Paul K. Whelton

Global burden of hypertension: analysis of worldwide data

BACKGROUND Reliable information about the prevalence of hypertension in different world regions is essential to the development of national and international health policies for prevention and control of this condition. We aimed to pool data from different regions of the world to estimate the overall prevalence and absolute burden of hypertension in 2000, and to estimate the global burden in 2025. METHODS We searched the published literature from Jan 1, 1980, to Dec 31, 2002, using MEDLINE, supplemented by a manual search of bibliographies of retrieved articles. We included studies that reported sex-specific and age-specific prevalence of hypertension in representative population samples. All data were obtained independently by two investigators with a standardised protocol and data-collection form. RESULTS Overall, 26.4% (95% CI 26.0-26.8%) of the adult population in 2000 had hypertension (26.6% of men [26.0-27.2%] and 26.1% of women [25.5-26.6%]), and 29.2% (28.8-29.7%) were projected to have this condition by 2025 (29.0% of men [28.6-29.4%] and 29.5% of women [29.1-29.9%]). The estimated total number of adults with hypertension in 2000 was 972 million (957-987 million); 333 million (329-336 million) in economically developed countries and 639 million (625-654 million) in economically developing countries. The number of adults with hypertension in 2025 was predicted to increase by about 60% to a total of 1.56 billion (1.54-1.58 billion). INTERPRETATION Hypertension is an important public-health challenge worldwide. Prevention, detection, treatment, and control of this condition should receive high priority.

A Randomized Trial of Intensive versus Standard Blood-Pressure Control.

BACKGROUND The most appropriate targets for systolic blood pressure to reduce cardiovascular morbidity and mortality among persons without diabetes remain uncertain. METHODS We randomly assigned 9361 persons with a systolic blood pressure of 130 mm Hg or higher and an increased cardiovascular risk, but without diabetes, to a systolic blood-pressure target of less than 120 mm Hg (intensive treatment) or a target of less than 140 mm Hg (standard treatment). The primary composite outcome was myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes. RESULTS At 1 year, the mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard-treatment group. The intervention was stopped early after a median follow-up of 3.26 years owing to a significantly lower rate of the primary composite outcome in the intensive-treatment group than in the standard-treatment group (1.65% per year vs. 2.19% per year; hazard ratio with intensive treatment, 0.75; 95% confidence interval [CI], 0.64 to 0.89; P<0.001). All-cause mortality was also significantly lower in the intensive-treatment group (hazard ratio, 0.73; 95% CI, 0.60 to 0.90; P=0.003). Rates of serious adverse events of hypotension, syncope, electrolyte abnormalities, and acute kidney injury or failure, but not of injurious falls, were higher in the intensive-treatment group than in the standard-treatment group. CONCLUSIONS Among patients at high risk for cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg, resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause, although significantly higher rates of some adverse events were observed in the intensive-treatment group. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01206062.).

Blood pressure and end stage renal disease in men

BACKGROUND End-stage renal disease in the United States creates a large burden for both individuals and society as a whole. Efforts to prevent the condition require an understanding of modifiable risk factors. METHODS We assessed the development of end-stage renal disease through 1990 in 332,544 men, 35 to 57 years of age, who were screened between 1973 and 1975 for entry into the Multiple Risk Factor Intervention Trial (MRFIT). We used data from the national registry for treated end-stage renal disease of the Health Care Financing Administration and from records on death from renal disease from the National Death Index and the Social Security Administration. RESULTS During an average of 16 years of follow-up, 814 subjects either died of end-stage renal disease or were treated for that condition (15.6 cases per 100,000 person-years of observation). A strong, graded relation between both systolic and diastolic blood pressure and end-stage renal disease was identified, independent of associations between the disease and age, race, income, use of medication for diabetes mellitus, history of myocardial infarction, serum cholesterol concentration, and cigarette smoking. As compared with men with an optimal level of blood pressure (systolic pressure < 120 mm Hg and diastolic pressure < 80 mm Hg), the relative risk of end-stage renal disease for those with stage 4 hypertension (systolic pressure > or = 210 mm Hg or diastolic pressure > or = 120 mm Hg) was 22.1 (P < 0.001). These relations were not due to end-stage renal disease that occurred soon after screening and, in the 12,866 screened men who entered the MRFIT study, were not changed by taking into account the base-line serum creatinine concentration and urinary protein excretion. The estimated risk of end-stage renal disease associated with elevations of systolic pressure was greater than that linked with elevations of diastolic pressure when both variables were considered together. CONCLUSIONS Elevations of blood pressure are a strong independent risk factor for end-stage renal disease; interventions to prevent the disease need to emphasize the prevention and control of both high-normal and high blood pressure.

