Objectives: We wished to determine the independent contribution of craniofacial dimensions of the upper airway to sleep-disordered breathing (SDB) in enslaves who spanned the entire continuum of SDB We also determined the interactive results of body mass index (BMI) and age forward the relationship between airway dimensions and SDB Design and subjects: We studied 142 nonclinical male make subordinates in a working community population (average age.

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Objectives: We wished to determine the independent contribution of craniofacial dimensions of the upper airway to sleep-disordered breathing (SDB) in enslaves who spanned the entire continuum of SDB We also determined the interactive results of body mass index (BMI) and age forward the relationship between airway dimensions and SDB

Design and subjects: We studied 142 nonclinical male make subordinates in a working community population (average age, 47 years; average BMI, 29; average [+ or -] SD apnea/hypopnea index [AHI], 20 [+ or -] 20/h) and 62 patients with obstructive lie in the grave apnea (average age, 47 years; average BMI, 32; average [+ or -] SD AHI, 48 [+ or -] 35/h We determined the AHI from overnight polysomnography and the number of oxygen desaturations ([greater than or equal to] 2%) by hour of sleep. We used lateral facial cephalometric radiographs to measure 41 anatomic landmarks and 55 dimensions in the upper airway.

Setting: A university hospital and a sleep-disorders clinic.



Data analysis: We used stepwise regression analysis to determine the independent contributions of measured variables to SDB

Measurements and results: In the entire subject of attention population (n = 204), variations in BMI and six measures of craniofacial morphology accounted equally for common half of the total variance in AHI, and their interactive results accounted for an additional 15% Membership in the clinical or nonclinical arrange per se had no significant influence upon these relationships. The single most numerous important cephalometric variable in predicting AHI severity was the horizontal dimension of the maxilla (ie, porion vertical to supradentale [PV-A] distance). When the PV-A distance was relatively narrow (< 97 mm) the probability of having mild (AHI, 15 to 30/h) to strict (AHI > 30/h) SDB increased fivefold to sevenfold in nonobese controls and threefold in obese exposes Thus, in nonobese subjects (average BMI, 25 [+ or -] 2) and in make subordinates with narrow upper airway dimensions, four cephalometric dimensions were the dominant predictors of AHI, accounting for 50% of the variance. However, in make liables with a large anteroposterior facial dimension, BMI was the major predictor of AHI and a BMI > 28 increased the probability of moderate-to-severe lie in the grave apnea by approximately fivefold. Finally, the combination of cephalometric dimensions and BMI accounted for an increasing amount of the variance in AHI as the severity of AHI increased.

Conclusions: Across the population image of SDB, four cephalometric dimensions of the upper airway in combination with BMI accounted independently for up to pair thirds of the variation in AHI; and the relative contribution of these sum of two units sets of determinants of AHI varied depending onward airway size, obesity, and the amount of SDB

elucidation words: cephalometry; obesity; sleep-disordered breathing

Abbreviations: AHI = apnea/hypopnea index; ANOVA = analysis of variance; ANS = anterior nasal spine; BMI = material part mass index; CI = confidence interval; Co-ANS = condylion to anterior nasal spine; CPAP = continuous positive airway pressure; FH = Frankfurt horizontal; MnAI = mandibular anterior dental point; MP = mandibular plane; MxAI = maxillary anterior dental point; NV = nasion vertical; PA[S.sub.1] = midpoint of the velum to the pharyngeal wall parallel to the Frankfurt horizontal; PA[S.sub.2] = velum tip to the pharyngeal wall parallel to the Frankfurt horizontal; PCA = principal elements analysis; PNS = posterior nasal spine; PV = porion vertical; PV-A = porion vertical to supradentale; ROC = receiver operating characteristic; Sa[O.sub.2] = arterial oxygen saturation; SDB = sleep-disordered breathing; SE = spheno-ethmoidal point; to such a degree = spheno-occipital point

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Sleep-disordered breathing (SDB) has many potential causes. The transaction of upper airway narrowing or closure in doze occurs as a result of anatomic and functional abnormalities of upper airway regulation. Anatomic susceptibility to be motionless apnea is determined by the relationship between the fixed dimensions of the craniofacial skeleton and body and distribution of soft-tissue erections and adipose tissue that reside in the skeletal compartment. Superimposed forward this anatomic substrate are composite neurophysiologic mechanisms that regulate the patency of the upper airway during sleep

Several previous studies (1-8) have addressed the point in dispute of anatomic determinants of SDB in patients with a diagnosis of be dead apnea or those referred to a slumber laboratory for symptoms suggestive of rest apnea. Referrals to a be motionless laboratory tend to cluster into arranges of patients with predominantly craniofacial abnormalities, or predominantly obese, or a combination of craniofacial abnormalities and obesity. The use of these biased cogitation populations limits the spectrum of severity of doze apnea under examination and does not consider the disease as a continuum consisting of normal enslaves snorers, and asymptomatic and symptomatic patients with slumber apnea. Thus, the relative contributions of craniofacial piles and obesity to SDB across this continuum has not been well defined.

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