Get documents about "Title Lifestyle Modifications for the Prevention of Hypertension
Document Sample
Title: Lifestyle Modifications for the Prevention of Hypertension: A Clinical and Cost
Effectiveness Review
Date: 26 March 2008
Context and policy issues:
Approximately 5 million Canadians have hypertension (high blood pressure).1 The condition is a
major risk factor for congestive heart failure, peripheral vascular disease, stroke, and coronary
heart disease.2-7 A vast epidemiological study describes an apparent association between
hypertension and lifestyle choices.8-10 Lifestyle factors such as weight reduction, physical activity
and reduction in salt and alcohol intake have long been regarded as a means to prevent and
control the occurrence of elevated blood pressure.1,4,5,11,12 A review of clinical and economic
evidence on the extent to which lifestyle modifications are associated with reduction or
prevention of cardiovascular morbidity and mortality in normotensive patients is essential in
aiding healthcare decision making processes.
Research questions:
1. What is the clinical effectiveness of lifestyle modifications (i.e. physical activity,
weight reduction, alcohol intake reduction and salt intake reduction) in preventing or
delaying the onset of hypertension in normotensive patients?
2. What is the clinical effectiveness of lifestyle modifications (i.e. physical activity,
weight reduction, alcohol intake reduction and salt intake reduction) in avoiding
cardiovascular events or reverting blood pressure values to normotensive levels in
hypertensive patients?
Disclaimer: The Health Technology Inquiry Service (HTIS) is an information service for those involved in planning and providing health care in
Canada. HTIS responses are based on a limited literature search and are not comprehensive, systematic reviews. The intent is to provide a list
of sources and a summary of the best evidence on the topic that CADTH could identify using all reasonable efforts within the time allowed.
HTIS responses should be considered along with other types of information and health care considerations. The information included in this
response is not intended to replace professional medical advice, nor should it be construed as a recommendation for or against the use of a
particular health technology. Readers are also cautioned that a lack of good quality evidence does not necessarily mean a lack of effectiveness
particularly in the case of new and emerging health technologies, for which little information can be found, but which may in future prove to be
effective. While CADTH has taken care in the preparation of the report to ensure that its contents are accurate, complete and up to date,
CADTH does not make any guarantee to that effect. CADTH is not liable for any loss or damages resulting from use of the information in the
report.
Copyright: This report contains CADTH copyright material. It may be copied and used for non-commercial purposes, provided that attribution
is given to CADTH.
Links: This report may contain links to other information on available on the websites of third parties on the Internet. CADTH does not have
control over the content of such sites. Use of third party sites is governed by the owners’ own terms and conditions.
3. What is the cost effectiveness of lifestyle modifications (i.e. physical activity, weight
reduction, alcohol intake reduction and salt intake reduction) in preventing or
delaying the onset of hypertension in normotensive patients?
4. What is the cost effectiveness of lifestyle modifications (i.e. physical activity, weight
reduction, alcohol intake reduction and salt intake reduction) in avoiding
cardiovascular events or reverting blood pressure values to normotensive levels in
hypertensive patients?
5. Are there subpopulations based on demographics (age, sex, and ethnicity) or co-
morbidities for which lifestyle modifications are more effective?
Methods:
A limited literature search was conducted on key health technology assessment resources,
including PubMed, The Cochrane Library (Issue 1, 2008), University of York Centre for Reviews
and Dissemination (CRD) databases, ECRI, EuroScan, international HTA agencies, and a
focused Internet search. Results include articles published between 2003 and the January
2008, and are limited to English language publications only. Filters were applied to limit the
retrieval to health technology assessments, systematic reviews, meta-analyses, randomized
controlled trials, observational studies, and economic studies. Some guidelines were also
identified.
Summary of findings:
Studies were included that examined the effects of lifestyle modifications on blood pressure
levels and cardiovascular events in normotensive and hypertensive patients. Four meta-
analyses, two systematic reviews, and 10 randomized controlled trials (RCT) were included. No
economic evaluation studies were identified. Two Canadian guidelines/recommendations were
identified.
Meta-analyses
Fagard13 performed a meta-analysis of RCTs on the effects of dynamic aerobic endurance
training or resistance training in hypertensive and normotensive patients. Training programs
involved “strength, weight, static or isometric exercises designed specifically to increase
muscular strength, power and endurance.”13 Included in the meta-analysis were 72 trials, 105
study groups and 9336 participants. The average training frequency ranged from one to 7 days
a week with intensity of training averaging between 30% and 87% of heart rate reserve (median
65). Average training time was between 15 and 63 minutes.
As Table 1 shows, resistance training was associated with a significant reduction in blood
pressure. The authors noted that when study groups were categorized according to their
baseline blood pressure values, normotensive patients experienced less reduction in blood
pressure than did hypertensive patients. Weighted average reductions were 13 mm Hg (95% CI:
15 to11) systolic, 8 mm Hg (95% CI: 10 to 6) diastolic in hypertensive group and 3mm Hg (95%
CI: 7 to +0.5) systolic, 2 mm Hg (95% CI: 5 to +1) diastolic in normotensive group. Also,
resistance training was associated with significant reduction in cardiovascular risks such as
systemic vascular resistance, norepinephrine, and plasma renin activity. The authors concluded
that available data, though few, suggest that resistance training can reduce hypertension and
thus, exercise is a cornerstone therapy for prevention, treatment and control of blood pressure.
