School-day and overall physical activity among youth.

BACKGROUND: Increasing school-day physical activity through policy and programs is commonly suggested to prevent obesity and improve overall child health. However, strategies that focus on school-day physical activity may not increase total physical activity if youth compensate by reducing physical activity outside of school. PURPOSE: Objectively measured, nationally representative physical activity data were used to test the hypothesis that higher school-day physical activity is associated with higher overall daily physical activity in youth. METHODS: Accelerometer data from 2003-2004/2005-2006 National Health and Nutrition Examination Surveys were analyzed in 2012 to estimate physical activity levels during the school day (8AM-3PM) among youth aged 6-19 years (n=2548). Fixed-effects regressions were used to estimate the impact of changes in school-day minutes of moderate-to-vigorous physical activity (MVPA) on changes in total daily MVPA. RESULTS: Each additional minute of school-day MVPA was associated with an additional 1.14 minutes (95% CI=1.04, 1.24; p<0.001) of total daily MVPA, or 0.14 additional minutes (95% CI=0.04, 0.24; p=0.008) outside the school day, controlling for total daily accelerometer wear time and age, gender, race/ethnicity, and other non-time varying covariates. There were no differences in the effect of school-day MVPA on total MVPA by age group, gender, race/ethnicity, poverty status, or degree of change in MVPA. CONCLUSIONS: Higher school-day MVPA was associated with higher daily MVPA among U.S. youth with no evidence for same-day "compensation." Increasing school-based physical activity is a promising approach that can improve total daily physical activity levels of youth.

Disparities in youth physical activity in the United States: 2003-2006.

PURPOSE: This study aimed to examine changes in physical activity among children and adolescents, by race/ethnicity, in the United States from 2003-2004 to 2005-2006. METHODS: Secondary analysis of the objectively measured accelerometer data among children and adolescents 6-19 yr: 2003-2004 (n = 1665) and 2005-2006 (n = 1716) from the nationally representative National Health and Nutrition Examination Survey 2003-2004 and 2005-2006. We estimated regression coefficients for change between the two periods by age group, accounting for sampling design and adjusting for age, sex, race/ethnicity, and number of hours monitored. We tested for differences in mean accelerometer counts per minute and minutes per day of moderate and vigorous physical activity trends by race/ethnicity and gender. RESULTS: Physical activity decreased with age, boys were more active than girls, and non-Hispanic black children were more active than non-Hispanic whites (all P < 0.01). Overall mean accelerometer counts increased from 2003-2004 to 2005-2006 for children ages 6-11 yr (+31.6 counts per minute; 95% confidence interval = 0.51-62.6) but not among adolescents ages 12-19 yr. There was an increase over time in mean accelerometer counts among 6- to 11-yr-old non-Hispanic white children (+52.4 counts per minute, P = 0.007; 95% confidence interval = 15.7-89) but a decrease among non-Hispanic black and Mexican American children. No changes over the period in moderate and vigorous physical activity were found in either age group. CONCLUSIONS: The lack of improvement in physical activity among all children and adolescents and a potentially emerging race-ethnic disparity indicate a need for further research on potential mechanisms underlying these differences. Effective interventions to improve physical activity opportunities and attenuate the decline in activity levels as children enter adolescence are needed.

Effect of an after-school intervention on increases in children's physical activity.

PURPOSE: Evaluate the effect of an after-school intervention on physical activity program changes and individual behaviors among children. METHODS: A quasi-experimental evaluation of a YMCA-driven environmental change intervention with 16 intervention and 16 control sites in four metropolitan areas in the United States. Intervention sites participated in learning collaboratives designed to promote physical activity and nutrition through environmental change, educational activities, and parent engagement. Behavioral foci included increasing overall physical activity levels as well as combined moderate and vigorous physical activity and vigorous physical activity. Outcomes were assessed longitudinally using preintervention and follow-up surveys of program implementation and accelerometer measures of physical activity. ActiGraph accelerometer data were collected from a sample of 212 children, ages 5-11 yr, attending the programs. On average, 3 d of data were gathered per child. Reliability of the accelerometer counts averaged 0.78. Multivariate regression models were used to control for potential confounding variables and to account for clustering of observations. RESULTS: Data indicate greater physical activity increases in children in intervention versus control sites after modest intervention implementation. Controlling for baseline covariates, children in intervention sites showed greater increases in average physical activity level than in control sites (76 counts per minute, P = 0.037, 95% confidence interval (CI) = 8.1-144) and more minutes of moderate and vigorous physical activity (10.5 min·d(-1), P = 0.017, 95% CI = 1.5-18.6), minutes of moderate physical activity (5.6 min·d(-1), P = 0.020, 95% CI = 0.99-10.2), and minutes of vigorous physical activity (5.1 min·d(-1), P = 0.051, 95% CI = 0.21-9.93). CONCLUSIONS: Results indicate significant increases in daily physical activity among children in intervention versus control sites. This study documents the effectiveness of an environmental change approach in an applied setting.

