Independent and Combined Effects of Sex and Biological Maturation on Motor Coordination and Performance in Prepubertal Children.

Sex differences and maturation-associated variation in fitness and motor coordination were examined in children aged 8-9 years (n = 128, 67 girls). Assessments included stature and body mass, two-component body composition, percentage of predicted adult stature (as an index of biological maturation), and motor performance and coordination (Körperkoordinationstest für Kinder). Compared to girls, boys were less advanced in maturation status, possessed larger fat mass, demonstrated superior performances in six tests of fitness, and obtained one superior score on the Körperkoordinationstest für Kinder. After controlling for somatic maturation, sex differences persisted in the two multivariate domains: motor performance and motor coordination.

Physical activity and neighborhood resources in high school girls.

BACKGROUND: Physical activity behavior is influenced by a person's physical environment, but few studies have used objective measures to study the influences of the physical environment on physical activity behavior in youth. The purpose of this study was to examine the relationship between selected neighborhood physical activity resources and physical activity levels in high school girls. METHODS: Participants were students in schools that had participated in a large physical activity intervention trial. The 3-Day Physical Activity Recall was completed by 1506 12th-grade girls. Data on physical activity facilities and resources in the participating communities were collected using a variety of methods. Physical activity resources within a 0.75-mile street-network buffer around each girl's home were counted using ArcGIS, version 9.1. Mixed-model regression models were used to determine if there was a relationship between three physical activity variables and the number of physical activity resources within the 0.75-mile buffer. Data were collected in 2002-2003 and analyzed in 2006-2007. RESULTS: On average, 3.5 physical activity resources (e.g., schools, parks, commercial facilities) were located within the 0.75-mile street-network buffer. Thirty-six percent of the girls had no physical activity resource within the buffer. When multiple physical activity resources were considered, the number of commercial physical activity facilities was significantly associated with reported vigorous physical activity, and the number of parks was associated with total METs in white girls. CONCLUSIONS: Multiple physical activity resources within a 0.75-mile street-network buffer around adolescent girls' homes are associated physical activity in those girls. Several types of resources are associated with vigorous physical activity and total activity in adolescent girls. Future studies should examine the temporal and causal relationships between the physical environment, physical activity, and health outcomes related to physical activity.

Commercial venues as supports for physical activity in adolescent girls.

OBJECTIVE: The purposes of this study were to describe the types and availability of commercial facilities for physical activity (PA) in six diverse geographic areas (Washington DC and Maryland; South Carolina; Minnesota; Louisiana; Arizona; and California) and to assess the relationship between those facilities and the non-school PA of adolescent girls. METHODS: A total of 1556 6th grade girls participating in the Trial of Activity for Adolescent Girls (TAAG) wore accelerometers for 7 days providing 6 days of complete data, completed questionnaires in 2003 and had their residential addresses geocoded. Nearby commercial facilities available to provide PA (i.e. dance studios, youth organizations) within a 1-mile radius of participants' residences were identified and geocoded. The association between the presence of any commercial PA facility and girls' PA was determined using a multi-level design and controlling for demographic characteristics and other potential confounders. Analyses were conducted in 2005-2006. RESULTS: Sixty-eight percent of the girls had at least one commercial PA facility near their homes. Availability and types of commercial PA facilities differed by where participants lived. Girls who lived near one or more commercial PA facilities had higher non-school MET-weighted moderate-to-vigorous PA than girls who had none near their homes. CONCLUSIONS: The findings suggest that commercial PA facilities are important contributors to the accumulation of PA among adolescent girls.

Validation and calibration of an accelerometer in preschool children.

OBJECTIVE: Obesity rates in young children are increasing, and decreased physical activity is likely to be a major contributor to this trend. Studies of physical activity in young children are limited by the lack of valid and acceptable measures. The purpose of this study was to calibrate and validate the ActiGraph accelerometer for use with 3- to 5-year-old children. RESEARCH METHODS AND PROCEDURES: Thirty preschool children wore an ActiGraph accelerometer (ActiGraph, Fort Walton Beach, FL) and a Cosmed portable metabolic system (Cosmed, Rome, Italy) during a period of rest and while performing three structured physical activities in a laboratory setting. Expired respiratory gases were collected, and oxygen consumption was measured on a breath-by-breath basis. Accelerometer data were collected at 15-second intervals. For cross-validation, the same children wore the same instruments while participating in unstructured indoor and outdoor activities for 20 minutes each at their preschool. RESULTS: In calibrating the accelerometer, the correlation between Vo(2) (ml/kg per min) and counts was r = 0.82 across all activities. The only significant variable in the prediction equation was accelerometer counts (R(2) = 0.90, standard error of the estimate = 4.70). In the cross-validation, the intraclass correlation coefficient between measured and predicted Vo(2) was R = 0.57 and the Spearman correlation coefficient was R = 0.66 (p < 0.001). Cut-off points for moderate- and vigorous-intensity physical activity were identified at 420 counts/15 s (Vo(2) = 20 mL/kg per min) and 842 counts/15 s (Vo(2) = 30 mL/kg per min), respectively. When these cutpoints were applied to the cross-validation data, percentage agreement, kappa, and modified kappa for moderate activity were 0.69, 0.36, and 0.38, respectively. For vigorous activity, the same measures were 0.81, 0.13, and 0.62. DISCUSSION: Accelerometer counts were highly correlated with Vo(2) in young children. Accelerometers can be appropriately used as a measure of physical activity in this population.

