Has there been a decline in subarachnoid hemorrhage mortality?

We studied subarachnoid hemorrhage in the population of Rochester, Minnesota, for the 40-year period from 1945 through 1984. The average annual incidence rate of subarachnoid hemorrhage in Rochester has remained constant at approximately 11 per 100,000 population. Age-specific incidence rates increased with age. However, the average annual mortality rate for subarachnoid hemorrhage in Rochester has shown a decreasing trend, from 6.8 per 100,000 population in 1955-1964 to 4.3 in 1975-1984. It is likely that this is due to a decrease in case-fatality rates from 57% in 1945-1974 to 42% in 1975-1984 (p = 0.10). This decreasing trend was also evident in annual mortality rates from subarachnoid hemorrhage for US white men and women. The reason for the improved case-fatality rate is unclear, but it may be related to changes in management. The interval from onset of subarachnoid hemorrhage to surgery decreased from a median of 12 days in 1975-1979 to 2 days in 1980-1984, and of those who survived to receive medical attention, more patients received some form of medical treatment in 1980-1984. Whether either or both of these changes have led to the decrease in the case-fatality rate is uncertain.     

Aneurysmal subarachnoid hemorrhage in Izumo City and Shimane Prefecture of Japan. Incidence

During the 5-year period from 1980 to 1984, the incidence of subarachnoid hemorrhage due only to rupture of aneurysms was investigated in Izumo City, a small city with a population of 79,026. Additionally, to ascertain the relation of incidence to the size of the geographic area and/or population, a similar analysis was made on a larger area of Shimane Prefecture, including Izumo City, with a total population of 789,712. During this 5-year period, a total of 83 patients with aneurysmal subarachnoid hemorrhage were hospitalized in Izumo City, 548 patients in Shimane Prefecture. Ruptured aneurysms were confirmed in 77 cases (93%) in Izumo City and 466 cases (85%) in Shimane Prefecture. The crude annual incidences of aneurysmal subarachnoid hemorrhage for Izumo City and Shimane Prefecture were 21.0 and 13.9 per 100,000 population for all ages, and the age-adjusted annual incidences (adjusted to the 1980 population of Japan) were 18.3 and 11.0 per 100,000 for all ages, respectively. For both Izumo City and Shimane Prefecture, the age-specific annual incidences peaked at the ages of 50-69 years, and the highest incidence was 92.3 per 100,000 men from Izumo City in the eighth decade of life. The annual incidence of subarachnoid hemorrhage for Izumo City is the highest reported to date. If a wider area, such as Shimane Prefecture, were studied many patients in poor condition, particularly elderly patients, would be missed. To determine accurately the incidence of aneurysmal subarachnoid hemorrhage, it thus might be better to conduct the study in a small city such as Izumo City.     

Epidemiological and clinical characteristics of ALS in Belgrade, Yugoslavia

We present the results of the first epidemiological study of ALS in Belgrade. The distribution of 58 newly discovered cases in a 7-year survey period (1985–1991) showed that the average annual age-adjusted incidence rate was 0.42 per 100,000 population (95% confidence interval, 0.18–0.83). The rate for males was 1.5 times higher than the rate for females. The greatest age-specific average incidence rate was observed in patients between 60 and 64 (3.66 per 100,000 population; 95% confidence interval, 2.17–5.78). The actual age-adjusted prevalence rate on December 31, 1991 was 1.07 per 100,000 (95% confidence interval, 0.71–1.71). The mean age at onset of the disease was 56.2 ± 9.8 and it ranged from 24 to 74. We studied the natural course of the disease through the mean duration and cumulative probability of survival. The mean duration of the disease was 27.7 ± 18.2 months. The cumulative probability of survival was 27% for the whole population in a 5-year interval. Elderly patients and those with bulbar signs at onset had a poorer prognosis. Patients under 49 at onset and those with the spinal form of the disease survived longer.     