Time trends in mortality associated with depression: findings from the Stirling County study.

OBJECTIVE: to address the question of whether a mortality risk associated with depression in a 1952 representative sample of Stirling County adults changed in a new sample in 1970, and whether there was a change in associations with cigarette smoking and alcoholism. METHOD: sample members were interviewed about depression and cigarette smoking. General physicians were interviewed by psychiatrists regarding alcoholism. Information about death as of December 31, 1992, was provided by Statistics Canada. Proportional hazards models were fitted in the 2 samples to assess the mortality risks associated with depression among men and women during 20 years of follow-up, and additionally among men with heavy smoking and alcoholism. Specific causes of death were investigated. RESULTS: hazard ratios representing the association between depression and premature death among men were 2.6 (95% CI 1.4 to 4.9) and 2.8 (95% CI 1.5 to 5.1), respectively, in the 1952 and 1970 samples for the first 10 years of follow-up. Hazard ratios for women were 1.4 (95% CI 0.6 to 3.2) and 1.2 (95% CI 0.5 to 2.9). The risk associated with depression among men was independent of alcoholism and heavy smoking. Depression and alcoholism were significantly associated with death by external causes and circulatory disease; heavy smoking was significantly associated with malignant neoplasms. CONCLUSION: the mortality associated with depression did not change during the period from 1952 to 1970. Depressed men experienced a significant mortality risk that was not matched among depressed women and also was not due to alcoholism and heavy smoking.

Mortality associated with depression: a forty-year perspective from the Stirling County Study.

BACKGROUND: This report concerns long-term mortality risks associated with depression, and the potentially confounding factors of alcoholism and cigarette smoking, as experienced by a general population assessed at a baseline in 1952, followed for re-assessment of survivors in 1968, and for death by 1992. METHODS: Self-report and physician-report information was gathered in 1952 and again in 1968 about a sample of 1,079 adults. At the end of follow-up in 1992, the vital status of all subjects was known. Comorbidity among depression, alcoholism, and smoking was investigated. Cox regression models were employed to estimate hazard ratios (HRs) as indicators of mortality risk. Models including age, gender, and depression were fit for the complete sample at baseline as well as for re-assessed survivors. Models simultaneously controlling for the mortality risks associated with depression, alcoholism, and heavy smoking were fit for men. RESULTS: At the baseline in 1952, depression was somewhat more common among women than men (4% compared to 6%) but was found to carry a significant mortality risk only among men (HR 2.7, 95% CI 1.6-4.7). Based on re-assessments made in 1968, depression was associated with mortality risk among both men (HR 2.2, 95% CI 1.0-4.5) and women (HR 2.1, 95% CI 1.2-3.8). In 1952, more than 20% of men smoked cigarettes excessively and 8% abused alcohol, but very few of these groups of men were also depressed. In the original sample and also among the survivors, depression, alcoholism, and heavy smoking were separately associated with mortality among men. Depression and alcoholism carried a more immediate mortality risk while heavy smoking a more delayed one. CONCLUSIONS: At the baseline of the Stirling County Study, the mortality risk associated with depression among men was not enhanced or explained by abuse of alcohol or nicotine, mainly because comorbidity was rare at that time. The longitudinal research of the study has pointed to a number of psychiatrically-relevant time-trends such as the fact that an association between depression and cigarette smoking did not appear until the 1990s. It is hypothesized that a similar trend may emerge over time regarding the comorbidity of depression and alcoholism. A trend reported here was that, while depressed women in the original sample did not carry a significant mortality risk, the surviving women who were depressed at the time of re-assessment exhibited a mortality risk that was as significant as that for men. Such information may provide a useful back-drop for future investigations.

Youths' perceptions of overweight-related prevention counseling at a primary care visit.

