Biomedical subjects

James N Roemmich

Publications and source records attributed to James N Roemmich.

At least 19 recordsLinked to original sources

PubMed2006

Relationship between parental estimate and an objective measure of child television watching.

Many young children have televisions in their bedrooms, which may influence the relationship between parental estimate and objective measures of child television usage/week. Parental estimates of child television time of eighty 4-7 year old children (6.0 +/- 1.2 years) at the 75th BMI percentile or greater (90.8 +/- 6.8 BMI percentile) were compared to an objective measure of television time obtained from TV Allowance devices attached to every television in the home over a three week period. Results showed that parents overestimate their child's television time compared to an objective measure when no television is present in the bedroom by 4 hours/week (25.4 +/- 11.5 vs. 21.4 +/- 9.1) in comparison to underestimating television time by over 3 hours/week (26.5 +/- 17.2 vs. 29.8 +/- 14.4) when the child has a television in their bedroom (p = 0.02). Children with a television in their bedroom spend more objectively measured hours in television time than children without a television in their bedroom (29.8 +/- 14.2 versus 21.4 +/- 9.1, p = 0.003). Research on child television watching should take into account television watching in bedrooms, since it may not be adequately assessed by parental estimates.

Journal Article↗

PubMed2006

Association of access to parks and recreational facilities with the physical activity of young children.

OBJECTIVE: To determine associations of the neighborhood and home television environments with young children's physical activity. METHOD: 32 boys and 27 girls age 4 to 7 years wore accelerometers for 3 weekdays and 1 weekend day. The number of televisions in the home and television watching of the child were monitored using TV Allowance units for 3 weeks. A geographic information system was used to measure neighborhood environment variables. RESULTS: Hierarchical regression analysis was used to predict physical activity, initially controlling for sex, age, socioeconomic status, adiposity, and child television watching in step 1. In step 2, the number of televisions did not significantly increase the amount of variability accounted for in the prediction of physical activity. In step 3, housing density and the interaction of housing density by sex accounted for an incremental 12% (p < 0.05) of the variability and in step 4 percentage park plus recreation area accounted for a further 10% (p < 0.05) of the variability. Greater housing density predicted increased physical activity of boys, but not girls. CONCLUSION: Neighborhoods with increased proximity between homes and a greater proportion of park area are associated with greater physical activity in young children.

Body Mass Index↗

PubMed2006

Bone age and onset of puberty in normal boys.

Many conditions that delay skeletal maturation also delay the onset of puberty, whereas conditions that accelerate skeletal maturation often hasten the onset puberty, raising the possibility that skeletal maturation influences pubertal onset. To determine whether this concordance is also present in normal children, we analyzed data from 30 normal boys participating in a longitudinal study. Height, weight, and serum testosterone concentrations were assessed every 6 months and bone age (Fels method) every year. Pubertal onset was defined by serum testosterone > or =30 ng/dL. The variability in bone age at onset of puberty was not less than the variability in chronological age. In addition, there was no significant correlation between skeletal advancement and pubertal advancement (r=0.01, P=0.9). Similarly, there was not a significant correlation between pubertal advancement and height age advancement, weight age advancement, or BMI age advancement. Our findings do not support the hypothesis that skeletal maturation directly influences the age of pubertal onset in normal boys.

Adolescent↗

PubMed2006

Relationship of mother and child food purchases as a function of price: a pilot study.

To our knowledge, there are no data on parental influences on child purchasing behavior of healthy or unhealthy foods. Mothers and children in ten families were given 5.00 US dollars to purchase portions of preferred fruits/vegetables and high energy-dense snack foods for each of ten trials of price manipulations. For five of the trials the price of the fruit/vegetable increased in price from 0.50 US dollars to 2.50 US dollars (in 0.50 US dollar increments), while the price of the energy-dense snack food remained constant at 1.00 US dollar. For the remaining five trials, the commodity that previously rose in price remained constant at 1.00 US dollars and the other commodity varied from 0.50 US dollars to 2.50 US dollars. Same-price elasticity was shown for both the child and parent purchases, and parent purchases were significantly related to child purchases of both healthy (regression estimate = 0.46, p < 0.001) and unhealthy (regression estimate = 0.12, p = 0.036) foods. Children's purchases of unhealthy snack food items were positively related to family socioeconomic status, and negatively related to child age. These results indicate that parental food choice and purchasing behaviors may play a role in the development of children's purchasing of both healthy and unhealthy foods.

