The Effect of Tongue Volume and Adipose Content on Obstructive Sleep Apnea: Meta-analysis & Systematic Review

Macroglossia is a risk factor for obstructive sleep apnea (OSA) and has been linked to an elevated apnea-hypopnea index (AHI). Obesity may contribute to macroglossia, but its exact relationship is unknown and likely multifactorial, and the degree to which increased adiposity of the tongue affects the development of OSA is not understood. The primary objective of this study was to evaluate how tongue fat and volume relate to the presence and severity of OSA.

Studies reporting the impact of tongue fat or volume were identified using predefined inclusion criteria from September 2002 to 2022.

All studies underwent a 2-stage blinded screening, extraction, and evaluation process. Primary outcomes were the effect of tongue fat and volume on OSA severity and evaluation of study quality. Secondary outcomes included the impact of obesity on tongue fat distribution and OSA severity.

Out of 930 studies, 6 studies with 219 patients and 133 controls were included in meta-analysis. All 6 studies were case-control designs. Included studies showed low (4) and moderate (2) risks of bias. All studies compared tongue volume with an observed significant increase in tongue volume in OSA patients (P < .00001) with a weighted mean difference of 19.00 cm³ [15.53, 22.47]. Two studies compared tongue fat, and there was a significant increase in tongue fat in patients with OSA (P < .00001) with a weighted mean difference of 8.04 cm³ [4.25, 11.82].

This meta-analysis supports increased tongue volume and tongue adipose as important risk factors associated with OSA. Larger studies investigating tongue fat distribution and the effect of weight changes on tongue fat and volume and OSA severity are needed to characterize this relationship better.