OBJECTIVE: We examined youths' report of receiving specific overweight-related preventive counseling and perceived readiness to adopt nutrition and physical activity behaviors recommended by their clinicians. RESEARCH METHODS AND PROCEDURES: We surveyed 324 youth 10 to 18 years old who had a physical exam within the past year. The survey included questions on height, weight, race/ethnicity, mother's education, and topics they discussed with their clinician during their visit. We used multivariable analyses to examine whether weight status and sociodemographic characteristics were predictors of which youth received counseling from their clinicians and which youth were ready to change. RESULTS: The mean (standard deviation) age of participants was 13.7 (1.8) years; 54% were black, and 22% were Hispanic. Less than one-half of participants reported discussing sugar-sweetened beverages [38%; 95% confidence interval (CI), 32% to 43%] or television viewing (41%; 95% CI, 36% to 47%) with their clinicians. In multivariable analyses adjusting for participant's age, sex, race/ethnicity, overweight status, and mother's educational attainment, youth whose mothers lacked education beyond high school were significantly less likely to report receiving counseling on any overweight-specific topic including television viewing [odds ratio (OR), 0.46; 95% CI, 0.27, 0.79], sugar-sweetened beverage (OR, 0.47; 95% CI, 0.28, 0.80), and fast food consumption (OR, 0.54; 95% CI, 0.32, 0.92). In addition, youth 10 to 14 years old were more likely than those 15 to 18 years old to report they would try to change their television viewing (OR, 4.10; 95% CI, 1.78, 9.44) if recommended by their clinician. DISCUSSION: Youth report infrequently receiving counseling on specific overweight prevention topics during routine primary care visits. Our findings suggest that greater efforts may be needed to reduce social class disparities in overweight prevention counseling and that counseling to prevent overweight in youth may be more acceptable to younger children.

Estimating the energy gap among US children: a counterfactual approach.

OBJECTIVE: Our goal was to quantify the magnitude of energy imbalance responsible for the increase in body weight among US children during the periods 1988-1994 and 1999-2002. METHODS: We adopted a counterfactual approach to estimate weight gains in excess of normal growth and the implicit "energy gap"--the daily imbalance between energy intake and expenditure. On the basis of Centers for Disease Control and Prevention growth charts, we constructed weight, height, and BMI percentile distributions for cohorts 2 to 4 and 5 to 7 years of age in the 1988-1994 National Health and Nutrition Examination Survey (N = 5000). Under the counterfactual "normal-growth-only" scenario, we assumed that these percentile distributions remained the same as the cohort aged 10 years. Under this assumption, we projected the weight and height distributions for this cohort at 12 to 14 and 15 to 17 years of age on the basis of their baseline weight-for-age and stature-for-age percentiles. We compared these distributions with those for corresponding age groups in the 1999-2002 National Health and Nutrition Examination Survey (N = 3091) approximately 10 years after the 1988-1994 National Health and Nutrition Examination Survey. We calculated differences between the counterfactual and observed weight distributions and translated this difference into the estimated average energy gap, adjusting for increased total energy expenditure attributable to weight gain. In addition, we estimated the average excess weight accumulated among overweight adolescents in the 1999-2002 National Health and Nutrition Examination Survey, validating our counterfactual assumptions by analyzing longitudinal data from the National Longitudinal Survey of Youth and Bogalusa Heart Study. RESULTS: Compared with the counterfactual scenario, boys and girls who were aged 2 to 7 in the 1988-1994 National Health and Nutrition Examination Survey gained, on average, an excess of 0.43 kg/year over the 10-year period. Assuming that 3500 kcal leads to an average of 1-lb weight gain as fat, our results suggest that a reduction in the energy gap of 110-165 kcal/day could have prevented this increase. Among overweight adolescents aged 12 to 17 in 1999-2002, results indicate an average energy imbalance ranging from 678 to 1017 kcal/day because of an excess of 26.5 kg accumulated over 10 years. CONCLUSIONS: Quantifying the energy imbalance responsible for recent changes in weight distribution among children can provide salient targets for population intervention. Consistent behavioral changes averaging 110 to 165 kcal/day may be sufficient to counterbalance the energy gap. Changes in excess dietary intake (eg, eliminating one sugar-sweetened beverage at 150 kcal per can) may be easier to attain than increases in physical activity levels (eg, a 30-kg boy replacing sitting for 1.9 hours with 1.9 hours walking for an extra 150 kcal). Youth at higher levels of weight gain will likely need changes in multiple behaviors and environments to close the energy gap.

Effects of a school-based obesity-prevention intervention on menarche (United States).

