Adiposity, Inflammation, and Risk for Death in Black and White Men and Women in the United States: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study
It has been proposed that adiposity is a protective response to excess caloric supply, but it is cardiometabolically harmful once adipocytes become inflamed.
The objective of the study was to assess whether elevated C-reactive protein (CRP), a measure of systemic inflammation, can differentiate individuals at higher mortality risk due to excess adiposity.
We conducted an observational study of 16,486 white and 11,168 black men and women in the Reasons for Geographic and Racial Differences in Stroke study, a U.S. national cohort.
The main outcome was all-cause mortality.
The mean age of the cohort was 64 ± 9 yr. Over a 6-yr period, 927 whites and 669 blacks died. The absolute risk of death was highest among underweight whites and blacks (9.2 and 14%, respectively), not the obese (4.7% whites; 4.0% blacks) or severely obese (5.9% whites; and 4.6% blacks). Among those with elevated CRP (≥3 vs. <1 mg/liter), underweight [hazard ratio (HR) 2.08, 95% confidence interval (CI) 1.03-4.21] and normal-weight (HR 2.62, 95% CI 1.87-3.67) whites were at significantly higher mortality risk but not severely obese whites (HR 1.55, 95% CI 0.77-2.96), resulting in a statistical interaction (P = 0.01). Similar results were also seen for blacks, although a higher mortality risk among severely obese blacks with CRP 3 or greater vs. less than 1 mg/liter was also demonstrated (HR 2.58, 95% CI 1.04-6.41). Among whites and black women, higher waist circumference was associated with an increased mortality risk, although this relationship was not modified by CRP levels (P = 0.47 for whites and P = 0.25 for blacks).
Among middle-aged and older adults, the addition of CRP was most informative among underweight and normal-weight individuals, not the obese. This negated our hypothesis that increased levels of CRP would differentiate individuals at higher mortality risk due to excess adiposity.
Available from: Katherine Mayhew Flegal
- "y SAHS) Atlantis et al, 64 2010 Lawlor et al , 58 2006( Renfrew / Paisley women ) Ferrie et al , 50 2009 ( men) Wändell et al , 56 2009 ( women) Cabrera et al , 65 2005 Lang et al , 23 2008 ( women) Lakoski et al , 51 2011 ( women) McTigue et al , 68 2006 ( egy for PubMed yielded 4142 articles , of which 128 met our criteria . A second PubMed search yielded 2892 additional articles , of which 13 met our criteria . "
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ABSTRACT: Estimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
To perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
PubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Articles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270,000 deaths.
Data were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
Random-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
Available from: Patricia Hartge
- "A limited number of studies have examined the association between BMI and total mortality in blacks and have reported inconsistent results. Several studies suggested an increased risk of death with higher BMI , , ,  while others found no association between BMI and total mortality , , , , , , . Earlier studies, such as a study of black members of the Kaiser Foundation Health Plan in northern California in 1966–1973  and the Charleston Heart Study , , found a J-shaped association between BMI and total mortality in black men, but no association in black women. "
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ABSTRACT: Although the prevalence of obesity (body mass index, kg/m(2), BMI ≥30) is higher in non-Hispanic blacks than in non-Hispanic whites, the relation of BMI to total mortality in non-Hispanic blacks is not well defined.
We investigated the association between BMI and total mortality in 16,471 non-Hispanic blacks in the NIH-AARP Diet and Health Study, a prospective cohort of adults aged 50-71 years.
During an average of 13 years of follow-up, 2,609 deaths were identified using the Social Security Administration Death Master File and the National Death Index. Cox proportional hazard models were used to estimate relative risks and two-sided 95% confidence intervals (CI), adjusting for potential confounders.
Among individuals with no history of cancer or heart disease at baseline and had a BMI of 20 or greater, the relative risk for total death was 1.12 (95% CI:1.05, 1.19, for a 5-unit increase in BMI) in men and 1.09 (95% CI:1.03, 1.15) in women. Among never smokers with no history of cancer or heart disease at baseline, relative risks for total death for BMI 25-<30, 30-<35, 35-<40, and 40-50, compared with BMI 20-<25, were 1.27 (95% CI: 0.91, 1.78), 1.56 (95% CI: 1.07, 2.28), 2.48 (95% CI: 1.53, 4.05), and 2.80 (95% CI: 1.46, 5.39), respectively, in men and 0.78 (95% CI: 0.59, 1.04), 1.17 (95% CI: 0.88, 1.57), 1.35 (95% CI: 0.96, 1.90), and 1.93 (95% CI: 1.33, 2.81), respectively, in women.
Our findings suggest that overweight is related to an increased risk of death in black men, but not in black women, while obesity is related to an increased risk of death in both black men and women. A large pooled analysis of existing studies is needed to systematically evaluate the association between a wide range of BMIs and total mortality in blacks.
Available from: sciencedirect.com
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ABSTRACT: This study sought to evaluate whether the relationship between C-reactive protein (CRP) and atherosclerosis is modified by body mass index (BMI).
CRP levels are affected by obesity, and it is unknown whether the associations between CRP and cardiovascular (CV) disease differ between obese and nonobese individuals.
We measured CRP and multiple atherosclerosis phenotypes, including coronary artery calcification (CAC) (n = 2,685), aortic wall thickness (AWT) (n = 2,238), and aortic plaque burden (APB) (n = 2,224), in subjects ages 30 to 65 years from the Dallas Heart Study. The associations of CRP with CAC, AWT, and APB were compared across categories of BMI (normal, 18.5 to <25 kg/m(2); overweight, 25 to <30 kg/m(2); obese, ≥30 kg/m(2)) in sex-stratified analyses.
The overall prevalence of obesity was 38% in men and 53% in women. Increasing CRP levels (<1 mg/l, 1 to 3 mg/l, >3 mg/l) were associated with increased CAC prevalence in normal and overweight men and in normal weight women (p < 0.01), but not in obese subjects of either sex. Likewise, the correlations between CRP and AWT and APB diminished with increasing BMI and were nonsignificant in obese individuals (p < 0.05 in nonobese, p > 0.1 in obese). Interaction tests between CRP and obesity were significant for all atherosclerosis measures in men and for AWT and ABP in women (p interaction <0.05 each). In both sexes, the c-statistics of CRP for all 3 atherosclerosis measures were greater for normal weight than obese individuals.
In a large, population-based study, the association between CRP and multiple measures of atherosclerosis is diminished in obese individuals. The role of CRP for predicting CV outcomes in obese subjects requires further evaluation.
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