An all-Ireland epidemiological study of MND, 2004–2005

Background and methods:  We conducted an all-Ireland population-based prospective epidemiological survey of motor neurone disease (MND) using the Northern Ireland and Republic of Ireland MND registers to examine the incidence and prevalence of the disease over the period 2004–2005.
Results and conclusions:  Incidence of MND was 1.9 per 100 000 person-years and rates were comparable in both the north and south of Ireland. Prevalence of MND was 5.0 per 100 000 population. When compared with previous published surveys of MND performed in the Republic of Ireland over the last 10 years, rates of disease have remained relatively constant. When standardized to the 1990 US population, the incidence of MND in Ireland was found to be consistent with other European prospective surveys of MND.     

Morning surge in circadian periodicity of ischaemic stroke is independent of conventional risk factor status: findings from the Takashima Stroke Registry 1990–2003

Background:  We examined the circadian periodicity of ischaemic stroke (IS) onset and its relationship with conventional risk factors using 14-year stroke registration data.
Methods:  Ischaemic stroke event data were acquired from the Takashima Stroke Registry, which covers a stable population of ≈55 000 in Takashima County in central Japan. During 1990–2003 there were 637 (353 men and 284 women) cases with classifiable onset time. IS incidence was categorized as occurring at night (midnight to 6  am ), morning (6  am to noon), afternoon (noon to 6  pm ), and evening (6  pm to midnight). The OR (with 95% CI) of having an IS in the morning, afternoon, and evening were calculated, with night serving as reference.
Results:  There was significant diurnal variation in IS incidence ( P  <   0.001). The proportion of events was highest in the morning (40.7; 95% CI: 36.9–44.5), and lowest in the night (14.0; 95% CI: 11.5–16.9). In the morning an excess incidence of IS was observed in both genders, in subjects <65 years and ≥65 years, and in all IS subtypes. The morning excess of IS incidence was similar across seasons and days of the week. For all IS, morning excess was higher (odds ratio: 2.91; 95% CI: 2.29–3.70) compared to the night period. Similar trends persisted after adjusting for age, gender, and risk factors.
Conclusion:  In the examination of circadian variation of IS onset, a predominant morning peak independent of conventional risk factors was observed in a Japanese population with similar pattern across seasons of the year and days of the week.     

Incidence,risk, and case fatality of first ever stroke in the elderly population. The Rotterdam Study

OBJECTIVE: To estimate the incidence, survival, and lifetime risk of stroke in the elderly population. METHODS: The authors conducted a study in 7,721 participants from the population based Rotterdam Study who were free from stroke at baseline (1990-1993) and were followed up for stroke until 1 January 1999. Age and sex specific incidence, case fatality rates, and lifetime risks of stroke were calculated. RESULTS: Mean follow up was 6.0 years and 432 strokes occurred. The incidence rate of stroke per 1,000 person years increased with age and ranged from 1.7 (95% CI 0.4 to 6.6) in men aged 55 to 59 years to 69.8 (95% CI 22.5 to 216.6) in men aged 95 years or over. Corresponding figures for women were 1.2 (95% CI 0.3 to 4.7) and 33.1 (95% CI 17.8 to 61.6). Men and women had similar absolute lifetime risks of stroke (21% for those aged 55 years). The survival after stroke did not differ according to sex. CONCLUSIONS: Stroke incidence increases with age, also in the very old. Although the incidence rate is higher in men than in women over the entire age range, the lifetime risks were similar for both sexes.     

