Biomedical subjects

Joanne S Harrell

Publications and source records attributed to Joanne S Harrell.

17 recordsLinked to original sources

PubMed2006

Prevalence of abnormal lipid and blood pressure values among an ethnically diverse population of eighth-grade adolescents and screening implications.

OBJECTIVES: Our goal was to report the prevalence of elevated blood pressure and lipid levels among eighth-grade adolescents from 3 US locations and differences by gender, ethnicity, and overweight percentile group. METHODS: Fasting blood samples and blood pressure levels were obtained from 1717 eighth-grade students from 12 predominantly minority schools in 3 states (Texas, California, and North Carolina) during spring 2003. Age, gender, ethnicity, weight, and height were ascertained and BMI calculated. The presence of abnormal total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides, prehypertension, hypertension, at risk for overweight, and overweight were calculated and compared with the findings of previous youth studies. We examined whether prevalence differed by gender, ethnicity, or BMI group. RESULTS: A total of 23.9% of participants had high blood pressure, 16.7% had borderline total cholesterol, 4.0% had high total cholesterol, 10.5% had borderline low-density lipoprotein cholesterol, 3.9% had high low-density lipoprotein cholesterol, 13.3% had low high-density lipoprotein cholesterol, and 17.2% had high triglycerides. A total of 19.8% of participants were at risk of overweight (BMI > or = 85th percentile, < 95th percentile) and 29% were overweight (BMI > or = 95th percentile). The prevalence of risk factors was associated (P < .05) with the overweight group and differed by age and gender. CONCLUSIONS: Prevalence of elevated blood pressure was higher in this sample than in previous national surveys in which subjects were less overweight. Associations between overweight and both elevated lipid and blood pressure levels suggest that adolescents overweight or at risk for overweight should be screened for elevated blood pressure and lipid levels.

Adolescent↗

PubMed2005

Central obesity, the metabolic syndrome, and plasminogen activator inhibitor-1 in young adults.

PURPOSE: To determine the association of central obesity with the components of the metabolic syndrome (i.e., hyperinsulinemia, hypertension, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol [HDL-C]) and plasma levels of plasminogen activator inhibitor-1 (PAI-1) in young adults. We hypothesized that central obesity as determined by waist circumference would be predictive of components of the metabolic syndrome and of PAI-1. DATA SOURCES: Participants in this descriptive study consisted of 85 healthy young adults aged 19-22 years, 62% women who fasted for 12 h prior to data collection in the General Clinical Research Center at a major university hospital medical center in the southeastern United States. CONCLUSIONS: The majority of the participants had one or more components of the metabolic syndrome (n= 43, 51%). Central obesity was present in 14.1% and was more common in women than men (chi(2)= 5.11; p= 0.021). Central obesity was significantly and positively correlated with elevated blood pressure (BP) and levels of insulin and PAI-1 while being negatively correlated with HDL-C. In multiple regression analyses, diastolic BP, insulin, and HDL-C were predictors of waist circumference (R(2)= 0.615). In a separate multiple regression, PAI-1 was predicted by waist circumference (R(2)= 0.331). IMPLICATIONS FOR PRACTICE: Many otherwise healthy young adults have one or more components of the metabolic syndrome. Assessment and institution of preventative measures for obesity and the components of the metabolic syndrome should begin in childhood. Furthermore, determination of waist circumference especially in young women may aid the practitioner to identify those at risk for the metabolic syndrome earlier in their disease trajectory. Furthermore, insulin resistance is believed to occur initially in the trajectory of the metabolic syndrome, making it a principal contender for suitable interventions to reduce risk for both type 2 diabetes and cardiovascular disease (CVD). Homeostatic model assessment for insulin resistance was used to assess for insulin resistance among the euglycemic participants. Recording the presence of insulin resistance will aid the practitioner in determining if a low-risk patient is in peril for development of type 2 diabetes and/or CVD. Early cardiovascular risk recognition is vital to clinical practice as it allows more time for the practitioner to counsel patients for the essential planning needed to make lifestyle changes.

Adipose Tissue↗

PubMed2005

Energy costs of physical activities in children and adolescents.

