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
ABSTRACT 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.
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ABSTRACT: REasons for Geographic and Racial Differences in Stroke (REGARDS) is a longitudinal study supported by the National Institutes of Health to determine the disparities in stroke-related mortality across USA. REGARDS has published a body of work designed to understand the disparities in prevalence, awareness, treatment, and control of coronary heart disease (CHD) and its risk factors in a biracial national cohort. REGARDS has focused on racial and geographical disparities in the quality and access to health care, the influence of lack of medical insurance, and has attempted to contrast current guidelines in lipid lowering for secondary prevention in a nationwide cohort. It has described CHD risk from nontraditional risk factors such as chronic kidney disease, atrial fibrillation, and inflammation (i.e., high-sensitivity C-reactive protein) and has also assessed the role of depression, psychosocial, environmental, and lifestyle factors in CHD risk with emphasis on risk factor modification and ideal lifestyle factors. REGARDS has examined the utility of various methodologies, e.g., the process of medical record adjudication, proxy-based cause of death, and use of claim-based algorithms to determine CHD risk. Some valuable insight into less well-studied concepts such as the reliability of current troponin assays to identify "microsize infarcts," caregiving stress, and CHD, heart failure, and cognitive decline have also emerged. In this review, we discuss some of the most important findings from REGARDS in the context of the existing literature in an effort to identify gaps and directions for further research.Current Hypertension Reports 04/2015; 17(4):541. DOI:10.1007/s11906-015-0541-5 · 3.90 Impact Factor
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ABSTRACT: Convention defines pediatric adiposity by the body mass index z-score (BMIz) referenced to normative growth charts. Waist-to-height ratio (WHtR) does not depend on sex-and-age references. In the HEALTHY Study enrollment sample, we compared BMIz with WHtR for ability to identify adverse cardiometabolic risk. Among 5,482 sixth-grade students from 42 middle schools, we estimated explanatory variations (R (2)) and standardized beta coefficients of BMIz or WHtR for cardiometabolic risk factors: insulin resistance (HOMA-IR), lipids, blood pressures, and glucose. For each risk outcome variable, we prepared adjusted regression models for four subpopulations stratified by sex and high versus lower fatness. For HOMA-IR, R (2) attributed to BMIz or WHtR was 19%-28% among high-fatness and 8%-13% among lower-fatness students. R (2) for lipid variables was 4%-9% among high-fatness and 2%-7% among lower-fatness students. In the lower-fatness subpopulations, the standardized coefficients for total cholesterol/HDL cholesterol and triglycerides tended to be weaker for BMIz (0.13-0.20) than for WHtR (0.17-0.28). Among high-fatness students, BMIz and WHtR correlated with blood pressures for Hispanics and whites, but not black boys (systolic) or girls (systolic and diastolic). In 11-12 year olds, assessments by WHtR can provide cardiometabolic risk estimates similar to conventional BMIz without requiring reference to a normative growth chart.Journal of obesity 01/2014; 2014:421658. DOI:10.1155/2014/421658
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ABSTRACT: Background: Metabolically healthy obesity may confer lower risk of adverse health outcomes compared with abnormal obesity. Diet and race are postulated to influence the phenotype, but their roles and their interrelations on healthy obesity are unclear. Objective: We evaluated food intakes of metabolically healthy obese women in comparison to intakes of their metabolically healthy normal-weight and abnormal obese counterparts. Methods: This was a cross-sectional study in 6964 women of the REGARDS (REasons for Geographic And Racial Differences in Stroke) study. Participants were aged 45–98 y with a BMI (kg/m2) ≥18.5 and free of cardiovascular diseases, diabetes, and cancer. Food intake was collected by using a food-frequency questionnaire. Body mass index (BMI) phenotypes were defined by using metabolic syndrome (MetS) and homeostasis model assessment of insulin resistance (HOMA-IR) criteria. Mean differences in food intakes among BMI phenotypes were compared by using ANCOVA. Results: Approximately one-half of obese women (white: 45%; black: 55%) as defined by MetS criteria and approximately one-quarter of obese women (white: 28%; black: 24%) defined on the basis of HOMA-IR values were metabolically healthy. In age-adjusted analyses, healthy obesity and normal weight as defined by both criteria were associated with lower intakes of sugar-sweetened beverages compared with abnormal obesity among both white and black women (P < 0.05). HOMA-IR–defined healthy obesity and normal weight were also associated with higher fruit and low-fat dairy intakes compared with abnormal obesity in white women (P < 0.05). Results were attenuated and became nonsignificant in multivariable-adjusted models that additionally adjusted for BMI, marital status, residential region, education, annual income, alcohol intake, multivitamin use, cigarette smoking status, physical activity, television viewing, high-sensitivity C-reactive protein, menopausal status, hormone therapy, and food intakes. Conclusions: Healthy obesity was not associated with a healthier diet. Prospective studies on relations of dietary patterns, which may be a better indicator of usual diet, with the phenotype would be beneficial.Journal of Nutrition 01/2014; 144(10):1-9. DOI:10.3945/jn.114.19834 · 4.23 Impact Factor