Diet and blood pressure: applying the evidence to clinical practice

Perception of obesity and overweight among adults living in suburban Nepal: a qualitative study

OBJECTIVE

To explore the perception of obesity and overweight among Nepalese adults living in a suburban community.

DESIGN

A qualitative study composed of focus group discussion (FGD) and in-depth interview (IDI).

SETTING

Community and healthcare facilities in Dhulikhel, Nepal.

PARTICIPANTS

Four FGDs were conducted with community members (n=22) and four IDIs were conducted with healthcare providers (HCPs).

RESULTS

Obesity is a rising problem in this suburban community. Participants had inadequate knowledge regarding the consequences of obesity, and they perceived overweight as normal, healthy and attractive. The participants above 40 years of age did not perceive themselves to be overweight or obese. Despite participants' awareness of the importance of diet control and exercise to prevent obesity, these were not translated into practice.

CONCLUSIONS

This study provided insight into perceptions of obesity in a suburban Dhulikhel community through both community members' and HCPs' perspective. Misconceptions and inadequate knowledge of obesity among people in this community indicate the need for health education and intervention programme to increase health awareness and preventive practices.

Long-term effects of weight-reducing diets in people with hypertension

BACKGROUND

All major guidelines for antihypertensive therapy recommend weight loss. Dietary interventions that aim to reduce body weight might therefore be a useful intervention to reduce blood pressure and adverse cardiovascular events associated with hypertension.

OBJECTIVES

Primary objectives To assess the long-term effects of weight-reducing diets in people with hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events). Secondary objectives To assess the long-term effects of weight-reducing diets in people with hypertension on change from baseline in systolic blood pressure, change from baseline in diastolic blood pressure, and body weight reduction.

SEARCH METHODS

For this updated review, the Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to April 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 3), Ovid MEDLINE, Ovid Embase, and ClinicalTrials.gov. We also contacted authors of relevant papers about further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of at least 24 weeks' duration that compared weight-reducing dietary interventions to no dietary intervention in adults with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risks of bias and extracted data. Where appropriate and in the absence of significant heterogeneity between studies (P > 0.1), we pooled studies using a fixed-effect meta-analysis. In case of moderate or larger heterogeneity as measured by Higgins I2, we used a random-effects model.

MAIN RESULTS

This second review update did not reveal any new trials, so the number of included trials remains the same: eight RCTs involving a total of 2100 participants with high blood pressure and a mean age of 45 to 66 years. Mean treatment duration was 6 to 36 months. We judged the risks of bias as unclear or high for all but two trials. No study included mortality as a predefined outcome. One RCT evaluated the effects of dietary weight loss on a combined endpoint consisting of the necessity of reinstating antihypertensive therapy and severe cardiovascular complications. In this RCT, weight-reducing diet lowered the endpoint compared to no diet: hazard ratio 0.70 (95% confidence interval (CI) 0.57 to 0.87). None of the trials evaluated adverse events as designated in our protocol. The certainty of the evidence was low for a blood pressure reduction in participants assigned to weight-loss diets as compared to controls: systolic blood pressure: mean difference (MD) -4.5 mm Hg (95% CI -7.2 to -1.8 mm Hg) (3 studies, 731 participants), and diastolic blood pressure: MD -3.2 mm Hg (95% CI -4.8 to -1.5 mm Hg) (3 studies, 731 participants). We judged the certainty of the evidence to be high for weight reduction in dietary weight loss groups as compared to controls: MD -4.0 kg (95% CI -4.8 to -3.2) (5 trials, 880 participants). Two trials used withdrawal of antihypertensive medication as their primary outcome. Even though we did not consider this a relevant outcome for our review, the results of these RCTs strengthen the finding of a reduction of blood pressure by dietary weight-loss interventions.

AUTHORS' CONCLUSIONS

In this second update, the conclusions remain unchanged, as we found no new trials. In people with primary hypertension, weight-loss diets reduced body weight and blood pressure, but the magnitude of the effects are uncertain due to the small number of participants and studies included in the analyses. Whether weight loss reduces mortality and morbidity is unknown. No useful information on adverse effects was reported in the relevant trials.

Effect of nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults

BACKGROUND/OBJECTIVES

Hypertension is the major risk factor for cardiovascular disease, a leading cause of deaths in Korea. The objective of this study was to evaluate the effect of a nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults.

