Exercise as it relates to Disease/Can training the heart combat the risk of cognitive decline and dementia?

This is an analysis of the journal article "Physical Activity and Risk of Cognitive Impairment and Dementia in Elderly Persons" by Laurin et al (2001)

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What is the background to this research?
Dementia is a disease in the brain that causes a progressive decline in cognitive and motor functions.

The cause of dementia is said to be linked to age, socioeconomics, education and lifestyle; symptoms may include but are not limited to:
 * Memory loss
 * Irritability/aggression
 * Out of the ordinary behaviour
 * Impaired perception and
 * Major depression

The prevalence of dementia is around 6-10% of individuals 65 years and older, and as we age the risk becomes greater. As of 2010, over 35million people lived with dementia with this number expected to double every 20 years to over 65million in 2030 and over 115million by 2050.

The aim of this study was to explore any correlations between physical activity and the risk of cognitive declined and dementia.

Where was this research from?
This study was coordinated through the University of Ottawa and the Division of Aging and Seniors, Health Canada.

What kind of research was this?
A case-control approach was used for this research with data coming from a prospective cohort study run by the Canadian Study of Health and Ageing (CSHA). This type of study will compare a population with a specific disease (Case group) to a population without the disease (Control group) and retrospectively look back to observe and determine factors that predispose them to a disease.

What did the research involve?
This research involved sourcing data from subjects with the CHSA prospective cohort study designed on the prevalence, incidence, and risk factors for dementia in elderly Canadians. As background, subjects in this study completed a screening and/or 3-stage clinical evaluation, including an interview on physical activity, health and medical status. Subjects without dementia also completed a self-administered risk factor questionnaire.

The researchers in this study used a case-control approach, subjects who remained without cognitive impairment or dementia at the end of cohort study, served as controls. Subjects with cognitive impairment or any type of dementia served as cases. Five separate analyses were performed in exploring the associations between exercise on cognitive loss and dementia. Age, sex, education, family and medical history, lifestyle, functional ability and self-rated health were factors taken into consideration within the analysis.

Some limitations did exist with this study such as self-reported health and levels of physical activity, it has been shown that people tend to over or under report on exercise. The type of exercise was not specified i.e. resistance or aerobic. Given this was a crucial measure, more information and clearer definitions would hold more merit. There was also a higher number of women participants than men, in addition the research is over 15 years old.

What were the basic results?
Overall, physical activity in the elderly was associated with a reduced risk of cognitive impairment or dementia compared to subjects that didn’t exercise.

From the original CHSA sample, there was 4615 eligible subjects for this study. 3894 subjects remained with no cognitive impairment or dementia (controls), 436 were diagnosed as having cognitive impairment - no dementia (CIND), 194 Alzheimer disease, 61 vascular dementia, and 30 other specific or unclassifiable dementia (cases).

Some of the key findings:
 * Subjects without any type of dementia were younger and had more years of education (avg 72 years and 11 years respectively) compared to those with CIND (78years and 9years) or dementia (80yrs and 10yrs). Gender had no major influence.
 * Reported regular exercise was more frequent for controls compared with CIND or dementia subjects
 * Moderate and high levels of physical activity were associated with significantly lower risks for CIND and most types of dementia
 * Regular exercise was associated with lower risks of CIND, Alzheimer disease, and dementia, this was observed in both genders however significant in women

The researchers found in their study that regular physical activity may slow down or prevent the onset of cognitive impairment and dementia in the elderly, with a notably higher correlation in women.

It was also suggested by the researchers that engaging in regular physical activity is not only good practice but could be potent protective factor against such diseases.

What conclusions can we take from this research?
This research has demonstrated positive results in preventing or delaying the onset of cognitive decline or dementia by being physically active in elderly. Although it was identified that higher intensity levels of exercise significantly reduced the risk, the type of exercise was unknown.

As the researchers noted, this was the first known study to show exercise as a potential protective measure to dementia, however the actual mechanisms as to how it helped were unclear.

More recent research has shown the effects of different types of exercise (resistance vs aerobic vs both) and cognitive decline and the underlying mechanisms however further research is required in these fields.

Practical advice
Dementia is a major health concern in Australia and worldwide, with the prevalence said to increase. Not only does this impact the individual and their families/caregivers but it is also an economic burden to both those impacted and on the public health system.

This research has shown that exercise can be a preventative measure against the onset of cognitive decline and dementia. Further research is required in studying the cause and effect including comparison of treatments in preventing dementia.

Further Information/Readings
For further information on the role exercise plays in reducing the risk of cognitive decline and dementia, please refer to the links below; alternatively contact the National Dementia Helpline on 1800 100 500 or consult with your health professional:
 * About Dementia - https://www.fightdementia.org.au/national/about-dementia
 * Frequently asked questions about Dementia - https://www.fightdementia.org.au/about-dementia-and-memory-loss/FAQs
 * Early Signs of Dementia - https://www.fightdementia.org.au/national/about-dementia/how-can-i-find-out-more/warning-signs-of-dementia
 * Physical exercise and Dementia: https://www.fightdementia.org.au/files/helpsheets/Helpsheet-DementiaQandA08-PhysicalExercise_english.pdf
 * Dementia preventative measures: http://www.helpguide.org/articles/alzheimers-dementia/alzheimers-and-dementia-prevention.htm