Long-distance skiers may have 'motor reserve' that can delay onset of Parkinson's disease

February 11, 2020

Science Daily IOS Press

To better understand the relationship between physical activity and Parkinson's Disease (PD) investigators in Sweden analyzed medical records of nearly 200,000 long-distance skiers who took part in the Vasaloppet cross-country ski race. They established that a physically active lifestyle is associated with close to a 30% reduced risk for PD, which might be explained by a motor reserve among the physically active, however, this dissipates as individuals age. Their results are published in the Journal of Parkinson's Disease (JPD).

Studies have shown the enormous benefits of exercise in many disorders including neurodegenerative diseases, but the reasons are not always clear. "Exercise seems to protect against the motor symptoms of PD but not necessarily against the brain damage caused by PD," explained co-lead investigator Tomas T. Olsson, MD, Department of Neurology, Skåne University Hospital, and Department of Experimental Medical Science, Experimental Dementia Research Unit, Lund University, Lund, Sweden.

"To understand the mechanisms behind the protective effects of exercise it is very important to establish whether exercise gives people a greater reserve or direct protection," noted co-lead investigator Martina Svensson, Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden.

To investigate the degree to which physical activity is associated with long-term lower risk of PD and whether this association can be explained by physically active people being able to sustain more PD neuropathology before the onset of clinical symptoms, investigators analyzed long-term data about the incidence of PD among long-distance skiers. They followed 197,685 participants (median age 36 years; 38% women) in the Vasaloppet, an annual cross-country ski race of up to 90 km, from 1989 to 2010 and compared them to 197,684 age-matched non-skiers. Incidence of PD was taken from the Swedish National Patient Registry

Investigators found that the skiers were almost 30% less likely to develop PD than non-skiers. However, this dissipates with time and increasing age and results in diagnoses of PD among skiers matching the general population.

"We speculate that this would be consistent with the hypothesis that individuals who are physically well-trained have a greater motor reserve, which for every given level of Parkinson's brain damage would result in less motor symptoms thus delaying the diagnosis of PD," noted senior investigator Tomas Deierborg, PhD, Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden. "This is analogous to the well-established concept of cognitive reserve in dementia in which the well-educated can sustain more brain pathology without clinical dementia. It highlights the importance of staying physically active throughout life in order to have a reserve to better cope when the frailties and diseases of old age inevitably arrive."

"If a person is physically active, it may be possible to maintain mobility for longer, despite the pathological changes in the brain," added Dr. Olsson.

JPD's Co-Editor-in-Chief Bastiaan R. Bloem, MD, PhD, Director, Radboudumc Center of Expertise for Parkinson & Movement Disorders, Nijmegen, The Netherlands, commented, "There is an enormous interest in developing new therapies that can help to lower the risk of developing PD. This present study by Olsson and colleagues is particularly exciting in that regard, because it suggests that a readily available intervention -- exercise -- can actually achieve this. The study also provides an explanation why exercise does not offer a complete protection against PD; it supports the motor reserve of the brain, and as such, probably helps to postpone rather than fully prevent the onset of manifest Parkinson symptoms."

PD is a slowly progressive disorder that affects movement, muscle control and balance. It is the second most common age-related neurodegenerative disorder affecting about 3% of the population by the age of 65 and up to 5% of individuals over 85 years of age.

https://www.sciencedaily.com/releases/2020/02/200211104915.htm

Socially active 60-year-olds face lower dementia risk

August 2, 2019

Science Daily/University College London

Being more socially active in your 50s and 60s predicts a lower risk of developing dementia later on, finds a new UCL-led study.

The longitudinal study, published in PLOS Medicine, reports the most robust evidence to date that social contact earlier in life could play an important role in staving off dementia.

"Dementia is a major global health challenge, with one million people expected to have dementia in the UK by 2021, but we also know that one in three cases are potentially preventable," said the study's lead author, Dr Andrew Sommerlad (UCL Psychiatry).

