angiography in control patients since the frequency of aneurysms in the adult population without specific risk factors is only 2-3% [15
All patients and controls were examined using a specially designed semistructured interview which included detailed information about the history of present and past diseases and the history of their pedigree, results of physical and neurological examinations, physician consultations and treatment. The semistructured interview contained detailed questions about present and past headache disorders allowing diagnosing headaches according to the International Classification of Headache Disorders [14
]. The interviews were all performed by the first author (ERL) during examination of patients with SIA at regional neurosurgical center after diagnosis of SIA and before surgical treatment. We asked patients with SIA and controls about headaches during their lifetime and about characteristics of headaches during 1 year before diagnosis of SIA or 1 year before interview in controls. Hypertension was defined as a history of high blood pressure (systolic values ≥140 mm Hg and/or diastolic pressure ≥90 mm Hg) or, if physician observed blood pressure of 140/90 mmHg or above on three consecutive measurements at least six hours apart. Systemic connective tissue dysplasia (CTD) was defined if patient had 3 or more visible markers of connective tissue dysplasia [16
]. Smoking was categorized as follows: never smoked, former (regular) cigarette smokers, and current cigarette smoker. Current cigarette smokers were defined as people who reported having smoked ≥100 cigarettes during their lifetime and who still smoked. We also asked about alcohol drinks, how many times per week and quantity in milliliters. Body mass index (BMI) was calculated as the weight in kilograms divided by height in meters squared. 194 patients with SIA (100 females and 94 males) and in 193 age- and sex-matched control patients were asked about occurrence of stroke, SIA, headache and some other disorders in their first degree relatives.
The Medical Ethics Committee of the Urals State Medical Academy approved this study. Informed consent was obtained from all participants.
The differences in mean values or frequencies between patients with SIA and controls were statistically examined by an unpaired t-test and chi-square test. Odds ratio (OR) and 95% confidence interval (CI) were estimated using multiple conditional logistic regression models.