Sleep Duration, Physical Activity, and Metabolic Syndrome for Adolescents
- PDF / 74,529 Bytes
- 2 Pages / 595.276 x 790.866 pts Page_size
- 24 Downloads / 201 Views
LETTER TO THE EDITOR
Sleep Duration, Physical Activity, and Metabolic Syndrome for Adolescents Tomoyuki Kawada, M.D., Ph.D.
# The Society of Behavioral Medicine 2013
I read the article by Countryman et al. with interest [1]. They analyzed the relationship among metabolic syndrome, sleep, and inflammation in combination with physical activity and aerobic fitness for pediatrics. They used two models to elucidate the relationship among several key factors. They set the average value of sleep duration and physical activity as predictors of metabolic syndrome and systemic inflammation, and peak VO2 was used as a mediator on the relationship in a structural equation model. They selected adolescents in cohorts 2 and 3, who had some elevated blood pressure and waist circumferences were also high from the data in their Table 1. They selected the majority of the sample from ethnic minorities, and the target adolescents had already suffered from cardiovascular risk. I fundamentally agree with their speculation that undesirable lifestyle and behavioral factors have a risk of metabolic syndrome in youth. But before accepting their conclusion, I have a query as follows. Their conclusion is difficult to accept because standardized coefficients were insignificant between sleep and metabolic syndrome or inflammation. Insignificant relationships were also observed between physical activity and both metabolic syndrome and inflammation. In addition, aerobic fitness as a mediator from sleep and physical activity, which was measured by peak VO2, showed significant, but not high standardized coefficients with sleep and physical activity. Significant and high standardized coefficients of aerobic fitness for metabolic syndrome or inflammation were observed in their study, and a strong correlation between metabolic syndrome and inflammation showed that sleep and physical activity were not core predictors of metabolic syndrome or inflammation. I understand that lifestyle factors such
as sleep and physical activity associate with pathophysiology of metabolic components, including inflammation, but their conclusion should be verified by more epidemiological evidences. Börnhorst et al. conducted a cross-sectional study and concluded the existence of an inverse relationship between sleep duration and body mass index (BMI) [2], and the serum insulin significantly attenuated the association between sleep duration and BMI. Sung et al. reported that there was no significant association between sleep duration and homeostatic model assessment of insulin resistance in obese adolescents [3]. These reports also recommend further study if insulin resistance becomes a mediator of the association between sleep and obesity. I previously conducted a 3-year follow-up study on the effect of habitual exercise on the metabolic syndrome [4], presenting insignificant odds ratio (95 % confidence interval) of 0.90 (0.66–1.2). I also conducted a cross-sectional study on the association between metabolic syndrome and lifestyle factors [5]. In this study for male ad
Data Loading...
