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Melissa C Nelson

Publications and source records attributed to Melissa C Nelson.

14 recordsLinked to original sources
PubMed2006

Built and social environments associations with adolescent overweight and activity.

BACKGROUND: Little is known about the patterning of neighborhood characteristics, beyond the basic urban, rural, suburban trichotomy, and its impact on physical activity (PA) and overweight. METHODS: Nationally representative data (National Longitudinal Study of Adolescent Health, 1994-1995, n = 20,745) were collected. Weight, height, PA, and sedentary behavior were self-reported. Using diverse measures of the participants' residential neighborhoods (e.g., socioeconomic status, crime, road type, street connectivity, PA recreation facilities), cluster analyses identified homogeneous groups of adolescents sharing neighborhood characteristics. Poisson regression predicted relative risk (RR) of being physically active (five or more bouts/week of moderate to vigorous PA) and overweight (body mass index equal or greater than the 95th percentile, Centers for Disease Control and Prevention/National Center for Health Statistics growth curves). RESULTS: Six robust neighborhood patterns were identified: (1) rural working class; (2) exurban; (3) newer suburban; (4) upper-middle class, older suburban; (5) mixed-race urban; and (6) low-socioeconomic-status (SES) inner-city areas. Compared to adolescents living in newer suburbs, those in rural working-class (adjusted RR[ARR] = 1.38, 95% confidence interval [CI] = 1.13-1.69), exurban (ARR = 1.30, CI = 1.04-1.64), and mixed-race urban (ARR = 1.31, CI = 1.05-1.64) neighborhoods were more likely to be overweight, independent of individual SES, age, and race/ethnicity. Adolescents living in older suburban areas were more likely to be physically active than residents of newer suburbs (ARR = 1.11, CI = 1.04-1.18). Those living in low-SES inner-city neighborhoods were more likely to be active, though not significantly so, compared to mixed-race urban residents (ARR = 1.09, CI = 1.00-1.18). CONCLUSIONS: These findings demonstrate disadvantageous associations between specific rural and urban environments and behavior, illustrating important effects of the neighborhood on health and the inherent complexity of assessing residential landscapes across the United States. Simple classical urban-suburban-rural measures mask these important complexities.

Adolescent↗
PubMed2006

Body mass index gain, fast food, and physical activity: effects of shared environments over time.

OBJECTIVE: The magnitude of environmental vs. genetic effects on BMI, diet, and physical activity (PA) is widely debated. We followed a sibling cohort (where individuals shared households in childhood and adolescence) to young adulthood (when some continued sharing households and others lived apart) to examine the role of discordant environments in adult twins' divergent trends in BMI and health behaviors and to quantify the variation in BMI and behavior among all siblings that is attributable to environmental and additive genetic effects. RESEARCH METHODS AND PROCEDURES: In the National Longitudinal Study of Adolescent Health, siblings sharing households for > or =10 years as adolescents (mean age = 16.5 +/- 1.7 years; N = 5524) were followed into adulthood (mean = 22.4 +/- 1.8 years; N = 4368), self-reporting PA, sedentary behavior, and dietary characteristics. Adult BMI and adolescent z scores were derived from measured height and weight. RESULTS: Compared with those living together, twins living apart exhibited greater discordance in change in BMI, PA, and fast food intake from adolescence to adulthood. Adolescent household environments accounted for 8% to 10% of variation in adolescent fast food intake and sedentary behaviors and 50% of variation in adolescent overweight. Adolescent household effects on PA were substantially greater in young adulthood (accounting for 50% of variation) vs. adolescence. Young adult fast food intake was significantly affected by young adult household environment, accounting for 12% of variation. DISCUSSION: These findings highlight important environmental influences on BMI, PA, and fast food intake during the transition to adulthood. Household and physical environments play an important role in establishing long-term behavior patterns.

Adolescent↗
PubMed2006

Inequality in the built environment underlies key health disparities in physical activity and obesity.

