Epidemiology of ALS

Around the world, a good deal of research is being undertaken into amyotrophic lateral sclerosis (ALS). Efforts have been boosted in recent years through the Ice Bucket Challenge which not only created more awareness about the disease but also raised significant money for research.

Scientists and medical professionals will focus on a variety of different areas to gain a better understanding of the disease. Some are taking on genetic research, others are looking at the mechanics of how this neurodegenerative disease affects the body. There are others working on developing medications which can slow the progression of the disease and alleviate the associated symptoms.

One research area that is helping gain a better overall understanding of ALS is epidemiology.

What is Epidemiology?

Epidemiology is a branch of research that looks at connections between a range of different factors. Studies are used to better inform other research and how potential future solutions are advanced. For example, an ALS epidemiology study may look at the connection between ALS and gender or investigate its incidence and prevalence in certain populations.

It may look at what factors are likely to put people at risk, often comparing data from people who are not affected by the disease. Over the years, this kind of ALS epidemiology research has uncovered many different relationships and allowed for a better understanding of the disease, who it affects and how prevalent it is.

ALS Incidence

Incidence is defined as the number of people who are diagnosed with the disease each year. In the US, some 5,000 people are diagnosed annually but this incidence can vary with age. The average number of new cases in the world population is 1.8 to 2 per 100,000.

The average age at which someone is likely to develop ALS is between 55 and 65. People over the age of 60 are more likely to be diagnosed with the disease than any other group. ALS does occur in younger people but to a much smaller degree.

ALS Prevalence

ALS prevalence differs from incidence as it refers to the number of people currently diagnosed and living with the disease. In the USA, there are thought to be between 15,000 and 21,000 people living with ALS. The worldwide prevalence is thought to be about 1 in 20,000 at any given time.

As with incidence, ALS prevalence is higher in older individuals than younger people. The highest worldwide prevalence is in the 70-79 age group.

Male vs Female Prevalence

Is ALS more prevalent in men or women? This is a question that is often asked in epidemiology studies as it can be a defining factor in research and treatment. In general, ALS is more prevalent in men than women – it occurs 1.56 more frequently in males.

Risk Factors

ALS epidemiology looks at certain risk factors to see if people are more likely to get the disease or whether certain activities contribute to developing it. There have been some interesting pieces of research in this area.

Recent studies have found that those who served in the military may be more likely to be diagnosed with ALS than those in the general population. Whilst this is a striking research finding, there is not much evidence at the moment as to why this should be the case.

There has been more study undertaken in the field of genetic risk factors.

Researchers have found that around 10% of cases have a genetic or familial component. That means if a parent had the gene for the disease (even if they didn’t develop ALS), they could pass it on to their son or daughter.

It is early days in the arena of ALS genetic research, but there does seem to be growing evidence that our genes could play a more important role in many more cases than what was first thought.

There is currently no cure for ALS and that makes undertaking the right research essential in the fight to combat this disease. ALS epidemiology has helped provide the framework for that research and allows us to find the connections which may eventually lead to a cure in the future.