Investigating the association between ambient particulate matter (PM10) exposure and blood pressure values: Results from the link between the Portuguese Health Examination Survey and air quality data

INTRODUCTION AND OBJECTIVES

High blood pressure (BP) remains a major modifiable cardiovascular (CV) risk factor. Several epidemiologic studies have been performed to assess the association between air pollution exposure and this CV risk factor but results remain inconsistent. This study aims to estimate the effect of short-term PM₁₀ exposure (average previous three-day concentration) on diastolic (DBP) and systolic (SBP) blood pressure values of the resident mainland Portuguese population.

METHODS

Our study was based on available DBP and SBP data from 2272 participants from the first Portuguese Health Examination Survey (INSEF, 2015) living within a 30 km radius of at least one air quality monitoring station, with available measurements of particulate matter with an aerodynamic equivalent diameter ≤10 μm (PM₁₀). We used data from the air quality monitoring network of the Portuguese Environment Agency to obtain the individual allocated PM₁₀ concentrations. Generalized linear models were used to assess the effect of PM₁₀ exposure on DBP and SBP values.

RESULTS

No statistically significant association was found between PM₁₀ exposure and both DBP and SBP values (0.42% DBP change per 10 μg/m³ of PM₁₀ increment (95% confidence interval (CI): -0.85; 1.70) and 0.47% SBP change per 10 μg/m³ of PM₁₀ increment (95% CI: -0.86; 1.79)). Results remain unchanged after restricting the analysis to hypertensive or obese participants or changing the PM₁₀ assessment methodology.

CONCLUSIONS

In view of the PM₁₀ levels observed in 2015, our results suggests that exposure to PM₁₀ concentrations have a small or no effect on the blood pressure values. Other air pollutants and mixtures of pollutants that were not included in our study should considered in future studies.

Effect of lifestyle on blood pressure in patients under antihypertensive medication: An analysis from the Portuguese Health Examination Survey

INTRODUCTION AND OBJECTIVES

Hypertension is one of the main risk factors for disability and death from cardiovascular disease. Current guidelines include initiatives to control blood pressure in hypertensive patients that focus on lifestyle changes. The main objective of this study was to analyze the association between lifestyle and blood pressure in patients under antihypertensive medication.

METHODS

Data collected in the Portuguese National Health Examination Survey (INSEF) were analyzed. Individuals who met INSEF inclusion criteria and reported being under antihypertensive medication in the two weeks prior to the questionnaire were studied. Lifestyle variables (alcohol consumption, smoking, added salt intake, fruit and vegetable consumption, and physical activity) were assessed by questionnaire, and systolic and diastolic blood pressure were measured by physical examination. Associations between lifestyle factors and blood pressure, stratified by gender and adjusted for sociodemographic variables and obesity, were estimated through a multiple linear regression model.

RESULTS

Alcohol consumption (beta=6.31, p=0.007) and smoking (beta=4.72, p=0.018) were positively associated with systolic blood pressure in men. Added salt intake, fruit and vegetable consumption, and physical activity were not associated with blood pressure in men. In women, no association was observed for any behavioral variable.

CONCLUSIONS

These conclusions highlight the need in the population under antihypertensive medication, particularly in men, to focus on the fight against high systolic blood pressure in the two modifiable and preventable behaviors of smoking and alcohol consumption.

Exploring the relationship of peripheral total bilirubin, red blood cell, and hemoglobin with blood pressure during childhood and adolescence

OBJECTIVE

Total bilirubin is beneficial for protecting cardiovascular diseases in adults. The authors aimed to investigate the association of total bilirubin, red blood cell, and hemoglobin levels with the prevalence of high blood pressure in children and adolescents.

METHODS

A total of 3776 students (aged from 6 to 16 years old) were examined using cluster sampling. Pre-high blood pressure and high blood pressure were respectively defined as the point of 90th and 95th percentiles based on the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Both systolic and diastolic blood pressure were standardized into z-scores.