SUBJECTS/METHODS

Subjects who participated in this study were 88 adults (28 males and 60 females) who were pre-hypertension or untreated hypertensive patients aged ≥ 30 yrs in Gyeonggi Province, Korea. These subjects were divided into 2 groups: a low-sodium education (LS) group and a low-sodium high-potassium education (LSHP) group. Nutrition education of 3 sessions for 12 weeks was conducted. Blood pressure, blood and urine components, nutrient intake, and dietary behavior were compared between the two education groups.

RESULT

Blood pressure was decreased in both groups after the nutrition education (P < 0.05). In the LSHP group, levels of blood glucose (P < 0.05), total cholesterol (P < 0.01), and low-density lipoprotein-cholesterol (P < 0.05) were decreased after the program completion. Sodium intake was decreased in both groups after the nutrition education (P < 0.05). However, Na/K ratio was only decreased in the LS group (P < 0.05). Intake frequency of fish & shellfish was only significantly reduced in the LS group (P < 0.05), while intake frequencies of cooked rice, noodles & dumplings, breads & snacks, stew, kimchi, and fish & shellfish were reduced in the LSHP group (P < 0.05). Total score of dietary behavior appeared to be effectively decreased in both groups after the education program (P < 0.001).

CONCLUSIONS

This education for reducing sodium intake was effective in reducing blood pressure and sodium intake. The education for enhancing potassium intake resulted in positive changes in blood glucose and serum cholesterol levels.

Behavioural Risk Factors, Hypertension Knowledge, and Hypertension in Rural India

Hypertension is an important health problem in India. The emergence of hypertension and other cardiovascular diseases are strongly related to various risk factors. Knowledge about hypertension and related risk factors is often stressed on their utility in prevention and management of the disease. Still, there is a poor understanding about associated behavioural risk factors of hypertension and importance of knowledge in adopting health-promoting behaviours and controlling hypertension among rural areas of India. This study aimed at assessing the association of behavioural risk factors with hypertension knowledge and hypertension among rural population. The present study focused on a south-western state of India from which a taluk with one of the lowest socioeconomic ratings was selected. A total of 263 participants were selected by using a multistage random sampling technique. Data were collected by in-person interview using behavioural risk factors questionnaire, hypertension knowledge questionnaire, and physical measurement. Data were analysed using descriptive statistics, chi square, Pearson correlation and binary logistic regression. Findings revealed that there is no significant relationship between risk factors index and knowledge of hypertension. It was also observed that factors such as smoking (OR = 0.29; CI: 090–0.961), fruit and vegetable consumption (OR = 1.32; CI: 1.01–1.74), body mass index (OR = 1.85; CI: 1.21–2.84), and age group (OR = 1.55; CI: 1.14–2.11) were significantly associated with the odds of hypertension. The factors such as smokeless tobacco use, alcohol consumption, physical activity, gender, education, and occupation were not associated with the odds of hypertension. Future research should focus on bringing down the associated risk factors to prevent and control hypertension.

Prevalence and knowledge of hypertension among people living in rural communities in Ghana: a mixed method study

BACKGROUND

Knowledge and understanding of hypertension and its associated health risks remain inadequate despite increasing trend of hypertension prevalence. This study was conducted to assess the prevalence, knowledge and perceptions of hypertension in rural communities in Ghana.

METHODS

A mixed method study involving 534 subjects was employed. Data was collected in six communities from May to December 2014 with structured questionnaires and interview guides. A logistic regression analysis was conducted to estimate the influence of the socio-demographic factors on knowledge of hypertension. Qualitative data was thematically analyzed.

RESULTS

The mean systolic blood pressure (BP) was higher in men than women (127.42mmHg versus 124.42mmHg). The proportion of hypertensives was 21.4% and was higher among men in all age categories. Knowledge on some risk factors of hypertension was extremely low. Having formal education was associated with higher odds of knowledge of hypertension (Adjusted odds ratio [AOR]; 95% confidence interval [CI]=2.28; 1.25-4.16). Several misconceptions such as the use of agro-chemicals, fertilizers and excess vitamins were identified as causes of hypertension.

