Suchergebnisse

Purpose. Investigate the relationship between body mass and hip bone mineral density (BMD) and the extent to which this association is influenced by potential mediating factors. Design. Cross-sectional. Setting. Approximately 20 cities in Utah and Wyoming. Subjects. Subjects were 262 apparently healthy, nonsmoking females. Measures. Hip BMD was assessed using dual energy X-ray absorptiometry. Physical activity (PA) was measured objectively using accelerometers. Calcium and vitamin D were measured using the Block food frequency questionnaire. Menopause status and bone drug use were measured using a questionnaire. Analysis. General linear models and partial correlations. Results. With body mass divided into three categories, hip BMD differed significantly across the groups in a dose-response manner: low mass (mean ± standard deviation [SD]), .876 ± .085 g/cm2; moderate, .932 ± .109 g/cm2; and high mass, .995 ± .112 g/cm2 (F = 21.5, p < .0001). The relationship between mass and hip BMD was not affected by differences in age, height, menopause status, calcium or vitamin D intake, PA, or use of bone prescription drugs. Conclusion. These findings suggest that women with low body mass tend to have low hip BMD and those with high mass tend to have high BMD. Controlling for the potential mediating variables did not influence the dose-response relationship between mass and BMD. It appears that lifestyle may not influence the body mass and BMD relationship, making it a challenge for women with low mass to avoid risk of low BMD.

Purpose. This study assessed the relationship between television viewing time and measured cardiorespiratory fitness and the influence of various potential confounders. Design. Cross-sectional. Setting. Intermountain West. Subjects. The sample was composed of 302 nonsmoking women aged 40.2 ± 3.0 years, with ∼90% Caucasian and 82% married. Measures. TV viewing was assessed by using a questionnaire, and cardiorespiratory fitness was measured by using a graded, maximum treadmill test. Physical activity (PA) was evaluated by using accelerometers for 7 days, and body fat percentage (BF%) was measured by using the Bod Pod. Analysis. Analysis of variance and partial correlation. Results. VO2max of Frequent (≥3 h/d) TV viewers (32.6 ± 6.4 mL/kg/min) was significantly lower than that of both Moderate (1–2 h/d) (36.2 ± 7.2 mL/kg/min) or Infrequent (<1 h/d) (36.5 ± 6.5 mL/kg/min) viewers (F= 8.0, p = .0004). The Infrequent and Moderate groups did not differ in VO2max. Age, education, body mass index, and season of assessment had no influence on the relationship when controlled statistically. Adjusting for PA (F = 4.2, p = .0157) and BF% (F = 5.0, p = .0071) weakened the relationship by 59% and 58%, respectively, but the relationships remained significant. After controlling for both PA and BF% simultaneously (F = 2.9, p = .0572), the relationship was weakened by 81% and was only borderline significant. Conclusion. Female Frequent TV viewers have significantly lower cardiorespiratory fitness levels than Moderate or Infrequent viewers. This association appears to be largely a function of differences in levels of PA and BF%.

Purpose. To identify independent patterns of diet using factor analysis to determine the extent to which dietary patterns account for differences in body fat percentage (BF%) and body mass index (BMI). Also, to ascertain the extent to which the associations are influenced by age, education, menopause, energy intake, and physical activity. Design. Study design was cross-sectional. Setting. Study setting was approximately 20 cities in the Mountain West. Subjects. The study included 281 apparently healthy female nonsmokers. Measures. Diet was assessed using 7-day weighed food records, and foods were categorized using the American Diabetes and American Dietetic Associations Exchange Lists and expressed as servings per 1000 kcal. BF% was measured using the Bod Pod, and physical activity was estimated using accelerometers worn for 1 week. Analysis. We used factor analysis, general linear models, and partial correlations. Results. Three dietary patterns were identified: (1) Prudent Pattern, (2) Low-fat Milk, and (3) Meat. Higher consumption of the Prudent Pattern corresponded with significantly lower BF% (F = 8.5, p = .0038) and BMI (F = 4.4, p = .0363). The Low-fat Milk pattern was inversely related to BF% (F= 5.4, p = .0207) and BMI (F= 9.5, p = .0023). Higher intake of the Meat pattern was related to higher levels of BF% (F= 4.5, p= .0346) and BMI (F= 4.2, p = .0418). Conclusion. These findings support an association between dietary patterns and body composition. Dietary patterns reflect the complex interrelationships inherent in day-to-day eating and are strongly related to differences in BF% and BMI in women.

Purpose. Examine the association between soft drink consumption and risk of weight gain over 4 years. Also, determine if the relationship between soft drink intake and weight gain is a result of differences in calorie intake or physical activity (PA), or other potential mediating factors. Design. Four-year prospective cohort. Setting. Approximately 20 cities in Utah and Wyoming. Subjects. One hundred seventy nonsmoking, apparently healthy women. Measures. At baseline, soft drink consumption and menopause status were measured using a questionnaire; calorie intake was estimated using 7-day, weighed food records; and PA was assessed using 7-day accelerometer data. Weight was assessed using an electronic scale at baseline and follow-up. Analysis. Multiple regression and partial correlation. Results. Four-year weight gain in participants who, at baseline, consumed sugar-sweetened soft drinks (2.7 ± 5.1 kg) was greater than in participants who consumed artificially sweetened soft drinks (–.1 ± 4.4 kg) or no soft drinks (.5 ± 5.1 kg) (F = 5.4, p = .022). Adjusting for objectively measured PA had no effect on risk of weight gain. However, controlling statistically for differences in calorie intake significantly weakened the relationship between soft drink consumption and weight gain by 28%. Conclusion. Consuming artificially sweetened soft drinks or no soft drinks instead of sugar-sweetened soft drinks may help to reduce risk of weight gain in women. The relationship appears to be partly a function of differences in calorie intake, but not differences in PA.

