Unhealthy and healthy weight control behaviours among bus operators.

BACKGROUND: Urban bus operators are an occupational group with high rates of overweight and obesity. Understanding methods bus operators use for weight control may be important; there may be increased risk for these workers to engage in less healthy weight management behaviours due to stressful working conditions. AIMS: To examine the prevalence of unhealthy and healthy weight control behaviours used by bus operators and examine associations between use of unhealthy weight control behaviours and work-related and sociodemographic variables. METHODS: Bus operators from four different transit garages were invited to complete a self-administered survey; height and weight were measured by research staff. Unhealthy and healthy weight control behaviours, work hours, work schedule and social support were measured with self-report items on the employee survey. Logistic regression analysis was conducted to estimate associations. RESULTS: Nearly 60% of bus operators endorsed at least one unhealthy method; over 50% reported skipping meals, 30% fasted and 10% reported taking diet pills in the past year. Bus operator gender, race, body mass index status and hours worked per week showed significant associations with using at least one unhealthy weight control behaviour. CONCLUSIONS: Worksite interventions should emphasize the benefit of healthy eating and physical activity but should also address the use of less healthy methods for weight control for individuals employed in transportation occupations.

CHECK: A randomized trial evaluating the efficacy and cost-effectiveness of home visitation in pediatric weight loss treatment.

BACKGROUND: Socioeconomically-disadvantaged households have a high prevalence of pediatric overweight/obesity, and also face barriers to accessing weight loss treatment in healthcare settings. Delivering family-based pediatric weight loss treatment in the home setting may enhance its efficacy by facilitating treatment attendance, enabling more tailored treatment recommendations informed by observations of the home environment, and increasing accountability. This paper describes the design of the Creating Health Environments for Chicago Kids (CHECK) Trial, which evaluates the efficacy, cost-effectiveness, and mechanisms of home visitation in family-based pediatric weight loss treatment for children in low-income households. DESIGN: CHECK is a two-arm, parallel group, randomized controlled trial that is enrolling N = 266 children, ages 6-12 y, who have overweight/obesity (BMI percentile ≥85) and live in a low-income household. Participants are randomized in a 1:1 ratio to either standard of care family-based weight loss treatment delivered in the home, or the identical intervention delivered in an academic medical center. The primary outcome is change in child BMI z-score from baseline to 12 months. Program delivery costs are rigorously documented to enable cost-effectiveness analyses from the societal and payer perspectives. Objectively-documented changes to the home environment and aspects of intervention delivery (e.g., hours of in-person contact received, quantity of behavioral goals set per session) will be tested as hypothesized treatment mechanisms. IMPLICATIONS: Findings will inform the design of future interventions, and treatment dissemination decisions by public health agencies and third-party payers. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03195790.

Physical changes in the home environment to reduce television viewing and sugar-sweetened beverage consumption among 5- to 12-year-old children: a randomized pilot study.

This study evaluated the feasibility of a home-based intervention to reduce sugar-sweetened beverage intake and television viewing among children. Lower income parents of overweight children aged 5-12 years (n = 40) were randomized to a home environment intervention to reduce television viewing with locking devices and displace availability of sugar-sweetened beverages with home delivery of non-caloric beverages (n = 25), or to a no-intervention control group (n = 15) for 6 months. Data were collected at baseline and 6 months. After 6 months, television viewing hours per day was significantly lower in the intervention group compared with the control group (1.7 [SE = .02] vs. 2.6 [SE = .25] hours/day, respectively, P < .01). Sugar-sweetened beverage intake was marginally significantly lower among intervention group compared to control group children (0.21 [SE = .09] vs. 0.45 [SE = .10], respectively, P < .09). Body mass index (BMI) z-score was not significantly lower among intervention compared to control children. Among a lower income sample of children, a home-based intervention reduced television viewing, but not sugar-sweetened beverage intake or BMI z-score.

Simulation of cardiac work transitions, in vitro: effects of simultaneous Ca2+ and ATPase additions on isolated porcine heart mitochondria.