PURPOSE: The primary aim was to determine the energy expenditure (EE: kcal.kg(-1).h(-1)) in terms of caloric cost and metabolic equivalents of activities commonly performed by children and adolescents. Secondary aims were to determine at what age and pubertal developmental stage values approach those of adults. METHODS: In this descriptive study, 295 volunteer youth 8-18 yr of age completed 18 common physical activities (including rest) while EE was measured continuously with a portable metabolic system. Three sets of activities were assigned in random order for each subject. Activities ranged from television viewing and video game play to running and rope skipping. Pubertal development was estimated from a self-report questionnaire. RESULTS: At rest, VO(2) and EE were highest in the youngest children and decreased with advancing age and higher pubertal stage in both genders. The age-adjusted and puberty-adjusted energy expenditure values were generally lower than the compendium MET values for sedentary and moderate activities but were more varied for high-intensity activities. However, the ratio of activity EE to REE was comparable in children and adults. CONCLUSIONS: Energy expenditure per kilogram of body mass at rest or during exercise is greater in children than adults and varies with pubertal status, thus using the definition of a MET in the compendium of physical activities without adjustment is inadequate for energy estimation in children, until a child reaches Tanner Stage 5. However, the ratio of activity EE to resting EE in children appears to be similar or slightly less than in the compendium, suggesting that the compendium MET increments used with our adjusted EE values more closely approximate the true EE of activities in children than present adult norms.

Adolescent↗

PubMed2005

The relationship between leptin, metabolic hormones, exercise and body composition in adolescents.

During adolescence, little is known about the relationship between leptin and metabolic hormones and how these are modified by body composition and exercise. This study determined: 1) the relationships between leptin, triiodothyronine, cortisol, and insulin, and 2) whether these relationships were modified by body composition and exercise. Fasting hormonal concentrations were assessed from 80 girls and 80 boys, aged 11-18 yr. In a multiple regression model, including the hormones and gender, only gender and insulin were significant predictors of leptin (R2 = 0.394; p <0.001). In a second model, including body fat and exercise, the levels of body fat, gender, free triidothyronine and cortisol explained 59.6% of the variance in leptin (p <0.05). The results suggest that in adolescents, the relationship between leptin and insulin is mediated by body fat. Leptin is negatively associated with cortisol in boys and with thyroid hormones in girls; these hormones possibly interact to sustain normal growth and maturation.

Adolescent↗

PubMed2004

Overweight in children: definitions, measurements, confounding factors, and health consequences.

The epidemic of childhood overweight continues to grow at staggering rates, increasing nearly four-fold between 1963 and 2000. Children that are overweight are more apt to be overweight adults and are more likely to suffer adverse health consequences associated with excess weight. Nurses have a unique presence in the healthcare environment to assess children for overweight, provide parent/child nutritional education, and conduct obesity-related research. This article provides an overview of the current body of literature surrounding the definition and measurement of overweight and the morbidity association with childhood overweight.

Adolescent↗

PubMed2003

Youth characteristics and contextual variables influencing physical activity in young adolescents of parents with premature coronary heart disease.

This study examined influences on physical activity of young adolescents whose parents have premature coronary heart disease (CHD). Consistent with Bronfenbrenner's theory, the influences examined were personal characteristics of the subjects and selected contextual variables (peers, family, and community). Subjects were 113 youths, aged 11 to 14, 53% boys, 73% Caucasian, all with parents with premature CHD. Children were most likely to be active if their fathers were active, and those living in the coastal region were less likely to be active than other children. Peer influence interacted with both pubertal status and geographic region in its effect on children's activity. Children were more active when they had active peers only when the youth were midpubertal or when they were in the coastal region. Results emphasize the importance of nursing interventions to influence behaviors of these vulnerable children.

Adolescent↗

PubMed2003

Gender and ethnic changes in physical work capacity from childhood through adolescence.

This study determined gender and ethnic differences in physical work capacity (PWC170) of 8-16-year-old American youth as they progress from elementary to high school. A multicohort group of 2,540 youth participated 50.4% girls (21.4% African Americans, and 78.6% Caucasians). PWC170 was predicted from cycle ergometer testing six times over a 7-year period. The absolute PWC170 of girls stabilized in early adolescence, while boys increased with each trial. The PWC170 relative to body weight of girls decreased steadily, whereas the boys remained stable. African Americans had greater absolute PWC170 values than Caucasians (p = .0001). The relative PWC170 was lower for African American girls than Caucasian girls (p = .0001), but there were no ethnic differences for boys (p > .05). Although correlations and grouping suggested moderate tracking; girls with high relative PWC170 tended to migrate to lower levels as they aged, where as high-peforming boys maintained their PWC170 as they aged.

