# Investigating the Effects of Metabolic and Bariatric Surgery on Systemic Immune‐Inflammation Index and Its Relationship With Smoking

## TL;DR

This study shows that metabolic and bariatric surgeries reduce inflammation markers, especially in the first three months, with some effects linked to smoking habits.

## Contribution

The study provides new evidence on how bariatric surgeries affect inflammation markers and their relationship with smoking.

## Key findings

- Metabolic and bariatric surgeries significantly reduced WBC, NEU, NLR, and SII at 3 months post-surgery.
- Nonsmokers who had sleeve gastrectomy showed significant decreases in WBC, NEU, and SII at 3 months.
- Smoking less than 10 cigarettes per day showed some inflammation reduction, but the effect was not long-lasting.

## Abstract

The contribution of obesity to inflammation may play a role in the progression of obesity‐associated medical problems. The systemic immune inflammation index (SII) has recently been identified as a prognostic indicator for many adverse conditions. The primary purpose of the present study was to investigate the effects of metabolic and bariatric surgeries on white blood cell (WBC), platelet (PLT), lymphocyte (LYN), neutrophil (NEU), neutrophil/lymphocyte (NLR), platelet/neutrophil (PLR), and systemic immune inflammation index (SII). The secondary aim was to evaluate the effects of sleeve gastrectomy (SG) and gastric bypass (GB) surgeries, the most commonly performed metabolic and bariatric procedures, on individual inflammation parameters and their relationship with smoking status.

The blood inflammatory markers of the participants who underwent surgery were analyzed using the data evaluated during routine clinic follow‐ups in the preoperative period and postoperative 1st, 3rd, 6th, and 12th months.

The primary result was a statistically significant decrease in WBC, NEU, NLR, and SII values in the 3rd postoperative month in those who underwent metabolic and bariatric surgery (MBS) (
p
values for each parameter: 0.000, 0.000, 0.028, and 0.006, respectively). A statistically significant decrease in WBC, NEU, and SII values in the 3rd postoperative month compared to preoperative values in nonsmoking individuals with obesity who underwent sleeve gastrectomy surgery was presented as our secondary result (
p
values for each parameter: 0.000, 0.000, and 0.015, respectively).

In our study, MBS provided significant regression in inflammation parameters at 3 months after surgery in people smoking less than 10 cigarettes per day, although this effect did not seem to persist long term.

ACTRN12623000162617

The contribution of obesity to inflammation may play a role in the progression of obesity‐associated medical problems. The systemic immune inflammation index (SII) has recently been identified as a prognostic indicator for many adverse conditions.