Obesity and All-Cause Mortality Among Blacks and Whites
Obesity and All-Cause Mortality Among Blacks and Whites
In recent pooled analyses among whites and Asians, mortality was shown to rise markedly with increasing body mass index (BMI; weight (kg)/height (m)), but much less is known about this association among blacks. This study prospectively examined all-cause mortality in relation to BMI among 22,014 black males, 9,343 white males, 30,810 black females, and 14,447 white females, aged 40–79 years, from the Southern Community Cohort Study, an epidemiologic cohort of largely low-income participants in 12 southeastern US states. Participants enrolled in the cohort from 2002 to 2009 and were followed up to 8.9 years. Hazard ratios and 95% confidence intervals for mortality were obtained from sex- and race-stratified Cox proportional hazards models in association with BMI at cohort entry, adjusting for age, education, income, cigarette smoking, and alcohol consumption. Elevated BMI was associated with increased mortality among whites (hazard ratios for BMI >40 vs. 20–24.9 = 1.37 (95% confidence interval (CI): 1.02, 1.84) and 1.47 (95% CI: 1.15, 1.89) for white males and white females, respectively) but not significantly among blacks (hazard ratios = 1.13 (95% CI: 0.89, 1.43) and 0.87 (95% CI: 0.72, 1.04) for black males and black females, respectively). In this large cohort, obesity in mid-to-late adulthood among blacks was not associated with the same excess mortality risk seen among whites.
The rise in obesity levels in the general population over the past 3 decades is expected to result in enormous health burdens and health-care costs as obesity is linked to many adverse health outcomes, including diabetes, cardiovascular disease, cancer, and overall mortality. Recent pooled cohort analyses have reported a J-shaped relation between body mass index (BMI) and all-cause mortality with more than doubled mortality risks among extremely obese whites and parallel but less pronounced risks among East Asians. Some previous studies have found a weaker obesity-mortality association among African Americans, but few studies have examined this question in large populations of African Americans, and none have been concentrated in low-income populations or in the southeastern United States where the obesity epidemic is pronounced. Our objective therefore was to prospectively examine the association between BMI and all-cause mortality in the Southern Community Cohort Study (SCCS), a unique cohort with a large African-American population as well as a sizeable group of socioeconomically comparable whites.
Abstract and Introduction
Abstract
In recent pooled analyses among whites and Asians, mortality was shown to rise markedly with increasing body mass index (BMI; weight (kg)/height (m)), but much less is known about this association among blacks. This study prospectively examined all-cause mortality in relation to BMI among 22,014 black males, 9,343 white males, 30,810 black females, and 14,447 white females, aged 40–79 years, from the Southern Community Cohort Study, an epidemiologic cohort of largely low-income participants in 12 southeastern US states. Participants enrolled in the cohort from 2002 to 2009 and were followed up to 8.9 years. Hazard ratios and 95% confidence intervals for mortality were obtained from sex- and race-stratified Cox proportional hazards models in association with BMI at cohort entry, adjusting for age, education, income, cigarette smoking, and alcohol consumption. Elevated BMI was associated with increased mortality among whites (hazard ratios for BMI >40 vs. 20–24.9 = 1.37 (95% confidence interval (CI): 1.02, 1.84) and 1.47 (95% CI: 1.15, 1.89) for white males and white females, respectively) but not significantly among blacks (hazard ratios = 1.13 (95% CI: 0.89, 1.43) and 0.87 (95% CI: 0.72, 1.04) for black males and black females, respectively). In this large cohort, obesity in mid-to-late adulthood among blacks was not associated with the same excess mortality risk seen among whites.
Introduction
The rise in obesity levels in the general population over the past 3 decades is expected to result in enormous health burdens and health-care costs as obesity is linked to many adverse health outcomes, including diabetes, cardiovascular disease, cancer, and overall mortality. Recent pooled cohort analyses have reported a J-shaped relation between body mass index (BMI) and all-cause mortality with more than doubled mortality risks among extremely obese whites and parallel but less pronounced risks among East Asians. Some previous studies have found a weaker obesity-mortality association among African Americans, but few studies have examined this question in large populations of African Americans, and none have been concentrated in low-income populations or in the southeastern United States where the obesity epidemic is pronounced. Our objective therefore was to prospectively examine the association between BMI and all-cause mortality in the Southern Community Cohort Study (SCCS), a unique cohort with a large African-American population as well as a sizeable group of socioeconomically comparable whites.
