Impact sur la tension artérielle au repos et à l’effort d’un programme d’intervention santé en milieu de travail ciblant les « signes vitaux » du mode de vie
L’article composant ce chapitre est intitulé
« Effects of a workplace health program targeting lifestyle "vital signs" on resting and
exercise blood pressure »
71 Résumé français
Titre: Impact sur la tension artérielle au repos et à l’effort d’un programme d’intervention
santé en milieu de travail ciblant les « signes vitaux » du mode de vie
Mise en contexte : L’hypertension artérielle est une condition hautement prévalente
nécessitant des approches innovantes pour sa prévention et sa gestion. Comme l’hypertension entraîne des conséquences coûteuses pour les employeurs, le milieu de travail a été proposé en tant qu’environnement pertinent pour le développement de meilleures stratégies préventives.
Objectif : Évaluer l’impact d’un programme d’intervention en milieu de travail ciblant les
saines habitudes de vie sur la tension artérielle au repos et à l’effort.
Méthodes : Le Grand Défi Entreprise est un programme d’intervention en santé
cardiométabolique de 3 mois où les employés participants s’engagent dans une compétition amicale en équipe de 5 employés dans le but d’adopter de saines habitudes de vie (bouger plus, manger mieux et cesser de fumer). Avant et après l’intervention, la qualité nutritionnelle et le niveau d’activité physique sont évalués à l’aide de questionnaires, la tension artérielle de repos ainsi que la circonférence de taille sont mesurées (n = 1952). Une épreuve d’effort sous-maximal comprenant un palier standardisé (3,5mph et 2% d’inclinaison) a été complétée chez un sous-groupe de participants (n = 879).
Résultats : En réponse à l’intervention, les hommes et les femmes ont montré des
réductions significatives de leur tension artérielle systolique et diastolique au repos (P<0.01). La variation de la circonférence de taille était associée au changement de la tension artérielle de repos durant l’intervention chez les deux sexes (P<0.01). Une diminution de la tension systolique à l’effort a été observée seulement chez les hommes (P<0.01). Même si les femmes ont augmenté leur niveau d’activité physique (P<0.05), seuls les hommes ont démontré une augmentation significative de leur condition cardiorespiratoire (P<0.01). La variation de la condition cardiorespiratoire était associée à l’amélioration de la tension systolique et diastolique à l’effort chez les deux sexes (P<0.01).
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Conclusion : Un programme d’intervention en milieu de travail ciblant le niveau
d’activité physique et la qualité nutritionnelle permet de réduire la tension artérielle au repos chez les deux sexes. Cependant, la tension systolique à l’effort s’est vue réduite seulement chez les hommes. L’absence de diminution de la tension systolique à l’effort chez les femmes pourrait possiblement être attribuée au fait que le programme n’ait pas entraîné d’amélioration de la condition cardiorespiratoire chez celles-ci.
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EFFECTS OF A WORKPLACE HEALTH PROGRAM TARGETING LIFESTYLE "VITAL SIGNS" ON RESTING AND EXERCISE BLOOD PRESSURE
Charles-Emanuel Côté, B.Sc.1,2, Paul Poirier, M.D., Ph.D.1,3, Caroline Rhéaume, M.D., Ph.D.1,4,
Jean-Pierre Després, Ph.D.1,2, Natalie Alméras, Ph.D.1,2
1Institut universitaire de cardiologie et de pneumologie de Québec – Université Laval,
Québec, QC, Canada
2Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, QC,
Canada
3Faculty of Pharmacy, Université Laval, QC, Canada
4Faculty of Medicine, Family Medicine and Emergency Medicine, Université Laval, QC,
Canada
Short title: Impact of cardiometabolic health intervention on blood pressure
Address of correspondence: Natalie Alméras, Ph.D.
