Effects of current smoking severity on brain gray matter volume in opioid use disorder – a voxel-based morphometry study

ABSTRACT

Background: Cigarette smoking (CS) and opioid use disorder (OUD) significantly alter brain structure. Although OUD and cigarette smoking are highly comorbid, most prior neuroimaging research in OUD did not control for smoking severity. Specifically, the combined effect of smoking and OUD on the brain gray matter volume (GMV) remains unknown.

Objectives: We used structural magnetic resonance imaging (sMRI) to examine: (1) the GMV differences between OUD and non-OUD individuals with comparable smoking severity; and (2) the differential effect of smoking severity on the brain GMV between individuals with and without OUD.

Methods: We performed a secondary analysis of existing sMRI datasets of 116 individuals who smoked cigarettes daily, among whom 60 had OUD (CS-OUD; 37 male, 23 female) and 56 did not (CS; 31 male, 25 female). Brain GMV was estimated by voxel-based morphometry analysis.

Results: Compared to the CS group, the CS-OUD group had a higher GMV in the occipital cortex and lower GMV in the prefrontal and temporal cortex, striatum, and pre/postcentral gyrus (whole-brain corrected-p < .05). There was a significant interaction between group and smoking severity on GMV in the medial orbitofrontal cortex (whole-brain corrected-p < .05), such that heavier smoking was associated with lower medial orbitofrontal GMV in the CS-OUD but not CS participants (r=–0.32 vs. 0.12).

Conclusions: Our findings suggest a combination of independent and interactive effects of cigarette smoking and OUD on the brain gray matter. Elucidating the neuroanatomical correlates of comorbid opioid and tobacco use may shed the light on the development of novel interventions for affected individuals.

KEYWORDS:

• Cigarette smoking
• gray matter volume
• magnetic resonance imaging
• opioid use disorder
• voxel-based morphometry

Author contributions

CPO, ARC and DDL designed the study and collected the data. ZS, KGL and CEW analyzed the data. ZS, XL, JB, JL, CEW and DDL interpreted the results. ZS, XL, CEW and DDL wrote the manuscript. All authors provided critical revision of the manuscript for intellectual content and approved the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by the Commonwealth of Pennsylvania CURE grant SAP#4100055577 (Childress) and the following National Institutes of Health grants: DA051709 (Shi), DA028874 (Childress), AA026892 (Wiers) and DA036028 (Langleben). The funding sources had no role in the study design, collection, analysis or interpretation of the data, writing the manuscript, or the decision to submit the paper for publication