Ethnicity, infant-feeding practices, and childhood adiposity

There has been professional concern that the type of milk used for infant-feeding may lead to adiposity. Studies of the relationship between infant milk-feeding and adiposity, however, have led to inconsistent results. This study investigated the relationship of infant-feeding practices to three indicators of adiposity: body weight, body mass index (BMI) and sum of seven skinfolds. The sample includes children at 3 or 4 years of age, in three ethnic groups. Multivariate techniques assessed the relationship among practices of infant-feeding with three indicators of adiposity, while considering potential confounding variables. Although a weak bivariate relationship was detected between the duration of breastfeeding and body weight, none of the measures of infant-feeding were related to the three indicators of adiposity. Black-American girls had smaller skinfolds than Anglo- or Mexican-American girls, with no ethnic group differences among boys. Concerns about adiposity due to methods of infant-feeding can be allayed, at least among 3- or 4-year-old children.

Scaling of response scale adverbs among black-American adults

Although some attention has been given to the scale characteristics of modifying adverbs in Likert scales, the existing work has been concerned primarily with majority group members. Toward the goal of identifying valid labels for use on Likert scales with black-American respondents, 105 black-American adults scaled each of 27 adverbs (e.g., very, most) on four different adjectives (e.g., important). Four criteria for a set of ideal adverbs were identified for univalent scales. No set of four adverbs, however, met the criteria. Differences in the mean ratings of eight of the adverbs were found by sex group and across the four adjectives modified. The adverbs were not scored at the extremes of the continuum, despite our asking the respondents to rate the adverbs used to define the end points of the continuum. High variances were found across all adverbs. Further research must address the respondents' perceptual frame in the use of such scales.

Children's frequency of consumption of foods high in fat and sodium

We administered a food frequency instrument to third-fifth grade students (n = 943) in four Texas schools. Comparison of foods reported on the food frequency questionnaire and on 24-hour dietary recalls (n = 7) produced a percent agreement of 83.3. The most frequent 25 foods accounted for 64.0% of food choices across all meals, 93.5% of breakfast choices, 76.4% of lunch choices, 70.5% of supper choices, and 76.0% of snack choices. Breads, milk, hamburger or steak, soda pop, tomato sauce or tomatoes, and cheese were the most frequently consumed foods. Fruits and juices accounted for 6.1% of total selections for boys and 6.6% for girls, while vegetables accounted for 15.7% of total selections for boys and 16.2% for girls. Fruit was more likely to be consumed for snacks than for meals, and vegetables were consumed in about the same frequency at lunch and supper and for snacks. We analyzed the total fat, saturated fat, and sodium content of the most frequently consumed foods. Seventeen of the top 25 foods for the total day and 13-16 for each meal or snack exceeded by at least 50% the recommended levels for fat, saturated fat, or sodium. The pattern of consumption was one of frequent consumption of a relatively small number of foods, many of which are high in fat or sodium.

A center-based program for exercise change among black-American families

A center-based program was designed and implemented to promote aerobic physical activity among healthy Black-American families with children in the fifth through seventh grades. Ninety-four Black-American families were actively recruited and randomly assigned to an experimental or control group. Families in the experimental group were encouraged to participate in a program with the following features: one education and two fitness sessions per week for 14 weeks; educational sessions that included individual counseling, small group education, aerobic activity, and snack components; located in a convenient building cherished by the community; aerobic activity sessions in a fitness center outfitted and staffed according to modern characteristics; a variety of incentives including free transportation and babysitting and reminders to promote attendance. Percent participation was low, with about 20% participating in the desired fitness center sessions by the end of the program. As a result of low participation, no differences were detected between experimental and control groups on indicators of cardiovascular fitness. In postprogram interviews, conflicts with work and school events were the most commonly reported reasons for nonattendance. We concluded that because of difficulties in attendance, center-based programs appear to have limited value as the sole modality for intervention in public health programs for promoting physical activity among healthy, low income Black-American families with young children. More comprehensive community-based programs are likely to be needed.

