A lower body mass index (BMI) does not protect smokers from fat-associated health risks, according to a Vanderbilt University Medical Center (VUMC) study published in PLOS Medicine.
While some smokers might rationalize the habit because it can lower body weight, VUMC researchers determined that smokers have a higher risk of depositing fat in and around organs and tissues compared to those who never smoked.
Excess fat, also known as adipose tissue, deposited in the abdomen and around organs such as the liver, and non-adipose tissues including muscles, may disrupt normal bodily functions and cause health complications such as cardiovascular disease and type 2 diabetes.
"We found that current smokers had abdominal muscles that were significantly higher in fat," said lead author James "Greg" Terry, research programs manager in Radiology and member of Vanderbilt Translational and Clinical Cardiovascular Research Center (VTRACC).
"Smokers also had a higher proportion of fat around their internal organs, compared to never smokers ... this might contribute to the higher prevalence of cardiovascular disease and age-related physical deconditioning and disability that is well-documented among those who smoke," he said.
Researchers used computed tomography (CT) body scans to measure abdominal fat deposited just below the skin's surface (subcutaneous fat), around organs including the intestines (visceral fat) and abdominal muscles (intermuscular fat), and inside the muscles (intramuscular fat) in 3,020 middle-aged participants in the federally funded Coronary Artery Risk Development in Young Adults (CARDIA) study.
Co-author David Jacobs, PhD, professor of Public Health at the University of Minnesota and one of the founding CARDIA investigators, said he considers "cigarette smoking as a weight-loss tool to be a risky strategy. Our data show that the fat deposition pattern apparent in smokers is associated with metabolic damage."
The longitudinal CARDIA study began in 1985 with the recruitment of young adult participants (ages 18-30), equally balanced by male and female sex and black and white race, at four locations in the United States. The CT measurements were taken at the 25-year mark. The investigation is published in the online, open access journal PLOS Medicine.
The CARDIA study is supported through National Heart, Lung and Blood Institute (NHLBI awards to University of Alabama at Birmingham (HHSN268201800005I & HHSN268201800007I), Northwestern University (HHSN268201800003I), University of Minnesota (HHSN268201800006I), and Kaiser Foundation Research Institute (HHSN268201800004I), and Vanderbilt University School of Medicine (R01-HL098445) and NIA an Intramural Research Program of the National Institute on Aging (NIA) and an intra-agency agreement between NIA and NHLBI (AG0005).