Summary This overview of population-based studies of incidence, prevalence, mortality, and case-fatality of stroke was based on studies from 1990. Incidence (first stroke in an individual's lifetime) and prevalence were computed by age, sex, and stroke type. Age-standardised incidence and prevalence with the corresponding 95% CI were plotted for each study to facilitate comparisons. The review shows that the burden of stroke is high and is likely to increase in future decades as a result of demographic and epidemiological transitions in populations. The main features of stroke epidemiology include modest geographical variation in incidence, prevalence, and case-fatality among the—predominantly white—populations studied so far, and a stabilisation or reversal in the declining secular trends in the pre-1990s rates, especially in older people. However, further research that uses the best possible methods to study the incidence, risk factors, and outcome of stroke are urgently needed in other populations of the world, especially in less developed countries where the risk of stroke is high, lifestyles are changing rapidly, and population restructuring is occurring.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474442203002667.pdf

Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century.

Parkinson's Disease (PD) is a common neurodegenerative disorder. We sought to synthesize studies on the prevalence of PD to obtain an overall view of how the prevalence of this disease varies by age, by sex, and by geographic location. We searched MEDLINE and EMBASE for epidemiological studies of PD from 1985 to 2010. Data were analyzed by age group, geographic location, and sex. Geographic location was stratified by the following groups: 1) Asia, 2) Africa, 3) South America, and 4) Europe/North America/Australia. Meta-regression was used to determine whether a significant difference was present between groups. Forty-seven studies were included in the analysis. Meta-analysis of the worldwide data showed a rising prevalence of PD with age (all per 100,000): 41 in 40 to 49 years; 107 in 50 to 59 years; 173 in 55 to 64 years; 428 in 60 to 69 years; 425 in 65 to 74 years; 1087 in 70 to 79 years; and 1903 in older than age 80. A significant difference was seen in prevalence by geographic location only for individuals 70 to 79 years old, with a prevalence of 1,601 in individuals from North America, Europe, and Australia, compared with 646 in individuals from Asia (P < 0.05). A significant difference in prevalence by sex was found only for individuals 50 to 59 years old, with a prevalence of 41 in females and 134 in males (P < 0.05). PD prevalence increases steadily with age. Some differences in prevalence by geographic location and sex can be detected. © 2014 International Parkinson and Movement Disorder Society

The prevalence of Parkinson's disease: A systematic review and meta‐analysis

Epidemiology and Estimated Population Burden of Selected Autoimmune Diseases in the United States

Summary The uneven distribution of multiple sclerosis (MS) across populations can be attributed to differences in genes and the environment and their interaction. Prevalence and incidence surveys could be affected by inaccuracy of diagnosis and ascertainment, and prevalence also depends on survival. These sources of error might play a part in the geographical and temporal variations. Our literature search and meta-regression analyses indicated an almost universal increase in prevalence and incidence of MS over time; they challenge the well accepted theory of a latitudinal gradient of incidence of MS in Europe and North America, while this gradient is still apparent for Australia and New Zealand; and suggest a general, although not ubiquitous, increase in incidence of MS in females. The latter observation should prompt epidemiological studies to focus on changes in lifestyle in females. New insights into gene–environment and gene–gene interactions complicate interpretations of demographic epidemiology and have made obsolete the idea of simple causative associations between genes or the environment and MS.

The Changing Demographic Pattern of Multiple Sclerosis Epidemiology

Objective: To review population-based studies of the prevalence and incidence of epilepsy worldwide and use meta-analytic techniques to explore factors that may explain heterogeneity between estimates. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed. We searched MEDLINE and EMBASE for articles published on the prevalence or incidence of epilepsy since 1985. Abstract, full-text review, and data abstraction were conducted in duplicate. Meta-analyses and meta-regressions were used to explore the association between prevalence or incidence, age group, sex, country level income, and study quality. Results: A total of 222 studies were included (197 on prevalence, 48 on incidence). The point prevalence of active epilepsy was 6.38 per 1,000 persons (95% confidence interval [95% CI] 5.57–7.30), while the lifetime prevalence was 7.60 per 1,000 persons (95% CI 6.17–9.38). The annual cumulative incidence of epilepsy was 67.77 per 100,000 persons (95% CI 56.69–81.03) while the incidence rate was 61.44 per 100,000 person-years (95% CI 50.75–74.38). The prevalence of epilepsy did not differ by age group, sex, or study quality. The active annual period prevalence, lifetime prevalence, and incidence rate of epilepsy were higher in low to middle income countries. Epilepsies of unknown etiology and those with generalized seizures had the highest prevalence. Conclusions: This study provides a comprehensive synthesis of the prevalence and incidence of epilepsy from published international studies and offers insight into factors that contribute to heterogeneity between estimates. Significant gaps (e.g., lack of incidence studies, stratification by age groups) were identified. Standardized reporting of future epidemiologic studies of epilepsy is needed.