Validation and calibration of the Actical accelerometer in preschool children.

PURPOSE: Decreased physical activity (PA) is likely a contributor to the rising prevalence of obesity in children. Lack of valid and acceptable measures of PA has been an issue in studies involving young children. The Actical accelerometer is a promising tool for measurement of PA in young children. The purpose of this study was to calibrate and validate the Actical accelerometer for use with 3- to 5-yr-old children. METHODS: Eighteen preschool children wore an Actical accelerometer and a Cosmed portable metabolic system during a period of rest, while performing three structured activities in a laboratory setting (used for calibration), and during 20 min each of unstructured indoor and outdoor activities at their preschool (used for cross-validation). Expired respiratory gases were collected, and oxygen consumption was measured on a breath-by-breath basis. Accelerometer data were collected in 15-s intervals. RESULTS: For the accelerometer calibration, the correlation between VO2 and counts was r = 0.89 across all activities. The calibration equation established was VO2 = counts x 15 s(-1) (0.01437) + 9.73 (R2 = 0.96, SEE = 3.02). The cut-point for moderate activity (20 mL x kg(-1) x min(-1)) was 715 counts x 15 s(-1) (sensitivity 97.2%, specificity 91.7%), and the cut-point for vigorous activity (30 mL x kg(-1) x min(-1)) was 1411 counts x 15 s(-1) (sensitivity 98.2%, specificity 61.1%). For the cross-validation, the intraclass correlation coefficient was R = 0.59 and the Spearman correlation coefficient was R = 0.80 (P < 0.001) between measured and predicted VO2. Percentage of agreement, kappa, and modified kappa for moderate activity were 0.73, 0.40, and 0.46, respectively. For vigorous activity, the same measures were 0.85, 0.26, and 0.71, respectively. CONCLUSION: The Actical accelerometer is a valid tool for measuring PA in young children.

Raloxifene is not associated with biologically relevant changes in hot flushes in postmenopausal women for whom therapy is appropriate.

OBJECTIVES: Raloxifene is approved for the treatment and prevention of postmenopausal osteoporosis. Previous studies have described a raloxifene-associated increase in hot flushes, reported as adverse events. This study was undertaken to provide a detailed evaluation of the potential of raloxifene to induce or exacerbate hot flushes in postmenopausal women. STUDY DESIGN: In this double-blind, placebo-controlled, parallel group multicenter study, 487 postmenopausal women were randomized to receive 8 months of treatment with either raloxifene (RLX) at the recommended dose of 60 mg/day, or by slow-dose escalation for the first 2 months, followed by the standard dose for the rest of the study (SDE), or placebo (PL). The frequency, duration, intensity, severity, and impact of hot flushes were measured. RESULTS: With 3-5 hot flushes per week, the mean number at baseline was low. During treatment, it increased by <1 hot flush/week in both active treatment groups and decreased by <1 hot flush/week with PL. The high proportion ( approximately 60%) of asymptomatic patients at baseline had increased further by the end of treatment in all groups. The proportion of women whose pre-existing hot flushes abated during treatment was significantly greater with SDE (P=.005) and PL (P=.050), but not with RLX, when compared with the proportion with treatment-emergent flushes. There were no statistically significant between-group differences in the distribution of the number of hot flushes after 2 months of treatment. At end point, there were no significant differences between SDE and either RLX or PL, but the difference between RLX and PL was statistically significant (P=.035). There were no significant between-group differences in the hot flush impact scores, in treatment satisfaction, and in the proportion of patients requesting symptomatic treatment to alleviate hot flushes. CONCLUSION: In a postmenopausal population meeting the criteria for the prescription of RLX, the overall effect of the drug on hot flushes is low. Previous studies using adverse event reports have overestimated the importance of hot flushes in postmenopausal women during treatment with RLX. Slow-dose escalation seems to decrease the number of symptomatic patients further and may be a useful strategy in women reporting flushes when starting RLX.

X-ray and deuterium labeling studies on the abnormal ring cleavages of a 5 beta-epoxide precursor of formestane.

A new convergent synthesis of the antitumor steroid formestane (4-OHA) 5 has been performed from the easily available epimeric mixture of 5 alpha- and 5 beta-androst-3-en-17-one 1a and 1b in order to attempt a yield improvement. A two-step oxidative route followed by base-catalyzed isomerization was applied to the 5 alpha- and 5 beta-epimers 1a and 1b, either as a mixture or separately, leading to the title compound 5. From epimer 1a an efficient process was attained to prepare the desired aromatase inhibitor formestane. Epimer 1b led to the formation of the same compound 5. Additionally, 1b have also been converted in 5 beta-hydroxyandrostane-3,17-dione 12 and androst-4-ene-3,17-dione 13, revealing an unexpected reactivity of the 3 beta,4 beta-epoxy-5 beta-androstan-17-one intermediate 6 formed from 1b during the first oxidative step with performic acid. Cleavage of the epoxide 6 led to the trans-diaxial and the trans-diequatorial vic-diols 7 and 8 and to the 1,3-diol 9. The formation of the abnormal products 8 and 9 were investigated through X-ray and deuterium labeling studies. Diol 8 was formed through a trans-diequatorial epoxide ring opening and the 1,3-diol 9 was formed through an intramolecular rearrangement involving a 1,2-hydride shift. All the vic-diols 3, 7 and 8 formed, proved to be good precursors for the synthesis of the target compound 5.