CONCLUSION

This study demonstrates an increased prevalence of hypertension, knowledge gaps and misconceptions surrounding hypertension in rural communities in Ghana. This evidence is useful in streamlining interventional programmes aimed at improving knowledge and prevention of hypertension.

Long-term effects of weight-reducing diets in people with hypertension

BACKGROUND

All major guidelines for antihypertensive therapy recommend weight loss. Thus dietary interventions that aim to reduce body weight might be a useful intervention to reduce blood pressure and adverse cardiovascular events associated with hypertension.

OBJECTIVES

Primary objectivesTo assess the long-term effects of weight-reducing diets in people with hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events). Secondary objectivesTo assess the long-term effects of weight-reducing diets in people with hypertension on change from baseline in systolic blood pressure, change from baseline in diastolic blood pressure, and body weight reduction.

SEARCH METHODS

We obtained studies from computerised searches of the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Hypertension Specialised Register, Ovid MEDLINE, and Ovid EMBASE, and from searches in reference lists, systematic reviews, and the clinical trials registry ClinicalTrials.gov (status as of 2 February 2015).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of at least 24 weeks' duration that compared weight-reducing dietary interventions to no dietary intervention in adults with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias and extracted data. We pooled studies using fixed-effect meta-analysis. In case of moderate or larger heterogeneity as measured by Higgins I(2), we used a random-effects model.

MAIN RESULTS

This review update did not reveal any new studies, so the number of included studies remained the same: 8 studies involving a total of 2100 participants with high blood pressure and a mean age of 45 to 66 years. Mean treatment duration was 6 to 36 months. We judged the risk of bias as unclear or high for all but two trials. No study included mortality as a predefined outcome. One RCT evaluated the effects of dietary weight loss on a combined endpoint consisting of the necessity of reinstating antihypertensive therapy and severe cardiovascular complications. In this RCT, weight-reducing diet lowered the endpoint compared to no diet: hazard ratio 0.70 (95% confidence interval (CI), 0.57 to 0.87). None of the studies evaluated adverse events as designated in our protocol. There was low-quality evidence for a blood pressure reduction in participants assigned to weight loss diets as compared to controls: systolic blood pressure: mean difference (MD) -4.5 mm Hg (95% CI -7.2 to -1.8 mm Hg) (3 of 8 studies included in analysis), and diastolic blood pressure: MD -3.2 mm Hg (95% CI -4.8 to -1.5 mm Hg) (3 of  8  studies included in analysis). There was moderate-quality evidence for weight reduction in dietary weight loss groups as compared to controls: MD -4.0 kg (95% CI -4.8 to -3.2) (5 of 8 studies included in analysis). Two studies used withdrawal of antihypertensive medication as their primary outcome. Even though we did not consider this a relevant outcome for our review, the results of these studies strengthen the finding of reduction of blood pressure by dietary weight loss interventions.

AUTHORS' CONCLUSIONS

In this update, the conclusions remain the same, as we found no new trials. In people with primary hypertension, weight loss diets reduced body weight and blood pressure, however the magnitude of the effects are uncertain due to the small number of participants and studies included in the analyses. Whether weight loss reduces mortality and morbidity is unknown. No useful information on adverse effects was reported in the relevant trials.

Self-reported health beliefs, lifestyle and health behaviours in community-based patients with diabetes and hypertension

OBJECTIVE

This study describes self-reported health and lifestyle behaviours and health risk beliefs among community patients diagnosed with type 2 diabetes and hypertension.

METHODS

Patients with both type 2 diabetes and hypertension were recruited from community family practices across 3 Canadian Maritime provinces. Patients completed a survey targeting health risk beliefs, and health and lifestyle behaviours. Analyses examined differences in patient beliefs by age and sex, as well by health and lifestyle behaviour.

RESULTS

Overall, 90.8% of patients believed that controlling both blood pressure and blood glucose were important, particularly women (p<0.01), and 92.8% felt that having both conditions put them at high risk for cardiovascular problems. Older patients reported higher antihypertensive medication adherence (p<0.0001). Most (90.8%) believed that prescription drug use was most helpful for controlling blood pressure, and this belief was associated with medication adherence (p<0.0001). Overall, patients who believed in the benefits of a given lifestyle behaviour were more likely to demonstrate the behaviour.