Institut universitaire de cardiologie et de pneumologie de Québec – Université Laval 2725 chemin Sainte-Foy, A-2085
Québec, QC, G1V4G5 CANADA
Tel:+1-418-656-8711 ext. 3600 Fax:+1-418-656-4527
74 Abstract
Hypertension is a highly prevalent condition requiring innovative approaches for its prevention/management. As hypertension has costly consequences for employers and individuals, the workplace has been proposed as a relevant locus for the development of efficient preventive strategies. In the present study, we evaluated the impact on resting and submaximal exercise blood pressure of a workplace lifestyle intervention program targeting what we have described as "lifestyle vital signs". "Le Grand Défi Entreprise" is a 3-month cardiometabolic health intervention program where teams of 5 employees are involved in a friendly competition to adopt healthier lifestyle habits (move more, eat better and stop smoking). In our cohort of 1952 participants, nutritional quality and physical activity level were assessed before and after the intervention through questionnaires, and resting blood pressure and waist circumference were measured. A submaximal exercise test including a standardized stage (3,5 mph, 2 % slope) was performed in a subgroup of participants (n = 820). In response to the intervention, men and women showed significant reductions of their resting systolic and diastolic blood pressure (P<0.01). Change in waist circumference was associated with 3-month changes in resting blood pressure in both sexes (P<0.01). A reduction in exercise systolic blood pressure was only observed in men (P<0.01). Although reported physical activity levels were increased in women (P<0.05), only men showed a significant improvement in their levels of cardiorespiratory fitness (P<0.01). Changes in estimated VO2max were predictive of changes in exercise SBP and DBP in both sexes in our model
(P≤0.01). In conclusion, a workplace intervention program targeting physical activity level and nutritional quality was found to lower resting blood pressure in both sexes
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whereas exercise systolic blood pressure was only reduced in men. The lack of reduction in exercise systolic blood pressure in women could possibly be attributed to the fact that the program was not successful in improving cardiorespiratory fitness in female workers.
KEYWORDS: resting blood pressure, exercise blood pressure, cardiorespiratory fitness, physical activity level, nutritional quality, workplace intervention.
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INTRODUCTION
Because of its well-established association with major clinical outcomes such as stroke, ischemic heart disease and end-stage renal disease1, hypertension (HT) is the leading
cause of global burden of disease in the world2. Moreover, the prevalence of HT is still
increasing in North America3, 4 although clear recommendations for its prevention have
been published5. It also has major economic consequences for employers and
individuals as HT is a highly prevalent and debilitating condition for the workforce6.
Thus, the workplace ecosystem represents an excellent locus for cardiometabolic health intervention programs aiming at preventing chronic conditions such as HT, allowing to reach a large segment of the population for the benefit of both employees and employers7.
The American Heart Association has proposed that behaviors are key components of its definition of cardiometabolic health8. For instance, four health behaviors (maintaining a
healthy weight, being physically active, eating healthy, and abstaining from smoking) and three biological risk factors (normal blood pressure [BP], cholesterol levels, and fasting blood glucose levels) have been proposed as the seven metrics to define cardiovascular health8. As physical inactivity and poor eating habits are highly prevalent
risk factors for cardiovascular outcomes and total mortality, they are also behaviors closely related to HT1. Thus, any cardiovascular disease prevention programs should
assess and target these two key behaviors. Unfortunately, clinicians are currently ill- equipped to assess these important behavioral risk factors.
We have reported that behavioural risk factors can be assessed through a workplace health program with resources such as a mobile cardiometabolic unit, and that such a
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program improves the overall cardiometabolic risk profile of workers. Our published results have documented the favorable effect of this program and approach on several cardiovascular disease risk factors of workers9, 10.
In the present paper, we document the impact on resting and exercise BP of this workplace cardiometabolic health intervention program targeting lifestyle. We also explore the respective contributions of changes in lifestyle, waist circumference (WC), and cardiorespiratory fitness to changes in BP.
