To the Editor: The Ginkgo Evaluation of Memory (GEM) study by Dr Snitz and colleagues1 provided empirical evidence in a randomized controlled trial that treatment with Ginkgo biloba does not slow the rate of cognitive decline in older adults. Through examination of the effect modification by baseline cognitive status (mild cognitive impairment [MCI] vs normal cognition), the authors concluded that G biloba affected neither cognitive changes associated with dementia prodrome nor cognitive changes associated with normal aging.
Using MCI at baseline to define dementia prodrome vs normal aging in the analysis is debatable. Although MCI is a useful theoretical construct, the distinction between normal cognition and MCI can be very subtle.2 In the GEM study, 324 participants who developed incident dementia during the follow-up period were defined as having normal cognition at baseline.3 It is very likely that there was dementia pathology in the brains of those participants at baseline and that cognitive decline among those participants reflected the cognitive changes associated with incipient dementia rather than the cognitive decline associated with normal aging.
Because of this, it is more appropriate to include incident dementia instead of MCI at baseline as a component of the linear mixed models. By examining the 3-way interaction term treatment × time × incident dementia, the effect of G biloba treatment on age-associated cognitive decline and cognitive changes associated with very early dementia could be differentiated clearly. This is important because preventing cognitive decline in normal aging is surely different from preventing cognitive decline in early dementia.
An earlier article from the GEM study reported that G biloba was not effective in reducing the overall incidence rate of dementia or Alzheimer disease.3 Taken together, results from both articles of the GEM study support the idea that a single agent administered in late life is not likely to be effective. Since multiple factors across the life course influence an individual's brain function in late life,4 - 5 individualized multidomain interventions might be more promising in the prevention of cognitive decline.
Financial Disclosures: Dr Feng reported receiving grant support from the National Medical Research Council, Singapore.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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