Adult↗

PubMed2006

Habituation and recovery of salivation and motivated responding for food in children.

Salivary responses habituate to repeated presentations of food cues, and these responses recover when new food stimuli are presented. Research suggests that within-session changes in motivated responding for food may also habituate, and motivated responding may, therefore, recover when new foods are presented. The purpose of this study was to evaluate similarities in the pattern of salivation and motivated responding for a cheeseburger stimulus in children, followed by either a novel stimulus (French fries) or another cheeseburger trial. The order of the task (salivation or motivation) was counterbalanced over days. Salivation and motivated responding for cheeseburger were reliably reduced over seven trials, and responses recovered after presentation of French fries on trial 8. Random regression models showed a significant relationship between the rate of change in motivated responding and salivation. These results provide additional support for similarities in processes that regulate salivation and motivated responding for food and strengthen support for the hypothesis that changes in motivated responding can be understood by habituation theory.

Child↗

PubMed2006

Somatotropic and gonadotropic axes linkages in infancy, childhood, and the puberty-adult transition.

Integrative neuroendocrine control of the gonadotropic and somatotropic axes in childhood, puberty, and young adulthood proceeds via multiple convergent and divergent pathways in the human and experimental animal. Emerging ensemble concepts are required to embody independent, parallel, and interacting mechanisms that subserve physiological adaptations and pathological disruption of reproduction and growth. Significant advances in systems biology will be needed to address these challenges.

Aging↗

PubMed2006

Purchases of food in youth. Influence of price and income.

One way to increase choice of healthy over unhealthy behaviors is to increase the cost of less healthy alternatives or reduce the cost of healthier alternatives. The influence of price on purchases of healthy and unhealthy foods was evaluated in two laboratory experiments. In Experiment 1, thirty-two 10- to 12-year-old youth were given $5.00 and allowed to purchase multiple portions of a healthy food (fruit or vegetable) and a less healthy food (higher-fat snack). The price of one type of food varied from $0.50 to $2.50, while the price of the other type was held at $1.00. Increasing the price of a type of food reduced purchases of that type of food, but did not lead to substitution with the alternative type of food. In Experiment 2, twenty 10- to 14-year-old youth were given $1.00, $3.00, and $5.00 to purchase healthy and unhealthy foods. The price of each food was raised and lowered by 25% and 50%. Raising the price of healthy or unhealthy foods resulted in decreased purchases of those foods, and income available interacted with price to predict the pattern of substitution of alternative foods. These results show the potential for controlled laboratory studies of price and food purchases, and show that the substitution of healthier for unhealthy food is related to available money.

Child↗

PubMed2006

Reducing sedentary behavior: the relationship between park area and the physical activity of youth.

This study was designed to determine whether the characteristics of the neighborhood environment are related to the substitution of physical activity for sedentary behavior among youth. Fifty-eight 8- to 15-year-old youth were studied in a within-subjects crossover design with three phases: baseline, increased sedentary behavior, and decreased sedentary behavior. The relations between changes in physical activity and design, diversity, and density attributes of the neighborhood environment were determined using random coefficient models. Compared with girls, boys showed greater increases in physical activity when sedentary behaviors were reduced and greater decreases in physical activity when sedentary behaviors were increased. Greater access to parks was associated with greater physical activity when sedentary behaviors were reduced.

Adolescent↗

PubMed2006

Validity of PCERT and OMNI walk/run ratings of perceived exertion.

PURPOSE: This study was conducted to test the validity of the Pictorial Children's Effort Rating Table (PCERT) and OMNI walk/run scales. METHODS: Children (26 boys age 11.2 yr +/- 1.6 and 25 girls age 11.1 yr +/- 1.4) performed a five-stage incremental exertion treadmill test. The undifferentiated perceived exertion from the PCERT and OMNI scales was assessed for construct validity using Pearson correlations with VO(2) and heart rate as criteria and concurrent validity by correlating PCERT and OMNI scores. RESULTS: Increases in PCERT and OMNI scale scores were correlated with increases in VO(2) (r = 0.90 and 0.92) and heart rate (r = 0.89 and 0.92). No difference was found in slope of the PCERT and OMNI scores when regressed against heart rate or VO(2) and the slopes were invariant across sexes. To test concurrent validity of the PCERT and OMNI scales, subject scores at each stage were converted to a percentage of the maximal scale. No effect of sex was noted on perceived exertion (P = 0.32), and the percentage of the maximal PCERT and OMNI scales was almost identical at each stage (P = 0.73). CONCLUSIONS: Validity of both the PCERT and OMNI scales was established for submaximal exercise. PCERT and OMNI scores are not interchangeable because they have different scales, but at a given exercise intensity youth assign similar percentages of the maximal scores.

