Comparing physical activity questionnaires for youth: seasonal vs annual format.

BACKGROUND: In large cohort studies of older children, self-report is the only practical way to assess physical activity. Assessing usual activity over the entire year is desirable, but children and adolescents may overestimate activities with high seasonal variability. Use of questionnaires in which individuals report each activity by season may improve accuracy. METHODS: A total of 6782 girls and 5110 boys, aged 9-14 years in 1996, completed self-administered activity questionnaires in 1996 and in 1997. In 1996, participants reported the average time spent in each of 17 activities during the previous 12 months; in 1997, we also asked for the average time spent in the previous year, but within each of the four seasons. RESULTS: Girls reported a median of 12.8 hours/week total activity in 1996 and 10.4 hours/week in 1997. For boys, the estimates were 15.5 hours/week and 13.4 hours/week, respectively. Girls and boys within 1-year age strata (e.g., comparison of 10-year olds in 1996 with 10-year olds in 1997) reported an average of 3.7 and 3.1 fewer hours per week, respectively, on the 1997 seasonal format versus the 1996 annual format questionnaire. In longitudinal analyses, the difference between the annual and the seasonal estimates was greater if participants did the activity in fewer seasons in 1997. CONCLUSIONS: In comparison to an annual format questionnaire, a seasonal format questionnaire may improve accuracy of self-report of physical activity by reducing over-reporting of activities in which pre-adolescents and adolescents engage in fewer seasons.

Weight concerns, weight control behaviors, and smoking initiation.

OBJECTIVE: To examine the cross-sectional relationships between weight concerns, weight control behaviors, and initiation of tobacco use among youths. STUDY DESIGN: Smoking status, weight concerns, and weight control behaviors were assessed in a cross-sectional sample of 16 862 children, 9 to 14 years of age, in 1996. Logistic regression was used to examine the relationship between weight concerns, weight control behaviors, and early stages of smoking initiation (precontemplation, contemplation, and experimentation). All analyses were adjusted for age, body mass index, and known predictors of initiation. RESULTS: Approximately 9% of participants had experimented with cigarettes, and 6% were contemplating cigarette smoking. Contemplation of tobacco use was associated with misperception of being overweight (boys: odds ratio [OR], 1.65; 95% confidence interval [CI], 1.10-2.48), unhappiness with appearance (girls: OR, 2.05; 95% CI, 1.48-2.84; boys: OR, 1.60; 95% CI, 1.05-2. 42), and a tendency to change eating patterns around peers (girls: OR, 2.87; 95% CI, 2.28-3.62; boys: OR, 1.83; 95% CI, 1.25-2.66). Experimentation with cigarettes was associated with daily exercise to control weight among boys (OR, 1.92; 95% CI, 1.07-3.43) and with monthly purging (OR, 2.54; 95% CI, 1.27-5.07) and daily dieting among girls (OR, 1.79; 95% CI, 1.09-2.96). CONCLUSIONS: Our findings suggest that, among both girls and boys, contemplation of smoking is positively related to weight concerns. Experimentation seems to be positively related to weight control behaviors. It is important for both pediatricians and comprehensive school health programs to address healthy methods of weight maintenance and to dispel the notion of tobacco use as a method of weight control.

Reproducibility and validity of maternal recall of pregnancy-related events.

We assessed the reproducibility and validity of a questionnaire that asks mothers to recall pregnancy-related events from thirty or more years ago. Among 146 women who completed the questionnaire twice, responses were highly reproducible for pre-pregnancy height and weight (r = 0.95), pregnancy complications (r = 0.74), substance use (r = 0.80), preterm delivery (r = 0.82), birthweight (r = 0.94), and breastfeeding (r = 0.89). Among 154 women whose questionnaire responses were compared to data collected during their pregnancies, recall was highly accurate for height (r = 0.90), pre-pregnancy weight (r = 0.86), birthweight (r = 0.91), and smoking (sensitivity = 0.86, specificity = 0.94). These findings suggest that long-term maternal recall is both reproducible and accurate for many factors related to pregnancy and delivery.