Epidemiological study of motor neuron disease in Hokkaido island--its incidence, prevalence and regional distributions--ALS Study Group]

The incidence, prevalence and regional distributions of sporadic motor neuron disease (MND) from 1980 through 1989 were evaluated in collaboration with multiple neurological institutes in Hokkaido island. Patients with sporadic MND were collected from three sources: 1) neurologist practicing in Hokkaido island, 2) sending inquiries to 620 major hospitals, 3) notification file of MND provided by Japanese Ministry of Welfare and Health. Three hundred and eighty-nine patients with sporadic MND were ascertained for this study. Of 389 patients, 238 patients were men and 151 patients were women, and the ratio of men to women was 1.6:1. The mean age of onset was 58.2 +/- 10.3 years old, 57.7 +/- 10.4 for men and 58.9 +/- 10.0 for women. Their clinical presentations were 303 patients with ALS, 52 patients were PBP and 34 patients were SPMA. The crude incidence rate for both sexes combined for 1980 through 1989 was estimated as 0.69 per 100,000 person-year. The age- and sex-adjusted incidence for men was 0.86 per 100,000 person-year (95% CI, 0.75 to 0.97) and that is higher than 0.53 per 100,000 person-year (95% CI, 0.45 to 0.61) for women. The average, crude prevalence rate from 1985 through 1989 was estimated as 2.25 per 100,000 person-year. There are no overall trends of changing the pattern in incidence and prevalence of MND in Hokkaido island, however the geographic distributions of the incidence of MND according to towns and cities disclosed the presence of some relative clustering areas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Smoke exposure increases the risk for multiple sclerosis

Purpose and methods:  To estimate the effect of exposure to smoking on the risk for multiple sclerosis (MS), we analyzed nicotine metabolite (cotinine) levels in biobank samples from 109 MS cases and 218 matched referents.
Results:  Elevated cotinine levels, even modest elevations, were associated with an increased risk for MS (all other categories versus lowest: OR = 2.9; 95% CI: 1.3–6.3). A similar but non-significant risk increase was observed also in the small subset of individuals with samples collected before the onset of MS (all other categories versus lowest: OR = 2.4; 95% CI: 0.26–21). Elevated cotinine was associated with an increased risk for MS predominantly in women (all other categories versus lowest category: OR = 3.9; 95% CI: 1.3–12), whereas the risk increase in men was smaller and non-significant.
Discussion:  Smoke exposure is associated with a higher risk for MS than previously estimated. There seems to be a threshold effect present in the lower range of cotinine in its relation to MS. Modestly elevated cotinine levels suggestive of passive smoking are associated with an increased risk for MS. Smoke exposure may explain the higher incidence of MS in women. These preliminary findings need to be confirmed in an expanded material of prospectively collected samples.     

A population-based study of irritable bowel syndrome in a non-Western population

Abstract  Previous studies have found no female predominance in irritable bowel syndrome (IBS) in non-Western countries. The aim of the study was to assess the prevalence and correlates of Rome II (IBS) in both sexes in Pakistan. A Population-based survey in a low-income inner city area using questionnaires to diagnose Rome II IBS and assess distress, disability and stressful life events. Data were collected from 880/938 (93%) randomly selected residents. 13.4% of women and 13.1% men met criteria for Rome II IBS; 34 (3.9%) had diarrhoea-predominant, 59 (6.7%) had constipation-predominant IBS and 24 (2.7%) had 'mixed IBS'. In logistic regression analysis, IBS was associated in men with high income (OR = 1.56; 95% CI: 1.05–2.3) and few years of education (OR = 2.17; 95% CI: 1.2–3.9) and in women with being married (OR = 3.6; 95% CI: 1.1–11.9) and stressful life events score (OR = 1.14; 95% CI: 1.01–1.3). Disability was associated with constipation-predominant IBS (OR = 1.99; 95% CI: 1.1–3.6), distress (OR = 1.19; 95% CI: 1.14–1.23) and stressful life events (OR = 1.19; 95% CI: 1.1–1.3). Investigations were more likely in men (54%) than in women (27%) ( P  = 0.003). These findings suggest that the equal sex ratio of IBS in urban Pakistan could result from a close association between marked distress and IBS in men similar to that found in women in western studies.     