Child↗

PubMed2006

Increases in overweight after adenotonsillectomy in overweight children with obstructive sleep-disordered breathing are associated with decreases in motor activity and hyperactivity.

OBJECTIVE: To examine the effect of adenotonsillectomy (T&A) in children with obstructive sleep-disordered breathing on growth, hyperactivity, and sleep and waking motor activity. METHODS: We studied 54 children who were aged 6 to 12 years and had adenotonsillar hypertrophy and an obstructive apnea-hypopnea index of > or =1 before and 12 months after they all received adenotonsillectomy (T&A). We measured their height, weight, percentage overweight (patient BMI - BMI at 50th percentile)/BMI at 50th percentile x 100) and obtained a hyperactivity score from parent report on a standardized behavior questionnaire scale. A subset of 21 of these children were also studied for motor activity by wrist actigraphy for 7 consecutive days and nights before and 12 months after T&A. RESULTS: After T&A, mean obstructive apnea-hypopnea index decreased from 7.6 to 0.6. Height percentile did not change, but weight percentile increased; as a consequence, percentage overweight increased from 32.0% to 36.3%. Hyperactivity scores and total daily motor activity were reduced after T&A. From linear regression, the reduction in hyperactivity scores predicted an increase in percentage overweight. Reduced motor activity was correlated with increased percentage overweight. CONCLUSIONS: An increase in percentage overweight after T&A in children with obstructive sleep-disordered breathing is correlated to decreased child hyperactivity scores and to decreased measured motor activity in the subset studied. These associations suggest that the increase in overweight may be attributable to reductions in physical activity and fidgeting energy expenditure.

Adenoidectomy↗

PubMed2005

Effects of allocation of attention on habituation to olfactory and visual food stimuli in children.

Responding to food cues may be disrupted by allocating attention to other tasks. We report two experiments examining the effects of allocation of attention on salivary habituation to olfactory plus visual food cues in 8-12-year-old children. In Experiment 1, 42 children were presented with a series of 8 hamburger food stimulus presentations. During each intertrial interval, participants completed a controlled (hard), or automatic (easy) visual memory task, or no task (control). In Experiment 2, 22 children were presented with 10 presentations of a pizza food stimulus and either listened to an audiobook or no audiobook control. Results of Experiment 1 showed group differences in rate of change in salivation (p=0.014). Children in the controlled task did not habituate to repeated food cues, while children in the automatic (p<0.005) or no task (p<0.001) groups decreased responding over time. In Experiment 2, groups differed in the rate of change in salivation (p=0.004). Children in the no audiobook group habituated (p<0.001), while children in the audiobook group did not habituate. Changes in the rate of habituation when attending to non-food stimuli while eating may be a mechanism for increasing energy intake.

Attention↗

PubMed2005

Pubertal alterations in growth and body composition: IX. Altered spontaneous secretion and metabolic clearance of growth hormone in overweight youth.

Deconvolution analysis was used to determine 12-hour spontaneous nocturnal growth hormone (GH) secretion and GH half-life in lean (body mass index, <85th percentile; n = 39) and overweight (body mass index, > or =85th percentile; n = 18) youth. The integrated GH concentration, GH burst mass, and half-life were lower (P < .05) in overweight than in lean youth. For each unit increase in percentage of body fat, integrated serum GH concentrations, secretory burst mass, and half-life declined by 83.6 microg/L per minute (r = -0.39, P < .01), 0.22 microg/L (r = -0.28, P < .05), and 0.2 minute (r = -0.38, P < .01), respectively. The effect of overweight on GH secretion was independent of pubertal status. Hierarchical regression models tested the hypothesis that altered GH secretion in youth is more related to total adiposity than abdominal visceral fat. When age, sex, fat-free mass, testosterone, and estradiol were held constant, the sequential addition of abdominal visceral fat did not increase R2 for any GH secretion variable. Sequential addition of percentage of body fat increased R2 (P < .05) for integrated GH concentration, total secretory rate, secretory burst mass, and pulsatile production rate. We conclude that serum GH concentrations are reduced in overweight youth primarily because of reduced GH burst mass with no change in the number of secretory events and secondarily to reduced GH half-life. Based on the model that GH-releasing hormone predominantly increases GH pulse amplitude whereas somatostatin primarily controls GH pulse frequency, these results suggest that overweight in youth diminishes GH-releasing hormone stimulation resulting in truncated GH bursts but does not alter the number of somatostatin withdrawal intervals so that GH burst frequency is conserved.