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MATERIALS AND METHODS
Participants (n = 1952, 1,271 men and 681 women) were recruited in 11 different workplaces among employees who participated in the "Grand Défi Entreprise" program between 2011 and 2017. Details of the cardiometabolic health assessment have been published elsewhere10. Briefly, in this cardiometabolic health intervention program,
participating employees are asked to increase their physical activity levels, improve their eating habits (nutritional quality) and stop smoking during a 3-month friendly competition taking place in each workplace. Voluntary participation was the only inclusion criteria and there were no exclusion criteria. Our local Institutional Review Board approved the study and participants signed an informed consent to allow investigators to use their denominalized data for research purposes.
Anthropometric Measurements
Height, weight11 and WC12 were measured according to standardized procedures. Body
mass index (BMI) was calculated. Body fat percentage was estimated using a bioelectric impedance analysis scale (TBF-300A, Tanita, Arlington Heights, IL, USA). Resting Hemodynamic Profile
Using appropriate cuff size, resting BP and heart rate (HR) were measured once on each arm after the participants had been sitting for at least 10 minutes, with an automated sphygmomanometer (SunTech247, SunTech Medical, Morrisville, NC, USA). Left arm values were used for analyses.
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Submaximal Exercise Testing
Submaximal exercise testing was performed at baseline as previously described10. A
subgroup of participants (n = 820) were reassessed for submaximal exercise test after the 3-month intervention. Data (HR, BP) collected at the standardized stage (3.5 mph and 2% slope)10 are presented as "exercise" variables in tables. Maximal oxygen
consumption (VO2max) was estimated by extrapolating oxygen consumption to age-
estimated maximal HR (220 - age)13 using ACSM’s Metabolic Equations14 and the least
square method.
Physical Activity Levels
Physical activity levels at baseline were assessed using a validated short questionnaire from the EPIC study15. Participants are asked to report physical activity at work and in
leisure time over the last year. Physical activity levels were expressed as hours of leisure time physical activity per week. Baseline levels of physical activity were compared with the physical activity reported by the participant in an online physical activity log during the 3-month intervention program. This log allows to compile every 15-minute period reported by the participant each day during the program.
Nutritional Quality
Nutritional quality index (NQI) was assessed using a validated dietary screening tool16
which provides a score from 0 to 100 based on 25 questions focusing on food-based eating habits. The questionnaire was completed at baseline and after the 3-month intervention.
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Intervention
Details of the intervention have been published elsewhere10. Briefly, after the initial
evaluation, a friendly in-house competition is conducted. Each team includes five employees to enhance peer support. Throughout the 3-month intervention, each member of the team cumulates points for every 15-minute period of continuous physical activity, every single daily personalized nutritional objective reached and, for each day without smoking (if they were a smoker at baseline). Physical activity and nutritional objectives are compiled on a web platform where participants can see their teams’ points. Participants also receive info letters on healthy lifestyles (tips, recommendations, information, etc.) by e-mail throughout the intervention. At the end of the intervention, teams with the greatest number of points have better odds of winning prizes offered by the management of companies (e.g. gift certificate, sports equipment, spa and massage packages). Although the prize incentive is part of the intervention, the study investigators had no requirement regarding the form and the value of the prizes. Our local Institutional Review Board approved the study and participants signed an informed consent to allow investigators to use their denominalized data for research purposes. Statistical Analyses
Data are presented as means±SD in tables and means±SE in figures. The Shapiro-Wilk test was used to examine the distribution of each variable and logarithmic transformations were applied to variables showing abnormal distribution. Age-adjusted paired t-tests were performed to compare baseline and post 3-month data. Unpaired t- tests were performed to compare men and women. Multivariate stepwise model analyses were performed to assess the contribution of changes in lifestyle, WC and
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cardiorespiratory fitness to changes in BP in response to the intervention. All statistical analyses were performed using SAS statistical package version 9.4 (SAS Institute, Cary, NC, USA).
Participants were classified into resting BP groups5: 1- Normal BP (NBP): BP <120/80
mmHg, 2- Elevated BP (EBP): BP 120-129/<80 mmHg, 3- HT Stage 1 (HT1): BP 130- 140/80-89 mmHg, 4- HT Stage 2 (HT2): BP ≥140/90 mmHg and 5- Treated HT: using any hypotensive drug. Individuals presenting systolic and diastolic BP (SBP and DBP) in two different categories were classified into the highest category. Resting BP values <130/<80 mmHg were considered as controlled HT in the Treated HT group.