Lifestyle Modifications for Hypertension 2
A major limitation of this study is that methods involved in identification and inclusion of the 72
trials and 105 study groups are not known. Similarly, the authors did not state whether quality
assessment of the trials was performed. Also, the authors stated that because the participants
were aware of which group (control or intervention) they were allocated to, this is a limitation to
the study. Furthermore, regular follow-up, control of changes in other lifestyle factors and
automated blood pressure measurements may be additional limitations to this study.13
In another meta-analysis, Dickson6 examined the effects of multiple lifestyle factors on blood
pressure in hypertensive adult patients (blood pressure: ≥ 140 mm Hg systolic and ≥ 85 mm Hg
diastolic). With a total of 105 trials, this study included parallel designed RCTs and studies
comparing a lifestyle factor with placebo or no treatment. Criteria used for quality assessment
included randomization, concealment of allocation, blinding, and loss to follow-up. The authors
found that improved diet (per dietary approaches to stop hypertension – DASH) and aerobic
exercise reduced systolic blood pressure by 5.0 mm Hg and 4.6 mm Hg, respectively, whereas
restriction in alcohol and salt intake lowered systolic blood pressure by 3.8 mm Hg and 3.6 mm
Hg, respectively (Table 1). In conclusion, the authors suggested that hypertensive patients
should follow a weight-reducing diet, get regular exercise and restrict salt and alcohol intake.
Several key limitations weaken the strength of evidence from this meta-analysis. First, non-
English RCTs were excluded under the assumption that such RCTs are of poor methodological
quality and tend to show larger treatment effects. Second, the authors stated restricting the
analysis to studies that lasted at least 6 months, the reductions in blood pressure were less.
While the study does not state why this is the case, this might be the result of significant
variations in active and control interventions, age and concomitant anti-hypertensive medication
in trial populations. Third, the study perhaps does not add to the investigation on the
effectiveness of lifestyle modifications in normotensive patients as only adult hypertensive
patients were studied.
He FJ14 performed a meta-analysis to assess the effects of restricting salt intake on blood
pressure in children (≤ 18 years). A total of 13 trials with 966 participants met selection criteria
(participants ≤ 18 years and controlled trial in which salt intake reduction is applied for ≥ 2
weeks), of which 10 were in children/adolescents and 3 were in infants.
The results showed that in the children group, salt intake was reduced by 42% [interquartile
range (IQR): 7% to 58%] and by 54% (IQR: 51% to 79%) in the infant group. The median
duration of salt reduction in the trials was one month, ranging from two weeks to 3 years. For
each included trial, percentage changes in salt intake were calculated using data derived from
an examination of 24-hour urinary sodium, overnight urinary sodium, and spot urinary
sodium/creatinine ratio, and food diary. In both groups salt reduction was associated with
significant reductions in systolic blood pressure (Table 1). The authors concluded that “a modest
reduction in salt intake causes immediate falls in blood pressure and, if continued, may well
lessen the subsequent rise in blood pressure with age. This would result in major reductions in
cardiovascular disease.”14
The strength of the evidence from the He FJ14 study is weakened by the small number and the
poor quality of the trials included. Only 10 trials were included in the children group and 3 in
infants group. Only one out of 10 trials in the children group was randomized and only one trial
was double blind, whereas two trials did not report any blinding procedure.
Lifestyle Modifications for Hypertension 3
The effects of resistance training on resting blood pressure were examined in a meta-analysis
conducted by Cornelissen.15 Inclusion criteria included such study characteristics as RCT,
minimum of 4 weeks of intervention, only resistance exercise training as the sole intervention,
no aerobic endurance exercise, and systolic and/or diastolic as the outcomes of the study. A
total of 9 RCTs, involving 12 study groups and 341 participants were included. Out of 9 trials, 3
were conducted in hypertensive patients and the rest in normotensive patients.
As Table 1 shows, the authors found that resistance exercise training was associated with
reductions in resting blood pressure: 3.2 mm Hg (95% CI: 7.1 – 0.7) systolic, 3.5 mm Hg (95%
CI: 6.1 - 0.9) diastolic, when weighted for the number of trained patients, and 6.0 mm Hg (95%
CI: 10.4 – 1.6) systolic, 4.7 mm Hg (95% CI: 8.1 - 1.4) diastolic, when weighted by the reciprocal
of variance for the blood pressure. In subgroup analysis, the authors noted that normotensive
patients experienced higher reduction in blood pressure than did hypertensive patients, but this
trend was not statistically significant (systolic P = 0.09 and diastolic P = 0.13).
The authors concluded that moderate intensity resistance training could be one intervention to
prevent and combat hypertension, but more studies were needed, particularly in the
hypertensive population. As noted by authors, there are a number of limitations in this study. A
significant limitation is the small number of trials studied along with the relatively small number
of participants in each trial. The characteristics of some trials raise a question about the validity
of the findings. Out of 6 RCTs in the normotensive group, one reported that participants were on
antihypertensive medications throughout the trial and 4 did not report on medication status of
the subjects prior to or during the trial. In the hypertensive group consisting of 3 RCTs, subjects
were on antihypertensive medication in one study and in one study subjects had
antihypertensive medications stopped a month prior to the trial.
