Philip R. Nader

The development of scales to measure social support for diet and exercise behaviors

The purpose of this study was to develop measures of perceived social support specific to health-related eating and exercise behaviors. In Study I, specific supportive and nonsupportive behaviors were identified through interviews with 40 individuals making health-behavior changes. In Study II, items derived from the interviews were administered to 171 subjects. Support from family and friends was assessed separately for both diet and exercise habits. Meaningful factors were identified for each of the four scales, and some factors were similar for family and friend scales. Both test-retest and internal consistency reliabilities were acceptable, and six factors can be used as subscales. Social support scales were correlated with respective self-reported dietary and exercise habits, providing evidence of concurrent criterion-related validity. A measure of general social support was not related to the specific social support scales or to reported health habits. These scales are among the first measures of social support behaviors specific to dietary- and exercise-habit change.

Moderate-to-vigorous physical activity from ages 9 to 15 years.

CONTEXT Decreased physical activity plays a critical role in the increase in childhood obesity. Although at least 60 minutes per day of moderate-to-vigorous physical activity (MVPA) is recommended, few longitudinal studies have determined the recent patterns of physical activity of youth. OBJECTIVE To determine the patterns and determinants of MVPA of youth followed from ages 9 to 15 years. DESIGN, SETTING, AND PARTICIPANTS Longitudinal descriptive analyses of the 1032 participants in the 1991-2007 National Institute of Child Health and Human Development Study of Early Child Care and Youth Development birth cohort from 10 study sites who had accelerometer-determined minutes of MVPA at ages 9 (year 2000), 11 (2002), 12 (2003), and 15 (2006) years. Participants included boys (517 [50.1%]) and girls (515 [49.9%]); 76.6% white (n = 791); and 24.5% (n = 231) lived in low-income families. MAIN OUTCOME MEASURE Mean MVPA minutes per day, determined by 4 to 7 days of monitored activity. RESULTS At age 9 years, children engaged in MVPA approximately 3 hours per day on both weekends and weekdays. Weekday MVPA decreased by 37 minutes per year [corrected], while weekend MVPA decreased by 39 minutes per year [corrected]. By age 15 years, adolescents were only engaging in MVPA for 50 minutes per weekday [corrected] and 36 minutes per weekend day [corrected]. Boys were more active than girls, spending 18 and 14 more minutes per day [corrected] in MVPA on the weekdays and weekends, respectively. The rate of decrease in MVPA was the same for boys and girls. The estimated age at which girls crossed below the recommended 60 minutes of MVPA per day was approximately 13.2 years for weekday [corrected] activity compared with boys at 14.9 years [corrected], and for weekend activity, girls crossed below the recommended 60 minutes of MVPA at 12.7 years [corrected] compared with boys at 13.6 years [corrected]. CONCLUSION In this study cohort, measured physical activity decreased significantly between ages 9 and 15 years.

Correlates of physical activity at home in Mexican-American and Anglo-American preschool children.

Twenty-two potential correlates of childrens physical activity were examined. Two hundred and one Mexican-American and 146 Anglo-American families with 4-year-old children were studied. Childrens physical activity was directly observed in the evening at home on 4 visits for 1 hr each time. Anglo-American children and male children were found to be more active. Demographic variables explained 11% of the variance in childrens physical activity. After adjusting for demographics, 3 childrens variables and 6 social-family variables did not account for significantly more variance. Five environmental variables accounted for 11% additional variance. Variables observed concurrently with physical activity, such as time spent outdoors and prompts to be active, were highly associated with childrens physical activity.

A Family Approach to Cardiovascular Risk Reduction: Results from The San Diego Family Health Project:

The effectiveness of a family-based cardiovascular disease risk reduction intervention was evaluated in two ethnic groups. Participants were 206 healthy, volunteer low-to-middle-income Mexican-American and non-Hispanic white (Anglo-American) families (623 individuals), each with a fifth or a sixth-grade child. Families were recruited through elementary schools. Half of the families were randomized to a year-long educational intervention designed to decrease the whole familys intake of high salt, high fat foods, and to increase their regular physical activity. Eighty-nine percent of the enrolled families were measured at the 24-month follow-up. Both Mexican- and Anglo-American families in the experimental groups gained significantly more knowledge of the skills required to change dietary and exercise habits than did those in the control groups. Experimental families in both ethnic groups reported improved eating habits on a food frequency index. Anglo families reported lower total fat and sodium intake. There were no significant group differences in reported physical activity or in tested cardiovascular fitness levels. Significant differences for Anglo-American experimental vs. control adult subjects were found for LDL cholesterol. Significant intervention-control differences ranging from 2.2 to 3.4 mmHg systolic and/or diastolic blood pressure were found in all subgroups. Direct observation of diet and physical activity behaviors in a structured environment suggested generalization of behavior changes. There was evidence that behavior change persisted one year beyond the completion of the intervention program. It is concluded that involvement of families utilizing school based resources is feasible and effective. Future studies should focus on the most cost-effective methods of family involvement, and the potential for additive effects when family strategies are combined with other school health education programs.

Home environmental influences on children's television watching from early to middle childhood.

ABSTRACT. Identifying correlates of children’s television (TV) watching could help identify strategies to reduce children’s TV watching and impact children’s weight status. Children’s TV time and home environment factors were assessed longitudinally among 169 families with children followed from 6 to 12 years of age. TV watching increased with age, as did the number of in-home TVs and the presence of videocassette recorders (VCRs), the frequency of meal eating while watching TV, and the percentage of children with bedroom TVs. Greater meal eating while watching TV was consistently related to overall TV watching and increases in TV watching over time. The number of in-home TVs and the presence of a bedroom TV were less consistent correlates. TV watching was related to weight status when children were younger, and when children were older, more than 2 hours of TV daily was a risk factor for higher weight. Modifying TV access, particularly by reducing the frequency of meals eaten while watching TV, could promote lower children’s TV watching and adiposity.