Lipids and lipoproteins in a triethnic sample of 5- or 6-year-old Type A or Type B children

The Type A behavior pattern (TABP) has been proposed as a risk factor for coronary heart disease (CHD). Several studies have indicated an association between Type A behavior and serum cholesterol levels. If the effects of TABP are mediated by conventional CHD risk factors, evidence for a causal relationship between TABP and CHD would be strengthened if associations were detected among the young. This paper addresses the following: (1) Do levels of serum lipids and lipoproteins among young children vary by ethnicity, gender, or TABP? (2) Can obtained differences be accounted for by possible confounding factors, such as SES or body composition? ANCOVA revealed no significant ethnic, gender, or TABP effects for total serum cholesterol or HDLc. Analyses of LDLc and triglycerides disclosed significant main effects for gender and for ethnicity. A Competition subscale by ethnicity interaction was the only effect to approach statistical significance for TABP. The strongest findings were a replication of differences in lipid and lipoprotein risk factors by ethnicity.

School promotion of healthful diet and physical activity: impact on learning outcomes and self-reported behavior

The Go For Health Program included classroom health education and environmental changes in school lunch and physical education to foster healthful diet and exercise among elementary school children. Interventions were based on social learning theory and implementation was based on an organizational change strategy for school innovations. Two schools were assigned to intervention and two to control conditions. Cognitive measures (behavioral capability, self-efficacy, behavioral expectations) and self-reported diet and exercise behavior were assessed at baseline and following intervention. Data were analyzed by ANOVA using the student and then the school as the unit of analysis. Statistically significant changes were observed for diet behavioral capability, self-efficacy, and behavioral expectations, use of salt, and exercise behavioral capability (fourth grade), self-efficacy (fourth grade) and frequency of participation in aerobic activity. The results provide evidence for program impact on learning outcomes and student behavior.

Ethnic differences in anthropometric characteristics of young children and their parents

The distribution of body fat, or fat patterning, is an important risk factor for cardiovascular disease and diabetes, independent of obesity. Furthermore, the incidence of cardiovascular disease and diabetes varies by ethnicity. We documented ethnic differences in anthropometric characteristics and body fat distribution between Anglo, Black, and Mexican American men (n = 101), women (n = 245), boys (n = 111), and girls (n = 111). We used aggregates of skinfold measures to examine ethnic differences in the deposition of fat in body compartments (body, trunk, leg, and arm) and analyzed trunk-extremity skinfold ratios to determine which best reflected ethnic differences in fat distribution. The results show that Mexican American mothers have larger skinfold ratios and more body fat (as determined by skinfold aggregates) than either Anglo or Black American mothers, whereas Black American mothers have larger ratios than Anglo American mothers. Mexican American fathers also have larger skinfold ratios but not more body fat (skinfold aggregates) than Anglo American fathers. Mexican American fathers have more body fat than Black American fathers, but we found no differences between skinfold ratios. The ethnic differences among children in skinfold ratios and aggregates are similar to those found among fathers, with more differences among girls than boys. Fat patterning differences do exist among the three ethnicities, with greater trunk fat among Mexican and Black Americans. Those ethnicities are known to be at higher risk for cardiovascular disease and diabetes.

A comparison of four commonly used nutrient database programs

The present study evaluated the comparability of two microcomputer systems and two mainframe nutrient database systems. Sixty 24-hour recalls were analyzed on each system. Analysis of the nutrient values obtained from each system revealed several significant differences between Short Report and the other three systems. There were no significant differences between DINE, NCC, and UTNDB. Attempts to reveal the source of this error were not successful.

Ethnic variation in blood pressure among preadolescent children

As part of a study on methods for assessing diet and exercise among 163 3rd to 6th grade students, data were collected on blood pressure, diet, urinary electrolytes, aerobic activity, resting pulse, and body composition. Data were collected on a stratified sample, with almost equal numbers of children of both sexes from 3rd or 4th and 5th or 6th grades; from three ethnicities: Anglo-, Black- and Mexican-American. Three resting blood pressures were obtained using a Hawksley random zero sphygmomanometer. Data analytic procedures relied on analyses of variance and covariance to assess differences across design factors in blood pressure, with dietary sodium, resting pulse, body surface area, and energy expended as covariates. No differences were detected across ethnic groups in systolic pressures, but Mexican-American children were shown to have significantly higher diastolic fourth phase pressures than Anglo- or Black-American children. Only the dietary variables differed across ethnic groups, but not in the same pattern. Differences in the covariates did not account for the difference across ethnic groups in diastolic pressures.

Aerobic physical activity among third- to sixth-grade children

We observed the level of activity, and determined which of 24 third- to sixth-grade children were present during that activity, for two weekdays per child. No events of aerobic activity, as defined by nationally accepted criteria, were detected in that 48 days of observation. By a less stringent criterion, only half the children engaged in aerobic activity on any one day. With regard to who was active, there was no evidence for day-to-day consistency. Fathers were virtually absent during periods of activity. Issues relating to promoting aerobic activity are discussed.