During increases in cardiac work there are net increases in cytosolic [Ca(2+)] and ATP hydrolysis by myofiliments and ion transport ATPases. However, it is still unclear what role Ca(2+)or the ATP hydrolysis products, ADP and Pi, have on the regulation of mitochondrial ATP production. In this study, work jumps were simulated by simultaneous additions of Ca(2+) and ATPase to porcine heart mitochondria. The net effects on the mitochondrial ATP production were monitored by simultaneously monitoring respiration (mVo2), [NADH], [ADP] and membrane potential (deltapsi) at 37 degrees C. Addition of exogenous ATPase (300 mlU.ml(-1))]ATP (3.4 mM) was used to generate a 'resting' background production of ADP. This resting metabolic rate was 200% higher than the quiescent rate while [NADH] and deltapsi were reduced. Subsequent ATPase additions (1.3IU.ml(-)) were made with varying amounts of Ca(2+)(0 to 535 nM) to simulate step increases in cardiac work. Ca(2+) additions increased mVo2 and depolarized deltapsi, and were consistent with an activation of Fo/F1)ATPase. In contrast, Ca(2+) reduced the [NADH] response to the ATPase addition, consistent with Ca(2+)-sensitive dehydrogenase activity (CaDH). The calculated free ADP response to ATPase decreased \2-fold in the presence of Ca(2+). The addition of 172nM free Ca(2+)] ATPase increased mVo2 by 300% (P<0.05, n=8) while deltapsi decreased by 14.9+/-0.1 mV without changes in [NADH] (P > or =0.05, n=8), consistent with working heart preparations. The addition of Ca(2+) and ATPase combined increased the mitochondrial ATP production rate with changes in deltapsi, NADH and [ADP], consistent with an activation of CaDH and F o /F(1)ATPase activity. These balancing effects of ATPase activity and [Ca(2+)] may explain several aspects of metabolic regulation in the heart during work transitions in vivo.

Weight cycling and cardiovascular risk factors in obese men and women.

This study examined the relationship between weight cycling and cardiovascular risk factors in 101 obese men and 101 obese women. Weight cycling was defined in three ways by retrospective self-report: 1) number of previous weight losses of greater than or equal to 4.5 kg, 2) total weight lost in prior weight-loss attempts, and 3) the difference between highest and lowest weight as an adult. Cardiovascular risk factors included blood pressure, total and high-density-lipoprotein cholesterol, triglycerides, fasting and 2-h glucose values, waist-to-hip ratio, and percent of dietary calories from fat. Results did not support the hypothesis that weight cycling increased cardiovascular risk factors in either men or women. Of 88 associations examined, only 7 showed differences with P less than 0.05 and of these, 6 were opposite in direction to that hypothesized. We conclude that warnings about the health hazards of repeated dieting may be premature.

Development of a questionnaire to assess knowledge, attitudes, and behaviors in American Indian children.

One aim of the Pathways study is to improve the knowledge, attitudes, and behaviors of American Indian children in grades 3-5 regarding physical activity and diet in. This article describes the development of a culturally sensitive, age-appropriate questionnaire to assess these variables. The questionnaire was designed to be administered in the classroom in two 30-min sessions. Questions were developed to assess 4 key areas: physical activity, diet, weight-related attitudes, and cultural identity. Potential questions were written after review of relevant literature and existing questionnaires. Numerous and extensive revisions were made in response to input from structured, semistructured, and informal data collection. Questions were pretested in 32 children in grades 3-5 by using semistructured interviews. Test-retest reliability and the internal consistency of scales were examined in 371 fourth-grade children and subsequently in 145 fourth-grade children. Questions were reviewed by American Indians from the communities involved in the Pathways study several times during the developmental process. The process described here serves as one model for the development of a culturally appropriate tool to assess knowledge, attitudes, and behaviors in American Indian children.

Covariations of unhealthy weight loss behaviors and other high-risk behaviors among adolescents.

OBJECTIVES: To determine if unhealthy weight loss methods are associated with other health-compromising behaviors among adolescents and to examine covariation patterns across gender and age groups. STUDY DESIGN AND PARTICIPANTS: The study sample was drawn from a larger population of 123 132 adolescents in the 6th, 9th, and 12th grades in Minnesota who completed a statewide school-based survey. The index group included all adolescents who used unhealthy weight loss methods (n=4514), and the comparison group comprised a random sample of 4514 adolescents who did not use these methods and who were matched for gender, ethnicity, and grade. MAIN OUTCOME MEASURES: Unhealthy weight loss methods included vomiting and use of laxatives, diuretics, and diet pills. Other health-compromising behaviors that were assessed included suicide attempts; delinquency; tobacco, alcohol, and marijuana use; unprotected sexual intercourse; and multiple sexual partners. RESULTS: Adolescents who used unhealthy weight loss methods were more likely to engage in other health-compromising behaviors. Odds ratios ranged from 1.9 to 14.8, and odds ratios were all highly significant among boys and girls in early, middle, and late adolescence. Among the girls, a monotonic decrease in the strength of all associations was found with increased age. CONCLUSIONS: Adolescents who engage in unhealthy weight loss methods are more likely to engage in a range of other health-compromising behaviors. Different perceptions of unhealthy weight loss behaviors (eg, normative vs problematic) may in part explain the differences in the strengths of associations between different grade and gender groups. Our results suggest that screening and counseling of adolescents who engage in unhealthy weight loss methods should be comprehensive and intervention programs aimed at the secondary prevention of disordered eating need to address other problematic behaviors.