No increased risk of adverse pregnancy outcomes for women with myasthenia gravis: a nationwide population-based study

Background:  This study aims to examine the risk of adverse pregnancy outcomes [low birthweight (LBW), preterm birth, cesarean sections (CS) and babies born small for gestational age (SGA)] in pregnant women with myasthenia gravis (MG), using a 3-year population-based database, taking characteristics of infant and mother into consideration.
Methods:  This study used two nationwide population-based datasets: the Taiwan National Health Insurance Research Dataset and the Taiwan birth certificate registry. We identified 163 pregnant women with MG during 2001–2003 as the study cohort and 815 randomly selected pregnant women as a comparison cohort. Conditional logistic regression analyses were performed.
Results:  The results showed that, although these patterns did not reach a statistically significant level, mothers with MG had higher percentages of LBW (6.8%, vs. 5.6%), SGA (17.8%, vs. 14.1%) and cesarean deliveries (44.8%, vs. 37.4%), except for preterm births (8.1%, vs. 8.1%). After adjusting for highest maternal education level, marital status, family monthly income and infant gender and parity, the odds ratios (OR) of LBW, preterm birth, SGA infants, and cesarean delivery for mothers with MG were 1.19 (95% CI = 0.60–2.38), 1.00 (95% CI = 0.54–1.87), 1.30 (95% CI = 0.83–2.04), and 1.33 (95% CI = 0.94–1.88), respectively, as compared to unaffected mothers.
Conclusions:  We conclude that there were no statistically significant differences in the risk of having preterm, LBW, SGA infants and cesarean deliveries between women with and without MG.     

Socioeconomic deprivation independent of ethnicity increases status epilepticus risk

Background:   A higher incidence of convulsive status epilepticus (CSE) has been reported in nonwhite compared to white populations. Socioeconomic factors can be intricately involved in observed ethnic "effects," and the importance of socioeconomic status on health conditions is widely recognized. Understanding the effect of socioeconomic factors on CSE would provide insights into etiology and management, leading to the development of novel prevention strategies.
Methods:   From a population-based UK study on childhood CSE, we tested the hypothesis that socioeconomic deprivation independent of ethnicity increases the risk of childhood CSE. Home postal codes were used to measure the socioeconomic status of the neighborhood in which patients lived relative to that of the borough in which the neighborhood was located. The child's ethnicity was reported by parent(s). Relationships between socioeconomic status, ethnicity, and incidence were investigated using Poisson regression analysis.
Results:   A total of 176 children were enrolled. The incidence of CSE in nonwhite children [18.5, 95% confidence interval (CI) 13.7–23.3/100,000/year] was 1.8 (95% CI 1.3–2.4) times greater than for white children (10.5, 95% CI 7.9–13.1/100,000/year) (p < 0.0005). Socioeconomic deprivation and Asian ethnicity were independently associated with increased incidence. For each point increase in Index of Multiple Deprivation (IMD) 2004, there was a 1.03 cumulative increased relative risk (95% CI 1.01–1.06, p = 0.007). Asian children were 5.7 times (95% CI 1.7–18.9) more likely than white children to have a first-ever episode of CSE (p = 0.004). Socioeconomic and ethnicity effects were related to etiology of CSE.
Interpretation:   Ethnic and socioeconomic factors independently affect risk for prolonged febrile seizures and acute symptomatic CSE, but not for other types of childhood CSE.     

Adherence to lithium in naturalistic settings: results from a nationwide pharmacoepidemiological study

Objectives:  To estimate adherence to lithium in a nationwide sample of all patients treated with lithium and to characterize adherence according to gender and age.
Methods:  Adherence to lithium was estimated using data obtained by linking Medicinal Product Statistics with the Danish Medical Register on Vital Statistics, identifying all persons who received lithium among the 5.3 million persons living in Denmark during the period 1995 to 2000 inclusive.
Results:  The median time to discontinuation of lithium was 181.0 days [95% confidence interval (CI) 135.7–181.0] and 25% of patients stopped treatment with lithium within 45.2 days. Adherence to lithium was significantly poorer for women (135.7 days; 95% CI 90.5–135.7) than for men (316.7 days; 95% CI 271.4–407.1) and for younger (18–39 years) and older (≥60 years) patients compared to middle-aged patients.
Conclusions:  The results highlight the need for increased focus on long-term adherence to lithium with intensified psychological support, especially among younger and older female patients.     