CONTEXT: Environmental factors are suggested to play a major role in physical activity (PA) and other obesity-related behaviors, yet there is no national research on the relationship between disparity in access to recreational facilities and additional impact on PA and overweight patterns in US adolescents. OBJECTIVE: In a nationally representative cohort, we sought to assess the geographic and social distribution of PA facilities and how disparity in access might underlie population-level PA and overweight patterns. DESIGN, SETTING, AND PARTICIPANTS: Residential locations of US adolescents in wave I (1994-1995) of the National Longitudinal Study of Adolescent Health (N = 20745) were geocoded, and a 8.05-km buffer around each residence was drawn (N = 42857 census-block groups [19% of US block groups]). PA facilities, measured by national databases and satellite data, were linked with Geographic Information Systems technology to each respondent. Logistic-regression analyses tested the relationship of PA-related facilities with block-group socioeconomic status (SES) (at the community level) and the subsequent association of facilities with overweight and PA (at the individual level), controlling for population density. MAIN OUTCOME MEASURES: Outcome measures were overweight (BMI > or = 95th percentile of the Centers for Disease Control and Prevention/National Center for Health Statistics growth curves) and achievement of > or = 5 bouts per week of moderate-vigorous PA. RESULTS: Higher-SES block groups had a significantly greater relative odds of having 1 or more facilities. Low-SES and high-minority block groups were less likely to have facilities. Relative to zero facilities per block group, an increasing number of facilities was associated with decreased overweight and increased relative odds of achieving > or = 5 bouts per week of moderate-vigorous PA. CONCLUSIONS: Lower-SES and high-minority block groups had reduced access to facilities, which in turn was associated with decreased PA and increased overweight. Inequality in availability of PA facilities may contribute to ethnic and SES disparities in PA and overweight patterns.

Adolescent↗
PubMed2006

Physical activity and sedentary behavior patterns are associated with selected adolescent health risk behaviors.

OBJECTIVE: Little is known about how physical activity (PA), sedentary behavior, and various adolescent health risk behaviors are associated. The objective of this study was to examine relationships between PA and sedentary behavior patterns and an array of risk behaviors, including leading causes of adolescent morbidity/mortality. METHODS: Nationally representative self-reported data were collected (National Longitudinal Study of Adolescent Health; wave I: 1994-1995; II: 1996; N = 11957). Previously developed and validated cluster analyses identified 7 homogeneous groups of adolescents sharing PA and sedentary behaviors. Poisson regression predicted the relative risk of health risk behaviors, other weekly activities, and self-esteem across the 7 PA/sedentary behavior clusters controlling for demographics and socioeconomic status. Main outcome measures were adolescent risk behaviors (eg, truancy, cigarette smoking, sexual intercourse, delinquency), other weekly activities (eg, work, academic performance, sleep), self-esteem. RESULTS: Relative to high television (TV) and video viewers, adolescents in clusters characterized by skating and video gaming, high overall sports and sports participation with parents, using neighborhood recreation center, strict parental control of TV, reporting few activities overall, and being active in school were less likely to participate in a range of risky behaviors, ranging from an adjusted risk ratio (ARR) of 0.42 (outcome: illegal drug use, cluster: strict parental control of TV) to 0.88 (outcome: violence, cluster: sports with parents). Active teens were less likely to have low self-esteem (eg, adolescents engaging in sports with parents, ARR: 0.73) and more likely to have higher grades (eg, active in school, ARR: 1.20). CONCLUSIONS: Participation in a range of PA-related behaviors, particularly those characterized by high parental sports/exercise involvement, was associated with favorable adolescent risk profiles. Adolescents with high TV/video viewership were less likely to have positive risk behavior outcomes. Enhancing opportunities for PA and sport may have a beneficial effect on leading adolescent risk behaviors.

Absenteeism↗
PubMed2006

Longitudinal and secular trends in physical activity and sedentary behavior during adolescence.