Solubility of cerium in LaCoO3-influence on catalytic activity.

The recent interest in the catalytic properties of lanthanum perovskites for methane combustion and three way catalysis has led to considerable debate as to their structure and defect chemistry. We have investigated the doping of LaCoO3 with the tetravalent cerium cation using atomistic simulation techniques. We have compared three routes for cerium insertion and identified the favoured doping mechanism, which explain experimental observations relating to the effect of cerium on catalytic activity.

Consequences of dieting to lose weight: effects on physical and mental health.

Concern has been raised that negative physiological and psychological effects of dieting may outweigh aesthetic and health benefits. This review of the literature concludes the following: (a) The measurement of dieting is an important unresolved issue; (b) current dieting, chronic dieting, desire to lose weight, specific weight control behaviors, and weight changes may have different effects on health and need to be distinguished; (c) dieting is usually not associated with nutritional deficiencies, adverse physiologic adaptations, severe psychological reactions, or the development of eating disorders; and (d) recommendations against weight loss efforts involving moderate changes in eating and exercise habits are not warranted.

Attributions for dietary failures: problems reported by participants in the Hypertension Prevention Trial.

Assigned participants in the Hypertension Prevention Trial to one of four diets for a period of 3 years: (a) weight loss, (b) reduced sodium, (c) weight loss plus reduced sodium, and (d) reduced sodium plus increased potassium. At 6-month intervals, they reported problems they were having adhering to their diets. Problem attributions were coded along the dimensions of internality, stability, and controllability and were categorized as intrapersonal or extrapersonal. Attributions were found to differ by type of diet and sex of participant. Participants assigned to weight-loss groups were significantly more likely than those assigned to non-weight-loss groups to blame themselves for their problems with adherence, making characterological as opposed to external or situational attributions. Men perceived problems to be more controllable than women. Attributions did not predict weight loss, change in urinary sodium, or change in potassium excretion.

Smoking status, dietary intake, and physical activity in a sample of working adults.

The present study examined differences in dietary intake and physical activity by smoking status in a sample of 3,250 working adults. Cross-sectionally, current smokers consumed alcohol, dairy products, meat, eggs, and french fries more frequently, and engaged in leisure time physical activity less frequently, than former or never smokers. Over 2 years, current smokers increased their intake of meat, soft drinks, eggs, and total calories from high fat and high calorie foods compared to never to former smokers. Smokers who quit during the 2-year observation period increased their frequency of sweets consumption. Dietary and physical activity variables appear to be weak predictors of postcessation weight change. Implications for studies of chronic disease etiology and mechanisms of postcessation weight gain are discussed.

Stage of change as a predictor of success in weight control in adult women.

Weight change over 3 years was examined in a large and heterogeneous sample of women as a function of stage of change for weight control. Women were classified into Precontemplation, Contemplation, Preparation, and Action stages on the basis of reports of current and past weight control behaviors and future intentions. Stage of change did not predict success in weight control. Mean weight changes over 3 years were 1.1 kg, 1.0 kg, 2.1 kg, and 2.3 kg for Precontemplation, Contemplation, Preparation, and Action stages, respectively. The findings call into question the generality of the stages-of-change classification system across behavioral domains.

Dieting behaviors and weight change history in female adolescents.

The prevalence of dieting, weight change history, and specific weight loss behaviors was examined in a population-based sample of 1,015 female 9th-12th graders. Healthy weight loss behaviors were reported much more frequently than unhealthy weight loss behaviors (e.g., healthy behaviors: exercise = 32.4%, decrease fat intake = 26.0%, reduce snacks = 25.0%, reduce kilocalorie intake = 22.4%; unhealthy behaviors: fasting = 8.1%, diet pills = 5.4%, vomiting = 4.4%). Obesity status and restrained eating scores were positively related to greater history of weight loss episodes, pounds lost, and weight fluctuations and to greater use of healthy weight loss methods and weight loss programs. Implications for public health recommendations regarding dieting and its associated behaviors in female adolescents are discussed.