Prevalence, incidence, and clinical characteristics of epilepsy—A community-based door-to-door study in northern Tanzania

Purpose:   The main aim of this door-to-door-study was to determine the prevalence, incidence, and clinical characteristics of epilepsy in northern Tanzania.
Methods:   A total of 7,399 people were screened with a standardized questionnaire using "multistage random sampling."
Results:   The prevalence rate of epilepsy was 11.2/1,000 [95% confidence interval (CI) 8.9–13.9/1,000] and the age-adjusted prevalence rate was 13.2/1,000. The prevalence of active epilepsy was 8.7/1,000 (95% CI 6.7–11/1,000). There was a preponderance of women. The average retrospective incidence including the last 5 years was 81.1/100,000 (95% CI 65–101/100,000). Fifty-four percent (45 of 83) of the people with epilepsy had generalized seizures without any identifiable cause; 71% (59 of 83) of the epilepsy patients had not visited health institutions prior to the study and 76% (63 of 83) had never received treatment.
Discussion:   Our study shows that the prevalence and incidence of epilepsy in northern Tanzania are higher compared to developed countries and that the majority of people with epilepsy do not access treatment.     

Incidence and prevalence of ALS in Ireland, 1995-1997: a population-based study

BACKGROUND: We conducted a prospective, population-based study of ALS in the Republic of Ireland for the 3-year period 1995 to 1997. METHODS: To ensure complete case ascertainment, multiple sources of information were used, including consultant neurologists, neurophysiologists, primary care physicians, and the Irish Motor Neuron Disease Association. The El Escorial diagnostic criteria for ALS were applied to all cases enrolled on the register and each patient was regularly followed up during his or her illness. RESULTS: Between January 1, 1995, and December 31, 1997, 231 patients were diagnosed with possible, probable, or definite ALS, including 133 men (57.6%) and 98 women (42.4%). The average annual incidence rate was 2.1 per 100,000 person-years (95% CI, 1.8 to 2.4), and 2.8 per 100,000 person-years for the population older than 15 years (95% CI, 2.4 to 3.1). The incidence rate was higher for men, being 2.5 per 100,000 person-years (95% CI, 2.0 to 2.9), than for women, at 1.8 per 100,000 person-years (95% CI, 1.5 to 2.2), and increased with age for both sexes. The median age at onset was 64.2 years for men and 67.8 years for women. On December 31, 1996, the crude prevalence was 4.7 per 100,000 of the total population (95% CI, 4.0 to 5.5), and 6.2 per 100,000 for the population older than 15 years (95% CI, 5.3 to 7.1). Adjusting to the 1996 Irish population as standard, the incidence of ALS in Ireland during the 3-year study period is the third highest reported to date. CONCLUSIONS: There was a trend toward a higher incidence of ALS in the northwestern region of Ireland, although the numbers of cases involved were small and further study is required.     

The incidence of motor nueron disease in Scotland

Abstract Between 1989 and 1998, 1226 cases of ALS/MND were identified in Scotland, with mean age of onset 65.2 (SD 11.9) years for men and 67.2 (SD 11.0) for women. Annual standardized incidence was 2.40 per 100,000 (95% CI 2.22–2.58). Using capture recapture methods we confirm a high level of case ascertainment for each year of study. Incidence and ascertainment of ALS has remained stable in a large population over a prolonged period of time. Large population-based databases can be used to test aetiological hypotheses.     

