Objective
The authors hypothesize that an untargeted metabolomics study will identify novel mechanisms underlying smokingâassociated weight loss.
Methods
This study performed crossâsectional analyses among 1,252 participants in the Bogalusa Heart Study and assessed 1,202 plasma metabolites for mediation effects on smokingâBMI associations. Significant metabolites were tested for associations with smoking genetic risk scores among a subset of participants (n = 654) with available genomic data, followed by direction dependence analysis to investigate causal relationships between the metabolites and smoking and BMI. All analyses controlled for age, sex, race, education, alcohol drinking, and physical activity.
Results
Compared with never smokers, current and former smokers had a 3.31âkg/m2 and 1.77âkg/m2 lower BMI after adjusting for all covariables, respectively. A total of 22 xenobiotics and 94 endogenous metabolites were significantly associated with current smoking. Eight xenobiotics were also associated with former smoking. Forty metabolites mediated the smokingâBMI associations, and five showed causal relationships with both smoking and BMI. These metabolites, including 1âoleoylâGPE (18:1), 1âlinoleoylâGPE (18:2), 1âstearoylâ2âarachidonoylâGPE (18:0/20:4), αâketobutyrate, and 1âpalmitoylâGPE (16:0), mediated 26.0% of the association between current smoking and BMI.
Conclusions
This study cataloged plasma metabolites altered by cigarette smoking and identified five metabolites that partially mediated the association between current smoking and BMI.