82 RESULTS
Data were available for 1,952 participants (1,271 men and 681 women) who completed the intervention. At baseline, 41% of participants were overweight (25 ≤ BMI < 30 kg/m2), and 26% were obese (BMI ≥ 30 kg/m2), whereas 13% were smokers (active or
former smokers for < 6 months). Moreover, 38% did not meet physical activity levels recommendations (at least 150 min/wk)8 and 43% showed low nutritional quality (NQI <
60). Normal BP was present in 22% of the cohort, elevated BP in 14%, hypertensive BP (HT1 and HT2) in 52%, and 12% were treated for HT (data not shown).
Participants’ baseline and post 3-month intervention characteristics are shown in Table 1. Both sexes improved BMI, WC, resting SBP and DBP, resting HR, and NQI in response to the intervention (P<0.01). Men showed greater improvements in their anthropometric variables than women (P<0.05). Reported physical activity levels only increased in women (P<0.01).
Changes in BP classification are shown in Figure 1. After the 3-month intervention, prevalence of non-hypertensive individuals (NBP and EBP) increased from 28.6% to 40.8% in men, and from 52.0% to 62.9% in women. Prevalence of hypertensive individuals (HT1 and HT2) decreased from 57.4% to 45.1% in men, and from 41.3% to 30.4% in women. In the Treated HT group, prevalence of individuals with controlled HT increased from 20.7% to 28.5% in men and from 13.0% to 30.4% in women (data not shown). Changes in resting BP are shown in Figure 2. Resting BP significantly improved within every BP category (p ≤ 0.05), except for SBP in the NBP category. Table 2 shows the results of the multivariate regression analyses on the contribution of changes in lifestyle variables to changes in resting BP in response to the intervention.
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Changes in WC predicted changes in resting SBP (P<0.01) and DBP (P≤0.05) for both sexes. Changes in NQI (P<0.01) and physical activity levels (P≤0.05) also contributed to changes in resting SBP in men, while age was independently associated with changes in resting SBP in women (P<0.01).
We investigated the impact of the 3-month intervention program on exercise variables and estimated VO2max in a subgroup of participants who performed exercise testing
before and after the 3-month intervention (n = 820, 82% of men). Changes in the participants’ exercise profiles are shown in Table 3. Men (P≤0.01) and women (P≤0.05) showed a reduction in their submaximal exercise HR (P≤0.05), the decrease being more substantial in men than women (P<0.05). Submaximal exercise DBP decreased in both sexes (P≤0.01), whereas only men improved exercise SBP (P≤0.01). Only men significantly increased estimated VO2max (P≤0.01), reduced SBP increase from rest
(P≤0.05), and showed a reduced HR increase from rest (P≤0.01), these changes being non-significant in women. However, women in this subgroup also did significantly increase their reported physical activity levels (4.5 ± 3.8 to 5.1 ± 3.0 hr/wk, P≤0.05), a finding not observed in men (5.1 ± 4.8 to 5.2 ± 3.3 hr/wk, NS).
We also performed multivariate stepwise regression analyses to assess the respective contributions of variation in WC, lifestyle habits and estimated VO2max to changes in
exercise BP (Table 4). Changes in estimated VO2max were predictive of changes in
exercise SBP and DBP in both sexes (P≤0.01). Age and changes in WC contributed to explain changes in exercise SBP in men (P≤0.01), while age (P<0.05) and changes in NQI (P<0.01) contributed to the variation in exercise DBP in women produced by the intervention.