OBJECTIVE: There is little epidemiologic research on longitudinal and secular trends in weight-related health behaviors throughout the stages of adolescence. In particular, few data are available to assess secular trends in various sedentary behaviors. The objective of this research was to investigate longitudinal and secular trends in physical activity and sedentary behavior in a large, diverse cohort of adolescents. METHODS: Project EAT-II is a 5-year longitudinal study (N = 2516) that includes 2 cohorts that allow for the observation of longitudinal changes from early to midadolescence (junior high to high school; n = 806; mean baseline age: 12.8 +/- 0.8 years) and mid- to late adolescence (high school to post-high school; n = 1710; mean baseline age: 15.8 +/- 0.8 years). EAT-II also examined secular trends in health behavior from 1999 to 2004 in midadolescence. The main outcome measures of the mixed-model regression analyses used in this research were self-reported weekly hours of moderate to vigorous physical activity, television/video viewing, and leisure-time computer use. RESULTS: Our findings indicate substantial longitudinal changes in moderate to vigorous physical activity, particularly among girls (decreasing 5.9-4.9 hours/week from early to midadolescence and 5.1-3.5 hours/week from mid- to late adolescence), and leisure-time computer use, particularly among boys (increasing 11.4-15.2 hours/week from early to midadolescence and 10.4-14.2 hours/week from mid- to late adolescence). Secular trends further indicate dramatic increases in midadolescent computer use from 1999 to 2004; girls increased from 8.8 to 11.1 hours/week, and boys increased from 10.4 to 15.2 hours/week. CONCLUSIONS: These adolescents experienced unfavorable shifts in activity patterns, such as longitudinal decreases in moderate to vigorous physical activity, coupled with longitudinal and secular increases in leisure-time computer use. Developing effective health promotion strategies that address a wide array of changing behavioral patterns will be important in promoting long-term health and active lifestyles among adolescents and young adults.

Adolescent↗
PubMed2005

Adolescent physical activity and sedentary behavior: patterning and long-term maintenance.

BACKGROUND: Little is known about physical activity (PA) and sedentary behavior patterning or its impact on long-term PA sustainability, particularly during the critical transition from adolescence to adulthood. METHODS: Nationally representative self-reported data were collected (National Longitudinal Study of Adolescent Health: Wave I, 1994-1995; Wave II, 1996; Wave III, 2001-2002). Cluster analyses identified homogeneous groups of adolescents with similar PA and sedentary behaviors. Logistic regression predicted odds of meeting national activity recommendations in adolescence and young adulthood. RESULTS: Seven clusters were characterized as follows: C1, high television (TV)/video, video gaming; C2, high skating, video gaming; C3, high sports participation with parents, high overall sports participation; C4, use of neighborhood recreation centers, high sports participation; C5, TV viewing limited by parents, moderate participation in school physical education (PE); C6, low parental TV control, reporting few activities overall; C7, active in school (team/individual sports, academic clubs, and PE). Odds of adolescents meeting PA recommendations were highest in C2 (odds ratio=13.1), C3 (5.8), C4 (4.2), and C7 (4.3) compared to C1. Independent of adolescent PA, absolute odds of meeting recommendations as young adults declined but were still relatively high in these clusters, indicating greater long-term PA sustainability. By young adulthood, however, overall PA declined dramatically in skaters/gamers (C2) and was notably low among those with TV viewing limited by parents (C5). CONCLUSIONS: While odds of meeting PA guidelines in adulthood declined in all clusters, the magnitude of this decline varied by cluster (declining most dramatically in skaters/gamers), providing insights into where to target effective intervention strategies that promote sustainable PA behaviors.

Adolescent↗
PubMed2005

Associations among active transportation, physical activity, and weight status in young adults.