Adolescent↗

PubMed2003

Assessing physical activity in adolescents: common activities of children in 6th-8th grades.

OBJECTIVES: To provide data for physical activity assessment in practice by describing the leisure time activities of adolescents and determining if the activities and the metabolic equivalents (MET levels) of those activities differ for boys and girls. DATA SOURCES: The study was conducted in five middle schools in three rural counties in North Carolina. Subjects were 1,211 6th, 7th, and 8th graders aged 11-14 (mean 12.2) years. Half (52.5%) were girls. The sample was 64% white, 24% African-American and 12% other races. RESULTS: The top five activities of boys were football, basketball, bicycling, running, and baseball; the top five activities of girls were talking, running, walking, bicycling, and dancing. The average MET was 5.3 for boys and 4.3 for girls (p = 0.000). By grade levels, 6th graders had an average MET of 4.9 and the MET of 8th graders was 4.5 (p < 0.05). Older youth, girls, and children of parents with more education reported significantly more sedentary activities than the other youth. IMPLICATIONS FOR PRACTICE: Physical activity is an integral component of overall health. Once activities and activity levels are known, current practices can be augmented or changed to accommodate improved understanding of physical activity. Because an active lifestyle is important in preventing obesity and other chronic conditions and for general health, nurse practitioners (NPs) should ask adolescents about their common activities and encourage them to continue the more vigorous activities and reduce time spent in sedentary pursuits. Prescriptive physical activity can be included for primary, secondary, or even tertiary prevention, thus crossing all levels of NP practice.

Adolescent↗

PubMed2003

Accuracy of three dry-chemistry methods for lipid profiling and risk factor classification.

The purpose of this project was to determine the accuracy in lipids measurement and risk factor classification using Reflotron, Cholestech, and Ektachem DT-60 dry-chemistry analyzers. Plasma and capillary venous blood from fasting subjects (n = 47) were analyzed for total cholesterol (TC), high density lipoprotein (HDL-C), and triglycerides (TG) using these analyzers and a CDC certified laboratory. Accuracy was evaluated by comparing the results of each portable analyzer against the CDC reference method. One-way ANOVAs were performed for TC, HDL-C, and TG between all portable analyzers and the reference method. Chi-square was used for risk classification (2001 NIH Guidelines). Compared to the reference method, the Ektachem and Reflotron provided significantly lower values for TC (p < .05). In addition, the Cholestech and Ektachem values for HDL-C were higher than the CDC (p < .05). The Reflotron and Cholestech provided higher values of TG than the CDC (p < .05). Chi-squares analyses for risk classification were not significant (p > .45) between analyzers. According to these results, the Ektachem and Cholestech analyzers met the current NCEP III guidelines for accuracy in measurement of TC, while only Ektachem met guidelines for TG. All 3 analyzers provided a good overall risk classification; however, values of HDL-C should be only used for screening purposes.

Adult↗

PubMed2003

Tracking of physical activity and aerobic power from childhood through adolescence.

PURPOSE: To evaluate the tracking of physical activity levels (PA) and aerobic power (VO2max) in African-American (AA) and Caucasian (CA) youth as they age from 8 to 16 yr. METHODS: Subjects were 529 girls and 535 boys for whom data were obtained at least three times over 7 yr and a subset of 387 girls and 404 boys who participated in all years. PA levels were obtained from a survey. VO2max was predicted from a cycle ergometer test. RESULTS: Spearman correlation for VO2max for years 1-7 for AA boys and girls were similar (rho approximately 0.53). Year 1-7 correlations for VO2max for the CA boys and girls were similar (rho approximately 0.50-0.53). The year 2-7 correlations for PA were similar for the AA and CA girls but higher for the AA than the CA boys. The kappa (kappa) statistics for VO2max indicated substantial year-to-year agreement on categorization (high, moderate, and low), with AA girls having the highest agreement and AA boys the lowest. The kappa statistic for high, moderate, and low PA groupings in girls of either ethnicity was quite low, whereas the kappa statistics for the boys were somewhat better. The general estimating equation (GEE) stability coefficients for tracking of VO2max were similar between the sexes and ethnicities (P<0.0001). The GEE stability coefficient for PA was better for the boys than girls and slightly better for the AA than CA. CONCLUSION: Although aerobic power and physical activity levels decline from childhood through adolescence, aerobic power tracks better than physical activity levels. Because tracking within the cohort is only moderate, change is possible if we intervene early in these youth.