OBJECTIVE: Early menarche is a risk factor for breast cancer. Since body composition influences age at menarche we decided to estimate the effects of a school-based intervention for the prevention of obesity on the initiation of menses in young girls. METHODS: Ten schools were randomized to a modified curriculum or no curricular changes for 2 school-years. Data of 508 pre-menarcheal girls at baseline (age range: 10-13 years) were analyzed. RESULTS: Girls attending an intervention school experienced menarche less frequently than girls attending control schools during the intervention period (intervention schools = 54%, control schools = 59%; RR = 0.76; 95% CI [0.66, 0.87]). Attending an intervention school was also associated with lower increase in BMI (-0.3 kg/m2; p = 0.003), lower gains in triceps skinfold thickness (-1.5 mm; p = 0.007), decreased television viewing (-0.6 h/day; p<0.0001) and increased physical activity (3.1 MET-h/week; p = 0.032). Including these changes as predictors of menarche incidence attenuated the intervention effect (RR = 0.94; 95% CI [0.80, 1.10]). CONCLUSIONS: The intervention delayed menarche in this group of girls. The delay was produced by increased physical activity, reduced television viewing and changes in BMI and fat distribution. These findings may have implications for the primary prevention of breast cancer.

Youth recall and TriTrac accelerometer estimates of physical activity levels.

PURPOSE: To examine significance of missing data and describe physical activity patterns using recall and accelerometer measures among youth in a nonlaboratory setting. METHODS: Fifty-four middle-school students wore TriTrac-R3D monitors (TTM) and completed an interviewer-prompted 24-h recall during two, 5-d monitoring sessions. We coded 2860 30-min recall intervals to a standard MET compendium. Complete TTM data were gathered for 43 students. Ordinal multinomial models tested for bias in TTM estimates of activity levels due to: 1) exclusion of subjects with incomplete TTM data, and 2) exclusion of intervals within days due to missing TTM data. RESULTS: Students with complete monitor data had an average 12.5 +/- 0.9 monitored hours per day over 5.5 +/- 2.1 d. Compared with students with incomplete monitoring data, they reported similar proportions of recall 30-min intervals at sedentary (68% vs 69%), light (14% vs 15%), moderate (11% vs 10%), and vigorous (7% vs 6%) intensity levels (P = 0.63). The proportion of recall intervals (within days) with and without simultaneous monitoring data did not differ by activity intensity (P = 0.64) across sedentary (69% vs 67%), light (14% vs 12%), moderate (11% vs 10%), and vigorous (6% vs 9%) categories. Recalls overestimated percent time per day in moderate and vigorous activity relative to TTM (22.8% vs 8.9%, P < 0.0001). Boys reported higher percent of time than girls in vigorous activity (10.9% vs 3.9%, P < 0.05). Girls reported more time than boys (9.5% vs 6.4%, P < 0.05) in light activities. No significant sex differences were observed using TTM. CONCLUSIONS: Missing TTM data did not bias estimates of activity levels. Self-reported activity measures overestimated moderate and vigorous activity relative to the TTM and varied by sex.

Impact of television viewing patterns on fruit and vegetable consumption among adolescents.

BACKGROUND: National data indicate that children and youth do not meet Healthy People 2010 objectives for fruit and vegetable intake. Television viewing is hypothesized as a contributing factor because of its documented role in encouraging consumption of highly advertised foods that may lead to the replacement of fruits and vegetables. METHODS: A sample of 548 ethnically diverse students (average age: 11.7 +/- 0.8 years) from public schools in 4 Massachusetts communities were studied prospectively over a 19-month period from October 1995 to May 1997. We examined the associations between baseline and change in hours of television and video viewing per day (the predictor variables) and change in energy-adjusted intake of fruits and vegetables by using linear regression analyses to control for potentially confounding variables and the clustering of observations within schools. FINDINGS: For each additional hour of television viewed per day, fruit and vegetable servings per day decreased (-0.14) after adjustment for anthropometric, demographic, dietary variables (including baseline percent energy from fat, sit-down dinner frequency, and baseline energy-adjusted fruit and vegetable intake), and physical activity. Baseline hours of television viewed per day was also independently associated with change in fruit and vegetable servings (-0.16). CONCLUSIONS: Television viewing is inversely associated with intake of fruit and vegetables among adolescents. These associations may be a result of the replacement of fruits and vegetables in youths' diets by foods highly advertised on television.

Cigarette smoking in relation to depression: historical trends from the Stirling County Study.