CONCLUSION

The majority of patients surveyed were knowledgeable about their increased risk for cardiovascular problems. Patient lifestyle behaviours tended to mirror their health beliefs. These results provide important insight into the health beliefs and lifestyle behaviours of patients who receive the majority of their care in the community.

Diabetes awareness and diabetes risk reduction behaviors among attendance of primary healthcare centers

AIMS

The aims of this study were to assess level of awareness about diabetes and the level of adoption of diabetes risk behaviors among adult attending primary healthcare centers.

METHODS

A cross-sectional descriptive study was conducted using a self-administrated questionnaire. In addition to demographic information, the questionnaire contained questions on diabetes awareness related to diabetes definition, symptoms, risk factors, complications and management of diabetes as well as questions on diabetes risk reduction behaviors and sources of information on diabetes. The data was analyzed with independent t-test, Pearson's correlation coefficient, and ANOVA test.

RESULTS

A total of 541 participants aged ≥ 18 years were recruited. The mean score of diabetes awareness was 27.5/40 [SD=5.7]. The participants performed best in symptoms section with a mean score of 6.3/8 [SD=1.6], and worst in the risk factors section with a mean score of 3.6/6 (SD=1.4). With respect to diabetes risk reduction behaviors the results showed that the highest mean score was for fat reduction 2.0/4 [SD=0.8]; and the lowest mean score was for weight control or losing 1.7/4 [SD=0.8].

CONCLUSIONS

The current study demonstrated that substantial numbers of adult Jordanian lack the sufficient awareness about diabetes to prevent and cope with the increasing prevalence of diabetes in Jordan. Also, it demonstrated that adoption of diabetes risk reduction behaviors was suboptimal. Raising public awareness of diabetes and diabetes risk reduction behaviors through population-based programs and mass media should be planned and implemented.

Long-term effects of weight-reducing diets in hypertensive patients

BACKGROUND

All major guidelines for antihypertensive therapy recommend weight loss. Thus dietary interventions that aim to reduce body weight might be a useful intervention to reduce blood pressure and adverse cardiovascular events associated with hypertension.

OBJECTIVES

Primary objectivesTo assess the long-term effects of weight-reducing diets in hypertensive patients on-   all cause mortality -   cardiovascular morbidity -   adverse events (including total serious adverse events, withdrawal due to adverse events and total non-serious adverse events)Secondary objectivesTo assess the long-term effects of weight-reducing diets in hypertensive patients on-   change from baseline in systolic blood pressure -   change from baseline in diastolic blood pressure -   body weight reduction

SEARCH STRATEGY

Studies were obtained from computerised searches of Ovid MEDLINE, EMBASE, CENTRAL and from searches in reference lists and systematic reviews.

SELECTION CRITERIA

Randomised controlled trials (RCT) in adult hypertensive patients were included if they had a study duration of at least 24 weeks and compared weight reducing dietary interventions to no dietary intervention in adult patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Studies were pooled using fixed-effect meta-analysis. In case of moderate or larger heterogeneity as measured by Higgins I(2), a random effects model was used.

MAIN RESULTS

Eight studies involving a total of 2100 participants with high blood pressure and a mean age of 45 to 66 years met our inclusion criteria. Mean treatment duration was 6 to 36 months. No study included mortality as a pre-defined outcome. One RCT evaluated the effects of dietary weight loss on a combined endpoint, consisting of the necessity of reinstating antihypertensive therapy and severe cardiovascular complications. In this RCT weight reducing diet lowered the endpoint, hazard ratio 0.70 (95% confidence interval [CI], 0.57 to 0.87) compared to no diet. None of the studies evaluated adverse events as designated in our protocol. Blood pressure was reduced in patients assigned to weight loss diets as compared to controls: systolic blood pressure (SBP): weighted mean difference (WMD): -4.5 mm Hg; 95% CI, -7.2 to -1.8 mm Hg (3 of  8  studies included in analysis), and diastolic blood pressure (DBP): WMD -3.2 mm Hg; 95% CI, -4.8 to -1.5 mm Hg (3 of  8  studies included in analysis). Patients' body weight was also reduced in dietary weight loss groups as compared to controls, WMD of -4.0 kg (95% CI: -4.8 to -3.2) (5 of  8  studies included in analysis). Two studies used withdrawal of antihypertensive medication as their primary outcome. Even though this was not considered a relevant outcome for this review, the results of these studies strengthen the finding of reduction of blood pressure by dietary weight loss interventions.