Table 1: Characteristics and Results of Meta-analyses Investigating Lifestyle
Interventions on Prevention of Hypertension
Study Lifestyle factor Patient population Results
Fagard R.H., Dynamic aerobic Normotensive and Blood pressure
and endurance training hypertensive reduction:
Cornelissen patients Resting
V.A, 200713 3.0 mm Hg ( 95% CI: 4.0
– 2.0) systolic, 2.4 mm
Hg 95% CI: 3.1 -1.7)
diastolic (P<0.001)
Daytime
3.3 mm Hg (95% CI: 5.8
– 0.9) systolic, 3.5 mm
Hg (95% CI: 5.2 -1.9)
diastolic (P<0.01)
Night-time
0.6 mm Hg (95% CI: 2.8
– 1.6) systolic, 1.0 mm
Hg (95% CI: 2.5 – 0.5)
diastolic (P<0.01)
Lifestyle Modifications for Hypertension 4
Study Lifestyle factor Patient population Results
Cardiovascular risk
factors reduction:
Systemic vascular
resistance 7.1%, plasma
norepinephrine 29%, and
plasma renin activity
20%.
Dickson H.O., Weight-reducing diet Adult patients with Blood pressure
et al., 20066 (DASH), regular raised blood reduction:
exercise, restrict pressure: ≥ 140 mm Improved diet
alcohol and salt Hg systolic and ≥ 85 5 mm Hg (95% CI: 7.0 –
(sodium) intake mm Hg 3.1) systolic, 3.7 mm Hg
(95% CI: 5.1 – 2.4)
diastolic (P=0.59)
Regular exercise
4.6 mm Hg (95% CI: 7.1
– 2.0) systolic, 2.4 mm
Hg (95% CI: 4.0 – 0.7)
diastolic (P=0.21)
Sodium restriction
3.6 mm Hg (95% CI: 4.6
– 2.5) systolic, 2.5 mm
Hg (95% CI: 3.2 – 1.7)
diastolic (P=0.008)
Alcohol restriction
3.8 mm Hg (95% CI: 6.1
– 1.4) systolic, 3.2 mm
Hg (95% CI: 5.0 – 1.4)
diastolic (P=0.73)
He F.J., and Intervention aimed Children ≤18 Blood pressure
MacGregor to reduce salt intake reduction:
GA, 200614
Children (10 trials)
1.17 mm Hg ( 95% CI:
1.78 – 0.56) systolic,
1.29mm Hg (95% CI:
1.94 - 0.65) diastolic
(P<0.0001)
Infants (3 trials)
2.47 mm Hg (95% CI: 4
– 0.94) systolic, (P<0.01)
diastolic not reported.
Lifestyle Modifications for Hypertension 5
Study Lifestyle factor Patient population Results
Cornelissen Resistance training Normotensive and/or Net blood pressure
V.A, and hypertensive reduction after
Fagard R.H., patients (≥ 18 years) adjustment for control
200515 observations:
Weighted for the number
of trained patients
3.2 mm Hg ( 95% CI: 7.1
– 0.7) systolic, 3.5mm
Hg (95% CI: 6.1 - 0.9)
diastolic
Weighted by the
reciprocal of variance for
the blood pressure
6.0 mm Hg ( 95% CI:
10.4 – 1.6) systolic, 4.7
mm Hg (95% CI: 8.1 -
1.4) diastolic
Systematic reviews
Walker9 examined the effects of reducing salt intake on preventing cardiovascular events or
mortality. The authors searched the Medline database using OVID interface from 1985 to 2007.
A total of 462 articles were identified but only 14 “represented the best evidence on the
subject.”9 Inclusion criteria were not reported in the review and it not known with certainty
whether the authors performed quality assessment on the included studies or not. The review
concluded that reducing salt intake to levels below 6 grams per day lowers blood pressure and
in turn may reduce the need for hypertension medications by as much as 30%. The authors
noted that the effect of salt intake reduction on preventing cardiovascular events is controversial
because the available evidence is derived either from underpowered RCTs or observational
studies with less scientific rigour.
A systematic review by Nicolson16 compared the effectiveness of lifestyle and drug intervention
for treating patients with essential hypertension. A total of 6 trials were included. Each trial
enrolled between 27 and 64 participants with a mean age 55 years, with follow-up of less than a
year; none of the trials reported cardiovascular outcomes. The authors could not pool the trials
due to heterogeneous populations, lifestyle practices and drug interventions. The authors found
that overall the trials were of poor quality and had inconsistence results. It was noted that
dietary interventions did not reduce blood pressure levels as much as antihypertensive
medications did. However, the limited evidence could not establish the superiority of blood
pressure medications over lifestyle interventions. The authors concluded that in the short-term,
lifestyle modifications may be effective for some individuals, but better quality larger clinical
trials of longer duration are required.
Lifestyle Modifications for Hypertension 6
Randomized controlled trials
Detailed characteristics, results, and conclusions of the 10 RCTs that investigated the effects of
lifestyle modifications on hypertension are presented in Table 2.
