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Biomedical subjects

J S Harrell

Publications and source records attributed to J S Harrell.

At least 37 records · Page 2Linked to original sources
PubMed1998

Predicting aerobic power in children. A comparison of two methods.

OBJECTIVE: To compare the accuracy of two equations for predicting VO2max of children using submaximal cycle ergometry. EXPERIMENTAL DESIGN: Repeated measures comparing treadmill measured maximal aerobic power (VO2max) with two methods of predicting VO2max using cycle ergometry testing. PARTICIPANTS: Thirty-three children (15 boys and 18 girls) aged 7-13 years served as subjects. MEASURES: Each child completed a treadmill graded exercise test (GXT) to volitional fatigue to assess VO2max. Each child also completed a progressive 9-min, three-stage, submaximal cycle ergometer test. Heart rates obtained during the last minute of each stage of the ergometer test were used to predict VO2max. Predictions were based on a gender-specific modification of the PWC170 (PWCGS) and a modification of the PWC195 using a 1.17 correction factor and an age and gender-adjusted estimate of resting metabolic rate. RESULTS: The correlations between both submaximal tests and the GXT were significant (p < 0.001); however, the correlation between the GXT and the PWC195 equation (r = 0.807) was higher than the correlation between the GXT and the PWCGS equation (r = 0.658). Analysis indicated that the PWCGS equation significantly underestimated the VO2max compared to either the GXT or PWC195 (GXT = 45.0 +/- 7.1, PWC195 = 44.7 +/- 6.2, PWCGS = 42.7 +/- 5.8 ml/kg/min; p < 0.01). CONCLUSIONS: These results suggest that although the gender-specific PWCGS method is easier to compute and may be acceptable, the modified PWC195 method is a more accurate estimate of VO2max in children.

Adolescent↗
PubMed1997

Family member discrepancies in report of a child's race.

This paper describes the types of discrepancies in self report of a child's race in a research study of cardiovascular health in school age children. Researchers sometimes make conclusions based on the percentage of subjects from each racial group included in the study. This is particular concern because in intervention studies researchers may report differing responses to treatment based on the race variable. This study increases awareness of issues surrounding assigning race of children participating in research studies.

Bias↗
PubMed1996

Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: the Cardiovascular Health in Children (CHIC) study.

OBJECTIVE: To test a classroom-based intervention to reduce cardiovascular disease risk factors in elementary school children. STUDY DESIGN: This was a randomized, controlled field trial in 12 schools across North Carolina, stratified by geographic region and urban/rural setting. Subjects were 1274 third and fourth graders (48% boys). The intervention, taught by regular classroom and physical education teachers, provided all children an 8-week exercise program and 8 weeks of classes on nutrition and smoking. Data were analyzed at the school level with survey regression models and at the individual level with multivariate analysis of variance and analysis of covariance models; 95% confidence intervals were computed. RESULTS: Children in the intervention group had significantly greater knowledge (7.9% more correct) and a significant increase in self-reported physical activity than children in the control group. Trends for the intervention group were a reduction in total cholesterol level (-5.27 mg/dl), an increase in aerobic power, a reduction in body fat, and smaller rise in diastolic blood pressure than control children. CONCLUSIONS: This classroom-based, public health approach improved children's cardiovascular disease risk profiles; it is practical and fairly easy to incorporate into the school day. All children directly receive the potential benefits of the intervention without a risk of labeling. This program can improve health knowledge, habits, and health outcomes of young children at a time when health habits are being formed.

Cardiovascular Diseases↗
PubMed1996

Promotion of cardiovascular health in children by nurse practitioners and physicians in family practice.

