Hypertension in an anthropological and evolutionary paradigm

[Factors associated with arterial hypertension: a systematic review]

A systematic review of demographic, socioeconomic, behavioral and anthropometric factors associated with hypertension. We included observational studies, of populations aged 18 or older, from the past ten years, published in English, Portuguese or Spanish from Pubmed, Web of Science, Scopus and Lilacs bases. The most found factors related to the greater chance of having hypertension were age and the Body Mass Index (BMI). Other factors associated with the disease were: gender (male), education (lower education), income (lower income) and waist circumference (high). Never having smoked, never having consumed alcohol and white skin color were characteristics related to a lower chance of having hypertension. As demonstrated, demographic, socioeconomic, behavioral and anthropometric characteristics are important factors associated with a greater chance of having hypertension in the adult population. However, while most of the factors associated with it are amenable to intervention, broader health promotion policies will be needed to reduce socioeconomic inequalities in the prevalence of the disease.

Prevalence of arterial hypertension in Brazilian adults and its associated factors and activity limitations: a cross-sectional study

BACKGROUND

Hypertension is a serious global public health problem that affects a large part of the Brazilian adult population and can cause limitations and losses of quality of life.

OBJECTIVE

The objective of this study was to analyze the association of hypertension and its correlated limitations, with sociodemographic and epidemiological factors.

DESIGN AND SETTING

Cross-sectional study analyzing information on 44,271 adults (30 years or older) from the Brazilian National Health Survey of 2013.

METHODS

The prevalence of hypertension and the degree of limitation of the patients' activities associated with hypertension, according to sociodemographic characteristics, anthropometric measurements and lifestyles, were calculated for both sexes. To analyze the strength of association, bivariate and multivariate Poisson regression were used.

RESULTS

Hypertension was the most prevalent risk factor among Brazilian adults aged 30 years or older (40.7%). It was strongly associated with the aging process (prevalence ratio, PR 3.51), obesity (PR 1.73), heart disease (PR 1.67) and stroke (PR 1.86). Furthermore, limitations associated with hypertension were more prevalent among those with comorbidities from noncommunicable diseases relating to hypertension complications (stroke PR 1.47; heart disease PR 1.69) and with incomplete elementary education (PR 1.19).

CONCLUSIONS

This study showed sociodemographic inequality in the prevalence of hypertension, especially in the population with some degree of limitation associated with hypertension. It showed that improvements in access to primary care services for controlling hypertension at its initial stages are essential in order to avoid comorbidities of greater severity and limitations and losses of quality of life, especially among socially disadvantaged people.

Association between SNP heterozygosity and quantitative traits in the Framingham Heart Study

Associations between multilocus heterozygosity and fitness traits, also termed heterozygosity and fitness correlations (HFCs), have been reported in numerous organisms. These studies, in general, indicate a positive relationship between heterozygosity and fitness traits. We studied the association between genome-wide heterozygosity at 706 non-synonymous and synonymous SNPs and 19 quantitative traits, including morphological, biochemical and fitness traits in the Framingham Heart Study. Statistically significant association was found between heterozygosity and systolic and diastolic blood pressures as well as left ventricular diameter and wall thickness. These results suggest that heterozygosity may be associated with traits, such as blood pressure that closely track environmental variations. Balancing selection may be operating in the maintenance of heterozygosity and the major components of blood pressure and hypertension. Genome wide SNP heterozygosity may be used to understand the phenomenon of dominance as well as the evolutionary basis of many quantitative traits in humans.

Methodological aspects of the assessment of gene-nutrient interactions at the population level

Nutritional-related diseases are the result of complex interactions between genes and diet. The understanding of these interactions will provide the rationale for dietary interventions based on the individual's genetic constitution. However, the approach to this kind of study is not easy, the complexity of the interactions increasing exponentially the dimensionality of the problem. The aim of this review is to analyze the major problems that arise in approaching complex interactions at the population level. Furthermore, several statistical tools available for this type of analysis are discussed. In conclusion, although analytic techniques able to reduce the dimensionality of the problem are suggested, sample size requirement seems to remain an inescapable challenge for the researcher. A synergy between traditional and nontraditional statistical approaches could be useful.

