Risk of Common Mental Disorders in Relation to Symptoms of Obstructive Sleep Apnea Syndrome among Ethiopian College Students

A narrative review of periodic breathing during sleep at high altitude: From acclimatizing lowlanders to adapted highlanders

Periodic breathing during sleep at high altitude is almost universal among sojourners. Here, in the context of acclimatization and adaptation, we provide a contemporary review on periodic breathing at high altitude, and explore whether this is an adaptive or maladaptive process. The mechanism(s), prevalence and role of periodic breathing in acclimatized lowlanders at high altitude are contrasted with the available data from adapted indigenous populations (e.g. Andean and Tibetan highlanders). It is concluded that (1) periodic breathing persists with acclimatization in lowlanders and the severity is proportional to sleeping altitude; (2) periodic breathing does not seem to coalesce with poor sleep quality such that, with acclimatization, there appears to be a lengthening of cycle length and minimal impact on the average sleeping oxygen saturation; and (3) high altitude adapted highlanders appear to demonstrate a blunting of periodic breathing, compared to lowlanders, comprising a feature that withstands the negative influences of chronic mountain sickness. These observations indicate that periodic breathing persists with high altitude acclimatization with no obvious negative consequences; however, periodic breathing is attenuated with high altitude adaptation and therefore potentially reflects an adaptive trait to this environment.

A Look into Obstructive Sleep Apnea among Ethiopians

Background

Obstructive Sleep Apnea (OSA) is prevalent throughout the world. However, there are currently limited data concerning the prevalence of OSA in populations that originate from developing countries; the prevalence of OSA is expected to rise in these countries. OSA is poorly characterized amongst Ethiopians, and our study is the first to describe clinical characteristics of OSA among Ethiopians.

Methods

We conducted a retrospective study of primarily Ethiopian patients at an internal medicine clinic in Rockville, Maryland. All patients (n=24) were evaluated for daytime sleepiness using the Epworth Sleepiness Scale (ESS) and received physical examinations and polysomnograms (PSG) by either portable monitoring (Itamar WatchPAT 200 device) or in-lab. Statistical analyses were performed in R.

Results

Linear regression model of Body-Mass Index (BMI) and Apnea-Hypopnea Index (AHI) indicated that for every 1-unit increase in BMI, there was a 0.8657-unit increase in AHI (p<0.05). Pearson's correlation coefficient indicateda positive linear relationship between BMI and AHI (0.47) (p<0.05). Adjusted linear regression model for AHI and oxygen saturation indicated that for every 1-unit increase of AHI, there was a 0.8452-unit decrease in nocturnal oxygen saturation (p<0.05). Pearson's correlation coefficient did not demonstrate significance between AHI and oxygen desaturation (p=0.062). Patients received either continuous positive airway pressure (CPAP) (n=15) or oral appliance therapy (n=3).

Conclusion

All patients who complied with therapy reported improved sleep quality, snoring resolution, and improved daytime alertness. Practitioners in developing countries should suspect OSA in the right clinical setting and offer diagnostic and therapeutic services when available.

Construct validity and internal consistency of three factor structures and two scoring methods of the 12-item General Health Questionnaire

Introducción. El análisis de las propiedades psicométricas de un instrumento reviste importancia para el control de sesgos en la medición.Objetivo. Comparar la validez de constructo y la consistencia interna de tres estructuras factoriales del cuestionario de salud general de 12 ítems.Materiales y métodos. Se hizo un estudio de validación en una muestra anidada de 483 estudiantes de odontología de Cartagena, Colombia. Además de las preguntas del instrumento, se hicieron otras sobre aspectos personales. Se evaluó la validez de constructo de la estructura unidimensional, de la unidimensional con corrección del sesgo de respuesta, y de la de dos y tres factores y sistemas de puntuación del tipo de la escala de Likert (0-1-2-3) y dicotómico (0-0-1-1). La validez se determinó con un análisis factorial confirmatorio y, la consistencia interna, con el coeficiente alfa de Cronbach para la escala de Likert y la fórmula 20 de Kuder-Richardson para el método dicotómico empleando los programas Stata™, versión 13.2 (Stata Corp, USA) y Mplus™, versión 7.11 (Muthen and Muthen, USA).Resultados. Los índices de ajuste revelaron que el mejor modelo era el unidimensional con corrección del sesgo de respuesta y puntación dicotómica (grados de libertad=36; ji al cuadrado=52,432; raíz cuadrada del error medio de aproximación=0,03; IC90% 0,008-0,048; índice comparativo de ajuste=0,982; índice de Tucker-Lewis=0,966). La consistencia interna fue de 0,70.Conclusiones. El ajuste del modelo obtenido en este estudio permitió controlar el sesgo de medición y, así, garantizar la validez externa de los resultados del uestionario de salud general de 12 ítems para la evaluación de las condiciones mentales en esta población. Las propiedades psicométricas de las escalas deben evaluarse críticamente antes del análisis de los resultados.