The purpose of this study was to describe cardiovascular (CV) health promotion practices of nurse practitioners (NPs) and physicians (MDs). Clinical practice was described for three age groups of children both with and without parental premature heart disease. Differences in clinical practice by type of provider and by age and risk level of the child were examined. A 42-question survey was mailed to all family NPs in North Carolina and to MDs randomly selected from the roster of the North Carolina Academy of Family Physicians; 94 responded. A high level of blood pressure measurement for all children and counseling regarding smoking for 13 to 19 year olds was found among all participants. Fewer health promotion activities were reported for other risk factors for the oldest group and for the younger children in general. Health promotion practices increased with the age of the child. Nurse practitioners had significantly higher total CV health promotion scores than did MDs, regardless of the age or risk level of the child. An increase in counseling about prudent diet and increased physical activity is needed for all children, regardless of risk level. In addition, there should be an increase in CV health promotion activities with younger children.

Adolescent↗
PubMed1996

An occupation based physical activity intervention program: improving fitness and decreasing obesity.

The purpose of this quasi-experimental study was to determine the effectiveness of an occupation based health and fitness program. Subjects were 1,504 police trainees (85% male, 15% female) with an ethnic distribution of 82% white, 16% African American, and 2% other. Data were collected at 25 sites across the state of North Carolina. The sites were randomly assigned to either the experimental group (implemented the intervention) or the control group (continued usual training). As compared with controls, subjects at the experimental sites improved significantly in cardiovascular fitness (aerobic power), general muscular strength (number of sit ups per minute), and flexibility, and lowered their body fat. The intervention required minimal equipment and was taught primarily by peers who received a 1 week training program. This occupational approach to improving health could be particularly useful in occupations with many workers who seldom engage in leisure time physical activity.

Adolescent↗
PubMed1996

The Youth Health Survey: reliability and validity of an instrument for assessing cardiovascular health habits in adolescents.

The Youth Health Survey (YHS) was developed as part of a school-based longitudinal study (Cardiovascular Health in Children and Youth) to assess and track behavior and attitudes related to cardiovascular risk factors in children and adolescents. This paper reports the psychometric properties of each of the subscales of the YHS and the results of a pilot study with sixth, seventh and eighth grade students (n = 205) at two schools in the Southeast. The eight subscales of the YHS assess health habits and attitudes of the adolescent as well as selected peer and family influences on those health behaviors. Internal consistencies for seven of the eight subscales ranged from .74 to .89. Test-retest reliability for six of the eight subscales ranged from .67 to .89. Construct validity was established through factor analyses of four of six of the subscales. Findings support using the YHS with some minor revisions to assess behaviors, attitudes and influences which may lead to CVD in adulthood.

Adolescent↗
PubMed1995

Childhood obesity elevates blood pressure and total cholesterol independent of physical activity.

OBJECTIVE: To compare the habitual physical activity, blood pressure, total cholesterol levels of obese and non-obese matched children. SUBJECTS: 546 obese children (BMI and sum of skinfolds > or = 90% tile) were matched for gender, race, age, and height (within 2 cm) with non-obese controls for a total sample of 1092 children. MEASUREMENTS: Systolic (BPsys) and diastolic (BPdia) blood pressure by mercury sphygmomanometer, total cholesterol by reflectance photometry, and physical activity by questionnaire. RESULTS: Mean comparisons indicated the obese children, regardless of gender, had higher BPsys (108 +/- 11 vs 104 +/- 10 mm Hg, P = 0.0001), BPdia (70 +/- 9 vs 68 +/- 8 mm Hg, P = 0.002), and greater total cholesterol levels (4.47 +/- 0.80 vs 4.11 +/- 0.75 mmol/L, P = 0.0001) than the non-obese subjects. Self-reported physical activity scores were not significantly different when comparing the obese and non-obese children. Correlations between self-reported activity and cholesterol or blood pressure were all very low and not significant (r < or = 0.06). CONCLUSION: These results suggest that childhood obesity is associated with higher blood pressures and greater circulating cholesterol levels independent of physical activity levels.

Aging↗
PubMed1994

Cardiovascular health promotion in children: program and policy implications.