Adolescent↗

PubMed2002

A school-based intervention can reduce body fat and blood pressure in young adolescents.

PURPOSE: To determine the effect of increasing the aerobic component of the school's physical activity program and improving the knowledge about weight control and blood pressure on the blood pressure and body fat of early adolescents. METHODS: The subjects were 1140 youth aged 11 to 14 years (630 females, 510 males; 64% white, 24.4% African-American, and 11.6% "other"), who were randomly assigned by school into four treatment groups: exercise only, education only, exercise and education combined, and control group. Heights, weights, and skinfold thicknesses were measured, and body mass index (BMI) was computed kg/m(2). Blood pressure was obtained in duplicate using a random-zero mercury sphygmomanometer. Maximal oxygen uptake was predicted from a submaximal cycle ergometer test. Data were analyzed using analysis of covariance statistics, adjusting for gender, ethnicity, age, socioeconomic status, and initial baseline characteristics. RESULTS: Systolic and diastolic blood pressures increased more in the control group than in the intervention groups (p =.001). The BMI did not change significantly (p =.709), but the sum of skinfolds increased less in subjects in the exercise intervention groups than the education only or control groups (p =.0001). The small increase in (p)VO(2)max of the combined exercise and education group was significantly greater than the education only group (p =.0001). CONCLUSION: An exercise program for youth can have a positive effect on blood pressure independent of body weight loss.

Adolescent↗

PubMed2002

Predicted maximal aerobic power in youth is related to age, gender, and ethnicity.

PURPOSE: To determine the effects of age, gender, and ethnicity on the predicted aerobic power of youth as they age from 8 to 16 yr. METHODS: The sample was a multicohort group of 2540 African Americans (N = 543) and Caucasians (N = 1997), 1279 (50.4%) girls and 1261 (49.6%) boys. Heights, weights, and sum of skin folds (triceps + subscapular) were measured. Aerobic power ((p)VO(2max)), expressed in relative (mL x kg(-1) x min(-1)) or absolute (L x min(-1)) terms, was predicted from a three-stage cycle ergometry test. RESULTS: Quadratic mixed-model analysis indicated that boys had higher relative and absolute (p)VO(2max) than the girls (P = 0.0004). The African American subjects had a higher absolute (p)VO(2max) (L x min(-1)) than the Caucasians, but their relative (p)VO(2max) was lower than the Caucasians (P = 0.031). Finally, age had a significant effect on (p)VO(2max) (P = 0.0001). The absolute (p)VO(2max) of the girls increased 9%.yr(-1) until age 14; but their relative (p)VO(2max) declined approximately 1.2 mL x kg(-1) x min(-1) x yr(-1). The absolute (p)VO(2max) for the boys increased yearly by approximately 14% from ages 8 to 16 yr, but the relative (p)VO(2max) of the African American males was stable from ages 8 to 11, then dropped, and stabilized again between ages 12 and 16 yr. The relative (p)VO(2max) of the Caucasian boys declined from ages 8 to 10, but then increased slightly from age 12 to 16 yr. In addition, the interactions of age and gender, and age squared and gender were significant (P < 0.02). CONCLUSION: These data indicate that although absolute (p)VO(2max) (L x min(-1)) increases from age 8 to 16 yr, relative (p)VO(2max) (mL x kg(-1) x min(-1)) declines. The decline appears to be related to increased fat mass. Similarly, the higher relative (p)VO(2max) (mL x kg(-1) x min(-1)) of the Caucasian youth compared with the African American youth was related to lower weights and skin folds of the Caucasian youth.

Adolescent↗

PubMed2002

Building a research program focused on vulnerable people.

The center is playing an important role in facilitating research by providing resources and an interchange of ideas to help researchers target the methodological and conceptual issues with which they are currently faced in working with elder, young, poor, rural, and minority participants. Through activities and collaborations, the center can advance the science beyond what individual studies can provide and continue to build our knowledge of the prevention and management of chronic illness in vulnerable people. The center is ideally positioned to explore interventions that draw on nursing's historic role in the care of the chronically ill while also addressing the health needs of the most vulnerable people in the state and in the Southeast.