Food preferences, eating patterns, and physical activity among adolescents: correlates of eating disorders symptoms.

PURPOSE: Food preferences, eating patterns, and physical activity patterns were examined in a cohort of adolescent females and males participating in a longitudinal study of the developmental antecedents of eating disorders. METHODS: All adolescents (n = 1494) in grades seven through ten in an entire school district completed a survey about their dieting behaviors, eating, and exercise patterns. RESULTS: Principal components analysis showed similar factor structures for food preferences and eating patterns among males and females. Gender differences were present in physical activity patterns. Sports participation was correlated with healthy food preference and was a significant predictor of eating disorders symptoms. Junk food preference was marginally inversely related to eating disorders symptoms in females. Preference for other types of foods and reported intake of foods were not related to eating disorders symptoms. The percent of variance in risk score accounted for by dietary intake and physical activity patterns was small. CONCLUSIONS: Psychological and social/environmental variables may explain a larger proportion of the variance in eating disorders risk than the dietary and physical activity variables examined in this study. Implications for understanding the etiology and behavioral expression of eating disorders are discussed.

Adolescent binge/purge and weight loss behaviors: associations with developmental assets.

PURPOSE: To study associations between binge/purge and weight loss behaviors and "developmental assets" among adolescent girls and boys. METHODS: The Search Institute's Profile of Student Life: Attitudes and Behaviors self-report questionnaire was administered to 48,264 girls and 47,131 boys in grades 6 through 12 at schools in 213 cities or towns across the United States. The 156-item questionnaire measured 40 "developmental assets," or protective factors associated with successful adolescent development. Developmental assets were examined using multiple logistic regression among students who reported binge/purge behaviors, weight loss behavior, both, or neither. RESULTS: Developmental assets related to positive identity were the strongest discriminators of binge/purge and weight loss behaviors in both girls and boys. Girls who reported binge/purge and weight loss behaviors were about half as likely to report feeling a sense of purpose [odds ratio (OR) = 0.45, 95% confidence interval (CI) = 0.40, 0.50] and high self-esteem (OR = 0.55, 95% CI = 0.49, 0.61), compared with girls not reporting either of these behaviors. Among boys the ORs were: sense of purpose OR = 0.53 (95% CI = 0.46, 0.61) and self-esteem OR = 0.76 (95% CI = 0.65, 0.88). Assets related to values about abstinence from alcohol, drugs, or sex ("restraint") were also significant correlates. Girls and boys who reported these values were less likely to report binge/purge and weight loss behaviors, compared with those who did not report these values (girls: OR = 0.56, 95% CI = 0.50, 0.63; boys: OR = 0.83, 95% CI = 0.70, 0.97). CONCLUSIONS: Internal assets such as self-esteem, sense of purpose, and values related to abstinence from alcohol and sex appear to be protective against unhealthy eating behaviors and may reflect a general resilience that buffers against a broad range of health risk behaviors.

Changes in psychological variables and health behaviors by dieting status over a three-year period in a cohort of adolescent females.

PURPOSE: Psychologic and behavioral changes associated with frequent dieting were examined. Compared to nondieters, frequent dieters were hypothesized to show more adverse psychologic changes and increased use of unhealthy weight control behaviors, but possibly healthier eating and exercise behavior changes, over the three-year period of observation. METHODS: A prospective study of female students, in grades 7-10 at baseline completed a health behavior survey in school once a year for a total of three years. RESULTS: Restrained eating, body dissatisfaction and drive for thinness, self-induced vomiting, laxative use, diet pill use, and alcohol use, significantly increased, and physical appearance and self-concept significantly decreased among frequent dieters, compared to non-dieters. Changes in scores on five EDI subscales, eight self-esteem subscales, weight fluctuations, dietary intake, and physical activity patterns did not significantly differ over time by dieting status. CONCLUSION: Dieting may reflect a general pattern of unhealthy behaviors adopted in adolescence, rather than act as a causal factor in promoting psychologic distress.

Consumer preferences in format and type of community-based weight control programs.

