# IL-6, calcium, salivary amylase activity and cortisol as a salivary biomarker-combination associated with obesity: a pilot study

## TL;DR

This pilot study explores salivary biomarkers like IL-6, calcium, amylase, and cortisol to identify potential non-invasive indicators of obesity.

## Contribution

The study introduces a novel salivary biomarker-combination for detecting obesity-related metabolic and inflammatory changes.

## Key findings

- Obese individuals had lower salivary calcium, amylase, and MUC5B levels compared to non-obese controls.
- Higher IL-6 and cortisol levels were observed in the obese group.
- Calcium correlated positively with salivary amylase and IL-6 in the obese group.

## Abstract

As obesity continues to escalate to pandemic levels worldwide, innovative approaches for early diagnosis, risk stratification, and disease monitoring are urgently needed. Saliva presents a promising non-invasive method for biomarker-based screening in obesity.

This study aimed to utilize a multi-biomarker approach to explore associations between salivary biomarkers and obesity. This was done by measuring a pre-selected panel of obesity-related salivary biomarkers and comparing their levels between individuals with and without obesity.

Unstimulated saliva was collected from 57 individuals, including 27 individuals diagnosed with obesity (BMI ≥ 30 kg/m2) and 30 non-obese controls (BMI < 30 kg/m2). Various biochemical techniques were used to quantify salivary total protein content, α-amylase activity (sAA), cortisol, interleukin 6 (IL-6), mucin 5B (MUC5B), albumin and calcium ions (Ca2+).

The results indicated lower Ca2+, sAA, and MUC5B levels (P < 0.05) and higher IL-6 and cortisol levels (P < 0.05) in the obese group compared to non-obese controls. In the obese group, Ca2+ correlated positively with most biomarkers, with sAA (r = 0.632, P < 0.05) and IL-6 (r = 0.449, P < 0.05) showing the strongest associations.

In conclusion, this study highlights IL-6, Ca2+, sAA, and cortisol as a potential salivary biomarker-combination associated with obesity warranting further investigation. The observed changes in the salivary biomarker levels of the obese group may reflect underlying metabolic dysregulations, highlighting the advantage of a multi-biomarker approach to better capture early metabolic and inflammatory processes associated with obesity. To further validate these findings, large clinical studies with diverse, well-matched cohorts, as well as longitudinal studies, are needed.