title: The relationship between weight loss and time and risk preference parameters: a randomized controlled trial.
abstract: This study aimed to assess the effectiveness of intervention (specifically, intervention by telephone and mails, known as 'tele-care') relative to self-help as a weight-loss method. The question of whether there is a correlation between changes in two preference parameters--time discounting (i.e. impatience) and risk aversion--and the level of commitment was examined. The study, spanning a period of 24 weeks in 2006-2007, comprised 118 participants, each of whom was randomly assigned to either the tele-care or the self-help group. A public-health nurse provided support through telephone and mail communications to the tele-care group, aiming to reduce their calorie intake and increase exercise via this intervention. There was a significant decrease in the body weight of the participants of the tele-care group from the baseline; however, there were no significant differences in the weight loss, median time discounting or risk aversion between the two groups. The subsequent analysis for weight loss with changes in time and risk parameters revealed a significant difference in the weight loss in the time-discounting-loss and risk-aversion-gain groups. From the results of the multiple regression analysis, the time discounting was noted to be associated with age, initial BMI and marital status among men, and risk aversion was associated with age and job status among women. There is a possibility that a decrease in time discounting and increase in risk aversion might correlate with the weight loss or effectiveness of commitment in this trial. This study suggests that time discounting and risk aversion may be useful in anti-obesity efforts, since they are accurate criteria of behavioural patterns associated with weight problems.
authors.affiliation: Department of Health Promotion and Behaviour Science, Health Determinants, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Takada
authors.forename: Ryota
authors.initials: R
authors.lastname: Nakamura
authors.forename: Masakazu
authors.initials: M
authors.lastname: Furukawa
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Shuzo
authors.initials: S
authors.lastname: Nishimura
authors.forename: Shinji
authors.initials: S
authors.lastname: Kosugi
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005260:Female; D006305:Health Status Indicators; D015277:Hotlines; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D015999:Multivariate Analysis; D015995:Prevalence; D011637:Public Health Nursing; D011788:Quality of Life; D012044:Regression Analysis; D012306:Risk; D040242:Risk Reduction Behavior; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D013997:Time Factors; D015431:Weight Loss; D055815:Young Adult