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Prevalence and incidence of epilepsy: A systematic review and meta-analysis of international studies.

• A door-to-door survey was carried out to screen a community of 14010 people (Parsis living in colonies in Bombay, India) for possible neurologic diseases. High school graduates, social workers, and medical students administered a screening questionnaire that had been shown in a pilot survey to have a sensitivity of 100% for identifying those with Parkinson's disease. Neurologists used defined diagnostic criteria to evaluate individuals positive on the screening survey. There were 46 people (25 men, 21 women) who suffered from Parkinson's disease (328.3 cases per 1000 population). The age-specific prevalence ratios increased consistently with age. Ageadjusted prevalence ratios were slightly higher for men.

Prevalence of Parkinson's disease in the Parsi community of Bombay, India.

A door-to-door survey was carried out to screen a community of 14,010 people (Parsis living in colonies in Bombay, India) for possible neurologic diseases. High school graduates, social workers, and medical students administered a screening questionnaire that in a pilot survey had a sensitivity of 100% for identifying persons with epilepsy. Neurologists used defined diagnostic criteria to evaluate individuals positive on the screening survey. Sixty-six persons (43 males, 23 females) suffered from epilepsy (4.7 cases/1,000). Of those, 50 (34 males, 16 females) had active epilepsy (3.6 cases/1,000). The age-specific prevalence ratios remained fairly constant for each age group except for a small peak in the group aged 20-39 years for all epilepsy cases combined. Age-adjusted prevalence ratios were higher for males. The most common seizure type was partial (36 cases). The most frequently associated conditions were cerebral palsy and mental retardation. The majority of individuals were receiving medication as of prevalence day (47 cases).

Prevalence of epilepsy in the Parsi community of Bombay.

A door-to-door survey of 14,010 Parsis living in colonies in Bombay, India, screened people for possible neurologic diseases. High school graduates, social workers, and a medical student administered a questionnaire that had been shown in a pilot study to have a sensitivity of 100% for identifying persons with stroke. Neurologists used defined diagnostic criteria to evaluate those who were positive on the screening survey. One hundred eighteen persons (57 men, 61 women) suffered from stroke (842.3 cases/100,000 population). The age-specific prevalence ratios increased with age for both sexes and for each age group. Age-adjusted prevalence ratios were slightly higher for men than for women. The most common type of stroke was ischemic (114 cases).

Prevalence of stroke in the Parsi community of Bombay.

• A door-to-door survey for neurologic diseases was conducted in a community of 14 010 people (Parsis living in colonies in Bombay, India). Neurologists used defined diagnostic criteria to evaluate persons with positive results on the screening survey. Two hundred thirtythree people (104 men; 129 women) were identified as having essential tremor. The overall prevalence ratio was 1591.7 per 100 000 population. Age-specific prevalence ratios increased with age. Ageadjusted prevalence ratios were similar for men and women. To the best of our knowledge, this is the first communitybased survey for essential tremor in Asia.

Prevalence of Essential Tremor in the Parsi Community of Bombay, India

We carried out a door-to-door-survey to screen a community of 14,010 people (Parsis living in colonies in Bombay, India) for possible neurologic diseases, and used defined diagnostic criteria to evaluate people who tested positive on the screening survey. There were three clinically definite cases of multiple sclerosis (21/100,000). This is the first prevalence survey for multiple sclerosis in a large developing country.

Anasuya V. Bhise

Papers

Prevalence of Parkinson's disease in the Parsi community of Bombay, India.

Prevalence of epilepsy in the Parsi community of Bombay.

Prevalence of stroke in the Parsi community of Bombay.

Prevalence of Essential Tremor in the Parsi Community of Bombay, India

Prevalence of multiple sclerosis in the Parsis of Bombay