OBJECTIVE: Building on findings about the prevalence and incidence of depression over a 40-year period, the authors provide data on trends in cigarette smoking and associations with depression. METHOD: Data come from interviews with adult population samples (1952, 1970, and 1992) and followed cohorts (1952-1970 and 1970-1992). Logistic regression models and survival regressions were used to analyze the data. RESULTS: The associations between smoking and depression were small and nonsignificant in 1952 and 1970. In 1992, however, the odds that a smoker would be depressed were three times the odds that a nonsmoker would be depressed. The interaction between smoking and study year was significant, indicating that the association was limited to the most recent sample. In the cohort analysis, smoking at baseline did not predict the onset of depression, but subjects who became depressed were more likely to start or continue smoking and less likely to quit than those who never had a depression. CONCLUSIONS: In terms of population trends, the association between depression and cigarette smoking became prominent as the use of tobacco declined because of awareness of the risks involved. The findings about individuals followed over time suggest that those who became depressed were more involved with nicotine than those who never had a depression. The authors discuss hypotheses involving "self-medication," risk-taking, and changes in the social climate but conclude that the relationships between smoking and depression are probably multiple and complex.

Incidence of major depression: prediction from subthreshold categories in the Stirling County Study.

BACKGROUND: Validity of the newly-proposed categories of Minor Depression (MinD) and Subsyndromal Depression (SSD) would be strengthened if they were found to be related to the incidence of Major Depressive Episode (MDE). In this report, the subsequent incidence of MDE was assessed in terms of baseline evidence about the two subthreshold categories and Dysthymic Disorder (DysD). METHODS: The Diagnostic Interview Schedule was used to interview 489 subjects twice between 1991 and 1995 as part of the Stirling County Study. Life table methods were used to calculate incidence rates and log linear analysis was employed for statistical assessment. RESULTS: The average annual incidence of MDE was 10 per 1000. The rates associated with the baseline categories were 210 per 1000 for DysD, 21 for MinD; 13 for SSD; and four for the remainder of subjects who constituted the reference group. Only the incidence related to DysD was significantly higher than that for the reference group. Comparing Time 1 and Time 2, one-third of the subjects gained or lost symptoms and the comorbidity of MDE and DysD increased. LIMITATIONS: The study population was, on average, 63 years of age. Older age and the small size of the cohort may have influenced the findings. Another limitation may relate to the use of lifetime rather than current symptomatology. CONCLUSIONS: DysD is strongly associated with MDE suggesting that the chronic and episodic forms of unipolar depression constitute one disorder. The other subthreshold categories should be further investigated in terms of prodromal qualities. The persistence of dysphoria, as in DysD, may be a more important feature of the depression prodrome than the number of symptoms.

Self-disparagement as feature and forerunner of depression: findings from the Stirling County Study.

Sleep disturbance has attracted considerable attention as an early indicator of depression. However, three epidemiologic investigations have shown psychological symptoms, such as self-disparagement, to be stronger predictors. This report examines the depressive symptoms commonly assessed in modern epidemiologic surveys and estimates the generalizability of this information using data from the Stirling County Study, a long-term epidemiologic investigation of psychiatric disorders. The Diagnostic Interview Schedule (DIS) was used to gather information about depression, defined as major depressive episode (MDE) and/or dysthymic disorder (DysD). A sample of 1,396 adults representing Stirling County in 1992 served to assess the prevalence of the different types of depressive symptoms and to investigate the associations between symptoms and lifetime diagnoses of MDE/DysD. A cohort of 489 follow-up subjects who were interviewed twice in the early part of the 1990s was used to examine the associations between baseline symptoms and subsequent incidence of MDE/DysD. Both "symptom groups" (such as appetite or psychomotor disturbances) and "individual symptoms" (such as weight gain or restlessness) were investigated. About one third of the representative sample had experienced the diagnostically required symptoms of "sadness" or "loss of pleasure," but many lacked sufficient other symptomatology to be diagnosed as depressed. Several of the symptom groups bore a different relationship to diagnosis than did the individual symptoms. Among the latter, "feeling worthless" and "having trouble concentrating" exhibited the strongest associations to diagnosis in the representative sample. The symptoms of "wanting to die" and "feeling worthless" were the most predictive of future depression in the twice-interviewed cohort. Thus, this study supports evidence from other epidemiologic studies that psychological symptoms are important in the prodromal phase of depression. Sleep disturbance, especially insomnia, cannot be ignored since it is a prominent manifestation of depression but it appears not to have as high specificity as some of the other symptoms. An exclusive focus on the symptom groups, as used to count symptoms according to diagnostic criteria, may obscure useful information about associations between individual symptoms and diagnosis. Feelings of personal inadequacy deserve particular attention in the population at large because they are strongly associated with lifetime diagnoses and forecast the incidence of depression when people are followed over time.