RESULTS

Peripheral total bilirubin, red blood cell and hemoglobin levels were significantly correlated with age, and also varied with gender. Peripheral total bilirubin was negatively correlated with systolic blood pressure in 6- and 9-year-old boys, whilst positively correlated with diastolic blood pressure in the 12-year-old boys and 13- to 15-year-old girls (p<0.05). Higher levels of red blood cell and hemoglobin were observed in pre-high blood pressure and high blood pressure students when compared with their normotensive peers (p<0.01). The increases in red blood cell and hemoglobin were significantly associated with high blood pressure after adjusting for confounding factors. The ORs (95% CI) of each of the increases were 2.44 (1.52-3.92) and 1.04 (1.03-1.06), respectively. No statistical association between total bilirubin and high blood pressure was observed (p>0.05).

CONCLUSION

Total bilirubin could be weakly correlated with both systolic and diastolic blood pressure, as correlations varied with age and gender in children and adolescents; in turn, the increased levels of red blood cell and hemoglobin are proposed to be positively associated with the prevalence of high blood pressure.

Should first blood pressure measurement be performed in the newborn?

Dilated cardiomyopathy is the most common form of cardiomyopathy and the main cause of cardiac transplantation in children and in adults. Infants and children have a wider spectrum of etiologies, hampering their identification. The most frequent initial manifestation of dilated cardiomyopathy is symptomatic heart failure during exercise or at rest (although many patients are asymptomatic). Some causes are potentially reversible, therefore the investigation should be carefully planned and immediately performed after diagnosis. In most children no cause is identified, which limits the targeted therapeutic approach and therefore the effectiveness of the treatment. The authors present a case of dilated cardiomyopathy secondary to renovascular hypertension diagnosed in an infant with 3.5 month-old, highlighting the etiological investigation, treatment and evolution. The authors present this case emphasising the fact that the arterial hypertension diagnose in infants is not always easy, questioning the current recommendations relating to an initial evaluation on blood pressure. We postulate that the assessment of blood pressure in newborns can detect early renovascular hypertension (and even other cardiovascular diseases) and help prevent the development of deleterious effects, including fatal episodes.

Blood pressure is associated with body adiposity indicators in children aged 4 to 7 years

INTRODUCTION AND OBJECTIVE

Studies in adults have shown an association between increased adiposity and hypertension, but few studies have analyzed this association in childhood. The aim of this study was to investigate the association between blood pressure (BP) and body adiposity indicators in children, controlling for the variables of birth conditions, sociodemographics, lifestyle and diet.

METHODS

In this cross-sectional study of 399 children aged 4 to 7 years, the dependent variable was BP, measured according to the protocol established by the 7th Brazilian Guidelines on Hypertension. The explanatory variables of the study were waist-to-height ratio (WHtR) and body mass index (BMI). Multiple linear regression was used to assess the independent association between adiposity and BP indicators adjusted for the variables of birth conditions, sociodemographics, lifestyle and diet. Statistical significance was set as α=5%.

RESULTS

BMI for age and WHtR correlated positively with systolic (SBP) and diastolic blood pressure (DBP). After multivariate analysis, higher values of BMI (model 1) and WHtR (model 2) were associated with increased SBP and DBP.

CONCLUSION

Increased body adiposity, as assessed by BMI and WHtR, was associated with increased SBP and DBP among the children studied. Thus, we suggest the use of BMI and WHtR in the nutritional assessment of children to detect changes in BP and other cardiometabolic risk factors in this population.

Birth weight and its association with blood pressure and nutritional status in adolescents

OBJECTIVE

The management of children with low birth weight is not the same in countries with different resources. The authors assessed the association of birth weight with blood pressure and nutritional status in a representative sample of adolescents from a Brazilian state, aiming to identify possible consequences of these differences.

METHODS

A cross-sectional school-based study was conducted with adolescents (12-18 years) enrolled in public and private schools. Birth weight, office blood pressure, home blood pressure measurements, and nutritional status (body mass index, height z-score for the age, and waist circumference) were assessed. The association of birth weight with the outcomes (blood pressure, height, body mass index, and waist circumference) was studied through univariate and multivariable linear regression models.

