Obesity Drives Heart Risk for Most Racial and Ethnic Groups
By Judith Groch
WINSTON, 13 may 2008-- Obesity rates in the U.S. , and attendant cardiovascular risk factors, were high among whites, blacks, and Hispanics but not among Chinese Americans, according to an observational cohort study.
Only 5% of Chinese Americans were obese compared with a range of 30% to 50% in the other population groups, Gregory L. Burke, M.D., of Wake Forest University, and colleagues reported in the May 12 issue of Archives of Internal Medicine.
Those of Chinese heritage were also less likely to be overweight (33%) than whites, blacks, and Hispanic participants, in whom percentages ranged from 60% to 85%, the researchers said.
An important component of this analysis, the researchers said, was the association between obesity and subclinical risk factors and markers for cardiovascular disease that persisted even after adjustment for traditional risk factors.
From 1960 to 2000, the percentage of the U.S. population categorized as obese increased from 11% to 28% in men and 16% to 34% in women, the researchers wrote, with higher rates observed in certain racial and ethnic groups.
Thus, they said, the obesity epidemic could reduce further gains in U.S. life expectancy, largely through obesity's effect on cardiovascular disease mortality.
To assess the importance of the obesity epidemic on cardiovascular disease risk, the researchers analyzed data from the Multi-Ethnic Study of Atherosclerosis (MESA), an observational cohort study of 6,814 men and women, ages 45 to 84, who were free of clinical cardiovascular disease at the 2000-2002 baseline.
They assessed the association between body size and cardiovascular disease risk factors, medication use, and subclinical vascular disease (coronary artery calcium, carotid artery intima-medial thickness, and left ventricular mass).
The most striking differences were seen across racial and ethnic lines, the researchers said.
A prevalence of 75% or more for overweight was observed in white men and African-American and Hispanic participants of both genders, with more than 60% prevalence observed in white women.
In contrast, only one-third of Chinese-American men and women were classified as overweight.
As for obesity, overall, more than 50% of black women, 40% of Hispanic women, and 30% of black and Hispanic men, and nearly 30% of white men and women, were obese.
In contrast only 5% of Chinese-American participants were classified as obese.
The pattern of being obese or overweight was similar in middle age and older adults, the researchers found.
Subclinical risk factors for heart disease and stroke -- including blood pressure, lipoproteins, and fasting glucose levels -- also rose with higher body mass index (BMI). This despite a much higher use of antihypertensive and/or antidiabetic medications.
Obesity was also associated with:
A 17% greater risk of coronary artery calcium
A 32% greater risk of internal carotid artery intima-medial thickness greater than the 80th percentile
A 45% greater risk of having a common carotid artery intimal medial thickness greater than the 80th percentile
A 2.7-fold greater risk of having a left ventricular mass greater than the 80th percentile compared with normal body size
These associations persisted after adjustment for traditional
cardiovascular disease risk factors, the investigators said.
Systolic blood pressure levels were significantly higher in the obese than in the normal BMI group in all racial/ethnic and gender groups (6-20 mm Hg higher, age adjusted).
HDL levels were significantly lower in all racial/ethnic and sex groups (4-14 mg/dL lower, age adjusted), and fasting glucose levels were significantly higher in white, African-American,
and Hispanic participants (8-17 mg/dL higher, age adjusted).
Triglyceride levels (18-55 mg/dL higher, age adjusted), and LDL particle size (109-173 nmol/L higher, age adjusted) were significantly greater in all racial/ethnic and gender groups.
No consistent differences across body size groups were observed for LDLs.
In addition, greater BMI was associated with a significantly higher Framingham coronary heart disease risk in all racial-ethnic and gender groups, except African-American and Hispanic women.
Chinese-American participants were an exception to these findings with much lower rates of obesity.
The researchers noted, however, that these findings could not be compared with national data because of a paucity of such data for these individuals. But, they said, international comparisons have documented similarly lower rates of overweight and obesity in China compared with the U.S.
The observed association between obesity and cardiovascular disease is likely mediated through a variety of different pathways, the investigators said, including the effect on blood pressure, dyslipidemia, and glycemic state, which in turn affect atherosclerosis progression and left ventricular mass over a lifetime.
Reviewing study limitations, the researchers said that because the morbidly obese were excluded, the true burden of obesity and cardiovascular disease may have been underestimated.
Also the data were cross-sectional and could not incorporate the known time lag between the development of cardiovascular risk factors and their impact on subclinical atherosclerosis. Adjusting for current levels of cardiovascular risks may not fully consider a past or lifelong history of a more adverse risk profile for heart disease, the researchers wrote.
The low prevalence of obesity in Chinese-American participants indicates that a high rate of obesity should not be viewed as being inevitable, the researchers said.
These findings, they added, "support the imperative to redouble our efforts to assist in increasing healthy behaviors and to remove environmental barriers to maintaining a healthy weight."
No financial conflicts were reported. This study was supported by contracts from the National Heart, Lung, and Blood Institute and by the Wake Forest University General Clinical Research Center.
Primary source: Archives of Internal MedicineSource reference:Burke GL, et al "The impact of obesity on cardiovascular disease risk factors and subclinical vascular disease: The multi-ethnic study of atherosclerosis" Arch Intern Med 2008; 168: 928-935.
