Sedentary Behavior and Obesity in a Large Cohort of Children

The purpose of this study was to examine the association between sedentary behavior and obesity among 12‐year‐old children, while adjusting for moderate‐to‐vigorous physical activity (MVPA) and other potential confounding variables. Cross‐sectional analyses were carried out with data from 5,434 children who participated in the Avon Longitudinal Study of Parents and Children (ALSPAC). Fat mass was derived using dual‐energy X‐ray emission absorptiometry, and height and weight measurements were used to calculate BMI (kg/m²). The children wore an accelerometer for 7 days. The cut points for sedentary behavior and MVPA were ≤199 and ≥3,600 counts per minute (cpm), respectively. Logistic regression analyses were performed to estimate odds ratios (ORs), adjusting for potential confounders of physical activity that included gender, social factors, early life factors, and maturation. The minimally adjusted association between sedentary behavior and obesity was positive, OR = 1.18 (1.08, 1.28). After adjusting for the series of potential confounders of physical activity the positive association remained, OR = 1.32 (1.14, 1.53). The crude association between 15 min of MVPA per day and obesity was negative, OR = 0.54 (0.48, 0.62). When 15 min of MVPA per day was additionally controlled for in the models, the positive associations between sedentary behavior and obesity were negated. Sedentary behavior was positively associated with obesity in the 12‐year‐old children, but this association was not independent of MVPA; low levels of MVPA among the sedentary children increased the odds of obesity. These findings support the importance of specifically engaging in MVPA during childhood to reduce the prevalence of obesity.     

Weight History in Clinical Practice: The State of the Science and Future Directions

Eliciting a weight history can provide clinically important information to aid in treatment decision‐making. This view is consistent with the life course perspective of obesity and the aim of patient‐centered care, one of six domains of health care quality. However, thus far, the value and practicality of including a weight history in the clinical assessment and treatment of patients with obesity have not been systematically explored. For these reasons, the Clinical Committee of The Obesity Society established a task force to review and assess the available evidence to address five key questions. It is concluded that weight history is an essential component of the medical history for patients presenting with overweight or obesity, and there are strong and emerging data that demonstrate the importance of life stage, duration of exposure to obesity, maximum BMI, and group‐based trajectory modeling in predicting risk for increased morbidity and mortality. Consideration of these and other patient‐specific factors may improve risk stratification and clinical decision‐making for screening, counseling, and management. Recommendations are provided for the key elements that should be included in a weight history, and several needs for future clinical research are outlined.     

Circadian Variations in Blood Coagulation Parameters, Alpha-Antitrypsin Antigen and Platelet Aggregation and Retention in Clinically Healthy Subjects

Ten clinically healthy subjects (5 men and 5 women), 31 11 yrs of age, were studied at six timepoints (0800, 1200, 1600, 2000, 0000, 0400) distributed over a 1-week span. Circadian rhythms in platelet aggregation in response to adenosine diphosphate (ADP) and adrenalin (A), platelet adhesiveness measured as retention in a glass bead column, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, Factor VIII activity and alpha-1-antitrypsin antigen showed circadian rhythms. The plasma concentrations of plasminogen, alpha-2-macroglobulin, and antithrombin III (AT III) antigen, Factor V and fibrinogen degradation products showed no circadian rhythm by ANOVA or cosinor analysis. The phase relations of the rhythms of different coagulation parameters are of interest in the physiology and pathobiology of the coagulation-fibrinolytic system. The extent of the circadian rhythm (range of change) described is not of a magnitude to lead to diagnostic problems in the clinical laboratory. The timing of these rhythms, however, may determine transient risk states for thromboembolic phenomena, including myocardial infarction and stroke. Several but not all coagulation parameters suggest a transient state of hypercoagulability during the morning hours. The recognition of these rhythmic, and thus in the time of the occurrence predictable temporary risk states for thromboembolic phenomena, may lead to timed treatment and/or effective prevention.