"Here we've found that social contact, in middle age and late life, appears to lower the risk of dementia. This finding could feed into strategies to reduce everyone's risk of developing dementia, adding yet another reason to promote connected communities and find ways to reduce isolation and loneliness."

The research team used data from the Whitehall II study, tracking 10,228 participants who had been asked on six occasions between 1985 and 2013 about their frequency of social contact with friends and relatives. The same participants also completed cognitive testing from 1997 onwards, and researchers referred to the study subjects' electronic health records up until 2017 to see if they were ever diagnosed with dementia.

For the analysis, the research team focused on the relationships between social contact at age 50, 60 and 70, and subsequent incidence of dementia, and whether social contact was linked to cognitive decline, after accounting for other factors such as education, employment, marital status and socioeconomic status.

The researchers found that increased social contact at age 60 is associated with a significantly lower risk of developing dementia later in life. The analysis showed that someone who saw friends almost daily at age 60 was 12% less likely to develop dementia than someone who only saw one or two friends every few months.

They found similarly strong associations between social contact at ages 50 and 70 and subsequent dementia; while those associations did not reach statistical significance, the researchers say that social contact at any age may well have a similar impact on reducing dementia risk.

Social contact in mid to late life was similarly correlated with general cognitive measures.

Previous studies have found a link between social contact and dementia risk, but they did not have such long follow-up times, so they could not rule out the possibility that the beginnings of cognitive decline may have been causing people to see fewer people, rather than the other way around. The long follow-up in the present study strengthens the evidence that social engagement could protect people from dementia in the long run.

The researchers say there are a few explanations for how social contact could reduce dementia risk.

"People who are socially engaged are exercising cognitive skills such as memory and language, which may help them to develop cognitive reserve -- while it may not stop their brains from changing, cognitive reserve could help people cope better with the effects of age and delay any symptoms of dementia," said senior author Professor Gill Livingston (UCL Psychiatry).

"Spending more time with friends could also be good for mental wellbeing, and may correlate with being physically active, both of which can also reduce the risk of developing dementia," added Professor Livingston, who previously led a major international study outlining the lifecourse factors that affect dementia risk.

The researchers were supported by Wellcome and the National Institute for Health Research UCLH Biomedical Research Centre, while the Whitehall II study is supported by the US National Institutes of Health, UK Medical Research Council and the British Heart Foundation.

The study was conducted by researchers in UCL Psychiatry, UCL Epidemiology & Public Health, Camden & Islington NHS Foundation Trust and Inserm.

Dr Kalpa Kharicha, Head of Innovation, Policy and Research at the Campaign to End Loneliness, said: "We welcome these findings that show the benefits of frequent social contact in late/middle age on dementia risk. As we found in our Be More Us Campaign, almost half of UK adults say that their busy lives stop them from connecting with other people. It's important we make changes to our daily lives to ensure we take the time to connect with others. We need more awareness of the benefits that social wellbeing and connectedness can have to tackle social isolation, loneliness and reduce dementia risk."

Fiona Carragher, Chief Policy and Research Officer at Alzheimer's Society, said: "There are many factors to consider before we can confirm for definite whether social isolation is a risk factor or an early sign of the condition -- but this study is a step in the right direction. We are proud of supporting work which helps us understand the condition better -- it is only through research that we can understand true causes of dementia and how best to prevent it.

"As the number of people in the UK with dementia is set to rise to one million by 2021, we must do what we can to reduce our risk -- so along with reducing your alcohol intake and stopping smoking, we encourage people across the country to get out into the sunshine, and do something active with family and friends.

"The Government's recent emphasis on health prevention is a welcome opportunity to reduce the risk of dementia across society. We now need to see Ministers prioritise better support initiatives to help people reduce the risk of dementia, and look forward to seeing this when the results of the Green Paper on Prevention are published later in the year."

https://www.sciencedaily.com/releases/2019/08/190802144414.htm