Overweight and hypertension: data from the 1992-1993 Mexican survey

BMI better explains hypertension in Chinese senior adults and the relationship declines with age

BACKGROUND

Researchers have been examining the relationship between obesity and hypertension. However, whether overall or abdominal obesity better explains senior adults' hypertension has not been studied.

OBJECTIVES

The purpose of the study was to examine whether body mass index or waist circumference better predicts hypertension in Chinese senior adults and how the magnitude of the relationship is attenuated as they continue to age.

METHODS

The study was based on the 2010 National Physique Monitoring data. There were 7,542 senior adults aged 60-69 years living in urban, suburban, and rural areas of Shanghai City. The participants were categorized into five age groups: 60-61, 62-63, 64-65, 66-67, and 68-69 years.

RESULTS

The percentage of participants who had hypertension increased as people aged, which was mainly caused by the increase of systolic blood pressure. Logistic regression analysis showed that when body mass index or waist circumference was entered into the model, both were significant predictors for hypertension (p < 0.05). However, when body mass index and waist circumference were mutually entered into the model, body mass index was the only important predictor (p < 0.05). The values of odds ratios were found to decrease from the 60-61 to 68-69 years age groups. More senior adults have hypertension as they age.

CONCLUSION

Body mass index, and not waist circumference, better predicts Chinese senior adults' hypertension. However, age attenuates the effects of obesity on hypertension as the senior adults continue to age.

[Relative importance of body mass index and waist circumference for hypertension in adults]

OBJECTIVE

To assess the relative importance of Body Mass Index (BMI) and waist circumference for the determination of hypertension in adults.

METHODS

Cross sectional analysis of a sample of employees (N=1,584), aged 18 to 64 years, from a private general hospital in the city of São Paulo, Brazil. Data collection included the application of a structured questionnaire and blood pressure, weight, high, and waist circumference measurements. Hypertension was defined as blood pressure levels >or= 140/90 mmHg or reported use of anti-hypertensive medication. The relative importance of BMI and waist circumference was evaluated by calculating the attributable fraction of hypertension corresponding to each anthropometric indicator, employing both the usual cut-off points as well as cut-off points based on the observed distribution of the indicator in the population. In addition, an indicator combining simultaneously BMI and abdominal circumference values was also developed.

RESULTS

Prevalence of hypertension was 18.9% (26.9% in men and 12.5% in women). In men, the fraction of hypertension attributable to BMI exceeded the fraction attributable to waist circumference based on the usual cut-off points for the indicators (56% vs. 48%, respectively) and also considering the quartiles of the observed distribution for these indicators (73% vs. 69%, respectively). In women, the fraction of hypertension attributable to waist circumference was slightly higher than the fraction attributable to BMI based on the usual cut off points for both indicators (44% vs. 41%), but the reverse was true when quartiles of the observed distribution were used (41% vs. 57%, respectively). In women only, the fraction of hypertension attributable to the indicator combining BMI and waist circumference (64%) was higher that observed using each indicator alone.

CONCLUSIONS

Both BMI and abdominal circumference were positively and independently associated with the occurrence of arterial hypertension, the influence of BMI being higher among men.

Hypertension, Overweight and Abdominal Adiposity in Women. An Analytical Perspective

BACKGROUND

The aim of our study was to determine in a group of premenopausal (preM) and postmenopausal women with hormone replacement therapy (postM-HRT) or without HRT (postM-noHRT) whether the strength of the association of body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) with hypertension is affected by the way in which these variables are used (i.e., continuous or dichotomous) in logistic regression modeling, where weight and age are set as continuous variables only.

METHODS

We studied 639 preM, 341 postM-noHRT, and 77 postM-HRT healthy women age 20-69 years. The main outcome variable was hypertension: BP > or =140 or 90 mmHg on two occasions or hypertension treatment. Risk factors were assessed as continuous variables (age, postmenopausal years, weight, stature, BMI, WC, hip circumference, and WHR); and dichotomous variables (overweight: BMI > or =25; high WC: WC > or =88 cm; and high WHR: WHR > or =0.84). Stepwise regression models for hypertension were developed for continuous (model 1) and dichotomous (model 2) variables in each group.