Worldwide prevalence of hypertension: a systematic review.

Purpose To examine the prevalence and the level of awareness, treatment and control of hypertension in different world regions. Study selection A literature search of the MEDLINE database, using the Medical Subject Headings prevalence, hypertension, blood pressure and cross-sectional studies, was conducted. Published studies, which reported the prevalence of hypertension and were conducted in representative population samples, were included in the review. The search was restricted to studies published from January 1980 through July 2003. Data extraction All data were extracted independently by two investigators using a standardized protocol and data collection form. Results The reported prevalence of hypertension varied around the world, with the lowest prevalence in rural India (3.4% in men and 6.8% in women) and the highest prevalence in Poland (68.9% in men and 72.5% in women). Awareness of hypertension was reported for 46% of the studies and varied from 25.2% in Korea to 75% in Barbados; treatment varied from 10.7% in Mexico to 66% in Barbados and control (blood pressure < 140/90 mmHg while on antihypertensive medication) varied from 5.4% in Korea to 58% in Barbados. Conclusion Hypertension is an important public health challenge in both economically developing and developed countries. Significant numbers of individuals with hypertension are unaware of their condition and, among those with diagnosed hypertension, treatment is frequently inadequate. Measures are required at a population level to prevent the development of hypertension and to improve awareness, treatment and control of hypertension in the community.

Prevalence of the metabolic syndrome and overweight among adults in China.

BACKGROUND The metabolic syndrome and obesity are major risk factors for cardiovascular disease. Little information exists on the prevalence of the metabolic syndrome in China. We aimed to provide up-to-date estimates of the prevalence of the metabolic syndrome and overweight in the general adult population in China. METHODS We did a cross-sectional survey in a nationally representative sample of 15,540 Chinese adults aged 35-74 years in 2000-01. Metabolic syndrome was defined according to guidelines from the US National Cholesterol Education Program. Overweight was defined as body-mass index of 25.0 kg/m2 or greater. FINDINGS The age-standardised prevalence of metabolic syndrome was 9.8% (95% CI 9.0-10.6) in men and 17.8% (16.6-19.0) in women. The age-standardised prevalence of overweight was 26.9% (25.7-28.1) in men and 31.1% (29.7-32.5) in women. The prevalence of the metabolic syndrome and overweight was higher in northern than in southern China, and higher in urban than rural residents. INTERPRETATION Our results indicate that a large proportion of Chinese adults have the metabolic syndrome and that overweight has become an important public health problem in China. These findings emphasise the urgent need to develop national strategies for the prevention, detection, and treatment of overweight and the metabolic syndrome, to reduce the societal burden of cardiovascular disease in China.

Epidemiology of hypertension

Cardiovascular disease is the main cause of death in virtually all industrialised countries. The limited information available from developing countries suggests that a similar epidemic is inevitable if current trends go unchecked. Treatment of patients with clinical manifestations is an important element in overall management but on its own is an insufficient and incomplete response. Sudden death is often the first manifestation of cardiovascular disease and, even when treatment of disease is applicable and effective, it is usually palliative rather than curative. Thus treatment and prevention directed at the underlying risk factors, including high blood pressure, constitute a complementary and more fundamental approach to reducing the burden of illness. Epidemiological studies provide the scientific foundation for such an approach by identifying the distribution and determinants of high blood pressure in the general population, by establishing the role of high blood pressure as a risk factor for cardiorenal complications, and by quantifying the potential value of treating and preventing high blood pressure in the general population.