Abdomen↗

PubMed2005

The relationship between parent and child self-reported adherence and weight loss.

OBJECTIVE: Better adherence to treatment strategies in family-based behavioral weight control programs may lead to greater weight reduction and improved weight maintenance in youth. This study assessed the influence of child and parent self-reported adherence to behavioral strategies on changes in 2-year child and parent percentage overweight. RESEARCH METHODS AND PROCEDURES: Participants included 8- to 12-year-old children in >or= 85th BMI percentile and their parents from 110 families taking part in two family-based randomized controlled weight control studies. This study examined whether self-reported adherence to behavioral strategies measured at 24 months increased prediction of child and parent percentage overweight change through 24-month follow-up after accounting for other factors that may influence weight change. RESULTS: Child adherence to weighing and to preplanning for celebrations where high-fat foods are served and parent adherence to praising the child and modeling healthy eating habits predicted 24-month child percentage overweight change (p<0.001). Child adherence to recording food and calories and parent adherence to modeling healthy eating habits predicted 24-month parent percentage overweight change (p<0.001). In hierarchical regression models, child weighing and preplanning and parent modeling were significant (p<0.01) incremental predictors (r2 of 24.8%) of 24-month child percentage overweight. Child recording and parent modeling were significant (p<0.01) incremental predictors (r2 of 14%) of parent 24-month percentage overweight change. DISCUSSION: Child and parent adherence to specific components of family-based behavioral weight control treatment are independent predictors of long-term child and parent percentage overweight change.

Adult↗

PubMed2005

Influence of changes in sedentary behavior on energy and macronutrient intake in youth.

BACKGROUND: Changes in sedentary behavior may be related to changes in energy intake. OBJECTIVE: The purpose of this study was to investigate how experimental changes in the amount of sedentary behaviors influence energy intake. DESIGN: Sixteen nonoverweight 12-16-y-old youth were studied in a within-subject crossover design with three 3-wk phases: baseline, increasing targeted sedentary behaviors by 25-50% (increase phase), and decreasing targeted sedentary behaviors by 25-50% (decrease phase). Repeated 24-h recalls were used to assess energy and macronutrient intakes during targeted sedentary behaviors. Accelerometers were used to assess activity levels. RESULTS: Targeted sedentary behaviors increased by 81.5 min/d (45.8%) and decreased by 109.8 min/d (-61.2%) from baseline (both: P<0.01). Girls increased sedentary behaviors significantly more than did boys (107.3 and 55.8 min/d, respectively; P<0.01) in the increase phase. Energy intake decreased (-463.0 kcal/d; P<0.01) when sedentary behaviors decreased: the decrease in fat intake was -295.2 kcal/d (P<0.01). No significant changes in energy intake were observed when sedentary behaviors were increased. Youth also increased their activity by 102.4 activity counts min-1d-1 (estimated at 113.1 kcal) when sedentary behaviors were decreased (P<0.05). CONCLUSIONS: Decreasing sedentary behaviors can decrease energy intake in nonoverweight adolescent youth and should be considered an important component of interventions to prevent obesity and to regulate body weight.

Adolescent↗

PubMed2005

Physical activity as a substitute for sedentary behavior in youth.