RESULTS

In preM, model 1 included BMI (OR=1.202, CI: 1.115-1.296) and age (OR=1.154, CI: 1.081-1.296); and model 2 included weight (OR=1.070, CI: 1.040-1.100) and age (OR=1.157, CI: 1.084-1.235). In postM-noHRT, both models included age (OR=1.074, CI: 1.035-1.113) and weight (OR=1.025, CI: 1.004-1.046). Overweight and age were associated with hypertension in preM and postM-noHRT; overweight being more relevant in preM, and age in postM-noHRT. No models were found for postM-HRT.

CONCLUSIONS

The strength of the association of risk factors with hypertension depends on how the variables are analyzed. Acknowledging these differential effects and assigning differential risks by age could be useful in intervention programs.

Association of visceral fat with coronary risk factors in a population-based sample of postmenopausal women

OBJECTIVE

To investigate in a population-based random sample of postmenopausal women the adjusted association of visceral adipose tissue (VAT) with coronary risk factors.

DESIGN

Cross-sectional population-based random sample study.

SUBJECTS

Ninety-eight postmenopausal women (age 50-65 y).

MEASUREMENTS

Visceral and subcutaneous fat areas by computer axial tomography, anthropometry, lipid profile, fasting glucose and insulin, diet, physical activity, smoking status and alcohol intake.

RESULTS

Compared to women with low VAT, women with high VAT (>117.8 cm(2)) had a less favorable metabolic profile with significantly higher fasting glucose (120+/-50 vs 98+/-39), insulin (7.9+/-10 vs 5+/-8), triglycerides (172+/-69 vs 127+/-72), apolipoprotein B (119+/-24 vs 98+/-32) and significantly lower HDL-C (38+/-10 vs 46+/-14) values in the whole sample (n=98). A similar profile was found in women without diabetes and hypertension (n=39). In multiple regression models, VAT explained a portion of the variance of TG (6.2%) in the entire sample and of total cholesterol (12.4%), LDL-C (15.8%), triglycerides (16.3%), apolipoprotein B (11.6%), and fasting glucose (28.4%) in the group of non-diabetic or hypertensive women. Our VAT cut-off point of 117.8 cm(2) corresponded to a waist circumference of 84 cm.

CONCLUSION

Our results in a random population-based sample of postmenopausal women confirm the association of VAT with most coronary risk factors. These associations persisted after adjusting for diet, physical activity, smoking status and alcohol intake.

Prevalence, awareness, treatment, control and risk factors of hypertension in Korea: the Ansan study

OBJECTIVES

To determine prevalence, awareness, treatment, and control of hypertension, and its risk factors in an urban Korean population.

DESIGN AND SETTING

A cross-sectional survey in Ansan-city, Korea.

SUBJECTS AND METHODS

Population-based samples of people aged 18-92 years in Ansan-city, Korea, were selected, yielding 2278 men and 1948 women, and their blood pressures were measured using a highly standardized protocol. Hypertension was defined as a systolic BP > or = 140 mmHg or diastolic BP > or = 90 mmHg or reported treatment with antihypertensive medications, and subclassified according to 1999 WHO-ISH guidelines. Isolated systolic hypertension (ISH) defined as a systolic BP > or = 140 mmHg and diastolic BP < 90 mmHg was also examined. Data were stratified by age and sex.

RESULTS

The overall prevalence of hypertension in this study was 33.7%. Among these, 64.9% had Grade 1 hypertension, 22.5% Grade 2, and 12.5% Grade 3. Age-specific prevalence of hypertension increased progressively with age, from 14.19% in 18 to 24 year-olds to 71.39% in those 75 years or older. Hypertension prevalence was significantly higher in men (41.5%) than in women (24.5%) (P < 0.001). Isolated systolic hypertension had significantly lower prevalence (4.33%) within the population, although in the elderly aged 55 years or more it rose by 11.13%. Overall, 24.6% of hypertensive individuals were aware that they had high blood pressure, as much as 78.6% were being treated with antihypertensive medications, and 24.3% were under control. Hypertension awareness as well as treatment and control rates varied by sex, with women higher in all three rates. Multivariate analysis revealed that age, body mass index and abdomen circumference were significantly associated with prevalence of hypertension both in men and women.

CONCLUSIONS

Hypertension is highly prevalent in Korea. Despite the high rate of treatment, the rates of awareness and control are relatively low, suggesting the nationwide demand for preventing and controlling high blood pressure in Korea in order to avert an epidemic of cardiovascular disease.