Hemifacial spasm in Rochester and Olmsted County, Minnesota, 1960 to 1984

The incidence of hemifacial spasm in residents of Olmsted County, Minnesota, was studied by reviewing the medical records of patients residing in the community between 1960 and 1984. The average annual incidence rate was 0.74 per 100,000 in men and 0.81 per 100,000 in women, age-adjusted to the 1970 US white population. The average prevalence rate was 7.4 per 100,000 population in men and 14.5 per 100,000 in women. The incidence and prevalence rates were highest in those from 40 to 79 years of age.     

The incidence of amyotrophic lateral sclerosis in southwestern Ontario, Canada

The incidence, prevalence, and mortality rates of amyotrophic lateral sclerosis in southwestern Ontario, Canada, were determined for the years 1978 through 1982. The average annual incidence rate was 1.63 per 100,000 population. The prevalence rate was 4.9 per 100,000 on January 1, 1983. The average annual mortality rate was 1.52 per 100,000 population and increased with age, reaching a peak in the 70 to 79-year decade in both sexes. The male:female ratio was 1.2:1. The average age at diagnosis was 62.5 years, and the average duration from date of diagnosis was 2.5 years. The distribution of the disease was uneven in 12 counties, with the highest incidence in Perth (3.33) and Essex (2.43) counties. The city of Windsor, in an industrial region, had a high average annual incidence rate of 2.81.     

Cerebrovascular disease in infants and children: a study of incidence, clinical features, and survival

A 10-year review of the Mayo Clinic experience with childhood cerebrovascular disease unrelated to birth, intracranial infection, or trauma identified 69 patients (38 with ischemic stroke, and 31 with subarachnoid or intracerebral hemorrhage). Although children with cerebral infarction had better survival, they experienced more residual disability than children with cerebral hemorrhage. The medical records-linkage system for Rochester, Minnesota residents made it possible for the first time to study cerebrovascular disease in a well-defined childhood population. Records from all medical facilities serving this population (average of 15,834 resident children) showed four strokes over 10 years (average annual incidence rate of 2.52 cases per 100,000 per year).     

Stroke in the urban population of Calcutta--an epidemiological study

A population-based cluster survey on stroke disorders was conducted for the first time in the city of Calcutta, India. The population surveyed totaled 50,291. The crude prevalence rate of stroke was 147/100,000 (age-adjusted prevalence 334/100,000). The annual incidence rate of stroke for the year 1998-1999 was 36/100,000 (age-adjusted annual incidence rate 105/100,000). Women outnumbered men regarding stroke prevalence in all age groups except in the 50- to 69-year age group. There were relatively more cases of cerebral haemorrhage in our study, compared to those in the western countries. Case-control analysis found hypertension to be the most significant risk factor for stroke.     

Incidence of Parkinson's disease in estonia

The incidence of Parkinson's disease (PD) was studied over a 9-year period (1990-1998) in Tartu county, Estonia, with a mean population of 156,417. Based on 264 patients, the average crude incidence rate of PD was 18.8 per 100,000 person-years. The age-adjusted incidence was 16.8/100,000; 18.3 for the urban group and 14.0 for the rural group; 16.6 for men and 17.1 for women. The age-specific incidence was 1.0/100,000 in the age range 30-39 years, reached a maximum of 117.2/100,000 in the age range 70-79 years and declined in the elderly. The incidence of PD was comparable with that found in developed countries, except for a slightly higher (not significant) incidence rate in the urban compared with the rural population in Estonia.     

Follow-up study on amyotrophic lateral sclerosis in Rochester, Minn., 1925 through 1984

The incidence, secular trend and survivorship of amyotrophic lateral sclerosis in the Rochester, Minn., population has been investigated over a 60-year period, 1925 through 1984. The crude average annual incidence rate was 2.0 per 100,000 population. The rate, age- and sex-adjusted to the US 1970 white population, was 2.4 per 100,000 population (3.0 for men and 2.0 for women), with a male to female ratio of 1.5:1. Incidence rates after 1955 showed a small but nonsignificant increase compared to those of the former 30-year period. Median age at onset was 67.5 years; the incidence rates increased significantly with advancing age, but without a peak. Median survivorship was 23.8 months, and younger patients had a better prognosis than patients with an advanced age at onset. No change in duration of survivorship was observed over the period studied. Two of the 44 patients (4.5%) had a family history of amyotrophic lateral sclerosis.     

