Improving Health Outcomes: Future Directions in the Field

Impact of a behaviorally-based weight loss intervention on parameters of insulin resistance in breast cancer survivors

BACKGROUND

Breast cancer survivors with excess weight are more likely to have negative breast cancer outcomes. Biomarkers related to insulin resistance may help explain this negative association. Weight loss is associated with improvements in insulin sensitivity. Our goal was to identify the impact of a behaviorally based weight loss intervention on indices of insulin resistance.

METHODS

Overweight, early stage breast cancer survivors who completed initial cancer therapy were enrolled in a 6 month behaviorally based weight loss intervention that included calorie reduction, exercise and behavior modification. Biomarkers related to insulin resistance were obtained at baseline and after the intervention. Results from participants who achieved ≥5% weight loss were compared to those who lost less weight.

RESULTS

Despite not having diabetes as a preexisting diagnosis prior to the study, 69% of all participants were considered to have pre-diabetes or diabetes at baseline based on American Diabetes Association definitions. Participants who achieved ≥5% weight loss had significantly lower fasting insulin, AUC insulin, and insulin resistance as measured by HOMA-IR. Beta cell function decreased as anticipated when insulin resistance improved. Additionally, leptin levels declined.

CONCLUSIONS

Breast cancer survivors who achieved ≥5% weight loss demonstrated significant improvements in indices of insulin resistance. Despite an exclusion criteria of diabetes at the time of enrolment, a high proportion met criteria for pre-diabetes or diabetes at baseline. Pre-diabetes appears to be under recognized in overweight breast cancer survivors. Behaviorally based weight loss interventions can result in weight loss and improvements in biomarkers related to breast cancer outcomes and additionally may decrease the chance of developing diabetes.

TRIAL REGISTRATION

NCT01482702 4/12/2010 (retrospectively registered).  https://clinicaltrials.gov/ct2/show/NCT01482702?term=Dittus&rank=4.

Investigating obesity risk-reduction behaviours and psychosocial factors in Chinese Americans

AIM

The purpose of this research was to examine the attitudes, beliefs and behaviours related to obesity risk reduction in Chinese Americans.

METHODS

A questionnaire was administered to a convenience sample of 300 US-born and foreign-born Chinese Americans residing in the New York metropolitan area, ranging from 18 to 40 years of age. Obesity risk reduction behaviours and psychosocial variables derived from the Theory of Planned Behaviour and Health Belief Model were measured. Acculturation was assessed using a modified Suinn-Lew Asian Self-Identity Acculturation Scale. Frequency distributions were delineated and stepwise regression analyses were analysed for different acculturation groups.

RESULTS

65% of the respondents were female and the mean age of the sample was 26 years. Respondents indicated the most commonly practised behaviour to be eating home-cooked meals instead of restaurant-prepared foods. Perceived barriers to adopting obesity risk-reduction behaviours included convenience of consuming fast foods, cost, lack of time to prepare home-cooked meals, and the physical environment of unhealthy foods. In predicting intention to perform obesity risk-reduction behaviours, attitude was significant for 'western-identified' individuals. In 'Asian-identified' individuals, perceived behavioural control, self-efficacy and perceived benefits were salient.

CONCLUSIONS

Nutrition educators working with Chinese Americans need to address self-efficacy in preparing plant-based, home-cooked meals and making healthy choices at fast-food restaurants with portion control. Concrete and perceived barriers such as lack of time and convenience need to be addressed in nutrition education interventions. Educators need to identify new channels and media outlets to disseminate practical, easy-to-implement behaviours for obesity risk reduction that are socially acceptable.

Necessary components for lifestyle modification interventions to reduce diabetes risk

Several efficacy trials and subsequent dissemination studies indicate that behavioral lifestyle interventions for diabetes risk reduction require, at a minimum, provision of 4 to 6 months of frequent intervention contact to induce clinically meaningful weight losses of at least 5% of initial body weight. Weekly contact during the first several months of intervention, followed by less frequent but regular therapeutic contact for a longer time period, appears necessary for participants to adopt and enact behavioral self-regulatory skills such as the self-monitoring of diet, weight, and physical activity and the problem solving of common physical, social, and cognitive barriers that impede sustained weight loss. In-person contact is associated with the largest effect sizes but may not be a necessary component for clinically meaningful weight loss. Regardless of intervention mode, setting, or provider, the interactive process of feedback and social support is crucial for skill development and sustained weight loss.

Psychosocial variables and obesity-risk-reduction behaviors in Chinese Americans

The objective of this study was to utilize social-psychological theories to explain obesity-risk-reduction behaviors. A questionnaire based on the health belief model and theory of planned behavior was administered to a convenience sample of 300 Chinese Americans in the New York metropolitan area. Psychosocial variables accounted for 40.4% of the variance of obesity-risk-reduction behaviors. Self-efficacy, behavioral intention, and perceived benefits emerged as most influential variables. Forty-eight percent of the variance of behavioral intention was accounted with self-efficacy predominating. Health professionals targeting Chinese Americans need to address self-efficacy, behavioral intention, and perceived benefits of adopting obesity-risk-reduction behaviors.

Wellness in community living adults: the Weigh to Life program

OBJECTIVE

To examine physiological and health-related quality of life (HRQOL) outcomes in community living adults attending a 12-week combined lifestyle wellness program.

METHODS

A sample of overweight and obese adults (n=319) and a subgroup who also had diabetes (n=46 of 319) were studied. The program focuses on dietary, physical activity, and behavioral strategies to promote cardiovascular health. Baseline and 12-week measures were obtained.

RESULTS

In the total sample, all physiological and HRQOL outcomes improved (p<.05), except HDL. High attendance was associated with the highest weight loss. In the diabetic subgroup, weight, steps/day, low density lipoprotein, and most aspects of HRQOL improved significantly.

CONCLUSION

Physiological and HRQOL benefits can be gained from a 12-week combined lifestyle program; greater benefits were obtained with higher attendance. Although the diabetic subgroup was not large, positive outcomes were realized.

PRACTICE IMPLICATIONS

The 12-week combined lifestyle program shows promise for improving outcomes in community living overweight and obese adults who may also be diabetic. By attending class, participants are reminded about strategies they are to apply during the 12-week program and, by program end, they are equipped with a tool kit of strategies for use in everyday life.

Understanding the causal factors of obesity using the International Classification of Functioning, Disability and Health

PURPOSE

Behavioural, personal, psychological, sociodemographic, environmental, biological and childbearing factors have been associated with obesity among women. This study quantitatively explored the effects of these factors on predicting body mass index (BMI) in U.S. women using the International Classification of Functioning, Disability and Health (ICF) and determined the effectiveness of using the ICF with population-level data.

METHODS

We used the ICF Core Sets for Obesity, and data from the 1999-2006 National Health and Nutrition Examination Survey (NHANES) in a sample of 8766 U.S. women to quantify the impact of all associated causal factors. Linear regression was used in the analyses.

RESULTS

Body image perceptions (42%) was the most significant contributor, followed by hypertension (12%), general health condition (11%), diabetes/borderline diabetes (10%), arthritis (9%) and performing vigorous activity (9%).

CONCLUSIONS

To decrease obesity prevalence rates in U.S. women, obesity prevention and treatment programmes should parallel the contributory effects of its most significant causal factors of psychological, biological and behavioural. In addition, more research and data are needed to explore the relationship between BMI in women and the multiple influencing factors by going beyond the more frequently available information of age, gender, race, education, income and parity.