Family variables and physical activity in preschool children.

Correlates of the physical activity habits of preschool children were studied in a multiethnic sample. Physical activity levels of 33 low-income children were observed systematically during free-play periods at preschool. Children spent 58% of free-play time in sedentary activities (e.g., sitting), and were vigorously active only 11% of the time. Independent variables studied were child body mass index (BMI), teacher-rated Type A behavior, and parent-reported mother BMI, father BMI, parent vigorous activity, and family cardiovascular disease (CVD) risk. The multiple regression of moderate-intensity activity was significant, with family CVD risk, parent vigorous activity, and father BMI accounting for significant amounts of variance. The results suggest that the effects of parental role modeling on child physical activity levels may extend to free-play settings far beyond the confines of the home environment. J Dev Behav Pediatr 9:57–61, 1988. Index terms: physical activity, obesity, Type A, family, cardiovascular disease, behavior.

Aggregation of physical activity habits in Mexican-American and Anglo families

It is believed that families are important influences on the development of health habits, and the purpose of the present study was to examine the familial aggregation of physical activity. Physical activity habits were assessed by standardized interview in adults and children in 95 Anglo families and 111 Mexican-American families. The results indicated a moderate degree of aggregation of physical activity in both samples, and adjustment for body mass index was inconsequential. Intrafamily correlations tended to be higher in Mexican-Americans. Mother-child correlations usually were higher than father-child correlations. These findings support the hypothesis that the family is a significant influence on physical activity.

Anglo- and Mexican-American preschoolers at home and at recess: activity patterns and environmental influences.

Habitual physical activity in children is related to physical fitness and appears to mediate cardiovascular disease (CVD) risk factors. We studied the physical activity patterns and associated variables of a large bi-ethnic cohort of 4-year-old children from low to middle socioeconomic families. Trained observers coded the behavior of 351 children (150 Anglo-American, 201 Mexican-American; 182 boys, 169 girls) during two 60-minute home visits and two unstructured recesses lasting up to 30 minutes each at 63 different preschools, Findings indicated that although children were much less active at home, there were low but significant correlations between their activity patterns at home and during recess (r = .13). Children who had activity-promoting toys at home also tended to have them available during preschool recess (r = .20). Ethnic differences were evident for both activity and environmental variables. Mexican-American children were less active than Anglo children at home (p < .002) and during recess (p < .03), thus adding to the adult literature that has found Mexican-Americans to be less active than Anglos, and supporting to the notion that physical activity life-style habits may be established in early childhood. In both settings, Mexican-American children spent more time in presence of adults (home, p < .04; recess, p < .03) and had access to fewer active toys (home, p < .001; recess, p < .05). Gender differences were also evident for both activity and environmental variables. Boys were more active both at home (p < .01) and during recess (p < .01) and at home watched television more frequently (p < .005). These data indicated some subgroups of preschool children are more active than others, and the findings may be useful for pediatricians and educators responsible for developing physical activity promotion programs for young children. J Dev Behav Pediatr 13:173–180, 1992. Index terms: preschool children, physical activity, systematic observation.

Reliability and Validity of Self Report of Aerobic Activity: Family Health Project

Abstract Two studies are presented which deal with the reliability and validity of self-reports of aerobic activity. The first study compared two forms of self-report data obtained as part of a study of intervention strategy. The two forms were daily self-report and weekly retrospective report. Analyses covering the overlapping time period revealed differences in mean minutes engaged in activity, but modest and statistically significant correlations between the two forms among adults participating in the intervention group. No meaningful results were obtained among adults in the control group, nor among children in either group. The need for the development and testing of self-report forms among children was noted, and was the subject of the second study. In Study II, six different forms on which third to sixth grade children recorded their aerobic activity were compared against two days of continuous observations of their behavior. The six forms varied along two dimensions. The first dimension varied the...

The ecology of childhood overweight: a 12-year longitudinal analysis

Objective:To investigate ecological correlates of the development of overweight in a multisite study sample of children followed from age 2 to 12.Design:Longitudinal examination of covariates of overweight status throughout childhood, with covariates drawn from three ecological levels: sociocultural or demographic, quality of the childs home environment, and proximal child experience that could directly affect the balance between energy intake and energy expenditure.Subjects:A total of 960 children participating in a long-term longitudinal study provided growth data at least once; 653 of the children had complete data on covariates.Measurements:Height and weight measured seven times between ages 2 and 12 were converted to a body mass index (BMI) and entered into a latent transition analysis to identify patterns of overweight across childhood. Ecological correlates measured longitudinally included demographic characteristics obtained by maternal report, home environment quality obtained by observation and maternal report, and proximal child experience factors obtained by observation, maternal report and child report.Results:Four patterns of overweight were found: never overweight, overweight beginning at preschool age, overweight beginning in elementary school, and return to normal weight after being overweight at preschool age. The weight status groups differed on home environment quality and proximal child experience factors but not on demographics. Children overweight at preschool had less sensitive mothers than never overweight children. Children overweight at school age had fewer opportunities for productive activity at home than did never overweight children. School-age overweight children also watched the most TV after school. Multivariate logistic regression analyses further indicated the significance to childrens weight status of proximal child experience variables. Less physically active children and those who watched more television after school were more likely to become overweight. Results did not vary by child sex.Conclusion:The results support the idea that childhood overweight is multiply determined. The one potentially important and changeable factor identified as a target for intervention centers on how children spend their time, especially their after-school time. Children who are more physically active and spend less time watching TV after school are less likely to become overweight by age 12.