Incidence and prognosis of subarachnoid hemorrhage in a Japanese rural community

Twenty-six first episodes of subarachnoid hemorrhage occurred among 1,621 Hisayama residents aged greater than or equal to 40 years during the 22-year follow-up of a prospective study. Subarachnoid hemorrhage was confirmed by both clinical and autopsy findings. The average annual incidence (96.1/100,000 population) was 3-13 times higher than any previously reported and steeply increased with age in both sexes, being 2.3 times higher for women than for men after adjusting for age. Nine patients (35%) died less than or equal to 8 hours after the onset of subarachnoid hemorrhage. None was correctly diagnosed on the death certificates, and four of the nine (44%) were misdiagnosed as intracerebral hemorrhage. We found the survival rate of patients suffering subarachnoid hemorrhage to be much lower than previously reported because we detected a large number of sudden deaths due to subarachnoid hemorrhage through the high rate of autopsy in our cohort (81.4%).     

Stroke in the young: incidence and pattern in Benghazi, Libya

Out of 329 cases of stroke registered in Benghazi between November 1, 1983 and October 30, 1984, 63 patients comprising 32 males and 31 females belonged to the 15-40-year age group (stroke in the young). The annual age-specific crude incidence of stroke in the young was 39.3 and 40.3 per 100,000 for men and women, respectively. The age-adjusted incidence rate for both sexes for the age-specific (15-40 years) population was 47 per 100,000. The sex-dependent difference in the incidence was not statistically significant. These results emphasize that the high incidence of stroke in the young in Benghazi is not a reflection of the age distribution of the population. Hypertension, diabetes mellitus, heart disease and hypercholesterolemia were important components of high stroke profile in the young. One or more risk factors were identified in 78% of total young stroke victims and in all the patients under the age of 30. Eight young stroke subjects died during the study period.     

Incidence and clinical features of glossopharyngeal neuralgia, Rochester, Minnesota, 1945-1984.

The annual crude incidence rate of glossopharyngeal neuralgia per 100,000 population in Rochester, Minn., for 1945 through 1984, was 0.7 for both sexes combined, suggesting that glossopharyngeal neuralgia is a rare disease. There were no significant differences between the sexes (p greater than 0.10) in the overall age-adjusted (to the total 1980 US population) rates: 1.1 for men and 0.5 for women. Overall age-specific crude rates increased slightly with age. Our results and conclusions, achieved by comparing our data with a large referral study at Mayo Clinic, suggest that glossopharyngeal neuralgia is generally a mild disease, since mild attacks are not uncommon, the average annual recurrence rate for a second episode is low (3.6%), and only one fourth of the cases had to have surgery for relief of symptoms. Bilaterality is not uncommon; it was observed in one fourth of the patients, all of whom had mild disease.     

Changes in the incidence of amyotrophic lateral sclerosis in Israel

The incidence of amyotrophic lateral sclerosis (ALS) in Israel was determined for the period 1959 through 1974. A total of 246 patients with ALS was ascertained. The male-female ratio was 1.62:1. The average annual age-adjusted incidence per 100,000 persons increased during this period by 41%. The increase was almost entirely due to a higher rate in persons more than 60 years of age and was greater in women than in men. This led to a decrease in the male-female ratio. The mean age of onset increased from 52.8 to 58.6 years during the same period. The increment in incidence could not be explained by better case ascertainment or increased life expectancy, but greater precision in diagnosis of ALS in the aged may have partially contributed to the increase.     

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.     

Incidence and clinical features of trigeminal neuralgia, Rochester, Minnesota, 1945-1984

The overall crude incidence rate of trigeminal neuralgia per 100,000 population in Rochester, Minnesota, for 1945 through 1984 was 4.3 for both sexes combined. The age-adjusted (to total 1980 US population) rate for women (5.9) was significantly higher than that for men (3.4). Annual incidence rates increased significantly with age in both women and men. Data based on evidence in the medical records suggest that trigeminal neuralgia is a rather rare and unpredictable disease: The number of episodes varies from 1 to 11, and length of episode from 1 day to 4 years. This study indicates an elevated relative risk associated with hypertension (both overall and among women in the cohort). Also, prevalence of multiple sclerosis was significantly greater among the group of 75 patients who had trigeminal neuralgia. Since the data on treatment in this study do not correspond to a randomized clinical trial, they are presented as empirical results only and show no single treatment of choice for trigeminal neuralgia.     