Long-Term Survival of People with Unprovoked Seizures: A Population-Based Study

Summary: Purpose : Few population-based studies of longterm survival in people with seizures or epilepsy have been made.
Methods: Between January 1, 1960 and December 31, 1964, we identified 224 incidence cases of unprovoked seizures in Iceland and determined survivorship status and date of death for the cases as of January 1, 1996. We compared survivorship with that expected based on data from age-/sex-specific life tables from the country for 1961–1990 and calculated the standardized mortality ratio (SMR).
Results: By 30 years after diagnosis, there were 45 deaths among patients with unprovoked seizures as compared with an expected 28 deaths [standardized mortality ratio (SMR) 1.6; 95% confidence interval (CI) 1.2–2.21. Patients with unprovoked seizures of unknown etiology did not have a significant increase in mortality overall (SMR 1.3, 95% CI 0.8–1.9) or in any time interval. For patients with remote symptomatic un provoked seizures, mortality was increased (SMR 2.3, 95% CI 1.4–3.5). This increase was attributable to excess mortality for the first 15 years after diagnosis (SMR 4.1, 95% CI 2.4–6.6), and SMR was not different after that time.
Conclusions: Survivorship was decreased for the population of patients with unprovoked seizures. The increased mortality was primarily due to excess mortality in patients with remote symptomatic seizures, occurring in the first 15 years after diagnosis. Overall mortality for idiopathic unprovoked seizures was not significantly increased.     

THE INCIDENCE OF THE GUILLAIN‐BARRE SYNDROME IN LOMBARDY,ITALY

The incidence of the Guillain-Barré syndrome (GBS) tends to vary between 0.4 and 4 cases per 100,000 population per year, depending on the size of the target population, the diagnostic criteria, and the accuracy of case ascertainment. In this study, the incidence of GBS was estimated for the year 1996 by searching the affected individuals in a large geographic area (Lombardy, population 8,924,870), using standard diagnostic criteria, and investigating multiple data sources. A case was included if he/she was a resident of Lombardy at the time of the diagnosis and there was muscle weakness and/or tendon areflexia with/without typical CSF or EMG features. With reference to the Asbury criteria (Ann Neurol 1978; 3: 565), GBS was defined as typical or atypical. Excluded were patients with HIV infection, botulism, poliomyelitis, and dyphteria. The source of data included the hospital discharge diagnoses, a prospective GBS regional registry, and a concurrent case-control study. A total of 136 cases met the inclusion criteria (regional registry, 87; hospital discharge diagnoses, 45; case-control study, 4). The sample included 72 men and 64 women aged 2 to 91 years. The overall crude incidence rate was 1.52 per 100,000 per year (95% CI 1.31–1.73) and the standardized rate was 1.51 per 100,000 per year (95% CI 1.43–1.59). The rate was 1.71 in men and 1.35 in women, and tended to increase with age until 80 years (<40 yr, 0.87; 40–59 yr, 1.54; 60–79 yr, 3.06; 80+ yr, 2.52). There were 10 patients with atypical GBS (cranial polyneuritis, 6; muscle weakness or tendon areflexia, 4). After excluding these cases, the incidence rate fell to 1.41 (95% CI 1.20–1.61). Our study suggests that the incidence of GBS in Lombardy, Italy, is fairly similar to that reported in the most accurate surveys of the disease, and that multiple data sources must be investigated to provide an accurate case ascertainment.     

