Independent association of resting energy expenditure with blood pressure: confirmation in populations of the African diaspora.

BACKGROUND: Obesity is a major risk factor for hypertension, however, the physiologic mechanisms linking increased adiposity to elevations in blood pressure are not well described. An increase in resting energy expenditure (REE) is an obligatory consequence of obesity. Previous survey research has demonstrated that REE is an independent predictor of blood pressure, and eliminates the co-linear association of body mass index. This observation has received little attention and there have been no attempts to provide a causal explanation. METHODS: At baseline in an international comparative study on obesity, 289 participants aged 25-44 were recruited from communities in the US, the Seychelles, Ghana and South Africa and had REE measured with indirect calorimetry. All participants were thought to be free of major illness. RESULTS: In multivariate regression models, both systolic and diastolic blood pressure were positively associated with REE (p < 0.01), while body mass index and fat mass were negatively correlated with systolic blood pressure (p < 0.01, and p < 0.05 respectively), but not diastolic blood pressure. CONCLUSIONS: These data confirm previous reports and suggest that a common physiologic abnormality links REE and blood pressure. Elevated catecholamines, a putative metabolic characteristic of obesity, is a possible candidate to explain this association. The direct role of excess adipose tissue is open to question.

Cardiovascular risk status of Afro-origin populations across the spectrum of economic development: findings from the Modeling the Epidemiologic Transition Study.

BACKGROUND: Cardiovascular risk factors are increasing in most developing countries. To date, however, very little standardized data has been collected on the primary risk factors across the spectrum of economic development. Data are particularly sparse from Africa. METHODS: In the Modeling the Epidemiologic Transition Study (METS) we examined population-based samples of men and women, ages 25-45 of African ancestry in metropolitan Chicago, Kingston, Jamaica, rural Ghana, Cape Town, South Africa, and the Seychelles. Key measures of cardiovascular disease risk are described. RESULTS: The risk factor profile varied widely in both total summary estimates of cardiovascular risk and in the magnitude of component factors. Hypertension ranged from 7% in women from Ghana to 35% in US men. Total cholesterol was well under 200 mg/dl for all groups, with a mean of 155 mg/dl among men in Ghana, South Africa and Jamaica. Among women total cholesterol values varied relatively little by country, following between 160 and 178 mg/dl for all 5 groups. Levels of HDL-C were virtually identical in men and women from all study sites. Obesity ranged from 64% among women in the US to 2% among Ghanaian men, with a roughly corresponding trend in diabetes. Based on the Framingham risk score a clear trend toward higher total risk in association with socioeconomic development was observed among men, while among women there was considerable overlap, with the US participants having only a modestly higher risk score. CONCLUSIONS: These data provide a comprehensive estimate of cardiovascular risk across a range of countries at differing stages of social and economic development and demonstrate the heterogeneity in the character and degree of emerging cardiovascular risk. Severe hypercholesterolemia, as characteristic in the US and much of Western Europe at the onset of the coronary epidemic, is unlikely to be a feature of the cardiovascular risk profile in these countries in the foreseeable future, suggesting that stroke may remain the dominant cardiovascular event.

Prevalence of cardiovascular risk factors in a middle-income country and estimated cost of a treatment strategy.

BACKGROUND: We assessed the prevalence of risk factors for cardiovascular disease (CVD) in a middle-income country in rapid epidemiological transition and estimated direct costs for treating all individuals at increased cardiovascular risk, i.e. following the so-called "high risk strategy". METHODS: Survey of risk factors using an age- and sex-stratified random sample of the population of Seychelles aged 25-64 in 2004. Assessment of CVD risk and treatment modalities were in line with international guidelines. Costs are expressed as USD per capita per year. RESULTS: 1255 persons took part in the survey (participation rate of 80.2%). Prevalence of main risk factors was: 39.6% for high blood pressure (> or =140/90 mmHg or treatment) of which 59% were under treatment; 24.2% for high cholesterol (> or =6.2 mmol/l); 20.8% for low HDL-cholesterol (<1.0 mmol/l); 9.3% for diabetes (fasting glucose > or =7.0 mmol/l); 17.5% for smoking; 25.1% for obesity (body mass index > or =30 kg/m2) and 22.1% for the metabolic syndrome. Overall, 43% had HBP, high cholesterol or diabetes and substantially increased CVD risk. The cost for medications needed to treat all high-risk individuals amounted to USD 45.6, i.e. 11.2 dollars for high blood pressure, 3.8 dollars for diabetes, and 30.6 dollars for dyslipidemia (using generic drugs except for hypercholesterolemia). Cost for minimal follow-up medical care and laboratory tests amounted to 22.6 dollars. CONCLUSION: High prevalence of major risk factors was found in a rapidly developing country and costs for treatment needed to reduce risk factors in all high-risk individuals exceeded resources generally available in low or middle income countries. Our findings emphasize the need for affordable cost-effective treatment strategies and the critical importance of population strategies aimed at reducing risk factors in the entire population.

Economic impact of hyperhomocysteinemia in Switzerland.

Since more than 20 years elevated homocysteine plasma levels have been associated with an elevated cardiovascular risk. It can be assumed that approx. 5-7% of the Swiss population suffers from hyperhomocysteinemia. These people have an odds ratio of 1.7 (95% confidence interval: 1.5-1.9) to develop a myocardial infarction and an odds ratio of 2.5 (95% confidence interval 2-3) of developing a stroke. These significant cardiovascular endpoints have monetary implications and lead to a loss in life years. The cost consequences and total life years lost were determined with an incidence-based epidemiological model utilizing a Swiss third party payer perspective. We could demonstrate that hyperhomocysteinemia-related sequelae (myocardial infarction and stroke) amount to 41.1-110.2 million CHF. In addition it can be estimated that 6'941-18'478 life years may be lost. Comparing these data with the total costs for cardiovascular disease in Switzerland of CHF 987 million, we estimate the share of the economic burden of hyperhomocysteinemia at approximately 10%. Preventive measures could thus yield a positive impact on total health care expenditure in the Swiss healthcare system and warrants further research.

Implications of emerging risk factors for therapeutic intervention.

Recently, the National Cholesterol Education Panel (NCEP) of the United States of America commented on the implications of new clinical trials for the Adult Treatment Panel III (ATP III) guidelines. In this commentary, new categories of "moderately high" and "very high" coronary risk were proposed with new "therapeutic options" for low-density lipoprotein (LDL) cholesterol of < or = 100 mg/dL and < or = 70 mg/dL respectively. In ATP III, these "moderately high" risk patients had been classified as moderate risk with an LDL treatment goal of < or = 130 mg/dL, while the "very high" risk patients had been classified as high risk with a treatment goal of < or = 100 mg/dL. Risk classification in the new NCEP publication is based essentially on the combination of the Framingham risk score plus counting of classical risk factors. In the present document, the International Task Force for Prevention of Coronary Heart Disease responds to this NCEP commentary and supports the suggestion of more intensive LDL cholesterol lowering in particular cases. However, the Task Force feels that a classification based on a combination of a risk score plus a count of emerging risk factors is a more logical way to identify such patients requiring lower LDL cholesterol levels than a scheme in which classical risk factors are taken into account twice, once in a count and once in a risk score.