Risk Factors for Clinically Significant Importance of Shape and
Weight in Adolescent Girls
Simon M. Wilksch and Tracey D. Wade
The objective of the current study was to conduct a longitudinal study of adolescent girls to determine
how temperament, attitudes toward shape and weight, life events, and family factors might contribute to
the growth of clinically significant importance of shape and weight, assessed using the Eating Disorder
Examination (EDE). Time 1 data were available from 699 female twins (M age ? 13.96 years) and 595
parents, and approximately 1.15 years later (Time 2) the twins completed the EDE again (M age ? 15.10
years). Twins were treated as singletons in the analyses. Time 1 importance of shape and weight was a
significant predictor of Time 2 lifetime disordered eating behaviors. Seven Time 1 variables were
significant univariate predictors of Time 2 importance of shape and weight. In multivariate analyses,
fathers’ sensitivity to reward was the only significant predictor of growth of Time 2 importance of shape
and weight. Some support was found for established risk factors of disordered eating risk, while the
multivariate analyses highlight the importance of developing conceptualizations of eating disorder
etiology beyond the individual level.
Keywords: eating disorders, risk factors, twin studies, adolescents
Eating disorders are well recognized for their multifaceted eti-
ology, and up to 30 different variables have been reported in the
literature as possible risk factors (Jacobi, Hayward, de Zwaan,
Kraemer, & Agras, 2004). However, conflicting evidence exists as
to which variables are most pertinent in the expression of clinical
eating disorders, with some researchers arguing that we are a long
way from understanding these complex problems (Polivy & Her-
man, 2002). It has been recommended that future research should
seek to clarify the relative importance of identified risk factors, and
in particular, the way in which they work together to promote
eating pathology (Stice, 2002). Therefore, the aim of the current
research was to use family data to investigate the variety of risk
factors that contribute to the growth of one of the diagnostic
criteria for both anorexia nervosa and bulimia nervosa: importance
of shape and weight, or “undue influence of body weight or shape
on self-evaluation” (American Psychiatric Association, 2000).
Importance of Shape and Weight
Importance of shape and weight has been described as the “core
Appearance Schemas Inventory (Cash, Melnyk, & Hrabosky, 2004)
and the Body Areas Satisfaction Scale (Giovannelli, Cash, Henson, &
Engle, 2008) have been designed to measure investment in certain
beliefs about the importance, meaning, and influence of their appear-
ance in life and evaluative body image in nonclinical samples. Where
eating disorders exist, clinically significant (or threshold) importance
of shape and weight is typically defined as a mean item score of ?4
on the importance of shape and importance of weight items of the
Eating Disorder Examination (EDE; Fairburn & Cooper, 1993), an
internationally accepted indicator of disordered eating severity
(Mond, Hay, Rodgers, & Owen, 2006). In the cognitive model of
eating disorders this construct is postulated to lead to the development
of extreme and rigid dietary behavior that can lead to the development
of disordered eating (Fairburn, Cooper, & Shafran, 2003). Previous
studies have shown a cross-sectional association between evaluative
body concern and abnormal eating patterns (Giovannelli et al., 2008),
and robust prospective evidence implicates weight concern—a con-
struct that includes items related to the importance of shape and
weight in addition to questions addressing body image—in the de-
velopment and maintenance of eating disorders (Goldfein, Walsh, &
Midlarsky, 2000; Gowers & Shore, 2001; Killen et al., 1996). Studies
of British adolescent girls found that 14.5% of 11- to 12-year-olds
have significant shape and weight concerns, and that this increases to
18.9% in 15- to 16-year-olds (Cooper & Goodyer, 1997). It is in this
latter group that the concerns become associated with a significant
level of behavioral disturbance, and adolescence is viewed as being
the greatest risk period for the development of shape and weight
concerns (Gowers & Shore, 2001).
Candidate Risk Factors
Although a large range of variables have been investigated with
respect to their impact on the growth of disordered eating behavior
and body dissatisfaction, very little research has focused specifi-
Simon M. Wilksch and Tracey D. Wade, School of Psychology, Flinders
University, South Australia, Australia.
National Health and Medical Research Council (NHMRC) Grant
324715 supported this work. Administrative support for data collection was
received from the Australian Twin Registry, which is supported by an
Enabling Grant (ID 310667) from the NHMRC administered by the Uni-
versity of Melbourne. We would like to thank the twins and their families
for their participation in this research and Judith Slater for coordinating the
Correspondence concerning this article should be addressed to Tracey D.
Wade, School of Psychology, Flinders University, P.O. Box 2100, Adelaide,
South Australia 5001, Australia. E-mail: firstname.lastname@example.org
Journal of Abnormal Psychology
2010, Vol. 119, No. 1, 206–215
© 2010 American Psychological Association
cally on risk factors for clinically significant levels of importance
of shape and weight. Genetic epidemiological research suggests
that risk factors for the cognitive and behavioral substrates of
eating disorders may differ somewhat (e.g., Wade et al., 1999;
Wade, Martin, & Tiggemann, 1998), and recent research suggests
that the risk factors for body dissatisfaction and importance of
shape and weight may also be different (Allen, Byrne, McLean, &
Davis, 2008). It has been postulated that a variety of factors impact
on this cognitive substrate—including genetic influences on tem-
perament, such as perfectionism, ineffectiveness, and impulsivity;
sociocultural influences on the ideal female shape, such as pressure
from media and peers; adverse experiences, such as sexual abuse
or bullying; and family factors, such as family attitudes and be-
liefs, parental eating, feeding practices, and family functioning
(Gowers & Shore, 2001).
