Determining whether weight status mediates the association between number of cigarettes smoked per day and all-cause mortality among US adults who smoke cigarettes

TL;DR

This study finds that weight status partially explains the link between cigarette smoking and mortality, suggesting weight management could help reduce smoking-related deaths.

Contribution

The novel contribution is identifying weight status as a partial mediator between cigarette use and mortality.

Findings

WC adjusted by BMI levels partially mediated the association between CPD and all-cause mortality.

The indirect effect of CPD on mortality through weight status was statistically significant.

Weight management programs could be a harm reduction strategy to reduce smoking-related mortality.

Abstract

While there is evidence demonstrating the association between cigarette smoking and weight status, and mortality and weight status, it has not been examined whether weight status is a mediator between number of cigarettes smoked per day (CPD) and all-cause mortality, limiting our knowledge of this association and potential novel approaches to reduce all-cause mortality due to cigarette smoking. We aimed to evaluate whether weight status mediated the association between CPD and mortality.

We harnessed the 2003-2018 NHANES and the Linkage Mortality Files, which included adults who smoked ≥ 100 lifetime cigarettes (unweighted n = 5,676). A generalized linear model estimated the association between cigarettes smoked per day (CPD) and weight status (e.g., Body Mass Index (BMI) or Waist Circumference (WC)). An Accelerated Failure Time model with a Weibull distribution estimated the association between CPD and all-cause mortality with weight status as a mediator, adjusting for age, SES, alcohol consumption, race/ethnicity, sex/gender, blood pressure, total cholesterol, and physical activity.

Between 2003-2018, the sample’s mean BMI was 27.97 kg/m2, sample’s mean WC was 97.58 cm and mean CPD was 13.21. The total effect in the mediation analysis of WC adjusted by BMI levels in the association between CPD and all-cause mortality was -0.44 (95% CI =  -2.00, -0.20; p =  0.016), the average direct effect was -0.35 (95% CI =  -1.86, -0.10; p =  0.036), and the average indirect effect was -0.10 (95% CI =  -0.23, -0.05; p < 0.001).

WC, as a surrogate measure of weight status, when adjusted by BMI levels, was a partial mediator between CPD and all-cause mortality. Public health interventions aimed to reduce mortality due to cigarette smoking at the population level should consider weight management programs as a harm reduction strategy to reduce mortality.

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