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 prevalence of motor neuron disease in Coastal and Mountainous Regions,Croatia, 1984–1993. A preliminary survey

In the period 1984–1993, we carried out an incidence and prevalence study of motor neuron disease in Coastal and Mountainous Regions, Croatia. This was the first epidemiological study on motor neuron disease in Croatia. A total of 22 incident cases were identified. The crude annual incidence rate was 0.68 (95% confidence interval 0.43-1.03) per 100,000 person-years; 0.95 (95% confidence interval 0.60-1.43) per 100,000 person-years for men and 0.42 (95% confidence interval 0.26-0.63) per 100,000 person-years for women. The rate adjusted to the European population was 0.63 (95% confidence interval 0.39-0.95) per 100,000 person-years. The age-adjusted incidence in our population is similar to the rates, standardized to the European population, observed in Italy, but lower than recent rates in the US and northern European studies. On 31st December 1993, there were 18 prevalent cases. The prevalence adjusted to the European population was 5.24 (95% confidence interval 3.10-8.28) per 100,000 population.     

Tuberous sclerosis complex in Olmsted County, Minnesota, 1950-1989

The incidence of tuberous sclerosis complex in Olmsted County, Minnesota, was 0.28 per 100,000 person-years from 1950 through 1989, the point prevalence on December 31, 1989, was 6.9 per 100,000 persons, and the incidence at birth was 6.0 per 100,000 live births. The incidence was 0.13 per 100,000 person-years from 1950 through 1974 and 0.46 per 100,000 person-years from 1975 through 1989. The higher rate of diagnosis during the later period is believed to be due to the use of computed tomography. Of the 12 patients considered in this study, one patient presented with seizures and severe intellectual disability, six patients presented with seizures, three patients presented with multiple facial angiofibroma, and two patients were asymptomatic.     

Multiple sclerosis: variation of incidence of onset over time in the Faroe Islands

Epidemiological studies of multiple sclerosis (MS) conducted in the Faroe Islands identified 10 annual incidences per 100,000 in 1945 and 4.5 in the period 1986-2007. The aim of this study was to estimate the annual incidence of onset of MS in the Faroe Islands in the six decades from 1943 to 2002 and during the period 2003-7.All patients diagnosed with MS between 1943 and 2007 were documented. The incidence of MS before 1943 was around 0.2 per 100,000 annually. During the period 1943-62, an annual incidence rate of 4.4 [confidence interval (CI) 2.9-6.1] per 100,000 was observed. During the 20-year period 1963-82, the level declined significantly (p < 0.001) to around 0.6 (0.3-1.5). Thereafter, an increase was seen during the period 1983-2002, evidencing a significant (p < 0.001) sevenfold increase in the annual incidence to 4.6 (3.2-6.2) per 100,000. Subsequently, for the period 2003-7, there was again a decline to 2.4 (2.1-3.3) (p = 0.003). This study confirms that significant variation in the incidence of MS has occurred in the Faroes over time. Because the rate of genetic change within the Faroese population is relatively slow, the study suggests environmental factors as a contributing cause of MS. If only genetic factors for susceptibility were important, the incidence rate should not wax and wane over time, as is observed.     

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.     

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.     

Trends in head injury incidence in New Zealand: a hospital-based study from 1997/1998 to 2003/2004

Traumatic brain injury (TBI) is a leading cause of disability and death in young adults. Globally, the incidence of TBI hospitalizations is estimated at 200-300 people per 100,000 annually. Using a national health database, we examined the incidence of TBI-related hospital discharges (including 1-day stays) to New Zealand Hospitals from 1997/1998 to 2003/2004. Crude annual hospital-based incidence rates for the total population ranged from 226.9 per 100,000 in 1998/1999 to a high rate of 349.2 in 2002/2003. There was a noticeable increase in rates with the change from ICD-9 to ICD-10 diagnostic codes and there was also disparity in incidence rates according to ethnicity, age and gender. Crude annual hospital-based incidence rates for males and females in Maori (689/100,000 and 302.8/100,000 person-years) and Pacific Island populations (582.6/100,000 and 217.6/100,000 person-years) were much higher than those for the remaining population (435.4/100,000 and 200.9/100,000 person-years), particularly for males. The overall age-standardized hospital- based incidence rate for 2003/2004 was 342 per 100,000 per year (95% CI = 337-349/100,000), and 458 per 100,000 per year for Maori (95% CI = 438-479/100,000) with Maori males experiencing a peak in incidence between 30 and 34 years of age that was not evidenced for the wider population. Standardized hospital-based incidence rates for the total population and for Maori by age, gender and ICD-10 diagnostic codes are also examined.     

