Related Experiment Videos
ALS incidence in Nova Scotia over a 20-year-period: a prospective study
J P Bonaparte1, I A Grant, T J Benstead
1Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.
Objective:
Previous studies have suggested that the incidence of amyotrophic lateral sclerosis (ALS) in Nova Scotia is relatively high and increasing over time. This study was performed to determine the current incidence of ALS in Nova Scotia and to compare this to data collected in 1984 and 1995.
Methods:
All physiatrists and neurologists were surveyed on a monthly basis over one year to record all new cases of ALS diagnosed in Nova Scotia. Data was compared to that collected using similar methods in 1984 and 1995. To validate our methods, we also performed a retrospective study using a provincial health care database.
Results:
There were 21 new ALS cases in Nova Scotia during the 2003 study period, yielding a crude incidence of 2.24/100,000. The age-adjusted incident rate for 2003 was 2.13 (95% CI = 0.11-4.15). The age-adjusted rate for 1995 was 2.3 (95% CI = 0.08-4.53) while the age-adjusted rate for 1984 was 2.22 (95% CI = 0.13-4.32). Analysis of provincial health records identified 24 cases of ALS and an age-adjusted incidence of 2.44/100,000.
Conclusions:
The age-adjusted incidence of ALS in Nova Scotia has remained stable over the period 1984-2003. The incidence is similar to that reported in several other parts of the world.
Related Concept Videos
Prevalence and Incidence
Prevalence indicates the proportion of individuals in a population who have a specific disease or health condition at a...
Longitudinal Research
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One example of...
Relative Risk
Bias in Epidemiological Studies
Data Collection by Observations
An astronomer viewing the motion and brightness of stars in the sky and recording the data is an example of observational data collection. A botanist recording...