By Judith Groch
WINSTON, 13 may 2008-- Obesity rates in the U.S. , and attendant cardiovascular risk factors, were high among whites, blacks, and Hispanics but not among Chinese Americans, according to an observational cohort study.
Only 5% of Chinese Americans were obese compared with a range of 30% to 50% in the other population groups, Gregory L. Burke, M.D., of Wake Forest University, and colleagues reported in the May 12 issue of Archives of Internal Medicine.
Those of Chinese heritage were also less likely to be overweight (33%) than whites, blacks, and Hispanic participants, in whom percentages ranged from 60% to 85%, the researchers said.
An important component of this analysis, the researchers said, was the association between obesity and subclinical risk factors and markers for cardiovascular disease that persisted even after adjustment for traditional risk factors.
From 1960 to 2000, the percentage of the U.S. population categorized as obese increased from 11% to 28% in men and 16% to 34% in women, the researchers wrote, with higher rates observed in certain racial and ethnic groups.
Thus, they said, the obesity epidemic could reduce further gains in U.S. life expectancy, largely through obesity's effect on cardiovascular disease mortality.
To assess the importance of the obesity epidemic on cardiovascular disease risk, the researchers analyzed data from the Multi-Ethnic Study of Atherosclerosis (MESA), an observational cohort study of 6,814 men and women, ages 45 to 84, who were free of clinical cardiovascular disease at the 2000-2002 baseline.
They assessed the association between body size and cardiovascular disease risk factors, medication use, and subclinical vascular disease (coronary artery calcium, carotid artery intima-medial thickness, and left ventricular mass).
The most striking differences were seen across racial and ethnic lines, the researchers said.
A prevalence of 75% or more for overweight was observed in white men and African-American and Hispanic participants of both genders, with more than 60% prevalence observed in white women.
In contrast, only one-third of Chinese-American men and women were classified as overweight.
As for obesity, overall, more than 50% of black women, 40% of Hispanic women, and 30% of black and Hispanic men, and nearly 30% of white men and women, were obese.
In contrast only 5% of Chinese-American participants were classified as obese.
The pattern of being obese or overweight was similar in middle age and older adults, the researchers found.
Subclinical risk factors for heart disease and stroke -- including blood pressure, lipoproteins, and fasting glucose levels -- also rose with higher body mass index (BMI). This despite a much higher use of antihypertensive and/or antidiabetic medications.
Obesity was also associated with:
A 17% greater risk of coronary artery calcium
A 32% greater risk of internal carotid artery intima-medial thickness greater than the 80th percentile
A 45% greater risk of having a common carotid artery intimal medial thickness greater than the 80th percentile
A 2.7-fold greater risk of having a left ventricular mass greater than the 80th percentile compared with normal body size
These associations persisted after adjustment for traditional
cardiovascular disease risk factors, the investigators said.
Systolic blood pressure levels were significantly higher in the obese than in the normal BMI group in all racial/ethnic and gender groups (6-20 mm Hg higher, age adjusted).
HDL levels were significantly lower in all racial/ethnic and sex groups (4-14 mg/dL lower, age adjusted), and fasting glucose levels were significantly higher in white, African-American,
and Hispanic participants (8-17 mg/dL higher, age adjusted).
Triglyceride levels (18-55 mg/dL higher, age adjusted), and LDL particle size (109-173 nmol/L higher, age adjusted) were significantly greater in all racial/ethnic and gender groups.
No consistent differences across body size groups were observed for LDLs.
In addition, greater BMI was associated with a significantly higher Framingham coronary heart disease risk in all racial-ethnic and gender groups, except African-American and Hispanic women.
Chinese-American participants were an exception to these findings with much lower rates of obesity.
The researchers noted, however, that these findings could not be compared with national data because of a paucity of such data for these individuals. But, they said, international comparisons have documented similarly lower rates of overweight and obesity in China compared with the U.S.
The observed association between obesity and cardiovascular disease is likely mediated through a variety of different pathways, the investigators said, including the effect on blood pressure, dyslipidemia, and glycemic state, which in turn affect atherosclerosis progression and left ventricular mass over a lifetime.
Reviewing study limitations, the researchers said that because the morbidly obese were excluded, the true burden of obesity and cardiovascular disease may have been underestimated.
Also the data were cross-sectional and could not incorporate the known time lag between the development of cardiovascular risk factors and their impact on subclinical atherosclerosis. Adjusting for current levels of cardiovascular risks may not fully consider a past or lifelong history of a more adverse risk profile for heart disease, the researchers wrote.
The low prevalence of obesity in Chinese-American participants indicates that a high rate of obesity should not be viewed as being inevitable, the researchers said.
These findings, they added, "support the imperative to redouble our efforts to assist in increasing healthy behaviors and to remove environmental barriers to maintaining a healthy weight."
No financial conflicts were reported. This study was supported by contracts from the National Heart, Lung, and Blood Institute and by the Wake Forest University General Clinical Research Center.
Primary source: Archives of Internal MedicineSource reference:Burke GL, et al "The impact of obesity on cardiovascular disease risk factors and subclinical vascular disease: The multi-ethnic study of atherosclerosis" Arch Intern Med 2008; 168: 928-935.
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