Table 2: Characteristics and results of RCTs investigating the effects of lifestyle
modification on hypertension
Study Population & Interventions Results Conclusion
Method
Obarzanek 810 participants Group 1: Weight lost (at Excluding weight loss, Multiple lifestyle
E., et al., in total (mean least 15 lb at 6 months), predicted reductions in modifications are
200717 age 50 years) moderate-intensity physical systolic blood pressure feasible and an
with SBP from activity (180 minutes/week), (SBP) ranged from 0.5 mm effective means of
120 to 159 mm daily intake of dietary Hg to 1.5 mm Hg for reducing blood
Hg and DBP sodium of no more than reduced sodium, improved pressure and risk
from 80 to 95 2400 mg, and daily alcohol fitness, and adherence to of cardiovascular
mm Hg. Of them intake of no more than 2 the DASH diet. disease.
62% were drinks for men and 1 for
women, 94% women. When weight loss was
were overweight included, predicted
or obese, 34% Group 2: DASH diet reduction in SBP was 4 mm
were African [increase daily intakes of Hg for the 4.6 kg weight
American, and fruits and vegetables (9-12 loss, independent of other
37% had servings), low-fat dairy changes,
hypertension. products (2-3 servings),
reduced intake of saturated
Multivariate fat (≤ 7% kcal) and total fat
model was built (≤ 25% kcal)] in addition to
to predict the intervention prescribed
reductions in to Group 1.
SBP at 6
months, without Group 3: Control group
and with weight (received advice and
changes was information materials on
performed. lifestyle factors that control
blood pressure, no further
lifestyle behaviour
counseling was provided)
Interventions were of 18-
month duration.
Melander 46 participants Intervention group: Meals Lowering salt intake from 9 Reducing salt
O., et al., without history of and drinks containing a g/day to 3 g/day led to a 24- intake with 6 g/day
200718 hypertension total of 3 grams (50 mmol) hour ABP blood pressure induces clinically
(mean age 39 of sodium chloride (NaCl) change of -5.8 mm Hg relevant ABP
years old) of per day for 8 weeks. In (95% CI: -3.4, -8.2) systolic reductions.
which 39 addition, 6 grams (100 and -2.6 mm Hg (95% CI: -
completed the mmol) of NaCl per day for 4 0.91, -4.4 mm Hg) diastolic.
trial. weeks
Daytime ABP changed to -
Ambulatory Control group: Meals and 5.5 mm hg (95% CI: -2.9, -
blood pressure drinks containing a total of 8.1) systolic and 2.3 mm
(ABP) after high 3 grams (50 mmol) of Hg (95% CI: -0.42, -4.1)
salt intake (150 sodium chloride (NaCl) per
Lifestyle Modifications for Hypertension 7
Study Population & Interventions Results Conclusion
Method
mmol or 9 gram day for 8 weeks, plus meals diastolic; night-time ABP -
a day) was and drinks containing 6.4 mm Hg (95% CI: -3.5, -
compared with placebo capsules per day 93) systolic and -3.4 (95%
ABP after low- for 4 weeks. CI: -1.4, -5.5)
salt intake (50
mmol or 3 grams NaCl and matching placebo
a day) capsules were administered
randomly The trial lasted for
8 weeks,
Elley R., et 35 hypertensive Group 1: 4 X 10 minute SBP changed by -7.5 mm 4 X 10 minute
al., 200619 patients (mean episodes of brisk walking Hg (95% CI: -8.0 to -6.0) episodes of brisk
age 53 years) per day with 40 minute regime; -7.3 walking were as
without mm Hg (95% CI: -8.7, -5.8) effective as 40
complications Group 2: 40 minutes with 4 X 10 minute regime; minutes of
continuous brisk walking and +1.0 mm Hg (95% CI: - continuous brisk
Outcome of per day 0.4, 2.5) with no brisk walking per day at
interests were walking regime (p < 0.001) reducing blood
change of SBP Group 3: no brisk walking. pressure
and DBP DBP changed by -4.0 mm
Each regime lasted 4 days Hg (95% CI: -5.0, -3.0) with
with 10 days of no exercise 40 minutes regime; -5.4
in between. mm Hg (95% CI: -6.4, -4.4)
with 4 X 10 minute regime;
and -0.2 mm Hg (95% CI: -
1.2, 0.8) with no brisk
walking regime (p < 0.001)
Cakir H. 60 hypertensive Intervention group: weight SBP and DPB decreased in Lifestyle
and Pinar patients (mean lost, stop smoking, learn intervention group with modification is
R., 200620 age 52 years for stress management, mean reductions of 8.8 mm feasible and
intervention moderate-intensity physical hg (standard deviation (SD) beneficial
group and 57 activity, reduction in daily = 5.2) and 6.9 mm Hg (SD
years for control intake of dietary sodium, = 5.3), respectively. In the
group). and daily alcohol intake. control group, both SBP
and DPB increased over
Outcome of Control group: received time: 1.2 mm Hg (SD = 5.3)
interests were routine outpatient services SBP and 1.6 mm Hg (SD =
change of SBP and asked to maintain their 4.6)
and DBP usual lifestyles, including
dietary and exercise habits
for 6 months until they were
reexamined
Trial lasted for 6 months.