Guillain-Barré syndrome. Clinicoepidemiologic features and effect of influenza vaccine

A study of the epidemiologic and clinical features of Guillain-Barré syndrome in the population of Olmsted County, Minnesota, over the 46-year period 1935 through 1980 was conducted through the centralized diagnostic index maintained at Mayo Clinic, Rochester, Minn. A total of 48 cases were identified, giving an age- and sex-adjusted incidence of 1.8 per 100,000 person-years. The rate increased over time from 1.2 in the interval 1935 through 1956 to 2.4 in the interval 1970 through 1980. Males were affected more than females (age-adjusted rates of 2.3 and 1.2, respectively). The rate increased with age from 0.8 in those under 18 years old to 3.2 for those 60 years and older. Antecedent infectious diseases were reported in 65% of the cases. Implications with regard to the incidence of Guillain-Barré syndrome associated with the A/New Jersey/76 (swine flu) vaccine are discussed.     

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.     

50-year trends in the incidence of anorexia nervosa in Rochester, Minn.: a population-based study

OBJECTIVE: The aim of the study was to determine incidence and prevalence rates and long-term trends in incidence of anorexia nervosa by identifying all persons residing in the community of Rochester, Minn., during the 50-year period 1935 through 1984 who had the disorder. METHOD: From a community-based epidemiologic resource, 13,559 medical records with diagnoses of amenorrhea, starvation, weight loss, anorexia nervosa, or other conditions were screened to identify true cases of anorexia nervosa determined by using standard diagnostic criteria. RESULTS: One hundred eighty-one residents (166 female and 15 male) fulfilled the diagnostic criteria for anorexia nervosa; these were the incidence cases. Due to a quadratic trend in the rates for girls 10-19 years old, the incidence rate among female residents fell from 16.6 per 100,000 person-years in the 1935-1939 period to a low of 7.0 in 1950-1954 and increased to 26.3 in 1980-1984. The incidence rates for women 20 years old and older and for males remained constant. For females 15-24 years old, there was a linear increase. The overall age-adjusted incidence rate per 100,000 person-years was 14.6 for females and 1.8 for males. The prevalence rate per 100,000 population was 269.9 for females and 22.5 for males. CONCLUSIONS: Anorexia nervosa is more common than previously recognized. Among girls 15-19 years old it is a very common chronic illness. Its incidence has increased among females 15-24 years old but not among older women or among males.     

Epidemiologic data on meningiomas in East Germany 1961-1986: incidence, localization, age and sex distribution.

From 1961 to 1986, 8119 new cases of meningioma were reported to the National Cancer Register of East Germany (former German Democratic Republic) with an average population of 16.9 million. The crude annual incidence was 1.85 per 100,000 population. The crude rates were 1.16 for males, and 2.44 per 100,000 for women; after age adjustment ("world" population) these rates were 0.90 and 1.92 per 100,000, respectively. Thus meningioma occurred 2.1 times more frequently in women than men. Independent of sex, the incidence rose continuously with increasing age. At the same time, there appeared to be an increase in meningioma frequency in the course of the 26-year reporting period. The overwhelming majority of cases, 7375, (90.8%) were intracranial in location but 711 (8.8%) were intraspinal. Some 50% of all cases were first discovered at autopsy, with the proportion of such cases being markedly higher in the older age groups.     

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.     

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.     

Incidence of the Guillain-Barré syndrome in Ferrara, northern Italy, 1981-1987

The few incidence estimates on Guillain-Barré syndrome (GBS) in Italy indicate rates lower than the values provided by other previous non-Italian population-based studies. The latter range from 0.6 to 1.9 cases per 100,000 population per year. To verify whether Italy may be considered a low-risk area for GBS we studied the incidence of the disease in Local Health Unit No. 31 (USL 31) of Ferrara, Northern Italy (mean population 180,701 inhabitants) for the years 1981-1987. The annual incidence rates were stable during this period with an average incidence of 1.26 cases per 100,000 population per year. No significant difference was found for urban or rural residence and there was no significant seasonal clustering. In 37.5% of the series an antecedent infection was recorded within 4 weeks before GBS onset. The survey seems to support the hypothesis of a homogeneous distribution of GBS in space and time and does not support the notion that GBS is less common in Italy than elsewhere.     