An increase in the incidence of multiple sclerosis in Western Norway

Abstract– In the county of Hordaland, Western Norway, the prevalence of MS has been shown to have increased from 20/100,000 in 1963 to 60/100,000 in 1983. This study shows that the increase in prevalence was caused by a highly significant and marked increase in incidence over a 30-year period. The average annual incidence of about 2 per 100,000 population in 1953–1962 increased to 4 per 100,000 in the period 1968–1977. The rise in incidence was parallel for both sexes until 1970. In the last 10 years, the incidence has continued to increase among females, whereas a decrease has been observed among males.     

Incidence and effectiveness of cerebrospinal fluid shunts in Olmsted County, Minnesota, 1956-1981

In the period 1956 through 1981, 129 cerebrospinal fluid (CSF) shunt operations were performed on 50 patients who were residents of Olmsted County, Minn. The overall average annual age- and sex-adjusted incidence of initial CSF shunts during this 26-year period was 2.3 per 100,000 person-years. Within 5-year calendar time intervals, the average annual incidence rates per 100,000 person-years ranged from 0.8 (1956-1960) to 4.6 (1971-1975). There were 4 shunt-related deaths, 1 due to a CSF shunt infection and 3 due to acute increases in intracranial pressure. In this analysis of shunt procedures in a defined population, the diagnostic indications and changes over time in CSF shunting devices are also described.     

Incidence of multiple sclerosis in Macomer, Sardinia, 1912-1981: onset of the disease after 1950

Intensive search of all cases of MS occurring in the Sardinian commune of Macomer since 1912 indicated that MS was absent up to the early 1950s. All 13 ascertained cases had clinical onset in the years 1952-1981. During this period, the average annual incidence was 4.8 per 100,000; the highest incidence was found in the period 1957-1961, slowly decreasing up to 1981. MS was probably introduced after 1945, when the centuries-old isolation of Macomer ended and the native population came into contact with individuals from high- and medium-risk areas.     

Subarachnoid hemorrhage in an isolated population. Incidence on the Faroes during the period 1962-1975

In a retrospective study of a 14-year period (1962-1975) the annual incidence of subarachnoid hemorrhage (SAH) was found to be 7.4 per 100,000 in an isolated population of about 40,000. The age-specific incidences in the age groups from 15-25 to 60 years are on the same level as found in Sweden, Rochester USA, England, and Iceland, but lower than the findings in Finland. The age-specific incidence among persons over 60 years of age was far lower than in Sweden, Rochester USA, and Finland. The possible causes of the lower incidence in all age groups than reported in the above-mentioned studies are discussed. Forty patients had a history of SAH. Two months after the episode 38% had died and at the end of 5 years 53%. The recurrence rate at 5 years was 24%.     

Incidence and prevalence of amyotrophic lateral sclerosis in Harris County, Texas, 1985-1988

The incidence of amyotrophic lateral sclerosis was determined in Harris County, Texas, for the period 1985 through 1988. Amyotrophic lateral sclerosis cases were ascertained from four sources: area neurologists, hospitals, death certificates, and the Muscular Dystrophy Association. The age-adjusted incidences of 1.27 per 100,000 person-years in males and 1.03 per 100,000 person-years in females were lower than recent rates in the northern US, Canadian, and northern European studies but higher than rates in southern European studies. Comparisons with other recent incidence studies show less uniformity in occurrence of amyotrophic lateral sclerosis, in both the overall rates and in the age- and sex-specific patterns, than was suggested by mortality studies. The incidence of amyotrophic lateral sclerosis among blacks and whites was similar. Hispanic males had incidences similar to white males, although a deficit of female Hispanic cases was found in Harris County. The prevalence of amyotrophic lateral sclerosis peaked in the 65- to 74-year age group at 33 per 100,000 population among males and 19 per 100,000 population for females.