Uric acid, evolution and primitive cultures

Hypertension is epidemic and currently affects 25% of the world's population and is a major cause of stroke, congestive heart failure, and end-stage renal disease. Interestingly, there is evidence that the increased frequency of hypertension is a recent event in human history and correlates with dietary changes associated with Westernization. In this article, we review the evidence that links uric acid to the cause and epidemiology of hypertension. Specifically, we review the evidence that the mutation of uricase that occurred in the Miocene that resulted in a higher serum uric acid in humans compared with most other mammals may have occurred as a means to increase blood pressure in early hominoids in response to a low-sodium and low-purine diet. We then review the evidence that the epidemic of hypertension that evolved with Westernization was associated with an increase in the intake of red meat with a marked increase in serum uric acid levels. Indeed, gout and hyperuricemia should be considered a part of the obesity, type 2 diabetes, and hypertension epidemic that is occurring worldwide. Although other mechanisms certainly contribute to the pathogenesis of hypertension, the possibility that serum uric acid level may have a major role is suggested by these studies.

Salt and hypertension: a phylogenetic perspective

Our hunter-gatherer ancestors appeared to survive on little salt. When today's rural dwellers move to urban environments, they increase their salt intake and the salt-sensitive among them become prone to age-related increase in blood pressure and hypertension. This paper reviews our knowledge of the mechanisms of salt disposal and plasma volume regulation, salt consumption in human evolution, salt intake and prevalence of hypertension, and the results of interventions aimed at modulating both. Finally, it discusses current hypotheses on the mechanisms of selective pressure that may have favored the emergence of a salt-sensitive, hypertensive genotype. Similar to 'thrifty' genes, which supported energy savers in times of scarcity, but may now be causing obesity and type 2 diabetes, 'thirsty' genes, by acting on salt and water retention, might have helped individuals survive the challenge of volume-depleting illnesses, especially when combined with stress-inducing situations, but may now cause high BP and related damage in the post-reproductive age.

Ambulatory blood pressure measurement is indispensable to good clinical practice

The traditional technique of blood pressure measurement is being phased out in most countries and is being replaced by automated measurement. The era of automated blood pressure measurement brings its own problems, not least being the need to evaluate blood pressure measuring devices independently for accuracy. Towards this end, the Working Group on Blood Pressure Monitoring of the European Society of Hypertension has published an international protocol with the aim of having all devices assessed for basic accuracy before being put on the market. The main thrust of this review is that if ambulatory blood pressure measurement has become indispensable to the management of patients with hypertension, it then becomes imperative to encourage the use of ambulatory blood pressure measurement (ABPM) in general practice rather than restricting its availability to specialist hospital centres. However, if ABPM is to be widely used in general practice, there is a need to establish appropriate educational processes and to improve the methods of presenting and analysing ABPM data.

Has conventional sphygmomanometry ended with the banning of mercury?

The banning of mercury from clinical practice will lead to the inevitable demise of traditional clinical sphygmomanometry. There are differences in approach to this important issue between European countries on the one hand, which generally have accepted that the mercury sphygmomanometer must be replaced with alternative devices, and the U.S. on the other, where the view is that the mercury sphygmomanometer should remain as the mainstay of blood pressure measurement. The availability of alternative devices for the mercury sphygmomanometer is improving but the problem of independent validation is a serious issue, which is being addressed by the European Society of Hypertension Working Party on Blood Pressure Monitoring, which has drafted an International Protocol for validating blood pressure measuring devices. The removal of the mercury sphygmomanometer from clinical practice has other implications, which merit careful consideration; the advent of automated devices must lead inevitably to the disappearance of the traditional clinical auscultatory technique of blood pressure measurement, and with the disappearance of mercury it will be argued that the Système International(SI) unit of measurement -- the kilopascal -- should replace the millimetre of mercury.