Incidence of multiple sclerosis in the town of Sassari, Sardinia, 1965 to 1985: evidence for increasing occurrence of the disease

Prevalence studies carried out in Sardinia from 1975 suggest an increasing occurrence of MS. However, it is questionable whether this increase represents a real change in MS incidence or simply reflects longer survival. Data from 79 patients indicated the average annual incidence for the period 1965 through 1985 was 3.4 per 100,000. On December 31, 1985, the prevalence rate was 69 per 100,000. Evaluation of MS temporal trends showed a significant increase in MS incidence during the study period: values ranged around two per 100,000 in the triennial periods 1965-1967, 1968-1970, and 1971-1973, and around five in each triennium from 1977 onward.     

A reappraisal of the epidemiology of multiple sclerosis in Olmsted County, Minnesota

A review of multiple sclerosis (MS) case reports, using the unified record system at the Mayo Clinic for the Olmsted County population, revealed age- and sex-adjusted prevalence rates per 100,000 persons of 160 for Olmsted County and 173 for Rochester, Minnesota, on January 1, 1985. The annual age- and sex-adjusted incidence rate per 100,000 person-years from 1975 to 1984 for Olmsted County was 6.2 and for Rochester, 6.3. This incidence rate is significantly higher than what had been reported previously in Rochester (3.6/100,000) or in other communities. The estimated 25-year survival of the MS population was 76.2% +/- 4.5% compared with 87.7% for the general US white population of a similar age and sex. Survival for men was less than for women. There was no increase in survival for patients diagnosed with MS in more recent decades. No significant increase was found in cancer or autoimmune disease rates in the MS patients.     

The decreasing incidence of primary intracerebral hemorrhage: a population study.

This population study describes the experience with primary intracerebral hemorrhage (PIH) in residents of Rochester, MN, for the 32-year period from 1945 through 1976. The average annual age-adjusted incidence rate for PIH was 12.1 per 100,000 population, and the incidence for all cases of spontaneous intracerebral hemorrhage was 15.2 per 100,000. The PIH rates were higher for males than for females, and they increased steadily with age. When patients on long-term anticoagulant therapy were excluded, there was a steady decrease in the average annual age-adjusted incidence rate for PIH in each succeeding 8-year interval since 1945. Prehemorrhage hypertension, present overall in 89% of patients, was much more frequent and severe in the earlier years of the study. The frequency and severity of prehemorrhage hypertension also varied inversely with age in the population with PIH. The median age at the onset of PIH increased from 65 years for the period 1945 through 1952 to 71 years for 1969 through 1976.     

Guillain-Barré syndrome in Larimer County, Colorado: a high-incidence area

During the period 1981-1983, 19 cases of Guillain-Barré syndrome (GBS) occurred in residents of Larimer County, Colorado, for an incidence of 4.0 cases per 100,000 population per year, compared with 1.2 cases per 100,000 per year in 1975-1980 (p less than 0.05). The higher incidence of GBS in 1981-1983 may represent an unusual chance occurrence, since no patient characteristics or predisposing events could be found to explain the increase. Nevertheless, the findings demonstrate that over a period of as long as 3 years, the crude average annual incidence of GBS in a large, well-defined population may exceed by twofold the upper limit of the previously reported range (0.6 to 1.9 cases per 100,000 per year).     

Incidence of unprovoked seizures and epilepsy in Iceland and assessment of the epilepsy syndrome classification: a prospective study

BACKGROUND: No population-based incidence studies of epilepsy have studied syndrome classification from the outset. We prospectively studied the incidence of a single unprovoked seizure and epilepsy in the population of Iceland, and applied the syndrome classification endorsed by the International League Against Epilepsy to this population. METHODS: We used a nationwide surveillance system to prospectively identify all residents of Iceland who presented with a first diagnosis of a single unprovoked seizure or epilepsy between December 1995 and February 1999. All cases were classified by seizure type, cause or risk factors, and epilepsy syndrome. RESULTS: The mean annual incidence of first unprovoked seizures was 56.8 per 100,000 person-years, 23.5 per 100,000 person-years for single unprovoked seizures, and 33.3 per 100,000 person-years for epilepsy (recurrent unprovoked seizures). Incidence was similar in males and females. Partial seizures occurred in 40% and a putative cause was identified in 33%. Age-specific incidence was highest in the first year of life (130 per 100,000 person-years) and in those 65 years and older (110.5 per 100,000 person-years). Using strict diagnostic criteria for epilepsy syndromes, 58% of cases fell into non-informative categories. Idiopathic epilepsy syndromes were identified in 14% of all cases. INTERPRETATION: Findings are consistent with incidence studies from developed countries. Although the epilepsy syndrome classification might be useful in tertiary epilepsy centers, it has limited practicality in population studies and for use by general neurologists.