Alzheimer’s & Lifestyle – No Strong Evidence, but . . .

Last week I posted a blog about two lifestyle factors that were linked to the risk of developing cognitive impairment problems – including Alzheimer’s (scroll down to Friday May 27).  The factors were being overweight or obese, and too little or too much sleep.  Both sets of associations were based on studies published in peer-reviewed medical journals.  But, a new article in the Archives of Neurology states that a recent National Institutes of Health Conference an independent panel found “insufficient evidence to support the association of any modifiable factor with risk of cognitive decline or Alzheimer’s disease”. 

The panel’s data base was a systematic collection of publications from 1984 to October 2009, so some recent important studies may not have been included.  The inclusion criteria were quite strict – the people studied had to come from general populations in developed countries, with a minimal cohort size of 300 individuals or 50 for randomized clinical studies, 2 years or more between ‘exposure’ and outcome assessment, and the use of well-accepted diagnostic criteria.

The panel concluded that there was low-quality evidence of associations between diabetes, high blood lipid levels, and tobacco use and an increased risk for Alzheimer’s, and a decreased risk with a Mediterranean-type diet, folic acid intake, low or moderate alcohol intake, cognitive activities, and physical activity. 

There were no studies which had a moderate or high quality of evidence.  Clearly one cannot draw any firm conclusions with this information.  Better, carefully-designed and executed studies are needed.  But a good healthy diet with plenty of physical and mental exercise wouldn’t hurt, and would help ward off a lot of chronic diseases of older people, including diabetes and coronary heart disease.