Passive Smoking and the Risk of Coronary Heart Disease — A Meta-Analysis of Epidemiologic Studies

BACKGROUND The effect of passive smoking on the risk of coronary heart disease is controversial. We conducted a meta-analysis of the risk of coronary heart disease associated with passive smoking among nonsmokers. METHODS We searched the Medline and Dissertation Abstracts Online data bases and reviewed citations in relevant articles to identify 18 epidemiologic (10 cohort and 8 case-control) studies that met prestated inclusion criteria. Information on the designs of the studies, the characteristics of the study subjects, exposure and outcome measures, control for potential confounding factors, and risk estimates was abstracted independently by three investigators using a standardized protocol. RESULTS Overall, nonsmokers exposed to environmental smoke had a relative risk of coronary heart disease of 1.25 (95 percent confidence interval, 1.17 to 1.32) as compared with nonsmokers not exposed to smoke. Passive smoking was consistently associated with an increased relative risk of coronary heart disease in cohort studies (relative risk, 1.21; 95 percent confidence interval, 1.14 to 1.30), in case-control studies (relative risk, 1.51; 95 percent confidence interval, 1.26 to 1.81), in men (relative risk, 1.22; 95 percent confidence interval, 1.10 to 1.35), in women (relative risk, 1.24; 95 percent confidence interval, 1.15 to 1.34), and in those exposed to smoking at home (relative risk, 1.17; 95 percent confidence interval, 1.11 to 1.24) or in the workplace (relative risk, 1.11; 95 percent confidence interval, 1.00 to 1.23). A significant dose-response relation was identified, with respective relative risks of 1.23 and 1.31 for nonsmokers who were exposed to the smoke of 1 to 19 cigarettes per day and those who were exposed to the smoke of 20 or more cigarettes per day, as compared with nonsmokers not exposed to smoke (P=0.006 for linear trend). CONCLUSIONS Passive smoking is associated with a small increase in the risk of coronary heart disease. Given the high prevalence of cigarette smoking, the public health consequences of passive smoking with regard to coronary heart disease may be important.

Prevalence, Awareness, Treatment, and Control of Hypertension in China

Abstract—The objective of this study was to estimate the prevalence and distribution of hypertension and to determine the status of hypertension awareness, treatment, and control in the general adult population in China. The International Collaborative Study of Cardiovascular Disease in ASIA (InterASIA), conducted in 2000–2001, used a multistage cluster sampling method to select a nationally representative sample. A total of 15 540 adults, age 35 to 74 years, were examined. Three blood pressure measurements were obtained by trained observers by use of a standardized mercury sphygmomanometer after a 5-minute sitting rest. Information on history of hypertension and use of antihypertensive medications was obtained by use of a standard questionnaire. Hypertension was defined as a mean systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, and/or use of antihypertensive medications. Overall, 27.2% of the Chinese adult population age 35 to 74 years, representing 129 824 000 persons, had hypertension. The age-specific prevalence of hypertension was 17.4%, 28.2%, 40.7%, and 47.3% in men and 10.7%, 26.8%, 38.9%, and 50.2% in women age 35 to 44 years, 45 to 54 years, 55 to 64 years, and 65 to 74 years, respectively. Among hypertensive patients, only 44.7% were aware of their high blood pressure, 28.2% were taking antihypertensive medication, and 8.1% achieved blood pressure control (<140/90 mm Hg). Our results indicate that hypertension is highly prevalent in China. The percentages of those with hypertension who are aware, treated, and controlled are unacceptably low. These results underscore the urgent need to develop national strategies to improve prevention, detection, and treatment of hypertension in China.

