A study of the relationship between physical activity and cardiovascular fitness and coronary heart disease risk factors in female adolescents

The association of measures of physical activity with coronary heart disease (CHD) risk factors in children, especially those for atherosclerosis, is unknown. The purpose of this study was to determine the association of physical activity and cardiovascular fitness with blood lipids and lipoproteins in pre-adolescent and adolescent girls. The study population was comprised of 131 girls aged 9 to 16 years who participated in the Children\u27s Nutrition Research Center\u27s Adolescent Study. The dependent variables, blood lipids and lipoproteins, were measured by standard techniques. The independent variables were physical activity measured as the difference between total energy expenditure (TEE) and basal metabolic rate (BMR), and cardiovascular fitness, VO\rm\sb{2max}(ml/min/kg). TEE was measured by the doubly-labeled water (DLW) method, and BMR by whole-room calorimetry. Cardiovascular fitness, VO\rm\sb{2max}(ml/min/kg), was measured on a motorized treadmill. The potential confounding variables were sexual maturation (Tanner breast stage), ethnic group, body fat percent, and dietary variables. A systematic strategy for data analysis was used to isolate the effects of physical activity and cardiovascular fitness on blood lipids, beginning with assessment of confounding and interaction. Next, from regression models predicting each blood lipid and controlling for covariables, hypotheses were evaluated by the direction and value of the coefficients for physical activity and cardiovascular fitness. The main result was that cardiovascular fitness appeared to be more strongly associated with blood lipids than physical activity. An interaction between cardiovascular fitness and sexual maturation indicated that the effect of cardiovascular fitness on most blood lipids was dependent on the stage of sexual maturation. A difference of 760 kcal/d physical activity (which represents the difference between the 25th and 75th percentile of physical activity) was associated with negligible differences in blood lipids. In contrast, a difference in 10 ml/min/kg of VO\rm\sb{2max} or cardiovascular fitness (which represents the difference between the 25th and 75th percentile in cardiovascular fitness) in the early stages of sexual maturation was associated with an average positive difference of 15 mg/100 ml ApoA-1 and 10 mg/100 ml HDL-C

Influences On Fruit and Vegetable Consumption by Low-Income Black American Adolescents

Objective: The purpose of this study was to identify personal, behavioral, and environmental factors influencing fruit and vegetable consumption among 10- to 13-year-old low-income black American youth in the lower Mississippi Delta region. Social Cognitive Theory, along with other theoretical constructs, guided focus group questions and analysis. Design: A qualitative study using focus group methodology. Setting: Enrichment program of a sports summer camp for low-income youth. Participants: Forty-two adolescents (21 female, 21 male) participated in 6 focus groups. Main Outcome Measures: Personal, behavioral, and environmental influences on fruit and vegetable consumption. Analysis: Content analysis methods were used by 3 independent reviewers to identify themes within the focus group transcripts. Themes were summarized and then categorized into the 3 domains of Social Cognitive Theory. Results: The major themes were taste, availability, extended family influence, visual proof of the benefits of fruit and vegetable consumption, and the need for gender-specific behavioral skills. Conclusions and Implications: This formative research will aid in the development of a culturally relevant nutrition intervention for low-income black American adolescents in the lower Mississippi Delta region. The results indicate that this group is more likely to respond to interventions that use role models who can provide proof that fruit and vegetable consumption is related to improved health

Child Health-Related Quality of Life and Household Food Security

Objective To examine the association of household food insecurity with child self- or proxy-reported health-related quality of life (HRQOL). Design Cross-sectional telephone survey from January 1, 2000, through June 30, 2000. Participants Three hundred ninety-nine children who live in 36 counties of the Delta region of Arkansas, Louisiana, and Mississippi. Main Outcome Measures Household food insecurity status was measured using the US Household Food Security Scale. Child HRQOL was measured by the Pediatric Quality of Life Inventory, QL version 4.0. Analysis Summary statistics, linear and logistic regressions, incorporating survey weights, performed with SUDAAN version 8. Results Household food insecurity was significantly associated with total child HRQOL (P\u3c.05) and physical function (P\u3c.05), adjusted for child age, ethnicity, gender, and family income. Children aged 3 through 8 years in food insecure households were reported by parents to have lower physical function (P = .001), while children aged 12 through 17 years reported lower psychosocial function (P = .007). Black males in food insecure households reported lower physical function (P\u3c.05) and lower total HRQOL (P\u3c.05). Conclusions Children who live in food insecure households have poorer HRQOL. The effect on physical or psychosocial function may differ by age, ethnicity, and gender. Food security should be considered an important risk factor for child health