Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnea

Dept of Internal Medicine, Fujita Health University, School of Medicine, Toyoake, Aichi, Japan.
European Respiratory Journal (Impact Factor: 7.64). 02/1999; 13(2):403-10. DOI: 10.1183/09031936.99.13240399
Source: PubMed


The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea.

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    • "In contrast, Sakakibara et al. observed that the etiology of OSA in nonobese patients appears to be somewhat different which includes bony structure discrepancies.[17] In accordance with this study, we observed shorter thyromental distance in the nonobese patients which signifies that the position of the chin is relatively low with reference to the thyroid cartilage and shorter length of the anterior cranial base.[31] "
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    ABSTRACT: This study was designed to compare the pattern of obstructive sleep apnea (OSA) among obese and nonobese subjects regarding clinical and polysomnographic data obtained for a polysomnographic study. A cross-sectional retrospective descriptive study was conducted by analyzing polysomnographic data in 112 consecutive patients underwent a sleep study at our sleep laboratory from January 2009 to July 2010. Out of them, 81 were diagnosed to have OSA (apnea-hypopnoea Index ≥5). These patients were classified in two groups with body mass index (BMI) < 27.5 kg/m(2) as nonobese and BMI≥27.5 kg/m(2) as obese. Clinical as well as polysomnographic data were evaluated and compared between the two groups. Patients were also evaluated for other risk factors such as smoking, alcoholism, and use of sedatives. Data were subjected to statistical analysis (χ(2)-test, P value <0.05 considered to be significant). The Fisher Exact test was applied wherever the expected frequency for a variable was ≤5. Of 81 patients with OSA, 36 (44.4%) were nonobese with a mean BMI of 26.62 ± 2.29 kg/m(2) and 45 (55.6%) were obese with a mean BMI of 35.14 ± 3.74 kg/m(2). Mean AHI per hour was significantly more in the obese than in the nonobese group (50.09 ± 29.49 vs. 24.36 ± 12.17, P<0.001). The use of one or more sedatives was more in nonobese as compared to obese (58.3% vs. 24.4%, P=0.002). The obese group had significantly higher desaturation and arousal index (P 0.001). The minimal oxygen saturation was lower in the obese than the nonobese group (68.5 ± 13.00 vs. 80.3 ± 7.40, P 0.001) and was well below 90% in both groups. Overall, the OSA in nonobese patients was mild-to-moderate as compared to that of the obese and no significant differences were observed between them as regard to age, gender, mean neck circumference, excessive daytime sleepiness, adenoid or tonsillar enlargement, smoking, and remaining polysomnographic parameters. Obstructive sleep apnea can occur in nonobese persons though with less severity as compared to obese leading to a concept that OSA is not restricted to obese persons only and there is a high demand of its awareness regarding evaluation, diagnosis, and management in such individuals.
    Full-text · Article · Mar 2012
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    • "These features can contribute to narrowing of the upper airway inlet and an increase in collapsibility of the pharyngeal muscle (9-11). In obese patients, upper airway narrowing by soft tissue enlargement may be mainly associated with the development or aggravation of SDB, while in non-obese patients craniofacial bony abnormalities may be primarily related with SDB (12). "
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    ABSTRACT: Anthropometric abnormalities of the mandible and neck may contribute to snoring in non-obese Asians. The study evaluated the clinical implications of mandible and neck measurements in non-obese Asian snorers. The external mandible and neck measurements (neck circumference, two lengths of neck, mandibular body angle, and lengths of mandibular ramus and body) were compared between snorers and non-snorers in a sample of 2,778 non-obese Koreans (1,389 males, 1,389 females) aged 40 to 69 years (mean, 48.47±7.72 years). The overall prevalence of snoring was 64.7% (899/1,389) and 48.3% (671/1,389) in non-obese male and female subjects, respectively. In non-obese males, snorers had significantly a greater neck circumference (P<0.0001) and shorter mandibular body length (P=0.0126) than non-snorers. In non-obese females, snorers had significantly greater neck circumferences (P=0.0165), compared with non-snorers. However, there were no statistically significant differences in other variables between non-snorers and snorers. Anthropometric abnormalities of the mandible and neck, including thick neck circumference in both genders and small mandible size in males, may be relevant contributing factors to snoring in non-obese Asian snorers.
    Full-text · Article · Mar 2011 · Clinical and Experimental Otorhinolaryngology
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    • "A previous study has reported that OSA patients showed a significant correlation between an increased MP-H distance and a higher AHI (22). However, another study reported that the difference in the position of the hyoid bone in non-obese and obese OSA patients was not significant, and that in obese patients upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnea (10). In our study, inferior shift of the hyoid bone, reflected by increased MP-H, was significantly associated with obesity. "
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    ABSTRACT: We investigated difference of parameters of polysomnography, cephalometry and dynamic multi-detector computerized tomography (MD-CT) in wake and sleep states according to obesity. We evaluated 93 patients who underwent polysomnography and cephalometry. MD-CT was performed in 68 of these 93 patients. Fifty-nine and 34 patients were classified as obese and non-obese, with obesity defined as BMI ≥25. Cephalometry results were analyzed for 12 variables. Using the MD-CT, we evaluated dynamic upper airway morphology in wake and sleep states and divided the upper airway into four parts named as high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). A minimal cross sectional area (mCSA) and collapsibility index (CI) were calculated for each airway level. Diastolic blood pressure (P=0.0005), neck circumference (P<0.0001), and apnea-hypopnea index (P<0.0001) were statistically significantly different between the obese and non-obese group. Among 12 cephalometric variables, there was a significant difference in only the distance from mandibular plane to hyoid bone (P=0.003). There was statistical difference in CI of HRG and LRG in sleep state (P=0.0449, 0.0281) but no difference in mCSA in wake and sleep states. The obese group had more severe sleep apnea than the non-obese group. We believe that the increased severity of apnea in the obese group may be have been due to increased collapsibility of the upper airway rather than decreased size of the upper airway.
    Full-text · Article · Sep 2010 · Clinical and Experimental Otorhinolaryngology
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