RESULTS

A total of 829 adolescents with a mean age of 14.6±1.62 years were included; 43.3% were male, and 37.0% from private schools. The prevalence of low birth weight was 8.7%. Mild low height prevalence was higher among those adolescents with low/insufficient birth weight when compared to those with normal/high birth weight (11.7 vs. 4.2%; p<0.001). In the multiple linear regression analysis, for each increase of 100g in birth weight, height increased by 0.28cm (95% CI: 0.18-0.37; p<0.01). Birth weight did not influence office blood pressure and home blood pressure, body mass index, or waist circumference of adolescents.

CONCLUSIONS

Birth weight was directly associated to height, but not associated to blood pressure, body mass index, and waist circumference in adolescents from an urban area of a developing country.

Aspirin and blood pressure: Effects when used alone or in combination with antihypertensive drugs

Arterial hypertension is a major risk factor for cardiovascular and renal events. Lowering blood pressure is thus an important strategy for reducing morbidity and mortality. Since low-dose aspirin is a cornerstone in the prevention of adverse cardiovascular outcomes, combined treatment with aspirin and antihypertensive drugs is very common. However, the impact of aspirin therapy on blood pressure control remains a subject of intense debate. Recent data suggest that the cardioprotective action of aspirin extends beyond its well-known antithrombotic effect. Aspirin has been shown to trigger the synthesis of specialized pro-resolving lipid mediators from arachidonic acid and omega-3 fatty acids. These novel anti-inflammatory and pro-resolving mediators actively stimulate the resolution of inflammation and tissue regeneration. Additionally, they may contribute to other protective effects on redox status and vascular reactivity that have also been attributed to aspirin. Of note, aspirin has been shown to improve vasodilation through cyclooxygenase-independent mechanisms. On the other hand, higher aspirin doses have been reported to exert a negative impact on blood pressure due to inhibition of cyclooxygenase-2 activity, which reduces renal blood flow, glomerular filtration rate and sodium and water excretion. This review aims to provide an overview of the effects of aspirin on blood pressure and the underlying mechanisms, focusing on the interaction between aspirin and antihypertensive drugs. Studies in both experimental and human hypertension are presented.

Cochrane Corner: Antihypertensive efficacy of beta-1 selective beta blockers for primary hypertension

Beta blockers are commonly used to treat hypertension. This Cochrane systematic review assessed the effect of beta-1 selective beta blockers on blood pressure (BP), pulse pressure (PP), heart rate (HR) and withdrawal due to adverse effects in patients with primary hypertension. Fifty-six randomized placebo-controlled trials were included, with a total of 7812 patients. These drugs reduced systolic/diastolic BP by 10/8 mmHg, PP by 2 mmHg and HR by 11 bpm; no difference was found between treatment and placebo regarding withdrawal due to adverse effects. Differences in efficacy were observed between the various beta-1 selective beta blockers, which may be due to methodological differences in the trials. The choice of an antihypertensive drug should take into account not only its efficacy in reducing BP but also its tolerability, its efficacy in preventing cardiovascular events, and other factors such as undesirable metabolic effects.

Effects of percutaneous renal sympathetic denervation on cardiac function and exercise tolerance in patients with chronic heart failure

INTRODUCTION

Sympathetic hyperactivity, a vital factor in the genesis and development of heart failure (HF), has been reported to be effectively reduced by percutaneous renal denervation (RDN), which may play an important role in HF treatment.

OBJECTIVE

To determine the effects of percutaneous RDN on cardiac function in patients with chronic HF (CHF).

METHODS

Fourteen patients (mean age 69.6 years; ejection fraction [EF] <45%) with CHF received bilateral RDN. Adverse cardiac events, blood pressure (BP), and biochemical parameters were assessed before and six months after percutaneous operation. Patients also underwent echocardiographic assessment of cardiac function and 6-min walk test before and at six months after percutaneous operation.

