Body Mass Index and All-Cause and Cardiovascular Mortality in United States Adults With and Without Atherosclerotic Cardiovascular Disease: Findings from the National Health Interview Survey

In a nationally representative population-based study of US adults, the authors sought to examine the association between body mass index (BMI) and all-cause and cardiovascular disease (CVD) mortality in a nationally representative sample of adults with and without atherosclerotic cardiovascular disease (ASCVD), and further stratified by age, sex, and race/ethnicity. The study used data from 2006 to 2015 National Health Interview Survey and categorized participants into the following BMI categories: normal weight (20–24.9), overweight (25–29.9), obesity class 1 (30–34.9), obesity class 2 (35–39.9), and obesity class 3 (‡40 kg/m²). Multivariable Cox proportional hazards models were used to assess the risk of all-cause and CVD mortality across successively increasing BMI categories overall, and by sociodemographic subgroups. A total of 210,923 individuals were included in the final analysis. In the population without ASCVD, the risk of all-cause and CVD mortality was lower in overweight and higher in obesity classes 2 and 3, compared with normal weight, with the highest risk observed in the young adult (age 18–39) population. Elderly adults (65 and above) and populations with ASCVD exhibited a BMI-mortality paradox. In addition, Hispanic individuals did not show a relationship between BMI and mortality compared with non-Hispanic White and Black adults. In conclusion, being overweight was associated with decreased risk, whereas obesity class 3 was consistently associated with increased risk of all-cause and CVD mortality in adults without ASCVD, particularly young adults. BMI-mortality paradox was noted in ASCVD, elderly, and non-Hispanic adults.