PURPOSE: The purpose of this study was to provide further information about preferences for types and formats (e.g., correspondence vs. face to face) of eating and exercise programs, actual participation rates in a variety of offered programs, and characteristics of program participants vs. nonparticipants. DESIGN: Over a 3-year period, a large sample of community volunteers was given the opportunity to participate in various forms of diet and exercise programs as part of a weight gain prevention study. SETTING: The study was conducted at a university and three local health department sites. SUBJECTS: Subjects in the study were 616 individuals participating in the Pound of Prevention study (POP), a 3-year randomized evaluation of an intervention for preventing weight gain. MEASURES: The primary outcomes assessed were participation rates for each program offering. Program participants were also compared to those who did not participate on demographic characteristics, smoking, diet behavior, exercise behavior, and weight concern. RESULTS: Survey results indicated that correspondence formats for delivery of health education programs were rated as more desirable than face-to-face formats. Participation for program offering ranged from 0 to 16% of the study population. Participation data were consistent with survey results and showed participants' preference for correspondence formats even more strongly. Program offering attracted health-conscious participants with higher education and income levels. CONCLUSIONS: These data suggest that some community members will get interested and take part in low-cost, minimal contact programs for exercise and weight control. Future research efforts should focus on investigating ways to increase participation in brief or minimal contact programs, particularly among groups that may be difficult to reach and at high risk for the development of obesity.

Restraint, food choice, and cognitions.

Restrained eaters were hypothesized to prefer high kilocalorie (KCAL) food when given a choice of both high and low KCAL foods after consuming a high KCAL preload. Study 1 found no differences between restrained and unrestrained eaters in food choice in either preload condition. Study 2 found that preloaded subjects preferred lower KCAL foods than subjects in the no preload condition. Both restrained and unrestrained eaters ate less food after consuming a high KCAL preload than after no preload. Preloaded restrained eaters expressed a greater number of control-related thoughts regarding food than any other group; however, these thoughts did not mediate disinhibited eating. Implications for restraint theory are discussed.

Current dieting, weight loss history, and weight suppression: behavioral correlates of three dimensions of dieting.

The present study investigated three dimensions of dieting (current dieting, history of dieting, weight suppression) and behaviors related to energy balance in a community sample of 999 women. The three dimensions, current dieting status, history of dieting, and weight suppression, were examined in relation to dietary intake, eating behaviors, physical activity, and weight concerns. Twenty-two percent of the women were current weight loss dieters, 8.3% were currently dieting for weight maintenance, and 69.3% were not currently dieting. Twenty-eight percent of the women were weight suppressers. Current dieting for weight loss or weight maintenance was associated with lower percent of kilocalories from fat (33% vs. 35% among nondieters), less frequent consumption of sweet foods, more frequent consumption of vegetables and fruits, more frequent self-weighing, and lower tolerance for weight gain prior to taking action (10 lb vs. 14 lb among nondieters). Current dieters and those with an extensive history of dieting self-reported a greater number of healthy and unhealthy weight loss practices during the past year, and they scored higher on measures of low-fat eating behaviors and restrained eating. Weight suppression was associated with higher physical activity levels and low-fat eating behaviors. Distinguishing weight suppression from current dieting status may provide insight into the behaviors related to successful weight loss maintenance, whereas measures of dieting history might be useful in clinical contexts.

Food intake and physical activity: a comparison of three measures of dieting.

We examined food preferences, dietary intake, and physical activity in dieters and nondieters using three different methods of dieting classification. One hundred three women and 99 men completed the cognitive restraint subscale of Stunkard and Messick's (1985) Three Factor Eating Questionnaire (TFEQ-R) and Herman and Polivy's (1980) Restraint Scale (RS), and answered questions about their current efforts to lose or maintain weight. Women identifying themselves as currently dieting to lose weight reported expending twice as much energy in physical activity compared to those reporting that they were either currently dieting to maintain weight or not dieting. There were no significant differences in dietary intake or physical activity by current dieting status in men. Women chronic dieters identified by high TFEQ-R scores reported lower total calorie intake and less frequent sweets consumption than women with low TFEQ-R scores. In men, those with high TFEQ-R scores reported consuming a greater percent of calories from protein and carbohydrate, less beef, pork, whole milk, and sweets. In women, the RS did not distinguish dieters from nondieters on any measure. In men, the RS results were similar to those from the TFEQ-R. These results show that current measures of dieting are only weakly related to behaviors thought to be indicative of dieting. Future research must develop more precise measures of dieting in order to examine the relationship between self-reports of dieting and behaviors thought to be related to dieting.