Buchman AS, Bennett DA
J Nutr Health Aging 2013;17:738-9
Publication date: November 1, 2013
The authors comment on the report of an international consensus conference on cognitive frailty published in the September 2013 of the Journal of Nutrition, Health & Aging.
While most studies examine late-life cognitive impairment and physical frailty separately, physical frailty, whose core features include loss of strength and muscle bulk, slowed gait and fatigue, may share a common etiopathogenesis with late-life cognitive impairment.
Cognitive frailty, defined as a syndrome in older adults with evidence of both physical frailty and cognitive impairment without a clinical diagnosis of AD or another dementia, extends the prior physical frailty construct in two ways. First, it adds a formal assessment of cognitive function. Second, it recommends a more comprehensive assessment of depressive symptoms to capture psychological in additional to physical aspects of fatigue.
Considering both physical frailty and cognition together as a single complex phenotype may have important clinical and research implications. Since both physical frailty and cognition predict adverse health outcomes, their co-occurrence is likely to identify people at particularly high risk. However, it is also likely that some individuals manifesting the proposed criteria for cognitive frailty may be particularly vulnerable due to combined risks and may be less responsive to interventions.
Decomposing complex heterogeneous phenotypes into smaller components can offer insights into common features and facets which might not be apparent if multiple clinical domains are summarized into a single complex clinical phenotype. However, eventually the decomposed clinical components must be reassembled as a range of phenotypes emerge and manifest in aging humans.
Aging research is complex and needs both efforts, i.e. efforts to develop more complex clinical phenotypes such as cognitive frailty while simultaneously pursuing studies which carefully deconstruct these phenotypes into dissociable components. These complementary research efforts are essential to facilitate the discovery and implementation of effective approaches to improve the health and well-being of the aging population worldwide.