Wednesday, December 7, 2011

The Joy of Meta

Here is an abstract from the very latest in autism research:

Recent studies have implicated physiological and metabolic abnormalities in autism spectrum disorders (ASD) and other psychiatric disorders, particularly immune dysregulation or inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures (‘four major areas’). The aim of this study was to determine trends in the literature on these topics with respect to ASD. A comprehensive literature search from 1971 to 2010 was performed in these four major areas in ASD with three objectives. First, publications were divided by several criteria, including whether or not they implicated an association between the physiological abnormality and ASD. A large percentage of publications implicated an association between ASD and immune dysregulation/inflammation (416 out of 437 publications, 95%), oxidative stress (all 115), mitochondrial dysfunction (145 of 153, 95%) and toxicant exposures (170 of 190, 89%). Second, the strength of evidence for publications in each area was computed using a validated scale. The strongest evidence was for immune dysregulation/inflammation and oxidative stress, followed by toxicant exposures and mitochondrial dysfunction. In all areas, at least 45% of the publications were rated as providing strong evidence for an association between the physiological abnormalities and ASD. Third, the time trends in the four major areas were compared with trends in neuroimaging, neuropathology, theory of mind and genetics (‘four comparison areas’). The number of publications per 5-year block in all eight areas was calculated in order to identify significant changes in trends. Prior to 1986, only 12 publications were identified in the four major areas and 51 in the four comparison areas (42 for genetics). For each 5-year period, the total number of publications in the eight combined areas increased progressively. Most publications (552 of 895, 62%) in the four major areas were published in the last 5 years (2006–2010). Evaluation of trends between the four major areas and the four comparison areas demonstrated that the largest relative growth was in immune dysregulation/inflammation, oxidative stress, toxicant exposures, genetics and neuroimaging. Research on mitochondrial dysfunction started growing in the last 5 years. Theory of mind and neuropathology research has declined in recent years. Although most publications implicated an association between the four major areas and ASD, publication bias may have led to an overestimation of this association. Further research into these physiological areas may provide insight into general or subset-specific processes that could contribute to the development of ASD and other psychiatric disorders.

I'm not sure how badly you'll want to delve into all that verbiage, but in short it's an assessment of various "abnormalities" associated with autism through the means of looking at research publication trends. For instance, the association of mitochondrial dysfunction with autism is assessed by looking at the rising number of mitochondria-autism research articles published over the calendar years from 1971 to 2010. It's the type of work that can be done with a good search engine and a spreadsheet program (3D color graphics would be a bonus).

In other words, it's a shitty piece of meta-analysis.

Of course, there have been better examples of meta-analysis applied to autism research, but this raises an intriguing question. How does one differentiate good meta-analysis from bad meta-analysis (think of how important this will be to Ben Goldacre as he's writing his next book, Bad Meta Science)? Well obviously, what we need to do is institute some standards, protocols and ethics for the general practice of meta-analysis, and once these are in place we can begin performing meta-analyses of all the meta-analyses. And if there happen to be any lingering problems, we can just ask Janet Stemwedel to remind the tribe of meta scientists of all their meta social duties.

No really. I think this would be a fruitful line of endeavor. As far as I can tell, the possibilities for employment are unlimited.

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