OBJECTIVE: To describe prevalence of active, public, and car transit by overweight status and amount of leisure-time physical activity in a nationally representative cohort of ethnically diverse young adults. RESEARCH METHODS AND PROCEDURES: Questionnaire data on patterns of transportation were collected from U.S. adolescents enrolled in Wave III (2001) of the National Longitudinal Study of Adolescent Health (N = 10,771). Measured height and weight data were used to calculate BMI and classify adults by overweight status (BMI > or = 25). Self-reported physical activity data were used to classify adults into those who achieved > or = 5 bouts of weekly moderate-vigorous physical activity and those who did not. Results were stratified by overweight and physical activity status. RESULTS: The vast majority of young adults used car transit (work, 90.4%; school, 74.7%). A small proportion of young adults used active means of transportation to work (8.1%) and school (26.7%), and fewer used public transportation to work or school (<10%). The proportion of individuals using active transportation was higher among the nonoverweight traveling to work (9.2%) and school (29.7%) and among the more active traveling to work (15.2%) and school (37.0%) relative to the overweight and less active young adults. DISCUSSION: The vast majority of young adults of all racial/ethnic backgrounds, particularly blacks and Hispanics, did not use active transportation to school and/or work. Active transportation was more common among nonoverweight and more active young adults, of high socioeconomic status, particularly full-time students. Population-level efforts (and environmental supports) to increase non-leisure physical activity, particularly active transportation, are sorely needed as a means of supporting and promoting overall physical activity.

Adolescent↗
PubMed2005

Are adolescents who were breast-fed less likely to be overweight? Analyses of sibling pairs to reduce confounding.

BACKGROUND: Cohort analyses suggesting that breast-feeding protects against being overweight have been criticized for inadequately controlling for confounding associated with the self-selection of feeding practices. METHODS: Using nationally representative U.S. data from the National Longitudinal Study of Adolescent Health (1994-1996), we performed traditional cohort analyses (n = 11,998) using logistic regression to estimate the relation between breast-feeding and adolescent overweight (body mass index > or =85 percentile, based on year 2000 CDC growth charts), controlling for known potential confounders. Breast-feeding also was assessed in a subsample of 850 sibling pairs to account for unmeasured genetic and environmental factors. RESULTS: Among girls in the full cohort, the odds of being overweight declined among those who had been breast-fed at least 9 months; odds ratios ranged from 0.90 (95% confidence interval = 0.74-1.09) for <3 months of breast-feeding to 0.78 (0.64-0.96) for > or =9 months. A similar effect was seen in boys, although these trends were less consistent. In contrast, an analysis of sibling pairs provided no evidence of breast-feeding effects on weight within discordant trends. CONCLUSION: Cohort data indicate that odds of being overweight decrease as breast-feeding duration increases, at least among girls. However, sibling analyses suggest that this relationship may not be causal but rather attributable to unmeasured confounding related to mothers' choice to breast-feed, or to other childhood risk factors for overweight. Our results illustrate the utility of sibling analyses in understanding the true effect of early life exposures (such as breast-feeding) on health outcomes over time, independent of confounding factors that may not be satisfactorily controlled using traditional prospective cohort methods.

Adolescent↗
PubMed2004

Longitudinal physical activity and sedentary behavior trends: adolescence to adulthood.

BACKGROUND: There is little national research on longitudinal patterns of physical activity and sedentary behavior in ethnically diverse teens as they transition to adulthood. METHODS: Longitudinal questionnaire data from U.S. adolescents enrolled in Wave I (1994-1995) and Wave III (2001) of the National Longitudinal Study of Adolescent Health (n =13,030) were analyzed in January 2004. Incidence, reversal, and maintenance of achieving five or more weekly bouts of moderate to vigorous physical activity (MVPA) and < or =14 hours of weekly TV and video viewing, computer/video game use (screen time) were assessed. Multinomial logistic regression models examined the likelihood of achieving five or more weekly sessions of MVPA week and < or =14 hours screen time per week as an adolescent and/or young adult, controlling for household income, parental education, age of adolescent, and seasonality. RESULTS: Of those achieving five or more weekly sessions of MVPA and < or =14 hours of weekly screen time as adolescents, few continued to achieve these favorable amounts of activity (4.4%) and screen time (37.0%) as adults. More failed to maintain these favorable amounts of activity (31.1%) and screen time (17.3%) into adulthood. Black versus white females were more likely to maintain less [corrected] favorable amounts of activity from adolescence to adulthood (odds ratio [OR]=3.09; 95% confidence interval [CI]=1.49-6.42), while black males (OR=1.50; CI=1.05-2.14) and females (OR=2.00; CI=1.40-2.87) were more likely than whites to maintain less (versus more) favorable screen time hours. CONCLUSIONS: The vast majority of adolescents do not achieve five or more bouts of moderate physical activity per week, and continue to fail to achieve this amount of activity into adulthood.