84 DISCUSSION
The 3-month workplace intervention targeting four key lifestyle vital signs had a positive impact on resting BP across sexes and BP categories. Overall, reductions of 4 and 2 mmHg for resting SBP and DBP respectively were observed in both sexes. Such improvements may appear, at first glance, relatively small at the individual level but such improvement would be expected to have a huge positive impact at the population level. For instance, a 2 mmHg reduction in SBP at the population level has been shown to lower stroke mortality by 10% and ischemic heart disease mortality by 7%17, while a 2
mmHg reduction in DBP has been associated with decreases of 15% and 6% in risk of coronary heart disease and stroke, respectively18. Therefore, targeting lifestyle habits at
the workplace could have an impact on cardiovascular diseases through its effect on resting BP.
Furthermore, BP reductions observed in the HT1 and HT2 groups were similar to the mean BP lowering effect reported for common hypotensive pharmacological agents (about 8 and 5 mmHg for SBP and DBP, respectively19-21). For instance, hypertensive
men (HT1 and HT2 combined) lowered their SBP and DBP by 6 and 4 mmHg respectively, while hypertensive women lowered their SBP and DBP by 9 and 5 mmHg respectively. Thus, this workplace intervention targeting simple lifestyle vital signs can induce reductions in BP close to those expected with prescribed drugs among subjects who would qualify for pharmacotherapy if managed in a clinical context. For instance, 36% of individuals classified as hypertensive (HT1 and HT2) at baseline reduced their resting BP values < 130/80 mmHg. Moreover, 19% of Treated HT subjects with uncontrolled BP (≥ 130/80 mmHg) at baseline achieved controlled levels of resting SBP
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and DBP post-intervention, while 40% of the EBP group at baseline reached normal BP values post-intervention. Thus, the present workplace lifestyle intervention produced substantial improvements in resting BP control within elevated BP category, with a high proportion of participants lowering their resting BP under clinical thresholds by simply assessing and adopting healthier lifestyle habits for a period of only 3 months. As recent guidelines have proposed lower values for controlled BP5, the prevalence of elevated
BP has increased as a consequence. For instance, in the present study sample, applying the target of 130/80 instead of 140/90 mmHg has reduced the prevalence of controlled HT from over half (54%) to less than a fifth (19%). Thus, lifestyle interventions can help reach control BP values in Treated HT individuals and should be given more importance as BP targets become harder to reach.
In our multivariate correlation model, the change in WC was the strongest predictor of change in resting BP in men and, to a lesser but still significant extent, also in women. Previous studies have shown that abdominal obesity is one of the strongest independent predictors of HT22 and that resting BP is closely related to variation in
WC23. Accordingly, we found that the decrease in WC modulated by the present
workplace program was associated with a decrease in resting BP. Physical activity levels and nutritional quality were also independently associated with changes in resting BP, but the shared variance was less than for changes in WC. These findings suggest that the influence of physical activity and of nutritional quality on BP in the present study were largely mediated by related decreases in WC.
Age was the strongest predictor of the response of resting BP changes in women. We therefore investigated the possible confounding contribution of menopause on such
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changes in resting BP since it is considered a risk factor for cardiovascular disease24
and has been associated with higher BP and changes in body fat distribution pattern25.
However, menopausal status (n = 119) was not found to be a predictor of BP changes in our cohort. Age also remained the strongest predictor of changes in resting BP in a separate multivariate analysis conducted in premenopausal women (n = 562). Thus, older women could expect more substantial improvement in their resting BP if they adopt healthier lifestyle habits, as improvements in resting BP related to healthy lifestyle are usually greater in those with higher initial values5.
Furthermore, men improved exercise SBP and DBP, exercise HR and estimated VO2max, and showed reduced SBP and HR responses to the standardized exercise
treadmill stage. On the contrary, women only improved exercise DBP and exercise HR. The fact that women did not improve their estimated VO2max is, at first glance, rather
surprising as only women significantly increased their levels of physical activity during this program. Although women did increase their volume of physical activity (min/week), which improved their metabolic profile and hemodynamic profile at rest, but without maybe increasing physical activity intensity, as hinted by the lack of significant increase in their VO2max. Our study did not assess the intensity of the physical activity performed,