Gait speed at usual pace as a predictor of adverse outcomes in community-dwelling older people an International Academy on Nutrition and Aging (IANA) Task Force

INTRODUCTION

The use of a simple, safe, and easy to perform assessment tool, like gait speed, to evaluate vulnerability to adverse outcomes in community-dwelling older people is appealing, but its predictive capacity is still questioned. The present manuscript summarises the conclusions of an expert panel in the domain of physical performance measures and frailty in older people, who reviewed and discussed the existing literature in a 2-day meeting held in Toulouse, France on March 12-13, 2009. The aim of the IANA Task Force was to state if, in the light of actual scientific evidence, gait speed assessed at usual pace had the capacity to identify community-dwelling older people at risk of adverse outcomes, and if gait speed could be used as a single-item tool instead of more comprehensive but more time-consuming assessment instruments.

METHODS

A systematic review of literature was performed prior to the meeting (Medline search and additional pearling of reference lists and key-articles supplied by Task Force members). Manuscripts were retained for the present revision only when a high level of evidence was present following 4 pre-selected criteria: a) gait speed, at usual pace, had to be specifically assessed as a single-item tool, b) gait speed should be measured over a short distance, c) at baseline, participants had to be autonomous, community-dwelling older people, and d) the evaluation of onset of adverse outcomes (i.e. disability, cognitive impairment, institutionalisation, falls, and/or mortality) had to be assessed longitudinally over time. Based on the prior criteria, a final selection of 27 articles was used for the present manuscript.

RESULTS

Gait speed at usual pace was found to be a consistent risk factor for disability, cognitive impairment, institutionalisation, falls, and/or mortality. In predicting these adverse outcomes over time, gait speed was at least as sensible as composite tools.

CONCLUSIONS

Although more specific surveys needs to be performed, there is sufficient evidence to state that gait speed identifies autonomous community-dwelling older people at risk of adverse outcomes and can be used as a single-item assessment tool. The assessment at usual pace over 4 meters was the most often used method in literature and might represent a quick, safe, inexpensive and highly reliable instrument to be implemented.

Prevention of progression to dementia in the elderly: rationale and proposal for a health-promoting memory consultation (an IANA Task Force)

Alzheimer's disease (AD) is the most frequent form of dementia and according to the most recent estimation it affects nearly 27 million people in the world. The onset of the disease is generally insidious. It is becoming increasingly evident that the underlying pathophysiological mechanisms are active long before the appearance of the clinical symptoms of the disease. In the current context, it is important to develop strategies to delay the onset of cognitive decline. Delaying the onset by 5 years would reduce the prevalence by half at term, and a delay of 10 years would reduce it by three-quarters. The effectiveness of currently suggested preventive approaches remains to be confirmed, but certain strategies could be applied straight away to at-risk subjects. We propose that a health-promoting memory consultation should be set up for elderly persons who have attended a specialized memory consultation and in whom the diagnosis of dementia and of AD in particular, has not been established by standardized tools. Through this consultation, they would be offered full multidimensional investigation of all aspects of their health status, follow-up could be organized, general practitioners in private practice could be made more conscious of this population and the elderly could be made more aware of the risk factors to which they are exposed. The development of an information policy for the elderly would meet a present need. In our reflection, we must take into account the question of how to give this preventive consultation its due place in the healthcare pathway of the elderly person in order to ensure coordinated follow-up with all the other health professionals involved. The principle of the health-promoting memory consultation is undergoing validation in a large French multicentre preventive trial in 1200 frail elderly persons aged 70 years followed for three years, the Multidomain Alzheimer Preventive Trial (MAPT).

IANA task force on nutrition and cognitive decline with aging

Cognitive impairment can be influenced by a number of factors. The potential effect of nutrition has become a topic of increasing scientific and public interest. In particular, there are arguments that nutrients (food and/or supplements) such as vitamins, trace minerals, lipids, can affect the risk of cognitive decline and dementia, especially in frail elderly people at risk of deficiencies. Our objective in this paper is to review data relating diet to risk of cognitive decline and dementia, especially Alzheimer's disease (AD). We chose to focus our statements on homocysteine-related vitamins (B-vitamins), antioxidant nutrients (vitamins E and C, carotenoids, flavonoids, enzymatic cofactors) and dietary lipids. Results of epidemiological studies may sometimes appeared conflicting; however, certain associations are frequently found. High intake of saturated and trans-unsaturated (hydrogenated) fats were positively associated with increased risk of AD, whereas intake of polyunsaturated and monounsaturated fats were protective against cognitive decline in the elderly in prospective studies. Fish consumption has been associated with lower risk of AD in longitudinal cohort studies. Moreover, epidemiologic data suggest a protective role of the B-vitamins, especially vitamins B9 and B12, on cognitive decline and dementia. Finally, the results on antioxidant nutrients may suggest the importance of having a balanced combination of several antioxidant nutrients to exert a significant effect on the prevention of cognitive decline and dementia, while taking into account the potential adverse effects of these nutrients. There is no lack of attractive hypotheses to support research on the relationships between nutrition and cognitive decline. It is important to stress the need to develop further prospective studies of sufficiently long duration, including subjects whose diet is monitored at a sufficiently early stage or at least before disease or cognitive decline exist. Meta analyses should be developed, and on the basis of their results the most appropriate interventional studies can be planned. These studies must control for the greatest number of known confounding factors and take into account the impact of the standard social determinants of food habits, such as the regional cultures, social status, and educational level.

The potential influence of silica present in drinking water on Alzheimer's disease and associated disorders

Silica present in drinking water may be protective with respect to the decrease of cognitive function as it was suggested by several epidemiologic studies. Data from French cohort have demonstrated that aluminium in drinking water seems to have a deleterious effect and increased the risk of cognitive impairment when the silica concentrations were low. Moreover, it has been shown that the performances to a cognitive test were positively correlated to the consumption of silica and that the risk of Alzheimer's disease (AD) was reduced in subjects who had the higher daily silica intake compared to the others. The silica is probably the natural antidote of the aluminium and could play a benefit role by decreasing the biodisponibility of aluminium, whose neurotoxicity is now clearly established. Data have suggested the possible use of silicates as a therapeutic agent for AD since both model tangles and precipitated beta-pleated sheets of betaA4 can be reversed to soluble forms by silicates. The role of silica in drinking water on cognitive function has been however little studied and clear results have not yet emerge. The potential benefit of silica needs to be confirmed in additional investigations to exclude causes of error related to certain methodological biases. If such association do indeed exist, interventional strategies could be set up to reduce the incidence of AD. The aim of this paper is to review articles published on silica present in drinking water in relation with AD and associated disorders.

IANA (International Academy on Nutrition and Aging) Expert Group: weight loss and Alzheimer's disease

Weight loss, together with psychological and behavioural symptoms and problems of mobility, is one of the principal manifestations of Alzheimer's disease (AD). Weight loss may be associated with protein and energy malnutrition leading to severe complications (alteration of the immune system, muscular atrophy, loss of independence). Various explanations have been proposed such as atrophy of the mesial temporal cortex, biological disturbances, or feeding behaviours; however, none has been proven. Prevention of weight loss in AD is a major issue. It requires regular follow-up and must be an integral part of the care plan. The aim of this article is to review the present state of scientific knowledge on weight loss associated with AD. We will consider four points: the natural history of weight loss, its known etiological factors, its consequences and the various management options.