Stewart 104 untreated Intervention group: Mean reductions in SBP Contrary to SBP, a
K.J., et al., hypertensive combined aerobic and and DBP, respectively, 6-month program
200521 patients (55 -75 resistance training exercise were 5.3 and 3.7 mm Hg in of aerobic and
years old), with the intervention group and resistance training
blood pressure Control group: educational 4.5 and 1.5 mm Hg in the lowered DBP
between 130 guidelines for activity and control group (p < 0.001). significantly. Both
mm Hg and 159 diet. No significant group in intervention and
mm Hg differences in mean SBP control group,
The trial lasted for 6 change from baseline (-0.8 body composition
months. mm Hg; p =0.67). The improvements
Lifestyle Modifications for Hypertension 8
Study Population & Interventions Results Conclusion
Method
intervention group were associated
experienced greater with blood
reduction in DBP (mean pressure
reduction of 2.2 mm Hg; p = reductions and
0.02). In both groups, aortic may be a pathway
stiffness measured by by which exercise
aortofemoral pulse-wave training improves
velocity, was not changed. cardiovascular
Body composition health in older
improvements explained patients.
8% of the SBP reduction
and 17% of the DBP
reduction.
Svetkey 810 participants Established group: Weight Mean net reduction in SBP Diverse groups of
L.P., et al., in total (mean lost (at least 15 lb at 6 in the established group people can adopt
200522 age 50 years) months), moderate-intensity were 1.2 mm Hg in African multiple lifestyle
with SBP from physical activity (180 American women, 6.0 mm modifications that
120 to 159 mm minutes/week), daily intake Hg in African American can lead to
Hg and DBP of dietary sodium of no men, 4.5 mm Hg in non- improved blood
from 80 to 95 more than 2400 mg, and African American women, pressure and
mm Hg. Of them daily alcohol intake of no and 4.2 mm Hg in non- reduced
62% were more than 2 drinks for men African American men. cardiovascular
women, 95% and 1 for women. risk.
were overweight Mean net reduction in SBP
or obese, 34% Established Plus DASH in the established Plus
were African group: DASH diet [increase DASH group were 2.1 mm
American, and daily intakes of fruits and Hg in African American
38% had vegetables (9-12 servings), women, 4.6 mm Hg in
hypertension. low-fat dairy products (2-3 African American men, 4.2
servings), reduced intake of mm Hg in non-African
saturated fat (≤ 7% kcal) American women, and 5.7
and total fat (≤ 25% kcal)] in mm Hg in non-African
addition to intervention American men.
prescribed to Group 1
above. Hypertensive participants
experienced greater
Advice only group: changes in blood pressure
Participants received verbal than did nomortensive
instructions and written participants.
materials with information
on established
recommendations and the
DASH dietary pattern. No
counseling or further
intervention was provided
until after end of the trial (6
months)
The interventions lasted for
18 months but the report
included the observations
of the first 6 months.
Lifestyle Modifications for Hypertension 9
Study Population & Interventions Results Conclusion
Method
Padilla J., et A total of 28 Accumulation of physical No blood pressure reduction Lifestyle physical
al., 200523 participants [8 activity (splitting logs, was found in normotensive activity reduces
normotensive mowing the lawn, digging, patients. In the pre- systolic blood
(mean age 42 tilling, raking, laying sod hypertensive group blood pressure in both
years, SBP ≤120 and brisk walking) over 8 to pressure was reduced by 6.6 pre-hypertensive
mm Hg), 10 pre- 12 hour period for the mm Hg and by 12.9 mm Hg and hypertensive
hypertensive intervention group. The in hypertensive group. patients but not in
(mean age 51 target volume of physical normotensive
years, SBP ≤ activity was an patients.
140 mm Hg), accumulation of 150 kcal.
and 10
medicating Control group participated
hypertensive in their usual activities of
(mean age 64 daily living and asked to
years, SBP ≤140 abstain from physical
mm Hg)]. activity and record duration
and mode of activity
The trial lasted from 2 to 7
days
Swift P.A., 46 black Intervention group: given In placebo group Reducing salt
et al., hypertensive placebo of 12 slow sodium (intervention), urinary intake from 10
200524 participants (17 tablets (10 mmol sodium sodium excretion g/day to 5 g/day
male and 23 per tablet) daily decreased from 10 g/day to reduced blood
female) with 5 g/day. Blood pressure pressure and urine
mean age of 50 Control group: 12 slow dropped from 159 to 151 protein excretion in
years. sodium tablets (10 mmol mm Hg (p < 0.01). Protein black hypertensive
sodium per tablet) daily excretion dropped from 93 patients. The
mg to 75 mg per 24 hours authors
Intervention lasted for 4 (p <0.008). recommended that
weeks each. all black
In the control group, urinary hypertensive
sodium excretion was 10 patients reduce
g/day and BP was 159 mm their salt intake to
Hg systolic and 101 mm Hg less than 5 g/day.
diastolic
Izdebska E., A total of 48 Intervention group SBP decreased by 19 ± 2.9 Antihypertensive
et al., participants with (hypertensive): moderate mm Hg and DBP by 10 ± 2 hemodynamic
200425 mean age of 23 training exercise performed mm Hg in hypertensive effects of
years (18 3 times a week for about participants, and total moderate dynamic
healthy one hour over 3 months. peripheral resistance (TPR) physical training
normotensive Subject performed their by 0.28 ± 0.05 TPR units. are associated
and 30 untreated favourite activity (running, There were no statistically with readjustment
hypertensive) swimming, tennis, walking significant decreases in of the autonomic
etc) either SBP or DBP in normo- cardiovascular
tensive participants. Physical control system.
Control group (healthy training increased pulse
normotensive): As in the interval values (PI) in hyper-
intervention group tensive participants, sugges-
ting a decrease in frequency
modulated sympathetic
activity and vagal modulation
of heart rate.