Hypertension in developing economies: a review of population-based studies carried out from 1980 to 1998

AIM

Hypertension is an established major risk factor underlying the epidemic of coronary and cardiovascular diseases in most developed countries, and it has been shown to be a public health problem in many developing countries since the 1970s. This review was carried out to illustrate the current situation with regard to blood pressure levels and the prevalence and management of hypertension in developing countries.

METHODS

A search for papers published in medical journals from 1991 to 1998 was performed using the MEDLINE database. A total of 40 articles were selected according to previously defined criteria.

RESULTS

Hypertension is a public health problem for most of the developing countries reviewed, and it is frequently associated with low levels of awareness, treatment and control. A positive association between the gross national product per capita and the prevalence of hypertension in developing countries is also evident.

CONCLUSIONS

Differences in methodology between national surveys make international comparisons difficult. Nevertheless, low-cost hypertension control programmes in developing countries are needed, along with development of the primary prevention of hypertension.

The relationship of oxidized lipids to coronary artery stenosis

A total of 1200 patients with angina were cardiac catheterized establishing that 63% had 70-100% stenosis, 12% had 10-69% stenosis of one or more of their coronary arteries and 25% had microvascular angina listed as 0% stenosis. Prior to catheterization 10 ml of blood was drawn and the plasma subjected to analysis for the concentration of cholesterol, lipid peroxides (LPX), total antioxidant capacity (TAOC), fibrinogen (FB), ceruloplasmin (CP) and activation of polymorphonuclear leukocytes (PMNLs). Comparisons were made to non-smoking controls without angina. Significant differences in LPX were found between the patients with 0 and 10-69% stenosis (P<0.001), with 10-69 and 70-100% stenosis (P<0.001), and with 0 and 70-100% stenosis (P<0.001). Under 70 years of age there was a significant difference in LPX between patients with all levels of stenosis and age and sex matched controls (P<0.001). Differences in the mean plasma cholesterol concentration for different levels in the degree of stenosis were not significant, indicating that LPX provided consistent data on the severity of stenosis while the plasma cholesterol concentration did not. Compared with controls an increase in activation of PMNLs (P<0.01), an increase in concentration of both FB and CP (P<0.01) and a decrease in total antioxidant capacity were noted in the plasma of catheterized patients. In summary the concentration of oxidation products rather than the concentration of cholesterol in the plasma identified stenosis in cardiac catheterized patients.

Obesity and hypertension

Substantial evidence from epidemiological data supports a link between obesity and hypertension. However, the relationship between the two disorders is not straightforward and most likely represents an interaction of demographic, genetic, hormonal, renal, and hemodynamic factors. Age, race, and sex also modulate the strength of the association between obesity and hypertension. Hyperinsulinemia, which is characteristic of obesity, can contribute to the probability of developing hypertension by activating the sympathetic nervous system (SNS) and by causing sodium retention. The pressor effect of insulin in obesity may be further enhanced by the observation that its vasodilator action can be blunted in obese subjects. Preliminary data have shown that leptin, whose levels are increased in most obese individuals, can contribute to hypertension in obesity through its effects on insulin, SNS, and sodium excretion. The kidney may also have a role in the pathophysiology of hypertension in obesity. Abnormal renal sodium handling coupled with structural changes in the kidney of an obese patient can raise blood pressure. In addition, obesity is associated with distinct cardiovascular hemodynamic alterations and development of eccentric myocardial hypertrophy. Most of these obesity-associated abnormalities, as well as hypertension itself, can be reversed by weight loss. Furthermore, weight loss can prevent, or at least delay, the development of hypertension in patients with high-normal blood pressure. Weight reduction should be the first-line treatment in every obese hypertensive patient. However, the majority of patients will need pharmacologic intervention in conjunction with weight loss. Selection of antihypertensive agents in the overweight patient should take into account the mechanisms leading to hypertension and the metabolic abnormalities that characterize the obese patient.

Weight change, ideal weight and hypertension

A growing body of evidence supports the fact that body weight is related to blood pressure. The risk of hypertension increases with increasing body mass index and weight gain; and weight loss reduces blood pressure. Birthweight may also be linked to adult blood pressure, possibly as a result of its relationship with later obesity.