Attitudes toward breastfeeding

To understand why some lower socioeconomic status mothers delivering at a state university hospital breastfeed, while others do not, 26 attitude items were administered in a survey of 358 mothers. A factor analysis of these items yielded four interpretable factors: benefits to infant, social inconvenience, personal inconvenience, and physical inconvenience-medical benefits to child. These factors were significantly related to breastfeeding within each level of ethnicity and marital status. The results imply that emphasizing the benefits for the infant, and providing strategies for minimizing personal inconveniences, should promote breastfeeding in these populations.

The influence of inorganic phosphate and ATP on the kinetics of bovine heart muscle pyruvate kinase

The mechanism of activation by inorganic phosphate and ATP of cardiac muscle pyruvate kinase was studied with the aid of steady-state kinetics. The enzyme was purified to homogeneity to a final specific activity of 400 units/mg (phosphate buffer, pH 7.6, 25 degrees C). At pH 7.6 the enzyme displays Michaelis-Menten kinetics with respect to both its substrates, phosphoenolpyruvate and ADP. Substrate kinetic constants are: app.Km(phosphoenolpyruvate) = 0.04 mM, app.Km(ADP) = 0.22 mM. Under the conditions used in the standard assay the specific activity is greatly enhanced by inorganic phosphate (50 mM) or ATP (2.5 mM). Each of these modifiers, acting separately, increases the Vmax without seriously affecting Michaelis constants and Hill coefficients. In the presence of both Pi and ATP, only a decrease in Vmax was observed. The kinetics of activation by inorganic phosphate of pyruvate kinase was examined. Studying the effect of varying concentrations of Pi on the initial rate we obtained a hyperbolic saturation curve with the app.Km(Pi) = 20 mM and Vmax = 167 units/mg. The evidence is presented that inorganic phosphate is a substrate for a side reaction catalyzed by cardiac pyruvate kinase. It is shown that in the presence of pyruvate, inorganic phosphate and ATP in the assay system, Pi is incorporated into acid-labile products of this reaction, inorganic pyrophosphate being one of them. These findings indicate the existence of an alternative reaction catalyzed by pyruvate kinase by which energy may be stored in the form of inorganic pyrophosphate.

Incidence of breast-feeding in a low socioeconomic group of mothers in the United States: ethnic patterns

Breast-feeding has been shown to have increased in incidence during recent years in the United States. However, this increase is not particularly evident in lower socioeconomic groups. Factors associated with the decision to breast-feed or not were investigated in a population of 379 mothers. Self-completed questionnaires were obtained from 94.5% of these mothers. Data with respect to demographics, reproductive history, prenatal care, and education were collected. Only 27.2% of the study population indicated that they intended to breast-feed. Using the chi2 test for equality of proportions, marital status, head of household, maternal and paternal ethnicity, maternal education, income, and number of pregnancy were found to be the most important variables associated with breast-feeding. The effect of ethnicity predominated over that of the other demographic variables when they were examined jointly within ethnic groups. The effect of ethnicity was apparent when the number of each ethnic group in the study population was compared with the percent of that group that intended to breast-feed: 145 Anglo-Americans, 43.5% breast-feeding; 131 black Americans, 9.2%; 62 Mexican Americans, 22.6%; 19 others, 42.1%. The importance of ethnicity in the decision to breast-feed has probably been underestimated. Efforts to increase breast-feeding in the United States ought to be designed with full consideration of this factor.

Theory-based health education activities for third to sixth grade children

Eight educational activities based on social learning and social support theories were used as part of a comprehensive cardiovascular risk reduction program for families with children in the third to sixth grades. These activities focused on providing the children with skills in recognizing high-salt and high-saturated fat foods, preparing such foods, resisting pressures to each such foods, increasing aerobic activity and providing support to peers and family in attempting such changes. Data analyses revealed significantly greater decreases in high-salt and high-saturated, fat food consumption and perceived increases in aerobic activity, in the experimental than the control group. The participative, enjoyment and inexpensive aspects of these activities are emphasized to encourage their use in school health programs.