Lifestyle Modifications for Hypertension 10
Study Population & Interventions Results Conclusion
Method
Svetkey 412 adults aged Intervention group: DASH Blood pressure control was Both the DASH
L.P., et al., ≤22 with diet [increase daily intakes defined as both SBP < 140 diet and reduced
200426 baseline blood of fruits and vegetables (9- mm Hg and DBP < 90 mm sodium intake
pressure 12 servings), low-fat dairy Hg at the end of given improved blood
between 120 products (2-3 servings), feeding period. pressure control.
and 159 mm Hg reduced intake of saturated
systolic and 80- fat (≤ 7% kcal) and total fat Hypertensive participants in
95 mm Hg (≤ 25% kcal)] for one month the control group: 32%,
diastolic. 51%, and 74% achieved
Control group: one month blood pressure control
on a typical American diet, levels after one month of
consuming three different higher, intermediate, and
sodium intakes ( higher 142 lower sodium intake,
mmol/day, intermediate 107 respectively. Corresponding
mmol/day, and lower 65 percentages for intervention
mmol/day) group were 63%, 65%, and
84%, respectively.
Intervention lasted for 30
days.
ABP = ambulatory blood pressure, BP = blood pressure, DBP = diastolic blood pressure, DASH = dietary approaches
to stop hypertension, SBP= systolic blood pressure, NaCl = sodium chloride, SD = standard deviation, TPR = total
peripheral resistance, CI = confidence interval
Economic evaluations:
No economic evaluation studies were identified.
Guidelines/recommendations:
The Canadian Hypertension Education Program (CHEP) published evidence-based
recommendations for the management of hypertension in 200427 and 2006.28 In 2004 CHEP
made the following recommendations aimed at preventing and controlling hypertension (see
Table 3 for grading scheme):
Table 3: Grading Scheme for the CHEP Recommendations27
Grade Definition
B Recommendation based on randomized trials, systematic reviews, or pre-specified subgroup
analyses of randomized trials that have lower precision, or there is a need to extrapolate from
studies because of differing populations or reporting of validated intermediate/surrogate
outcomes rather than clinically important outcomes.
C Recommendation from trials that have lower levels of internal validity and/or precision, or
report unvalidated surrogate outcomes, or results from non-randomized observational studies.
D Recommendations based on expert opinion alone
Physical exercise
• To reduce the chances of becoming hypertensive, non-hypertensive individuals should
prescribe to 30 minutes to 45 minutes of accumulation of moderate intensity dynamic
Lifestyle Modifications for Hypertension 11
exercise (such as walking, jogging, cycling or swimming) three days to five days per
week (Grade B). Higher intensities of exercise are no more effective (Grade B)
• To reduce blood pressure, hypertensive patients should prescribe the accumulation of
30 minutes to 45 minutes of moderate intensity dynamic exercise (such as walking,
jogging, cycling or swimming) four to five days per week (Grade B). Higher intensities of
exercise are no more effective (Grade B)
Weight reductions
• To prevent hypertension, a body mass index (BMI) of 18.5 kg/m² to 24.9 kg/m² for non-
hypertensive individuals is recommended (Grade C)
• Maintenance of a healthy BMI (18.5 kg/m² to 24.9 kg/m²) is recommended for
hypertensive patients to reduce blood pressure. All overweight (BMI greater than 25
kg/m²) hypertensive individuals should be advised to lose weight (Grade B)
• Weight loss strategies should use a multidisciplinary approach and include dietary
education, increased physical activity and behavioural modification (Grade B)
Alcohol consumption
• Healthy adults should limit alcohol intake to two drinks or fewer per day, and intake
should not exceed 14 standard drinks per week for men or 9 standard drinks per week
for women (Grade B) (one standard drink is considered to be 13.6 g or 17.2 mL of
ethanol, or approximately 1.5 ounces of 80 proof (40%) spirits, 12 ounces of 5% beer or
5 ounces of 12% wine).
Dietary recommendations
• With Grade B evidence, a diet that emphasizes vegetables, fruits, and low fat dairy
products and that is reduced in fat and cholesterol (per DASH) is recommended for
hypertensive patients
Salt intake
• In normotensive individuals at increased risk of becoming hypertensive who are
considered salt sensitive such as Canadian of African descent, people over 45 years of
age, and individuals with impaired renal function or diabetes, salt intake should be
restricted to less than 100 mmol/day (Grade D)
CHEP updated these recommendations in 2006 as follows:28
Physical exercise
• To reduce the chances of becoming hypertensive, non-hypertensive individuals should
prescribe to 30 minutes to 45 minutes of accumulation of moderate intensity dynamic
exercise (such as walking, jogging, cycling or swimming) 4 days to 7 days per week
(Grade D). Higher intensities of exercise are not more effective (Grade D)
• To reduce blood pressure, hypertensive patients should prescribe the accumulation of
30 minutes to 45 minutes of moderate intensity dynamic exercise (such as walking,
jogging, cycling or swimming) 4 to 7 days per week (Grade D). Higher intensities of
exercise are no more effective (Grade D)
Lifestyle Modifications for Hypertension 12
Weight reductions
• Height, weight and waist circumference (WC) should be measured and body mass index
calculated for all adults (Grade D)
• Maintenance of a healthy BMI (18.5 kg/m² to 24.9 kg/m²) and a WC less than 102 cm for
men and less than 88 cm for women is recommended for non-hypertensive individuals to
prevent hypertension (Grade C) and for hypertensive patients to reduce blood pressure
(Grade B). All overweight hypertensive individuals should be advised to lose weight
(grade B)
• Weight loss strategies should use a multidisciplinary approach and include dietary
education, increased physical activity and behavioural modification (grade B)
Recommendations and respective grade on Salt intake, alcohol consumption, and diet were
unchanged.