Chronic Disease↗

PubMedDate not supplied

Fostering prevention in the pediatric population.

Although cardiovascular disease is seldom manifested clinically before the fourth or fifth decade of life, atherosclerotic cardiovascular disease processes begin in early childhood. Fatty streaks and atherosclerotic lesions have been found post-mortem in the aorta and coronary vessels of children as young as 6 years of age. The modifiable risk factors for heart and vascular disease that are found in adults, such as hypertension, dyslipidemia, smoking, obesity, and physical inactivity, are also present in children. Available evidence emphasizes the need for both population-based and individual approaches to primary prevention of CVD beginning in childhood. This article summarizes this evidence and outlines strategies for promoting primary prevention in children and adolescents.

Adolescent↗

PubMedDate not supplied

Maintaining regular physical activity in women: evidence to date.

Physical activity is well established as a primary health promotion and cardiovascular disease prevention behavior, yet over 60% of the population does not participate in regular physical activity. Maintenance of regular physical activity is a complex behavior influenced by variables from several domains. This review includes studies of the relationship between physical activity in women and psychological, social environmental, demographic, physiologic, health status, and physical activity variables. A key issue in physical activity research is development of interventions for maintaining a physically active lifestyle. Interventions for maintenance of regular physical activity that have a strong theoretical basis will be beneficial to women in primary care settings, occupational settings, wellness centers as well as public health departments and other organizations that address the needs of women.

Activities of Daily Living↗

PubMedDate not supplied

Changing our future: obesity and the metabolic syndrome in children and adolescents.

Obesity, or overweight, in childhood is a major risk factor for the metabolic syndrome in adolescence, as the prevalence in US children tripled between 1970 and 2000. An increase in the metabolic syndrome in youth has followed this increase. In population-based studies, the prevalence of the syndrome ranged from 3.6% to 4.2%. In smaller studies with many overweight youth, the prevalence was 28.7% to 39.7% in those who were overweight and 49.7% in those who were severely obese. Overweight children are likely to have hyperinsulinemia, high-density lipoprotein cholesterol, high triglycerides, and hypertension, which are components of the metabolic syndrome. Nurses have an important role in screening for these metabolic syndrome components. Screening is especially important in boys and girls who are overweight and in girls with early menarche. A problem when screening children and adolescents is determining normative values, but guidelines are available. Prevention and management of the metabolic syndrome are not specific to the syndrome, but rather should be focused on the underlying problem of overweight and related problems that comprise the syndrome. We must use all avenues available to us, including influencing public and school policies, and pay close attention to overweight and metabolic syndrome components in our clinical practice, whether with children or adults. Preventing and managing the metabolic syndrome should be a family matter, and the necessary lifestyle changes will benefit the entire family.

Adolescent↗

PubMedDate not supplied

Racial and socioeconomic differences in risk factors for cardiovascular disease among Southern rural women.

BACKGROUND: African American women living in the Southeast experience a higher mortality due to cardiovascular (CV) disease than their White counterparts. It is unclear if this vulnerability to CV disease is due to race, socioeconomic status, or health behaviors. OBJECTIVES: To examine the disparities in cardiovascular health between Southern rural, African American and White women to determine if a CV Risk-Index differed by race, education, or income levels and if differences persisted when controlling for body mass index (BMI). METHODS: Subjects were 1,110 women (27% African American, 73% White) residing in rural North Carolina. Data were collected by mailed questionnaire and analyzed using analysis of variance (ANOVA) and analysis of covariance (ANCOVA). RESULTS: African American women had significantly lower education and lower income than Whites, higher BMI, and a much greater prevalence of hypertension, angina, and diabetes. In a three-way ANOVA including race, income, and education, education and race were significant predictors of the CV Risk Index, but when adjusted for BMI race was no longer significant (p =.3039); the only significant predictors were BMI and educational level. DISCUSSION: Women with the least education had the highest CV Risk-Index, regardless of race. These findings suggest the need to focus risk reduction interventions on all Southern rural women with limited education, not only African American women. This supports the current literature that suggests race should be viewed as a risk marker rather than a risk factor.

Adult↗