Association between non-Insulin based Insulin resistance indices, Weight-Adjusted Waist index (WWI), systemic inflammation, periodontitis and hypertension- An observational study

Periodontitis is a common inflammatory disease caused by a dysbiotic biofilm and affects the soft and hard tissues around teeth. Inflammation is considered an important driver of vascular dysfunction and is implicated in the development and progression of hypertension. Recent evidence suggests a possible causal link between periodontitis and hypertension. In patients with periodontitis, microbial dysbiosis from increased bacteria in periodontal pockets is related to metabolic dysfunction and inflammation-induced Insulin resistance (IR). Hyperinsulinemia closely related to IR activates the renin-angiotensin-aldosterone system, promotes renal sodium retention and ultimately leads to hypertension.

The non-Insulin bases IR indices, including the Triglyceride index (TyG), Triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) and metabolic score for insulin resistance index (METS-IR) have been identified as useful markers for assessing insulin resistance. A significant association is also present between periodontitis and non-Insulin based IR indices. The TyG index is acknowledged as the preferred method for assessing IR in hypertensive individuals; TG/HDL-C ratio and METS-IR are also associated with a higher prevalence of hypertension.

The weight-adjusted waist index (WWI) provides a more detailed evaluation of central obesity compared to traditional measures like body mass index (BMI) & waist circumference (WC). Central obesity, characterized by excess visceral fat, is particularly concerning due to its strong link to metabolic issues and IR. A direct link has also been postulated between WWI and the risk of developing hypertension.

In periodontitis, bacterial components or locally produced pro-inflammatory cytokines may enter the circulation and cause systemic inflammation. Recent evidence implicates oral microorganisms in the nitrate-nitrite-nitric oxide (NO) pathway and the pathogenesis of hypertension. The serum inflammatory biomarkers, high sensitivity C-reactive protein (hs-CRP) and white blood cells (WBCs), can act as a proxy of systemic inflammation associated with both these diseases.

Recent evidence suggests periodontitis, hypertension and IR are closely linked but limited data is available on the nature of the association. Hence in this cross-sectional study we seek to examine the correlation between these diseases & to investigate the role of non-insulin-based IR indices, WWI, and systemic inflammation in otherwise healthy participants with or without generalised periodontitis and hypertension.