General limitations:
The available evidence is limited both in quantity and quality. No economic studies on lifestyle
modifications were identified. Similarly, literature on the effects of lifestyle modifications in
subpopulations (age, sex, and ethnicity, and/or co-morbidities) is scarce.
Also, the results of some RCTs are questionable due to poor quality. For example, participants
in the study by Padilla23 were on anti-hypertension medication throughout the trial; participants
in 5 studies18,19,23-25 were less than 50; and the intervention duration in 4 studies19,23,24,26 lasted
for 4 weeks or less.
The applicability of the available evidence to a Canadian setting is unknown as none of the
studies were conducted in Canada. Given that dietary habits and lifestyle vary across countries,
the applicable study to Canada would take into account diet behaviours and lifestyle specific to
Canadians.
Conclusion and implications for decision or policy making:
Despite the limitations, the studies consistently demonstrate beneficial effects of dietary
intervention and lifestyle modification to hypertensive individuals. The evidence is in line with
CHEP recommendations (moderate intensity exercise, maintenance of health body weight,
reduction of alcohol intake to two drinks per day, reduction of salt intake to <100 mmol/day).
Lifestyle modifications combined with DASH dietary intervention reduces blood pressure.
Individual effects of lifestyle factors (physical activity, reduction in alcohol and salt intake)
appear modest, particularly in normotensive individuals, yet the combined effects can be
substantial.
The effects of lifestyle modification and the DASH diet are minimal in normotensive individuals.
However, from a societal perspective, even a small reduction in blood pressure would have a
tremendous, beneficial effect on prevention of hypertension and its complications. The effect of
diet (especially reduction in salt intake) on blood pressure appears to be greater in specific
subpopulations, such as hypertensive patients, blacks, and older-aged individuals. Given the
substantial societal and economic burden of cardiovascular disease, adequate implementation
Lifestyle Modifications for Hypertension 13
of dietary intervention in such groups would prove particularly beneficial in limiting the
occurrence of hypertension.
With hypertension affecting almost 25% of Canadian adults29 and available evidence suggesting
beneficial influence of lifestyle modifications and dietary intervention, the challenge to
healthcare decision makers and healthcare providers is to devise and implement clinical and
public health strategies that promote and maintain the combination of healthy diet and lifestyle
modifications.
Prepared by:
Stephen K Membe, BA (Hon), MDE, Health Economist
Kelly Farrah, MLIS, Information Specialist
Health Technology Inquiry Service
Email: htis@cadth.ca
Tel: 1-866-898-8439
Lifestyle Modifications for Hypertension 14
References:
1. 5 million Canadians affected - minister Dosanjh attends blood pressure clinic event to
mark world hypertension day. In: Heart and Stroke Foundation [website]. Ottawa: The
Foundation; 2005. Available:
http://ww2.heartandstroke.ca/Page.asp?PageID=33&ArticleID=3984&Src=news&From=
SubCategory (accessed 2008 Mar 24).
2. McGuire HL, Svetkey LP, Harsha DW, Elmer PJ, Appel LJ, Ard JD. Comprehensive
lifestyle modification and blood pressure control: a review of the PREMIER trial. J Clin
Hypertens (Greenwich) 2004;6(7):383-90. Available:
http://www.medscape.com/viewarticle/483503_print (accessed 2008 Mar 24).
3. Graham I, Atar D, Borch-Johnsen K, Boysen G, Burell G, Cifkova R, et al. European
guidelines on cardiovascular disease prevention in clinical practice: full text. Fourth Joint
Task Force of the European Society of Cardiology and other societies on cardiovascular
disease prevention in clinical practice (constituted by representatives of nine societies
and by invited experts). Eur J Cardiovasc Prev Rehabil 2007;14 Suppl 2:S1-113.
4. Viera AJ, Kshirsagar AV, Hinderliter AL. Lifestyle modification advice for lowering or
controlling high blood pressure: who's getting it? J Clin Hypertens (Greenwich)
2007;9(11):850-8.
5. Touyz RM. Highlights and summary of the 2006 Canadian Hypertension Education
Program recommendations. Can J Cardiol 2006;22(7):565-71.
6. Dickinson HO, Mason JM, Nicolson DJ, Campbell F, Beyer FR, Cook JV, et al. Lifestyle
interventions to reduce raised blood pressure: a systematic review of randomized
controlled trials. J Hypertens 2006;24(2):215-33.
7. Bacon SL, Sherwood A, Hinderliter A, Blumenthal JA. Effects of exercise, diet and
weight loss on high blood pressure. Sports Med 2004;34(5):307-16.
8. Reusser ME, McCarron DA. Reducing hypertensive cardiovascular disease risk of
African Americans with diet: focus on the facts. J Nutr 2006;136(4):1099-102. Available:
http://jn.nutrition.org/cgi/reprint/136/4/1099 (accessed 2008 Mar 24).