Cardiovascular disease is the leading cause of death in the United States; it is also a major factor in rising health care costs. Risk factors for the disease are present in childhood, at the time when lifelong health habits are forming. Thus, strategies for improving the cardiovascular health of children through programs and policy may be expected to have a maximum effect. The cardiovascular health in children study identified the prevalence of cardiovascular risk factors in 2209 children age 8 to 11 years, attending 21 rural and urban public schools in North Carolina. Schools were randomly selected from three regions of the state (coastal, piedmont, mountain) in which the frequency of cardiovascular disease differs. Initial results of the study demonstrate the use of such findings in formulating health policy and in designing intervention programs.

Cardiovascular Diseases↗
PubMed1993

Parental influences on childhood fitness and activity patterns.

The purpose of this study was to determine the effect of parental attitudes and self-reported exercise habits on the fitness and activity levels of their children. One parent from each of 1,253 families was asked about exercise habits and completed the Exercise Benefits and Barriers Scale (EBBS) to determine their personal attitudes toward exercise. The children completed a self-reported activity questionnaire (SRA) and had their aerobic power predicted using a cycle ergometer test. Multiple regression indicated that the parents' EBBS scores were weakly associated with the child's maximal oxygen uptake (VO2max); the mothers' association was significant, but the fathers was not. The children's SRA scores were not correlated with parents' attitudes or exercise habits. These results suggest either that factors other than parental attitudes and exercise habits are more influential in determining the fitness and activity levels of children or that the instruments lack precision. Thus, to improve the cardiovascular fitness of children, we need to examine factors in the child's environment that may be more influential than parental attitudes and examples.

Attitude↗
PubMed1992

Cardiovascular risk factors in textile workers: prevalence and intervention.

This study included 1,390 textile workers from a southern state who received a screening for risk factors for heart disease. Occupational health nurses then provided an education/counseling intervention and one or more American Heart Association pamphlets using the results of the screening. Over half of the workers had at least one modifiable risk factor for heart disease. The most common modifiable risk factor was smoking. Most of the participants (60.8%) had a cholesterol level less than 200 mg/dL, but 27.4% were in the borderline high range of 200-239 mg/dL, and 11.8% had a cholesterol of 240 mg/dL or higher. Almost 26% of the participants had a blood pressure of 140/90 or higher. Findings on a subset of 544 workers re-screened at 6 months were: workers with hypertension were able to lower their blood pressure significantly; cholesterol levels increased slightly in all participants except white males; and although some smokers stopped smoking, others began smoking, so the total number of smokers at the second test was actually slightly higher than at the first screening.

Adult↗
PubMed1992

Predictors of smokeless tobacco use by adolescents.

Sixth and seventh graders (N = 2,020) were surveyed to determine the prevalence of smokeless tobacco (SLT) use and peer and parental influences on SLT use. Nearly 34% of boys and 12% of girls had used SLT at some time, and 8% of boys and 1% of girls were current users. While most associations were significant, the strongest relationships were between subjects' and peers' use of SLT. Logistic regression showed that the odds ratios for predicting adolescent's current use of SLT were 13.6 for peer use, 6.0 for male gender, 2.8 for white race, 2.8 for fathers' and 8.0 for mothers' ever use of SLT, and 2.6 if the mother was not a high school graduate. Results support the need for a multidisciplinary approach to research, education, treatment, and prevention to combat this growing health risk.

Adolescent↗
PubMed1991

Cardiovascular responses to weighing in healthy subjects.

This study examined the cardiovascular responses of 22 healthy subjects (mean age 48 years) to two methods of weighing--over bed and standing scale. Variables were measured at one-minute intervals during the weighing treatments and a rest period after each treatment and included: cardiac output, stroke volume, heart rate, the ratio of pre-ejection period to left ventricular ejection time (a measure of contractility), blood pressure, mean arterial pressure and total peripheral resistance. Mean changes during the weighing treatments demonstrated activation of reflex responses to gravitational shifts in blood volume, which were opposite in direction between the two methods and attributed to posturally-induced shifts in venous return. During the five-minute rest period after weighing, all values rapidly returned to baseline. Compared to baseline measures, responses during the weighing treatments differed significantly between treatments (p less than 0.01), but none differed significantly between rest periods.