BACKGROUND: Youth may choose to be sedentary rather than physically active. PURPOSE: The purpose of this study was to use behavioral economics methods to investigate how experimental changes in the amount of sedentary behaviors influenced physical activity. METHODS: Fifty-eight 8- to 16-year-old youth were studied in a within-subject crossover design with three 3-week phases: baseline, increasing, and decreasing targeted sedentary behaviors by 25% to 50%. RESULTS: At baseline, boys were more active than girls (518.9 vs. 401.2 accelerometer counts/min, p = .02), and obese youth more sedentary than nonobese youth (240.5 vs. 174.4 min/day, p = .003). During the increase sedentary behavior phase, targeted sedentary behaviors increased by 52.1%, with girls increasing sedentary behaviors more than boys (114.7 vs. 79.8 min/day, p = .04). Physical activity decreased (-48.3 counts/min, p < .01) when sedentary behaviors increased, with obese youth decreasing total and moderate to vigorous physical activity (MVPA) more than nonobese youth (-110.4 vs. 8.9 counts/min, p < .001; -3.3 vs. -.03 % MVPA, p = .013). During the decrease sedentary behavior phase, targeted sedentary behaviors decreased by 55.6% from baseline as nonobese youth increased physical activity, whereas obese youth decreased physical activity (55.8 vs. -48.0 counts/min, p = .042; 1.1 vs. -2.1% MVPA, p = .021). Youth who substituted physical activity when sedentary behaviors were increased had greater standardized body mass index (z-body mass index = 1.4 vs. 0.4, p = .018), whereas youth who substituted physical activity when sedentary behaviors were decreased were less active at baseline (396.1 vs. 513.7 counts/min, p = .035). CONCLUSIONS: Behavioral economics provides a methodology to understand changes in physical activity when sedentary behaviors are modified and to identify factors associated with substitution of physically active for sedentary behaviors.

Activities of Daily Living↗

PubMed2005

The challenge of identifying behavioral alternatives to food: clinic and field studies.

BACKGROUND: One of the basic principles of behavioral economics interventions is identification of alternative behaviors to compete with the reinforcing value of a highly rewarding commodity. PURPOSE: Two experiments that attempt to increase alternatives to eating in obese youth are presented. METHODS: A randomized, controlled trial was used in Study 1 to compare a comprehensive family-based behavioral treatment program or an experimental treatment that incorporated reinforcing children for engaging in alternative behaviors to eating for 41 overweight 8- to 12-year-old children. Study 2 used a within-subject design with baseline, enriched environment and a second baseline phase to determine the influence of providing activities that compete with eating for 13 overweight 8- to 12-year-old children. Measurements included body mass index (BMI) change, alternatives to eating, eating, and physical activity. RESULTS: In Study 1 both treatments were associated with significant (p < .05) and maintained reductions in z-BMI over the 24 months of observation. The experimental group showed a significantly (p < .05) greater increase in alternatives to eating, and both groups showed significant (p < .05) increases in physical activity. In Study 2 alternative behaviors to eating were increased by almost 1 hr/day (p < .001) but were not associated with significant changes in energy intake or physical activity. CONCLUSION: These results suggest that using the methods studied, increasing behaviors that could compete with eating did not influence relative weight in a clinical outcome study or energy intake in a controlled field study.

Analysis of Variance↗

PubMed2005

Endocrine control of body composition in infancy, childhood, and puberty.

Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.

Adipose Tissue↗

PubMed2005

Magnesium deficiency is associated with insulin resistance in obese children.

OBJECTIVE: Magnesium deficiency has been associated with insulin resistance (IR) and increased risk for type 2 diabetes in adults. This study was designed to determine whether obese children exhibit serum or dietary magnesium deficiency and its potential association with IR. RESEARCH DESIGN AND METHODS: We studied 24 obese nondiabetic children (BMI > or =85th percentile) and 24 sex- and puberty-matched lean control subjects (BMI <85th percentile). We measured serum magnesium, indexes of insulin sensitivity, dietary magnesium intake (using a food frequency questionnaire), and body composition (by air displacement plethysmography). RESULTS: Serum magnesium was significantly lower in obese children (0.748 +/- 0.015 mmol/l, means +/- SE) compared with lean children (0.801 +/- 0.012 mmol/l) (P = 0.009). Serum magnesium was inversely correlated with fasting insulin (r(s) = -0.36 [95% CI -0.59 to -0.08]; P = 0.011) and positively correlated with quantitative insulin sensitivity check index (QUICKI) (0.35 [0.06-0.58]; P = 0.015). Dietary magnesium intake was significantly lower in obese children (obese: 0.12 +/- 0.004 vs. lean: 0.14 +/- 0.004 mg/kcal; P = 0.003). Dietary magnesium intake was inversely associated with fasting insulin (-0.43 [-0.64 to -0.16]; P = 0.002) and directly correlated with QUICKI (0.43 [0.16-0.64]; P = 0.002). CONCLUSIONS: The association between magnesium deficiency and IR is present during childhood. Serum magnesium deficiency in obese children may be secondary to decreased dietary magnesium intake. Magnesium supplementation or increased intake of magnesium-rich foods may be an important tool in the prevention of type 2 diabetes in obese children.

Adipose Tissue↗