9. Walker J, MacKenzie AD, Dunning J. Does reducing your salt intake make you live
longer? Interact Cardiovasc Thorac Surg 2007;6(6):793-8. Available:
http://icvts.ctsnetjournals.org/cgi/reprint/6/6/793 (accessed 2008 Mar 24).
10. Braith RW, Stewart KJ. Resistance exercise training: its role in the prevention of
cardiovascular disease. Circulation 2006;113(22):2642-50. Available:
http://circ.ahajournals.org/cgi/reprint/113/22/2642 (accessed 2008 Mar 24).
11. Controlling blood pressure. Cheaper may be better. Mayo Clin Health Lett 2003;21(6):4-
5.
12. Baster T, Baster-Brooks C. Exercise and hypertension. Aust Fam Physician
2005;34(6):419-24.
Lifestyle Modifications for Hypertension 15
13. Fagard RH, Cornelissen VA. Effect of exercise on blood pressure control in hypertensive
patients. Eur J Cardiovasc Prev Rehabil 2007;14(1):12-7.
14. He FJ, MacGregor GA. Importance of salt in determining blood pressure in children:
meta-analysis of controlled trials. Hypertension 2006;48(5):861-9.
15. Cornelissen VA, Fagard RH. Effect of resistance training on resting blood pressure: a
meta-analysis of randomized controlled trials. J Hypertens 2005;23(2):251-9.
16. Nicolson DJ, Dickinson HO, Campbell F, Mason JM. Lifestyle interventions or drugs for
patients with essential hypertension: a systematic review. J Hypertens
2004;22(11):2043-8.
17. Obarzanek E, Vollmer WM, Lin PH, Cooper LS, Young DR, Ard JD, et al. Effects of
individual components of multiple behavior changes: the PREMIER trial. Am J Health
Behav 2007;31(5):545-60. Available: http://www.atypon-
link.com/PNG/doi/pdf/10.5555/ajhb.2007.31.5.545 (accessed 2008 Mar 24).
18. Melander O, von Wowern F., Frandsen E, Burri P, Willsteen G, Aurell M, et al. Moderate
salt restriction effectively lowers blood pressure and degree of salt sensitivity is related
to baseline concentration of renin and N-terminal atrial natriuretic peptide in plasma. J
Hypertens 2007;25(3):619-27.
19. Elley R, Bagrie E, Arroll B. Do snacks of exercise lower blood pressure? A randomised
crossover trial. N Z Med J 2006;119(1235):U1996. Available:
http://www.nzma.org.nz/journal/119-1235/1996/ (accessed 2008 Feb 1).
20. Cakir H, Pinar R. Randomized controlled trial on lifestyle modification in hypertensive
patients. West J Nurs Res 2006;28(2):190-209.
21. Stewart KJ, Bacher AC, Turner KL, Fleg JL, Hees PS, Shapiro EP, et al. Effect of
exercise on blood pressure in older persons: a randomized controlled trial. Arch Intern
Med 2005;165(7):756-62.
22. Svetkey LP, Erlinger TP, Vollmer WM, Feldstein A, Cooper LS, Appel LJ, et al. Effect of
lifestyle modifications on blood pressure by race, sex, hypertension status, and age. J
Hum Hypertens 2005;19(1):21-31.
23. Padilla J, Wallace JP, Park S. Accumulation of physical activity reduces blood pressure
in pre- and hypertension. Med Sci Sports Exerc 2005;37(8):1264-75.
24. Swift PA, Markandu ND, Sagnella GA, He FJ, MacGregor GA. Modest salt reduction
reduces blood pressure and urine protein excretion in black hypertensives: a
randomized control trial. Hypertension 2005;46(2):308-12.
25. Izdebska E, Cybulska I, Izdebskir J, Makowiecka-Ciesla M, Trzebski A. Effects of
moderate physical training on blood pressure variability and hemodynamic pattern in
mildly hypertensive subjects. J Physiol Pharmacol 2004;55(4):713-24. Available:
http://www.jpp.krakow.pl/journal/archive/1204/pdf/713_1204_article.pdf (accessed 2008
Mar 24).
Lifestyle Modifications for Hypertension 16
26. Svetkey LP, Simons-Morton DG, Proschan MA, Sacks FM, Conlin PR, Harsha D, et al.
Effect of the dietary approaches to stop hypertension diet and reduced sodium intake on
blood pressure control. J Clin Hypertens (Greenwich) 2004;6(7):373-81.
27. Touyz RM, Campbell N, Logan A, Gledhill N, Petrella R, Padwal R. The 2004 Canadian
recommendations for the management of hypertension: part III--lifestyle modifications to
prevent and control hypertension. Can J Cardiol 2004;20(1):55-9.
28. Khan NA, McAlister FA, Rabkin SW, Padwal R, Feldman RD, Campbell NR, et al. The
2006 Canadian Hypertension Education Program recommendations for the management
of hypertension: part II - therapy. Can J Cardiol 2006;22(7):583-93.
29. Jamnik VK, Gledhill N, Touyz RM, Campbell NR, Logan AG, Padwal R, et al. Lifestyle
modifications to prevent and manage hypertension for exercise physiologists and fitness
professionals. Can J Appl Physiol 2005;30(6):754-61.
Lifestyle Modifications for Hypertension 17
