Page 20 - Hello Philippines January 2016 'A' Issue

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Walking reduces heart disease in people at risk
“AN extra walk each day wards off
killer heart illnesses,” reports the Daily
Express.
The traditional New Year’s Day
stroll is good for “blowing the cobwebs
away”, and pledging to walk more as a
New Year’s Resolution is a great idea,
but this headline needs to be taken with
a degree of caution.
The news is actually based on the
results of a large international study, but of a cardiovascular event (death due
it focussed on adults with a high risk of
type 2 diabetes and heart disease. For
this reason, people at lower risk of these
diseases may not get the same benefit.
The researchers found that for this
specific group of people, every extra
2,000 steps per day at the start of the
study was associated with a 10% lower
risk of a “cardiovascular event”, such
as a heart attack. A year later, each
extra 2,000 steps per day a person
took beyond their original amount
was associated with an additional 8%
difference in the cardiovascular event
rate.
The researchers tried hard to adjust
their findings for many confounding
factors, but because of the study design
it remains possible that there were
other differences between people who
took more or fewer steps per day and
that was responsible for the association
seen.
Where did the story come
from? The study was carried out by
researchers from the NIHR Leicester-
Loughborough Diet, Lifestyle, and
Physical Activity Biomedical Research
Unit and the University of Leicester, and
Duke University School of Medicine,
US, in collaboration with researchers
from other universities and research
institutes from around the world. It was
funded by Novartis Pharmaceuticals
which makes both of the drugs used in
the study. The study was published in
the peer-reviewed medical journal, The
Lancet.
Neither the Express nor the Mail
Online made it clear at the start of
their stories that the figures they were
quoting were from a study of adults at
high risk of diabetes and cardiovascular
disease. Both papers failed to point out
HEALTH and Lifestyle
that the findings were associations, and
from the results of the current study
it cannot be concluded that walking
caused the reduction in risk seen.
What kind of research was this?
This was a cohort study which aimed
to determine whether the amount of
walking a person did and the change
in the amount of walking a person does
over time are associated with the risk
to cardiovascular disease, a non-fatal
stroke, or a heart attack) in people
at high risk who also have impaired
glucose tolerance.
The group of people in this study
were taking part in a randomised of two
drugs: nateglinide and valsartan.
A cohort study is the ideal study
design to address this question, and is
likely to be the best form of evidence for
this question. However, cohort studies
cannot show causation. Although the
researchers adjusted for a number of
potential confounders it could be that
there were other differences between
people who took more or fewer steps
per day and that was responsible for the
association seen.
What did the research involve? The
researchers recruited 9,306 people
(with an average age of 63) from
around the world with impaired glucose
tolerance and either:
• existing cardiovascular disease (if
aged 50 or older)
• at least one cardiovascular risk
factor (if aged 55 or older)
The group of people in this study
were taking part in a randomised
controlled trial of two drugs: nateglinide
and valsartan. People could receive one
of either of the two drugs, both drugs,
or placebo. Everyone in this trial also
participated in a lifestyle modification
programme. One of the aims of this
programme was to increase physical
activity to 150 minutes per week.
The average number of steps that
people took per day was assessed at the
start of the study and after 12 months
using a pedometer.
People were followed-up for an
average of six-years for cardiovascular
events (death due to cardiovascular
disease, a non-fatal stroke, or a heart
attack).
The researchers analysed the
association between:
• the number of steps taken at
the start of the study and risk of a
cardiovascular event
• the change in the number of
steps taken between the start of the
study and 12 months and the risk of a
cardiovascular event
The researchers adjusted their
analyses for:
• the treatment people were
randomised to
• body-mass index (BMI)
• age
• geographical location (continent)
• gender
• current smoking status
• coronary heart disease composite
(previous heart attack, angina, positive
stress test, or coronary revascularisation) event rate for everyone, regardless of
and cerebrovascular composite (stroke,
Each 2,000 steps per day increase
or decrease in the number of
steps taken per day between
baseline and 12 months was
associated with an additional 8%
lower or higher cardiovascular
event rate, respectively.”
transient ischaemic attack)
• other biochemical and clinical
factors
What were the basic results? Each
2,000 steps per day taken at the start of was associated with an additional 8%
the study were associated with a 10%
lower cardiovascular event rate (hazard
ratio (HR) 0.90, 95% confidence
interval (CI) 0.84 to 0.96).
Each 2,000 steps per day increase
or decrease in the number of steps
taken per day between baseline
and 12 months was associated with
an additional 8% lower or higher
cardiovascular event rate, respectively.
When the researchers adjusted
for change in BMI (which might
be expected if people increased or
decreased the number of steps they
took) the results did not change.
The researchers also found that
increasing or decreasing the number of
steps taken changed the cardiovascular
the number of steps taken at the start
of the study (baseline). The results were
also not changed by a previous history
of cardiovascular disease, sex, age or
location.
How did the researchers interpret
the results? The researchers concluded
that, “both baseline ambulatory activity
and change in ambulatory activity
over 12 months were associated
independently with the risk of a
cardiovascular event in the ensuing five
years.
“Specifically, every 2,000 step per
day increment in ambulatory activity
at baseline (roughly equivalent to 20
min a day of moderately-paced walking
activity) was associated with a 10%
January 2016 – No. 01 • UK & Europe Edition
It’s good to aim for about 10,000 walking steps every day
lower risk of a cardiovascular event.
“Moreover, each 2,000 step per day
change from baseline to 12 months
difference in the cardiovascular event
rate. This difference was unaffected
when further adjusted for change in
body-mass index and other potential
confounding factors at 12 months.
Results were not modified by sex, age,
level of baseline activity, or pre-existing
cardiovascular disease.”
Conclusion. This study of adults at
high risk of type 2 diabetes and heart
disease has found that every 2,000
steps they normally took each day was
associated with a 10% lower risk of a
cardiovascular event. And 12 months
later, each extra 2,000 steps per day
people did beyond their original
number of steps was associated with
an additional 8% difference in the
cardiovascular event rate.
This large study recruited
participants from around the world and
the researchers adjusted for a number
of potential confounders.
However, the study had a number of
limitations, including:
• A large amount of information
on the number of steps taken per day
was missing, and had to be adjusted for
using statistical techniques.
• Although pedometers were used
to objectively collect information on
the number of steps taken, participants
knew they were wearing pedometers
and were not blinded to the number
of steps taken: it could be that people
took more steps than normal when they
were wearing a pedometer.
• Cohort studies cannot show
causation. Although the researchers
adjusted for a number of potential
confounders it could be that there
were other differences between people
who took more or fewer steps per day
and these were responsible for the
association seen.
• It should also be remembered that
all people in this population were at
high risk of type 2 diabetes and heart
disease. This means that other people
may get a different level of benefit from
walking.
In any case, this research further
emphasises the health benefits of
walking. n NHS Choices