AUTHORS' CONCLUSIONS

In patients with primary hypertension, weight loss diets reduced body weight and blood pressure, however the magnitude of the effects are uncertain as a result of the small number of patients and studies that could be included in the analyses. It is not known whether weight loss reduces mortality and morbidity. No useful information on adverse effects was reported in the relevant trials.

The Future of Antihypertensive Treatment

Despite progress in recent years in the prevention, detection, and treatment of high blood pressure (BP), hypertension remains an important public health challenge. Hypertension affects approximately 1 billion individuals worldwide. High BP is associated with an increased risk of mortality and morbidity from stroke, coronary heart disease, congestive heart failure, and end-stage renal disease; it also has a negative impact on the quality of life. Hypertension cannot be eliminated because there are no vaccines to prevent the development of hypertension, but, its incidence can be decreased by reducing the risk factors for its development, which include obesity, high dietary intake of fat and sodium and low intake of potassium, physical inactivity, smoking, and excessive alcohol intake. For established hypertension, efforts are to be directed to control BP by lifestyle modification (LSM). However, if BP cannot be adequately controlled with LSM, then pharmacotherapy can be instituted along with LSM. Normalization of BP reduces cardiovascular risk (for cardiovascular death, myocardial infarction, and cardiac arrest), provides renoprotection (prevention of the onset or slowing of proteinuria and progression of renal dysfunction to end-stage renal disease in patients with hypertension, diabetes mellitus types 1 and 2, and chronic renal disease), and decreases the risk of cerebrovascular events (stroke and cognition impairment), as has been amply demonstrated by a large number of randomized clinical trials. In spite of the availability of more than 75 antihypertensive agents in 9 classes, BP control in the general population is at best inadequate. Therefore, antihypertensive therapy in the future or near future should be directed toward improving BP control in treated hypertensive patients with the available drugs by using the right combinations at optimum doses, individually tailored gene-polymorphism directed therapy, or development of new modalities such as gene therapy and vaccines. Several studies have shown that BP can be reduced by lifestyle/behavior modification. Although, the reductions appear to be trivial, even small reductions in systolic BP (for example, 3-5 mm Hg) produce dramatic reduction in adverse cardiac events and stroke. On the basis of the results of clinical and clinical/observational studies, it has been recommended that more emphasis be placed on lifestyle/behavior modification (obesity, high dietary intake of fat and sodium, physical inactivity, smoking, excessive alcohol intake, low dietary potassium intake) to control BP and also to improve the efficacy of pharmacologic treatment of high BP. New classes of antihypertensive drugs and new compounds in the established drug classes are likely to widen the armamentarium available to combat hypertension. These include the aldosterone receptor blockers, vasodilator beta-blockers, renin inhibitors, endothelin receptor antagonists, and dual endopeptidase inhibitors. The use of fixed-dose combination drug therapy is likely to increase. There is a conceptual possibility that gene therapy may yield long-lasting antihypertensive effects by influencing the genes associated with hypertension. But, the treatment of human essential hypertension requires sustained over-expression of genes. Some of the challenging tasks for successful gene therapy that need to be mastered include identification of target genes, ideal gene transfer vector, precise delivery of genes into the required site (target), efficient transfer of genes into the cells of the target, and prompt assessment of gene expression over time. Targeting the RAS by antisense gene therapy appears to be a viable strategy for the long-term control of hypertension. Several problems that are encountered in the delivery of gene therapy include 1) low efficiency for gene transfer into vascular cells; 2) a lack of selectivity; 3) problem in determining how to prolong and control transgene expression or antisense inhibition; and 4) difficulty in minimizing the adverse effects of viral or nonviral vectors. In spite of the hurdles that face gene therapy administration in humans, studies in animals indicate that gene therapy may be feasible in treating human hypertension, albeit not in the near future. DNA testing for genetic polymorphism and determining the genotype of a patient may predict response to a certain class of antihypertensive agent and thus optimize therapy in individual patients. In this regard, there are some studies that report the effectiveness of antihypertensive therapy based upon the genotype of selected patients. Treatment of human hypertension with vaccines is feasible but is not likely to be available in the near future.