Adolescent↗
PubMed2004

Five-year obesity incidence in the transition period between adolescence and adulthood: the National Longitudinal Study of Adolescent Health.

BACKGROUND: No nationally representative longitudinal data have been analyzed to evaluate the incidence of obesity in the transition between adolescence and adulthood. OBJECTIVE: The objective was to examine dynamic patterns of change in obesity among white, black, Hispanic, and Asian US teens as they transitioned to young adulthood. DESIGN: We used nationally representative, longitudinally measured height and weight data collected from US adolescents enrolled in wave II (1996; ages 13-20 y) and wave III (2001; 19-26 y) of the National Longitudinal Study of Adolescent Health (n = 9795). Obesity incidence was defined on the basis of International Obesity Task Force (IOTF) cutoffs (wave II), which link childhood body mass index (BMI) centiles to adult cutoffs (BMI > or = 30; wave III), for comparability between adolescence and adulthood. In addition, the more commonly used cutoff of BMI > or = 95th percentile for age- and sex-specific cutoffs from the 2000 Centers for Disease Control and Prevention growth charts for adolescents (wave II) were compared with adult cutoffs (BMI > or = 30; wave III). RESULTS: On the basis of the IOTF cutoffs, obesity incidence over the 5-y study period was 12.7%; 9.4% of the population remained obese and 1.6% shifted from obese to nonobese. Obesity incidence was especially high in non-Hispanic black (18.4%) females relative to white females. The prevalence of obesity increased from 10.9% in wave II to 22.1% in wave III, and extreme obesity was 4.3% at wave III on the basis of a BMI > or = 40. CONCLUSIONS: During a 5-y transitional period between adolescence and young adulthood, the proportion of adolescents becoming and remaining obese into adulthood was very high. This upward trend is likely to continue. Effective preventive and treatment efforts are critically needed.

Adolescent↗
PubMedDate not supplied

Vitamin B6 status of children with sickle cell disease.

PURPOSE: In vitro, vitamin B(6) has antisickling properties, but the effect of vitamin B status on the health of children with sickle cell disease-SS (SCD-SS) is not well described. The purpose of this study was to assess vitamin B(6) status of children with SCD-SS ages 3 to 20 years and determine its relationship to growth, dietary intake, and disease severity. PATIENTS AND METHODS: Vitamin B(6) status was assessed by serum pyridoxal 5-phosphate (PLP) concentration in subjects with SCD-SS and by urinary 4-pyridoxic acid (4-PA) concentration in other subjects with SCD-SS and healthy control children. Concentration of PLP was compared with anthropometric measures of growth and nutritional status, dietary intake, hematologic indices, and frequency of SCD-related illness. RESULTS: The PLP concentration of subjects with SCD-SS was 15.6 +/- 15.2 nmol/L. Seventy-seven percent had a PLP concentration below the deficiency criterion (20 nmol/L) suggested by the Dietary Reference Intakes (1998). Controlling for alkaline phosphatase, age, and gender, PLP concentration was associated positively with weight, body mass index, and arm circumference -scores and negatively with reticulocyte count. Urinary 4-PA was lower in children with SCD-SS versus controls, although 4-PA/creatinine values did not differ between groups. CONCLUSIONS: Children with SCD-SS had apparently low serum PLP concentrations in the absence of excess vitamin B(6) excretion, suggesting low vitamin B(6) status. Low serum PLP concentration was associated with indicators of poor nutritional status and may be related to increased hemolysis in children with SCD-SS.

Adolescent↗