REOLOGÍA SANGUÍNEA Y RIESGO CARDIOVASCULAR

REOLOGÍA SANGUÍNEA Y RIESGO CARDIOVASCULA

Associations between positive and negative social media experiences and sleep disturbance among young adults

Objectives: We sought to examine the association of positive and negative experiences using social media (SM) and sleep disturbance in a national survey of U.S. young adults. Methods: Experiences using SM were assessed with 2 items asking participants about the percentage of time using SM that involved a negative/positive experience that they were personally involved in. Sleep disturbance was assessed using the validated PROMIS 4-item short form. Ordinal logistic regression was used to examine associations between positive and negative SM experiences and high sleep disturbance, while controlling for relevant covariates. Results: Although reporting high levels of negative experiences was significantly associated with greater odds of high sleep disturbance (AOR = 1.49, 95%CI = 1.18-1.89), reporting high levels of positive experiences was not associated with sleep disturbance. Conclusions: These findings suggest that more robust examinations of negative SM experiences—especially as they relate to sleep disturbance—may be warranted

The association between social media use and sleep disturbance among young adults

Introduction: Many factors contribute to sleep disturbance among young adults. Social media (SM) use is increasing rapidly, and little is known regarding its association with sleep disturbance. Methods: In 2014 we assessed a nationally representative sample of 1788 U.S. young adults ages 19-32. SM volume and frequency were assessed by self-reported minutes per day spent on SM (volume) and visits per week (frequency) using items adapted from the Pew Internet Research Questionnaire. We assessed sleep disturbance using the brief Patient-Reported Outcomes Measurement Information System (PROMIS®) sleep disturbance measure. Analyses performed in Pittsburgh utilized chi-square tests and ordered logistic regression using sample weights in order to estimate effects for the total U.S. population. Results: In models that adjusted for all sociodemographic covariates, participants with higher SM use volume and frequency had significantly greater odds of having sleep disturbance. For example, compared with those in the lowest quartile of SM use per day, those in the highest quartile had an AOR of 1.95 (95% CI = 1.37-2.79) for sleep disturbance. Similarly, compared with those in the lowest quartile of SM use frequency per week, those in the highest quartile had an AOR of 2.92 (95% CI = 1.97-4.32) for sleep disturbance. All associations demonstrated a significant linear trend. Discussion: The strong association between SM use and sleep disturbance has important clinical implications for the health and well-being of young adults. Future work should aim to assess directionality and to better understand the influence of contextual factors associated with SM use

El músculo liso vascular de las grandes arterias: ¿sitio de control local de la función de amortiguamiento arterial?

Introducción y objetivos. Determinar la viscosidad y elasticidad de las arterias aorta y pulmonar y el efecto de la activación del músculo liso vascular sobre la capacidad de amortiguamiento arterial. Material y método. En 6 ovejas anestesiadas se midieron la presión y el diámetro aórtico y pulmonar, en condiciones basales y de hipertensión: a) pasiva, mediante la oclusión mecánica vascular, y b) activa, mediante fenilefrina intravenosa. Se calcularon la elasticidad y viscosidad parietal y se caracterizó la capacidad de amortiguamiento: a) la parietal, mediante el cociente viscosidad/elasticidad, y b) la global de cada circuito mediante la constante de tiempo de descenso de la presión arterial diastólica. Resultados. La viscoelasticidad aórtica fue mayor que la pulmonar (p < 0,05), mientras que ambas arterias tuvieron un amortiguamiento parietal similar. El circuito sistémico presentó un mayor amortiguamiento global (p < 0,05). Durante la hipertensión pasiva se produjo un aumento significativo de la elasticidad sin cambios en la viscosidad, lo que determinó una reducción significativa del amortiguamiento parietal, mientras que el amortiguamiento global de cada circuito disminuyó significativamente. En la hipertensión activa aumentó la viscosidad (p < 0,05), mientras que el amortiguamiento parietal y global recuperaron los valores basales. Conclusiones. La aorta presentó mayor viscoelasticidad que la arteria pulmonar, con un amortiguamiento parietal similar. El amortiguamiento global sistémico fue mayor que el pulmonar. Mientras que la elasticidad depende de la presión intravascular, la viscosidad es un marcador de la activación muscular. La activación muscular resultaría beneficiosa para el sistema cardiovascular, al mantener las funciones de amortiguamiento parietal y global