The family health project: cardiovascular risk reduction education for children and parents

The principles of family support and of social learning theories were applied to a feasibility study of working directly with family units in a health education program. Twenty-four Anglo, Black, and Mexican-American families of young elementary school children participated in a 3-month cardiovascular risk reduction education project which included eight weekly evening sessions designed to assist families to decrease the frequency of consumption of foods high in sodium and in saturated fats, and to increase the frequency of aerobic exercise. Statistically significant differences between randomly assigned treatment and control groups were noted for reported consumption of high sodium foods and of foods high in saturated fats. Experimental subjects gained more knowledge of factors influencing cardiovascular risk, even though the intervention was behaviorally, rather than cognitively, based. This method of health promotion is deserving of further study.

Social support, social influence, ethnicity and the breastfeeding decision

A survey was conducted of all mothers delivering infants at a university medical center hospital in the month of July, 1981. The survey was conducted within 48 hours of delivery and addressed factors related to the breastfeeding decision. The mother's response to the question concerning choice of infant feeding was verified against the feeding records. One set of questions concerned the perceived general supportiveness toward breastfeeding of six individuals significant to the mother. Another set of questions identified who was most influential in the mother's breast or bottle feeding decision. The pattern of significant bivariate relationships between a person's supportiveness and breastfeeding varied across ethnic and maritial status groups. Single and multiple logistic analyses were conducted within ethnic groups to identify from whom support was most important for initiating breastfeeding. Among Black-Americans, support from a close friend was most important. Among Mexican-Americans, support from the mother's mother was most important. Among Anglo-Americans, support from the male partner was important. A broad variety of ensuing research issues are raised. An implication is that social support may be an important interventive variable, but the potentially supportive individual to be reached by an interventive program varies by ethnic group.

Consumer health educators in health care institutions in West Virginia

A two-phase survey was conducted of administrators of health care institutions (hospitals, rural primary care clinics, and community mental health centers) and, in turn, people conducting consumer health education (patient and community) in these settings. The purposes of the surveys were to identify the people who were conducting health education activities, their training, the tasks they were performing, and how they practiced health education. A broad variety of professionals was identified who perform consumer health education in these health care institutions. Only two professionally trained health educators were identified out of 232 respondents. The type of health education practice varied by type of institution, with hospitals being patient education oriented, mental health centers being community education oriented, and rural clinics requiring both patient and community education activities from their health educators. Most respondents reported the distribution of printed materials and individual counseling as their most frequently employed health education techniques. A need was documented for training in health education techniques. A broad variety of approaches to meeting this need are discussed.

Kinetic properties of human muscle pyruvate kinase

The steady-state kinetics of human skeletal muscle pyruvate kinase (MA) and its RNA-complex (MB) has been examined and compared. Kinetic studies revealed significant differences in kinetic properties with respect to free and complex form of pyruvate kinase. The MA form follows a simple Michaelis-Menten kinetics in contrast with the MB form, which displays a negative cooperativity with respect to ADP. Vmax for the complex is 40-60% that for free enzyme. Heterologous RNA is a noncompetitive inhibitor of free enzyme but the kinetics of the complex (MB) is not affected. In presence of 1.0 mM ATP in an assay mixture the kinetic constants of the complex were unchanged except for Vmax, which increased by nearly 60%. Aged preparations of free enzyme (MA) were activated by 100% and more, but the native enzyme was inhibited by 22%. Inorganic phosphate is a potent activator of both forms of pyruvate kinase. In presence of 50 mM K-phosphate the apparent Michaelis constant and interaction coefficient are unchanged, but Vmax for free enzyme increases by 35% and for the complex by 70%, respectively. The specific activity of aged MA form can be restored to the original value after incubation of the enzyme in 50 mM K-phosphate, pH 7.6, or by addition of ATP (1.0 mM) to the assay mixture.

Pyruvate kinase from human skeletal muscle

A simple method is described for the isolation of crystalline pyruvate kinase from human skeletal muscle. The enzyme was purified by ammonium sulfate fractionation, heat treatment and crystallization. Two crystal forms of pyruvate kinase differing in solubility but not in specific activity were found. The homogenous enzyme preparations in triethanolamine buffer, pH 7.6 reveal at 25 degrees a specific activity of 245 U per mg protein, and of 340 U/mg in potassium phosphate buffer (50 mM). The enzyme is activated by inorganic phosphate and fructosediphosphate to the same extent, and inhibited non competetively by ammonium ion. The molecular weight as measured by gel filtration is 220,000 daltons and the enzyme molecule is composed of 4 subunits.