Evaluating Craniofacial Morphology Ratios as Predictors of Obstructive Sleep Apnea Severity in Non-Obese Adult Males

<b>Background</b>: This study aimed to examine the connection between craniofacial morphology, particularly the horizontal and vertical dimensions of the mandible, and the severity of obstructive sleep apnea (OSA) in non-obese adult males by utilizing a cephalometric analysis and introducing a new skeletal ratio index. <b>Methods</b>: A cohort of 44 non-obese adult males with OSA, diagnosed via the apnea-hypopnea index (AHI) from polysomnographic recordings, was evaluated using a lateral cephalometric analysis. OSA severity was classified as mild (5 ≤ AHI < 15) in 19 patients, moderate (15 ≤ AHI < 30) in 15 patients, and severe (AHI ≥ 30) in 10 patients. The S-Go distance divided by the N-Me distance (S-Go/N-Me) was used as a vertical ratio of craniofacial morphology, the Go-Me distance divided by the S-N distance (Go-Me/S-N) was used as a horizontal ratio, and the results were compared between groups. Correlations between each ratio and craniofacial morphology based on the five factors from the Ricketts analysis were examined for each group. <b>Results</b>: A significant difference was found in the horizontal ratio Go-Me/S-N between the mild and moderate groups (<i>p</i> < 0.05) and the mild and severe groups (<i>p</i> < 0.05). However, no significant differences in Ricketts analysis factors were observed across OSA severity groups. Correlations between the Go-Me/S-N and Ricketts factors were identified in the mild and moderate groups but not in the severe group. The horizontal skeletal dimension Go-Me/S-N was strongly associated with OSA severity. <b>Conclusions</b>: The horizontal mandibular ratio Go-Me/S-N, independent of body shape, may offer a valuable morphological marker for differentiating OSA severity in non-obese males.