From: 23x11.5c@gmail.com   
      
   RELIABLE MENTAL HEALTH RESEARCH, POLICY AND GUIDANCE   
   The Mental Elf   
      
      
      
      
   Lifestyle changes for cognition and dementia: better than a new drug?   
      
      
   NOV   
   21   
   2014   
      
   Mark Horowitz   
   Posted by   
   Mark Horowitz   
      
      
   Cognitive impairment and the dementias, of which Alzheimer's disease is the   
   most common, are some of the largest health challenges to our society. There   
   are 50 million people with dementia worldwide, and this has been projected to   
   increase to 180 million    
   by 2050. There are about 180,000 new cases of dementia each year in the UK   
   alone.   
      
   Following the usual interventionist model, we look to advances in molecular   
   pathology and pharmacology to provide treatments for dementia.  Sadly, the   
   best current drug treatment only delays the symptoms by a modest time period,   
   perhaps months (Ballard    
   et al, 2011).   
      
   Could a different answer be right under our nose?  What if we could reduce the   
   burden of dementia markedly just by changing our lifestyle?   
      
   A recent systematic review and meta-analysis sheds some interesting light on   
   these questions (Beydoun et al, 2014).   
      
   Is it possible that we should be prescribing parklife?   
   Should we be prescribing parklife?   
   Methods   
      
   The authors wanted to determine what proportion of cognitive health outcomes,   
   including Alzheimer's disease, could be attributed to modifiable risk factors.   
      
   To do this they conducted a systematic review and meta-analysis of   
   cross-sectional and cohort studies in MEDLINE.   
      
   The following factors were focused on, with exposure defined in brackets:   
      
   Socio-economic status as indicated by educational level (less than 8 years);   
   Smoking status (ever smoked);   
   Homocysteine levels (low);   
   Omega-3 Fatty Acids (low);   
   Physical activity (<2-3 times per week).   
   They calculated the risk ratio of incident Alzheimer's disease based on   
   presence of the risk factor.   
      
   They also calculated the population-attributable risk (PAR), a measure of how   
   much a disease would be reduced in incidence if a risk factor was eliminated   
   entirely.   
      
   The authors ignored every database except MEDLINE, which is a serious weakness   
   in their methodology.   
   The authors ignored every database except MEDLINE, which is a serious weakness   
   in their methodology.   
   Results   
      
   31 studies (with samples sizes>300) were entered into the meta-analysis.   
      
   Meta-analysis found that:   
      
   Lower educational status increased your risk of AD by almost double (RR=1.99,   
   95% CI: 1.30 to 3.04)   
   A high homocysteine level increased your risk almost by double as well   
   (RR=1.93, 95% CI: 1.50 to 2.49)   
   Having ever smoked increased your risk of AD by 37% (95% CI: 23-52%)   
   Higher physical activity decreased your risk by 42% (95% CI: 30-51%)   
   Increased intake of omega-3 fatty acids decreased your risk by 33% (95% CI:   
   4-53%)   
   For physical activity the PAR was 31.9% (95% CI: 22.7-41.2%)   
   This means that if everyone in the UK was to move out of the category of   
   'physically inactive' there would be almost a third less cases of Alzheimer's,   
   equating to 60,000 less new cases a year in the UK   
   For smoking the PAR was 31.09% (95% CI: 17.9-44.3%), meaning if everyone in   
   the UK was a non-smoker there would also be about a decrease of a third in the   
   incidence of Alzheimer's.   
   Publication bias was not found to be present in the studies used for the   
   meta-analysis.   
      
   There was found to be significant heterogeneity in the studies of education   
   and smoking, but other studies were found to be largely homogeneous.   
      
   It seemed like such a good idea at the time, but this review suggests that   
   bunking off school for a fag may increase your risk   
   It seemed like such a good idea at the time, but could bunking off school for   
   a fag actually increase your risk of Alzheimer's Disease?   
   Limitations   
      
   However, there are several pinches of salt to take with this heady meal.   
      
   Only one medical database was used (MEDLINE), so it's highly likely that   
   studies exist that could have been included in the review   
   Significant heterogeneity was detected in the studies, which explored the   
   effect of smoking and education   
   There was no quality assessment of the individual studies   
   The attribution of causation is limited as all studies were observational   
   It is worth noting, however, how consistent this paper's findings are with   
   another study recently published in Lancet Neurology (Norton et al, 2014),   
   which found the population-attributable risk for Alzheimer's to be:   
      
   19% for low educational attainment;   
   22% for physical activity;   
   and attributed 30-50% of all Alzheimer's cases to seven modifiable risk   
   factors.   
   There are significant limitations with this review, but given that drug   
   treatments have many problems in this population, we should be looking at this   
   in detail.   
   There are significant limitations with this review, but given that drug   
   treatments have many problems in this population, clinicians and other   
   researchers should be looking at this evidence in detail.   
   Conclusions   
      
   Despite the limitations of this study, and the lack of clear evidence of   
   causation, the findings of a number of studies demonstrating the link between   
   cognitive outcomes, including Alzheimer's disease, and modifiable risk factors   
   are startling.   
      
   The size of the effects detected are particularly interesting in comparison to   
   the, at best, modest effects of the best drugs available.   
      
   Is it heretical in our age of technological enthusiasm to suggest that the   
   best way to reduce the incidence of these devastating diseases involves change   
   at the level of our societies (in healthcare, research funding and lifestyles)   
   rather than at the    
   level of protein folding? Could we change the way we eat, the way we travel,   
   target socioeconomic disadvantage, and the complex social issues underlying   
   tobacco and obesity use to tackle this problem?   
      
   Is that really so much more difficult than spending billions of dollars trying   
   to understand the most complex system yet encountered (the human brain) and   
   then attempt to find a molecular switch that will reverse the accumulated   
   damage of years of    
   neurotoxic living?   
      
   Research waste   
      
   Could the research that we conduct also connect up to the social implications   
   for our society more closely? The issue of wasted research funding has been   
   addressed recently by a series in the Lancet. These papers suggested that up   
   to 85% of the 240    
   billion dollars spent each year on biomedical research was wasted.   
      
   In particular, waste is caused by:   
      
   Funding medical research that does not match the actual needs of the public   
   Ignoring what is already known   
      
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