A few personal thoughts to round the year off.

At Predict-PD Towers we have had a busy and successful year. We have rebuilt the website from scratch, taking the opportunity to really review all the questions in the surveys, and select the very best questions to help us answer our research questions. We have pioneered new techniques that are now included in the website, including an online trailmaking task and making the tap-test even better. We have made excellent progress with the imaging substudy: selecting some high risk and similar low risk controls to see if we can see some of the early changes associated with Parkinson’s using cutting edge MRI techniques. We’ve been travelling the length and breadth of the country seeing many of the participants in our ‘special groups’: people with smell loss, and people with a certain kind of sleep disorder, to conduct physical and cognitive examinations in their own homes. We have grown our team allowing us to do similar in person assessments in the homes of many of our ‘regular’ participants, and now have some specialist statistical and techincal data management help. Most crucially of all, we have launched the second phase of the study, in which we aim to recruit 10,000 new participants aged 60-80 – please spread the word, and encourage as many friends and relatives to head to the website (www.predictpd.com) and consider taking part. It takes only about 25 minutes and could potentially change the future of Parkinson’s disease.

I also wanted to reflect on the festive period and what advice or suggestions I could make to individuals or families with someone who has Parkinson’s.

Christmas is a time for family and celebration. When someone has Parkinson’s not only can movement be slow, but many non-motor symptoms can make this time of year hard. Depression, apathy and difficulty keeping up with conversations can make participation in family events so much harder. If Parkinson’s affects your family, friends or neighbours, please try and make the effort not to leave them behind. Social and physical exercise are vital to people with Parkinson’s, so make the effort to make that easy. The post-Christmas lunch walk may doesn’t need to be fast, but by making it inclusive you’ll make a real difference.

Another, far less pleasant aspect of this time of year, is flu. Flu continues to be a significant cause of illness and even death, and although there is no magic bullet, for many people it is potentially preventable. The simplest things are the most effective: handwashing with soap and water (especially after using public transport, before eating, and after coughing and sneezing), using disposable tissues (catch it, bin it, kill it), and the flu jab. It is worth busting a few common flu-jab myths: the immunisation does not contain the live virus – therefore you cannot catch the flu from the jab. While the recommended time to have the jab is October – November, flu cases continue to be common all the way through to the end of March, so better late than never. Each year the vaccine covers different strains of the flu, so that is why it is recommended to have it every year. This also means that the vaccine won’t protect you from evey strain  of flu (there are hundreds), but it will protect you from the ones that are likely to be the most common each year. Being otherwise healthy doesn’t protect you: despite running around 50 miles a week and generally enjoying excellent health, I’ve had a grotty end to the year, with the flu, which then predisposed me to pneumonia (and as a responsible health professional, yes I did get the jab in October, but that just means I was unlucky, and would still recommend it). 

We are of course indebted and grateful to Parkinson's UK for the funding that has allowed us to do this research, and for the support they continue to give. I'm looking forward to my first training run on Christmas day for the London Marathon, where I'll be aiming to break both my targets: under 3 hour finishing time and over £2500 for Parkinson's UK (http://bit.ly/RNR4Parkinsons for those that are interested).

Finally, from the entire team at Predict-PD, we thank you for your interest and participation throughout this year, and wish you and your family a very merry Christmas, and a happy and healthy 2019.

RNR

Raising a glass to Parkinson's?

Lifestyle factors have been studied at length in relation to Parkinson's Disease and there is good evidence that having ever smoked is associated with reduced risk of the disease. Alcohol drinking has also been linked to reduced risk of disease, and multiple studies have looked at the association. The difficulty with drawing robust conclusions in this area relates to the design of the studies - many of the studies are case control, taking people with and without the disease and asking them to report whether and how much they drink now and in the past. This kind of study suffers from problems with bias - if you have been diagnosed with the disease you are more likely to have attended hospital, to be the kind of person who worries about their health and so makes more health-conscious choices, you may recall things differently in light of your diagnosis and you are likely to have made different choices subsequent to diagnosis.

Longitudinal studies of populations who are healthy at baseline are less likely to suffer from these biases as reporting of alcohol consumption is made prior to subsequent diagnosis. This problem with investigating causation in medicine is illustrated nicely by a study published in the Journal of Neurology by a Spanish team. They looked at 31 studies in the field and broke down the analysis into different types of study as well as looking seperately at men and women and different ways of classifying alcohol consumption.

When looking at the case-control studies, as in previous studies, they found higher numbers of 'never-drinkers' in the group with Parkinson's. However, when looking at longitudinal studies, there was no difference in having ever drunk alcohol between people who went on to develop Parkinson's and people who didn't. However, there were far more case-control studies in the article, giving more power to detect these kind of effects, as  you can see in the diagram below.

Pooled odds ratios comparing "never drinking" to "ever drinking"alcohol in a)case control and b)prospective longitudinal studies, showing higher likelihood of Parkinson's disease in those who never drank in case control but not longitudinal studies. From https://link.springer.com/article/10.1007/s00415-018-9032-3 

All in all, alcohol consumption remains an interesting part of the puzzle of Parkinson's causation, especially given possible genetic links the authors discuss between variants of the alcohol dehydrogenase gene which cause adverse effects of alcohol and dopaminergic function. In the PREDICT-PD study we are collecting data on alcohol use in all of our participants and will continue to study these links.

-Anna

J Neurol. 2018 Aug 28. doi: 10.1007/s00415-018-9032-3. [Epub ahead of print]

Alcohol consumption and risk for Parkinson's disease: a systematic review and meta-analysis.

Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JAG

The possibility that alcohol consumption should be considered as a "protective factor" for Parkinson's disease (PD) has been suggested by several case-control studies. However, other case-control studies and data from prospective longitudinal cohort studies have been inconclusive. We carried out a systematic review which included all the eligible studies published on PD risk related with alcohol consumption, and conducted a meta-analysis according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The systematic review was performed using two databases, and the meta-analysis of the eligible studies with the software Meta-Disc1.1.1. Heterogeneity between studies was tested with the Q-statistic. The meta-analysis included 26 eligible retrospective case-control studies (8798 PD patients, 15,699 controls) and 5 prospective longitudinal cohort studies (2404 PD patients, 600,592 controls) on alcohol consumption and PD. In retrospective case-control studies the frequency of PD patients never drinkers was higher and the frequency of heavy + moderate drinkers was lower [diagnostic OR (95% CI) 1.33(1.20-1.48) and 0.74(0.64-0.85)], respectively, when compared to healthy controls. In contrast, in prospective studies, the differences were not significant with the exception of a trend towards a higher frequency of non-drinkers in PD women and a significantly lower frequency of moderate + heavy drinkers in PD men in those studies which stratified data by gender. The present meta-analysis suggests an inverse association between alcohol consumption and PD, which is supported by the results of case-control studies but not clearly by prospective ones.