Adult↗
PubMed1991

Effects of occupied and unoccupied bed making on myocardial work in healthy subjects.

Strict bed rest prescribed after acute myocardial infarction provides rest for the heart in an effort to lessen myocardial work. However, bed rest has been implicated as a threat to physical and psychosocial well-being. Nurses must question whether activities associated with bed rest, such as bed making by hospital personnel while the patient is occupying the bed, actually require less myocardial work than out-of-bed activities. In this study we examined cardiovascular function of 22 healthy individuals, 10 (45.5%) men and 12 (54.5%) women ranging in age from 34 to 69 years (mean 48 years), during occupied (side to side method) and unoccupied (patient up to chair) bed making. Cardiac output, heart rate, stroke volume, systolic blood pressure, diastolic blood pressure, mean arterial pressure, total peripheral resistance, and the ratio of preejection period to left ventricular ejection time were measured by using an impedance cardiograph and vital signs monitor. Although differences between these measurements during the two bed making procedures were statistically significant (p less than 0.001), they were not deemed clinically significant for healthy subjects because they represent transient reflexive responses to posturally induced changes in venous return rather than substantial increases in myocardial work. When the goal is minimal myocardial energy expenditure, making the bed when it is unoccupied may offer a sound alternative to making an occupied bed.

Bed Rest↗
PubMed1990

A comparison of two fitness programs to reduce the risk of coronary heart disease in public safety officers.

The purpose of this investigation was to determine the effectiveness of a fitness program designed as an alternative to the standard weight-training and running program and using limited resources and facilities. Forty-three men from the North Carolina Justice Academy, randomly assigned into two groups, completed 12 weeks of physical training. The WT group used a standard weight training and running, whereas the REC group ran and completed a resistive exercise circuit. The REC circuit consisted of nine exercises designed to improve muscular strength and endurance separated by 30 seconds of aerobic exercise. The exercises used chairs, tables, sawhorses, and body weight to provide the resistance. The results indicated that the REC program improved muscular strength and aerobic capacity as well as the WT program. Furthermore, the REC group lost more weight, reduced body fat, and improved their lipid profiles significantly more than the WT group. Thus, the REC program is a viable alternative for the training of public safety officers when only limited resources are available.

Cholesterol↗
PubMed1990

Heart sound simulation: how useful for critical care nurses?

Forty critical care nurses participated in a 2-hour teaching program using a heart sound simulator to increase skill in recognition of heart sounds. Mean test scores increased 10 points from the pretest to the first posttest (t = 11.9, p = 0.0001), and this increase was maintained on the second posttest 3 weeks later. Medical intensive care unit and coronary care nurses scored higher than the other critical care nurses. There was a low correlation between recognition of sounds and years of critical care experience. The correlation between the subjects' self-rating of knowledge of heart sounds and their actual skills was also low. These findings suggest that a similar teaching program might be useful for critical care nurses.

Adult↗
PubMed1989

Do nursing diagnoses affect functional status?

1. Nurses in this study often made diagnoses pertaining to physiological or physical problems rather than psychosocial problems. One diagnostic category, "impaired home maintenance management," was consistently used incorrectly, suggesting a need for careful clinical training of nursing staff in diagnostic reasoning. 2. Patients who had a greater number of nursing diagnoses had greater improvements in function during the hospital stay. One explanation is that more nursing diagnoses may lead to more independent nursing actions, resulting in improvements in functional abilities. 3. Functional status on admission measured by the Katz ADL was the most powerful predictor of functional status at discharge. The scale can readily be used by nurses to document basic functioning and to quickly identify patients needing or coordinated discharge planning. 4. Institutionalized had a higher mean number of nursing diagnoses than those who were discharged to their own homes. The most powerful predictor of institutionalization was the Katz ADL score.

Aged↗