Purpose. To determine the effect of two jumping programs on hip bone mineral density (BMD) in women. Design. Randomized controlled trial. Setting. Approximately 20 cities in the Mountain West. Subjects. Sixty premenopausal women, aged 25 to 50 years, completed the intervention. Intervention. Subjects were randomly assigned to a control group or one of two jumping groups. The Jump 10 group performed 10 jumps with 30 seconds rest between jumps, twice daily for 16 weeks, while the Jump 20 group performed the same protocol but with 20 jumps. Measures. Hip BMD was measured by using dual-energy x-ray absorptiometry. Analysis. Analysis of variance and covariance. Results. At 8 weeks, unadjusted percentage change in hip BMD was significantly different among groups (F = 5.4, p = .0236). Specifically, compared with controls, the Jump 20 women had significantly greater gains in hip BMD and the Jump 10 women had marginally greater improvements. Following 16 weeks of jumping, differences between the Jump 10 and the Jump 20 groups compared with controls were significant (F = 4.2, p = .0444), especially after adjusting for the covariates (F = 7.3, p = .0092). Conclusion. After 16 weeks of high-impact jump training, hip BMD can be improved in premenopausal women by jumping 10 or 20 times, twice daily, with 30 seconds of rest between each jump, compared with controls.

Purpose. To determine the extent to which objectively measured intensity of physical activity (PA) predicts change in body fat (BF%) in women. Design. Prospective cohort study of PA intensity and body composition in middle-aged women. Setting. The study took place in a metropolitan Mountain West community. Subjects. Two hundred and twenty-eight women participated in two assessment periods separated by 20 months. Measures. Each assessment period consisted of seven consecutive days of monitoring, followed by body composition testing. Analysis. The general linear model using partial correlations and Mantel-Haenszel χ2 tests were performed. Results. At baseline and follow-up, women who participated in vigorous PA were leaner than women who participated in moderate or light PA (p < .05). Longitudinal results indicated that a greater proportion of women who decreased PA intensity over the 20 months also increased BF% (66%), compared to participants who increased or maintained PA intensity (47%) (p < .05). Conclusions. PA intensity seems to play a role in long-term weight maintenance. Reducing PA intensity increases the risk of BF% gain in women. Efforts to help women maintain PA intensity along with other weight management strategies may prove beneficial in preventing unwanted body fat gain in middle-aged women.

Purpose. To assess a single-semester university general education (GE) health and wellness course influence on physical activity (PA) and dietary habits among university students and to compare the course delivered through lecture or online for these outcomes. Design. A 15-week intervention with pre-post one-group design, allowing for comparative assessments in dietary and PA habits across time by delivery method (classroom lecture vs. online). Setting. A large Western university. Participants. Participants (n = 1638, female; n = 1333, male) were 82% university freshman or sophomores. Intervention. Participants were required to take a GE health and wellness course either by classroom lecture or online. The lecture and online curriculum content were similar. Participation in the study was entirely voluntary and was not connected to course grade. Measures. PA and dietary outcomes were determined from questions used in the Behavioral Risk Factor Surveillance System survey and were assessed pre- and post-intervention. Other validated questions were used to assess fitness. Analysis. The general linear model was utilized to determine group x period interactions when comparing the classroom lecture vs. online course. Results. Students improved overall level of PA by 12%, daily minutes of moderate-intensity PA by 8%, and fitness level by 2%. Students improved fruit/vegetable consumption by 4%, bran/whole grain cereal consumption by 8%, and brown rice/whole wheat bread consumption by 11%. All improvements were statistically significant (p < .001) with percent values indicating the size of the effect. The classroom lecture course yielded stronger improvements in several PA and dietary outcomes than the online course. Conclusions. A single-semester university wellness course may positively influence multiple PA and dietary behaviors; however, classroom lecture may be superior to online delivery.

Purpose. The purpose of this study was to examine the relationship between sleep patterns and adiposity in young adult women. Design. Cross-sectional. Setting. The study took place at two Mountain West region universities and surrounding communities. Subjects. Subjects were 330 young adult women (20.2 ± 1.5 years). Measures. Sleep and physical activity were monitored for 7 consecutive days and nights using actigraphy. Height and weight were measured directly. Adiposity was assessed using the BOD POD. Analysis. Regression analysis, between subjects analysis of variance, and structural equation modeling were used. Results. Bivariate regression analysis demonstrated that sleep efficiency was negatively related to adiposity and that the 7-day standard deviations of bedtime, wake time, and sleep duration were positively related to adiposity (p < .05). Controlling for objectively measured physical activity strengthened the relationship between sleep duration and adiposity by 84% but had a statistically negligible impact on all other relationships that were analyzed. However, multivariate structural equation modeling indicated that a model including sleep efficiency, sleep pattern inconsistency (latent variable consisting of the 7-day standard deviations of bedtime, wake time, and sleep duration), and physical activity was the best for predicting percent body fat. Conclusion. Inconsistent sleep patterns and poor sleep efficiency are related to adiposity. Consistent sleep patterns that include sufficient sleep may be important in modifying risk of excess body fat in young adult women.