RESULTS

The distance achieved by the 14 patients in the 6-min walk test increased significantly from 152.9±38.0 m before RDN to 334.3±94.4 m at six months after RDN (p<0.001), while EF increased from 36.0±4.1% to 43.8±7.9% (p=0.003) on echocardiography. No RDN-related complications were observed during the follow-up period. In 6-month follow-up, systolic BP decreased from 138.6±22.1 mmHg to 123.2±10.5 mmHg (p=0.026) and diastolic BP from 81.1±11.3 mmHg to 72.9±7.5 mmHg (p=0.032). Creatinine levels did not change significantly (1.3±0.65 mg/dl to 1.2±0.5 mg/dl, p=0.8856).

CONCLUSION

RDN is potentially an effective technique for the treatment of severe HF that can significantly increase EF and improve exercise tolerance.

Influence of breastfeeding in the first months of life on blood pressure levels of preschool children

OBJECTIVE

To investigate whether breastfeeding in early life affects blood pressure of preschoolers.

METHODS

Cross-sectional study nested in a cohort from a municipality in the state of Minas Gerais, Brazil. All children in the cohort were invited for this study. Thus, between 2009 and 2010, blood pressure of 230 preschool children and their mothers, in addition to anthropometric variables, previous history, and socioeconomic status were evaluated. Blood pressure measurement was assessed in the morning, using automatic Omron^® HEM-714INT and HEM-781INT devices to measure the blood pressure of preschool children and their mothers, respectively. Logistic regression was used to study the association between breastfeeding and blood pressure. The significance level was set at 5%.

RESULTS

This study identified 19 (8.26%) preschool children with high blood pressure (values above the 90th percentile). High systolic blood pressure was associated with low birth weight (OR=5.41; 95% CI=1.45-20.23) and total breastfeeding duration of less than six months (OR=4.14; 95% CI=1.40-11.95). High diastolic blood pressure was not associated with any variable, whereas high systolic blood pressure/diastolic blood pressure ratio was associated with breastfeeding duration of less than six months (OR=3.48; 95% CI=1.34-9.1).

CONCLUSION

The results of this study indicate that preschoolers breastfed for a period of less than six months were more likely to have high blood pressure when compared to those breastfed for a longer period, suggesting a protective effect of breastfeeding against high blood pressure in this population.

Association of eating frequency with anthropometric indices and blood pressure in children and adolescents: the CASPIAN-IV Study

OBJECTIVES

This study was conducted to explore the association of eating frequency (EF) with anthropometric indices and blood pressure (BP) in children and adolescents.

METHODS

This nationwide cross-sectional study was performed on a multi-stage sample of 14,880 students, aged 6-18 years, living in 30 provinces in Iran. Parents were asked to report dietary intake of children as frequency of food groups and/or items. EF was defined as the sum of the daily consumption frequency of main meals and snacks. Association of EF with weight disorders, abdominal obesity, and elevated BP was assessed using different logistic regression models adjusted for potential confounding factors.

RESULTS

Eating more frequently (≥ 6 vs. ≤ 3) was found among students who were at younger age (11.91 vs. 13.29 years) (p<0.001). Students who reported an EF of 4 (OR: 0.67, CI: 0.57-0.79), 5 (OR: 0.74, CI: 0.62-0.87), and 6 (OR: 0.54, CI: 0.44-0.65) had lower odds of being obese compared to those who had EF ≤ 3. Having EF of 4 (OR: 0.82, CI: 0.71-0.94), 5 (OR: 0.86, CI: 0.74-0.99), and ≥ 6 (OR: 0.73, CI: 0.63-0.85) was related to lower prevalence of abdominal adiposity.

CONCLUSION

Higher EF was associated with lower mean values of anthropometric and BP measures, as well as with lower prevalence of generalized and abdominal obesity in children and adolescents. Longitudinal studies are needed to assess the long-term effects of EF on body composition in the pediatric age group.