Serum Cholesterol in Young Men and Subsequent Cardiovascular Disease

BACKGROUND The increased risk of cardiovascular disease associated with higher serum cholesterol levels in middle-aged persons has been clearly established, but there have been few opportunities to examine a potential link between serum cholesterol levels measured in young men and clinically evident premature cardiovascular disease later in life. METHODS We performed a prospective study of 1017 young men (mean age, 22 years) followed for 27 to 42 years to quantify the risk of cardiovascular disease and total mortality associated with serum cholesterol levels during early adult life. The mean serum cholesterol level at entry was 192 mg per deciliter (5.0 mmol per liter). RESULTS During a median follow-up of 30.5 years, there were 125 cardiovascular-disease events, 97 of which were due to coronary heart disease. The serum cholesterol level at base line was strongly associated with the incidence of events related to coronary heart disease and cardiovascular disease, as well as to total mortality and mortality due to cardiovascular disease. The risks were similar whether the events occurred before or after the age of 50. In a proportional-hazards analysis adjusted for age, body-mass index (the weight in kilograms divided by the square of the height in meters), the level of physical activity, coffee intake, change in smoking status, and the incidence of diabetes and hypertension during follow-up, a difference in the serum cholesterol level at base line of 36 mg per deciliter (0.9 mmol per liter)--the difference between the 25th and 75th percentiles of cholesterol level in the study population at base line--was associated with an increased risk of cardiovascular disease (relative risk, 1.72; 95 percent confidence interval, 1.39 to 2.14), coronary heart disease (relative risk, 2.01; 95 percent confidence interval, 1.59 to 2.53), and mortality due to cardiovascular disease (relative risk, 2.02; 95 percent confidence interval, 1.23 to 3.32). A difference in the base-line serum cholesterol level of 36 mg per deciliter was significantly associated with an increased risk of death before the age of 50 (relative risk, 1.64; 95 percent confidence interval, 1.03 to 2.61), but not with the overall risk of death (relative risk, 1.21; 95 percent confidence interval, 0.93 to 1.58). CONCLUSIONS These findings indicate a strong association between the serum cholesterol level measured early in adult life in men and cardiovascular disease in midlife.

Long-Term Effects of Weight Loss and Dietary Sodium Reduction on Incidence of Hypertension

To examine the long-term effects of weight loss and dietary sodium reduction on the incidence of hypertension, we studied 181 men and women who participated in the Trials of Hypertension Prevention, phase 1, in Baltimore, Md. At baseline (1987 to 1988), subjects were 30 to 54 years old and had a diastolic blood pressure (BP) of 80 to 89 mm Hg and systolic BP <160 mm Hg. They were randomly assigned to one of two 18-month lifestyle modification interventions aimed at either weight loss or dietary sodium reduction or to a usual care control group. At the posttrial follow-up (1994 to 1995), BP was measured by blinded observers who used a random-zero sphygmomanometer. Incident hypertension was defined as systolic BP > or =160 mm Hg and/or diastolic BP > or =90 mm Hg and/or treatment with antihypertensive medication during follow-up. Body weight and urinary sodium were not significantly different among the groups at the posttrial follow-up. After 7 years of follow-up, the incidence of hypertension was 18.9% in the weight loss group and 40.5% in its control group and 22.4% in the sodium reduction group and 32.9% in its control group. In logistic regression analysis adjusted for baseline age, gender, race, physical activity, alcohol consumption, education, body weight, systolic BP, and urinary sodium excretion, the odds of hypertension was reduced by 77% (odds ratio 0.23; 95% confidence interval 0.07 to 0.76; P=0.02) in the weight loss group and by 35% (odds ratio 0.65; 95% confidence interval 0.25 to 1.69; P=0.37) in the sodium reduction group compared with their control groups. These results indicate that lifestyle modification such as weight loss may be effective in long-term primary prevention of hypertension.