Prevalence of essential tremor in the city of Kolkata, India: a house-to-house survey

Background and purpose:  Prevalence of essential tremor (ET), one of the most common movement disorders, has not been properly evaluated amongst heterogeneous population in India.
Methods:  We conducted a cross-sectional epidemiological study on the prevalence of ET in a randomly stratified population in the metropolitan city of Kolkata (erstwhile Calcutta), India, by a field team headed by a specialist doctor. A two-stage house-to-house survey was carried out with a validated screening instrument.
Results:  A population of 52377 was screened and a total of 184 cases of ET were identified as per pre-defined criteria and the prevalence rate adjusted to World Standard Population was 3.95 per 1000 (95% CI: 3.40–4.56). Age-specific prevalence showed increasing prevalence with aging. Sex-specific prevalence did not show significant difference between men and women. Socio-economic factors appeared to influence the prevalence and risk of ET was higher amongst slum dwellers versus non-slum population (odd ratio-2.29). Family history was positive in about one-fifth of the cases.
Conclusion:  This study has documented that the prevalence of ET above 40 years in India is similar to that of many countries globally and common amongst slum dwellers and there are fewer familial cases.     

Metabolic syndrome and cognitive impairment amongst elderly people in Chinese population: a cross-sectional study

Background and purpose:  Recent studies have demonstrated an association between metabolic syndrome (MetS) and cognitive impairment in elderly individuals, however a relationship between MetS and cognitive impairment in the Chinese population has been less frequently reported. Therefore, the present study was designed to investigate the relationship between MetS and cognitive impairment in an elderly Chinese population.
Methods:  Of 3216 participants (1740 men and 1476 women), aged 60 years old and over were selected from three districts of Chongqing City. The presence of MetS was defined according to the updated Adult Treatment Panel III criteria, and cognitive function was measured by Mini-Mental State Examination and the Activity of Daily Living tests.
Results:  Of the 3216 participants, 733 (22.8%) fulfilled the criteria for MetS, and 470 participants (14.6%; 236 men and 234 women) fulfilled the criteria for cognitive impairment. Amongst those with MetS, 183 participants (25%) also had cognitive impairment. In univariate analysis, MetS was significantly associated with cognitive impairment [odds ratio (OR) 2.55; 95% confidence interval (CI) 2.07–3.13]. Taking age, current smoking, hypertension and diabetes into account, multivariate logistic regression analysis showed that MetS was significantly associated with cognitive impairment (OR 2.31; 95% CI 1.91–2.95).
Conclusion:  MetS is associated with cognitive impairment amongst elderly people in the Chinese population.     

Incidence of multiple sclerosis in the United Kingdom

Existing data on the incidence of multiple sclerosis (MS) in the UK have some limitations. Few studies have reported age- and sex-specific incidence rates of MS, and none of those is based on a large sample of the general population. Further, no published reports have provided age- and sex-specific incidence rates of MS by clinical course from onset. To estimate the age- and sex-specific incidence rate and lifetime risk of multiple sclerosis, we identified all new cases of MS during the period 1993–2000 in the General Practice Research Database, which includes health information on over three million Britons. Based on 642 incident cases, incidence rates of MS adjusted to the world population were 7.2 (95 % CI 6.5, 7.8) in women and 3.1 (95 % CI 2.6, 3.5) in men. The incidence of MS with relapsing-remitting onset was higher in women than in men (incidence rate ratio 2.5, 95% CI 2.1, 3.1), but there were no sex differences for primary-progressive MS (incidence rate ratio 1.1, 95% CI 0.7, 1.8). The estimated lifetime risk from birth of receiving an MS diagnosis was 5.3 per 1,000 in women and 2.3 per 1,000 in men. These results confirm the relatively high incidence of MS in the UK and show marked differences in the sex-specific pattern of MS incidence by clinical course from onset.     

