Alan Dangour and colleagues report results from the CENEX (Cost-effectiveness
Evaluation of a Nutritional supplement and EXercise program for older people)
trial, which evaluates a nutritional and exercise program aiming to prevent
pneumonia and physical decline in Chilean people.
Background
Ageing is associated with increased risk of poor health and functional
decline. Uncertainties about the health-related benefits of nutrition and
physical activity for older people have precluded their widespread
implementation. We investigated the effectiveness and cost-effectiveness of
a national nutritional supplementation program and/or a physical activity
intervention among older people in Chile.
Methods and Findings
We conducted a cluster randomized factorial trial among low to middle
socioeconomic status adults aged 65–67.9 years living in Santiago,
Chile. We randomized 28 clusters (health centers) into the study and
recruited 2,799 individuals in 2005 (∼100 per cluster). The
interventions were a daily micronutrient-rich nutritional supplement, or two
1-hour physical activity classes per week, or both interventions, or
neither, for 24 months. The primary outcomes, assessed blind to allocation,
were incidence of pneumonia over 24 months, and physical function assessed
by walking capacity 24 months after enrolment. Adherence was good for the
nutritional supplement (∼75%), and moderate for the physical
activity intervention (∼43%). Over 24 months the incidence rate
of pneumonia did not differ between intervention and control clusters (32.5
versus 32.6 per 1,000 person years respectively; risk
ratio = 1.00; 95% confidence interval
0.61–1.63; p = 0.99). In
intention-to-treat analysis, after 24 months there was a significant
difference in walking capacity between the intervention and control clusters
(mean difference 33.8 meters; 95% confidence interval
13.9–53.8; p = 0.001). The
overall cost of the physical activity intervention over 24 months was
US$164/participant; equivalent to US$4.84/extra meter walked.
The number of falls and fractures was balanced across physical activity
intervention arms and no serious adverse events were reported for either
intervention.
Conclusions
Chile's nutritional supplementation program for older people is not
effective in reducing the incidence of pneumonia. This trial suggests that
the provision of locally accessible physical activity classes in a
transition economy population can be a cost-effective means of enhancing
physical function in later life.
Trial registration
Current Controlled Trials ISRCTN 48153354
Please see later in the article for the Editors' Summary
Editors' Summary
Background
By 2050, about a quarter of the world's population will be aged 60 years
or over, with Asia and Latin America experiencing the most dramatic
increases in the proportion of older people. For example, in Chile, which
has recently undergone rapid demographic transition, the proportion of the
population aged 60 years or over has increased from 8% to 12%
over the past 25 years.
Current global policy initiatives that promote healthy ageing include an
emphasis on adequate nutrient intakes, as longitudinal studies (conducted in
high-income countries) suggest that achieving nutritional sufficiency and
maintaining moderate levels of physical activity both decrease risk of
mortality by preserving immune function and lean body mass and so reduce the
numerous risk factors for disability and chronic disease in later life. Such
interventions may also decrease the risk of infection, particularly
pneumonia, a common cause of death in older people. However, older people in
low- and middle-income countries frequently have diets with insufficient
calories (energy) and/or micronutrients.
Why Was This Study Done?
Currently, there is no high-quality evidence to support the benefits of
improved nutrition and increased physical activity levels from low-income or
transition economies, where the ongoing demographic trends suggest that the
needs are greatest. National policies aimed at preserving health and
function in older people with interventions such as cash-transfers and
provision of “food baskets” are often used in Latin American
countries, such as Chile, but are rarely formally evaluated. Therefore, the
purpose of this study (the Cost-effectiveness Evaluation of a Nutritional
supplement and EXercise program for older people—CENEX) was to
evaluate Chile's national nutritional supplementation program and/or
physical exercise, to investigate whether this program prevented pneumonia
and physical functional decline in older people in Santiago, and also to
investigate whether these interventions were cost-effective.
What Did the Researchers Do and Find?
The researchers randomly allocated 28 participating health centers in
Santiago, Chile, into one of four arms: (1) nutritional supplementation; (2)
nutritional supplementation+physical activity; (3) physical activity
alone; (4) control. From May to December 2005, 2,799 eligible adults aged
65–67.9 years and living in low to middle socioeconomic circumstances,
who attended each health center, were recruited into the study and received
the allocated intervention—daily micronutrient-rich nutritional
supplement, or two 1-hour physical activity classes per week, or both
interventions or neither—for 24 months. The researchers did not know
the allocation arm of each patient and over the course of the study assessed
the incidence of pneumonia (viral and bacterial as based on diagnosis at the
health center or hospital) and physical function was measured by walking
capacity (meters walked in 6 minutes). The researchers used administrative
records and interviews with staff and patients to estimate the
cost-effectiveness of the interventions.
Participant retention in the study was 84%, although only
three-quarters of patients receiving the nutritional intervention and less
than half (43%) of patients in the physical activity intervention arm
adhered to their respective programs. Over 24 months, the incidence rate of
pneumonia did not differ between intervention and control groups (32.5
versus 32.6 per 1,000 person years, respectively), but at the end of the
study period, there was a significant difference in walking capacity between
the intervention and control clusters (mean difference 33.8 meters). The
number of falls and fractures in the study arms were similar. The overall
costs over 24 months were US$91.00 and US$163.70 per
participant for the nutritional supplement and physical activity
interventions, respectively. The cost of the physical activity intervention
per extra meter walked at 24 months was US$4.84.
What Do These Findings Mean?
The results of this trial suggest that there is little evidence to support
the effectiveness of Chile's national nutritional supplementation
program in reducing the incidence of pneumonia for 65.0–67.9 year
olds. Therefore, given Chile's high burden of infectious and
nutrition-related chronic diseases and the associated high health costs,
this program should not be considered as a priority preventive public health
intervention. However, the provision of locally available physical activity
classes to older people could be of clinical benefit, especially in urban
settings such as Santiago, although future challenges include increasing the
uptake of, and retention to, such programs.
Additional Information
Please access these Web sites via the online version of this summary at
http://dx.doi.org/10.1371/journal.pmed.1001023.
The World Health Organization provides information about the
state of
health in Chile
Wikipedia also provides information about health and health care in Chile (please note that
Wikipedia is a free online encyclopedia that anyone can edit;
available in several languages)