title: Body image discrepancy and subjective norm as mediators and moderators of the relationship between body mass index and quality of life.
abstract: OBJECTIVE
  Despite the strength and consistency of the relationship between body mass index (BMI) and quality of life (QoL), a reduction in BMI does not necessarily lead to an improvement in QoL. Between-subject variability indicates the presence of mediators and moderators in the BMI-QoL association. This study aimed to examine the roles of body image discrepancy (BID) and subjective norm (SN) as potential mediators and moderators.
  
  
  METHODS
  In 2012, 3,016 volunteers (aged ≥18 years) participated in a community-based survey conducted in the French-speaking region of Belgium. Participation was enhanced using a large multimedia campaign (which was supported by a large network of recruiters) that employed the nonstigmatizing slogan, "Whatever your weight, your opinion will count". Participants were invited to complete a web-based questionnaire on their weight-related experiences. Self-reported measures were used to calculate each participant's BMI, BID, SN, and QoL (a French obesity-specific QoL questionnaire was used to calculate the participants' physical dimension of QoL scores [PHY-QoL], psychosocial dimension of QoL scores [PSY/SOC-QoL], and their total scores). The covariates included gender, age, subjective economic status, level of education, household size, and perceived health. The mediation/moderation tests were based on Hayes' method.
  
  
  RESULTS
  Tests showed that the relationships between BMI and PHY-QoL, PSY/SOC-QoL, and TOT-QoL were partially mediated by BID in both males and females and by SN in females. Moreover, BID was a moderator of the relationship between BMI and PSY/SOC-QoL in males and females. SN was a moderator of the relationship between BMI and PSY/SOC-QoL in males and between BMI and total scores in males (when used without BID in the models).
  
  
  CONCLUSIONS
  BID and SN should be considered as important factors in obesity management strategies. The study shows that targeting BMI only is not sufficient to improve the QoL of overweight and obese subjects, and that other variables, including perceptual factors, should be considered.
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Pétré
authors.affiliation: Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, CHU Sart Tilman, University of Liège, Liège, Belgium.
authors.forename: André J
authors.initials: AJ
authors.lastname: Scheen
authors.affiliation: Department of Diabetes, Metabolic Diseases and Nutrition, Nancy University Hospital, Nancy, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Ziegler
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Donneau
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Nadia
authors.initials: N
authors.lastname: Dardenne
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Eddy
authors.initials: E
authors.lastname: Husson
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Adelin
authors.initials: A
authors.lastname: Albert
authors.affiliation: Department of Public Health, University of Liège, Liège, Belgium.
authors.forename: Michèle
authors.initials: M
authors.lastname: Guillaume
keywords: body image; mediators and moderators; obesity; quality of life