Cardiovascular disease and hypertension among adults with bipolar I disorder in the United States

Objective:  Despite ample evidence of excess cardiovascular mortality in bipolar disorder (BD), few studies have demonstrated increased prevalence of cardiovascular disease (CVD) and/or hypertension (HTN) in BD. We therefore examined this topic in a representative epidemiologic sample.
Method:  The 2001–2002 National Epidemiologic Survey on Alcohol and Related Conditions was used to determine whether prevalence of physician-diagnosed CVD and HTN is elevated among subjects with lifetime bipolar I disorder (BD-I), and whether CVD and HTN are prevalent at earlier ages among subjects with BD-I.
Results:  The age-, race-, and sex-adjusted prevalence of CVD was significantly greater among subjects with BD-I versus controls [odds ratio (OR) = 4.95, 95% confidence interval (CI): 4.27–5.75] and versus subjects with major depressive disorder [(MDD); OR =1.80, 95% CI: 1.52–2.14], as was the prevalence of HTN (OR = 2.38, 95% CI: 2.16–2.62 versus controls, OR = 1.44, 95% CI: 1.30–1.61 versus MDD; p < 0.0001 for all). Controlling additionally for marital status, education, income, obesity, smoking, anxiety disorders, and substance use disorders did not substantially alter these findings. The mean age of BD-I subjects with CVD and HTN was 14 and 13 years younger, respectively, than controls with CVD and HTN.
Conclusions:  Adults with BD-I are at increased risk of CVD and HTN, prevalent over a decade earlier than non-BD adults. Strategies are needed to prevent excessive and premature cardiovascular burden in BD-I.     

Total daily sleep duration and the risk of dementia: a prospective population-based study

Background and purpose:  We determined in a population-based study whether sleep duration was associated with an increased risk of incident dementia.
Methods:  In a population-based study in central Spain, participants were evaluated at baseline and 3 years later. Baseline demographic variables were recorded and participants indicated their daily sleep duration as the sum of night-time sleep and daytime napping. The average daily total sleep duration was grouped into five categories: ≤5 (short sleepers), 6, 7 (reference), 8, and ≥9 h (long sleepers). We identified all cases with incident dementia, diagnosed using DSM-IV criteria.
Results:  Three thousand two hundred eighty six participants with baseline information about sleep duration had a median duration of follow-up of 3.2 years. There were 140 incident cases of dementia. The relative risks (RR) for short sleepers and for long sleepers were 2.36 (95% CI = 1.07–5.21, P  = 0.03) and 2.40 (95% CI = 1.20–4.81, P  = 0.01), respectively. After adjustment for potential confounders, the RR was only marginally increased for short sleepers (1.87, 95% CI = 0.85–4.15, P  = 0.12) but remained increased for long sleepers (2.18; 95% CI = 1.09–4.37, P  = 0.03).
Conclusions:  Prolonged sleep duration (night-time sleep and daytime napping) may be associated with an increased risk of dementia.     

Cerebral vein and dural sinus thrombosis in adults in Isfahan, Iran: frequency and seasonal variation

Objective –  To estimate the frequency of cerebral vein and dural sinus thrombosis (CVST) and its seasonal variation.
Methods –  A clinic-based prospective case-register study was conducted from 2001 to 2004. Hundred and twenty-two consecutive definite CVST patients (26 men and 96 women) treated in two major neurological centres of Isfahan, Iran, were included in the study. Part of examination included an assessment of CVST including conventional angiography and/or magnetic resonance imaging and self-reported medical history. Population data were obtained from the 1996 Iran Census. The mean (standard deviation) age of participants was 35.5 (11.9) years.
Results –  The annual frequency (95% confidence interval) of CVST was 12.3 (10.1, 14.5) per million in a population of 2,472,751, with higher rate in women than in men [19.9 (15.5, 23.9) women and 5.1 (3.2, 7.1) men] and with increasing age in women (up to 50 years), but not in men. The female/male ratio was 3.9 (2.5–6.0). The monthly frequency of CVST ranged from 0.6 per million (0.1, 1.1) in August to 2.1 (1.2, 3.0) in September. The seasonal CVST rate ranged from 2.2 per million (1.3, 3.2) in summer to 4.3 (3.1, 5.7) in autumn. The differences were statistically significant either for the months or season ( P  < 0.05).
Conclusion –  The findings of this study show the CVST frequency in adults. More women than men are present with CVST and its frequency increased during autumn.