Theoretical explanations in eating disorders consistently suggest
that an underlying temperament style, including perfectionist ten-
dencies, low self-esteem (or dissatisfaction with life and self), and
sensitivity to stress, creates an environment where control over
shape and weight is valued as an observable and measurable
indicator of self-worth (Fairburn et al., 2003; Schmidt & Treasure,
2006; Slade, 1982). A recent investigation of adult twins showed
that anorexia nervosa may represent the expression of a common
underlying familial liability to a temperament style that reflects a
striving for perfectionism, a need for order, and sensitivity to
praise and reward (Wade, Tiggemann, et al., 2008). Additionally,
eating disorders characterized by bingeing and purging have been
consistently found to be associated with novelty seeking, indicat-
ing higher levels of impulsivity and excitability (Wade, Bulik,
Prescott, & Kendler, 2004). Therefore temperament styles selected
for investigation in the current study included ineffectiveness,
concern over mistakes (perfectionism), obsessionality, sensitivity
to punishment, and sensitivity to reward. These two latter variables
are informed by Gray’s (1981) model of personality, where sen-
sitivity to punishment has been proposed as an indicator of anxiety,
while sensitivity to reward has been suggested as an indicator of
Sociocultural influences have been postulated to account for the
higher prevalence of eating disorders in girls and the increase of
body dissatisfaction and eating disorders in cultures exposed to the
Western thin ideal (e.g., Becker, Gilman, & Burwell, 2005). Lon-
gitudinal studies have shown that trying to look like a person in the
media predicted binge eating and purging in girls over a 7-year
follow-up (Field et al., 2008). Therefore variables reflecting atti-
tudes toward weight and appearance that were likely to be influ-
enced by sociocultural norms were chosen for investigation in the
current study, including body dissatisfaction, thin-ideal internal-
ization (the extent to which individuals invest in societal ideals of
size and appearance to the point where they become rigid, guiding
principles), and perceived pressure to be thin. These three vari-
ables feature in Stice’s (2001) dual pathway model of bulimic
pathology and have been found to prospectively predict growth of
With respect to adverse life experiences, sexual abuse has been
identified as a nonspecific variable risk factor of medium potency
for eating disorders. In contrast, general adverse life events have
been identified as a nonspecific retrospective correlate of small
potency (Jacobi et al., 2004). Weight teasing has been shown to
predict frequent dieting in girls and binge eating and unhealthy
weight control in boys (Haines, Neumark-Sztainer, Eisenberg, &
Hannan, 2006). Recent interest has focused on the potency of
perinatal events to influence the later development of disordered
eating (e.g., Favaro, Tenconi, & Santonastaso, 2006). Therefore
adverse life experiences included in the current study were weight-
related peer teasing, adverse life events, and perinatal complica-
Finally, family factors have consistently been postulated as
being involved in the development of eating disorders despite little
evidence to support their status as risk factors (Jacobi et al., 2004).
Recent evidence highlights two possible pathways between paren-
tal behavior and disordered eating. The first relates to the quality
of the relationship with parents. Maladaptive paternal behavior
was uniquely associated with risk for eating disorders after con-
trolling for maladaptive maternal behavior, childhood maltreat-
ment, and other co-occurring adversities (Johnson, Cohen, Kasen,
& Brook, 2002), and recent research has shown that low levels of
paternal care predicted the development of objective binge eating
in adult women (Wade, Treloar, & Martin, 2008). In this latter
study, low levels of both paternal and maternal care predicted the
development of self-induced vomiting, and retrospective correlates
identified higher levels of parental conflict, expectations, and
criticism to be associated with the onset of binge eating. A second
potential pathway implicates parental attitudes and behavior asso-
ciated with weight and eating. For example, longitudinal studies
show that the father’s eating attitudes predicted the growth of
disturbed eating in adolescent girls (Westerberg, Edlund, & Gha-
deri, 2008); when boys reported weight as being important to their
father, it predicted development of binge eating (Field et al., 2008);
children of women with eating disorders showed disturbed eating
compared to control individuals (Stein et al., 2006); eating meals
together as a family protects adolescents from developing disor-
dered eating (Neumark-Sztainer, Eisenberg, Fulkerson, Story, &
Larson, 2008); and the presence of struggles over food from ages
0 to 8 years predicts the emergence of disordered eating (Kotler,
Cohen, Davies, Pine, & Walsh, 2001). Therefore family factors
were also evaluated in the current study, including the twins’
perceptions of parental expectations, criticism, conflict, and care,
as well as parental dieting and food struggles from ages 0 to 8
The primary objective was to conduct a longitudinal study of
adolescent twins and their parents in order to identify which
specific temperament, sociocultural influences, adverse life events,
and family factors, individually and in combination, contribute to
our dependent variable, the growth of the core cognitive psycho-
pathology of eating disorders, importance of shape and weight.
The investigation was conducted with 12- to 16-year-old adoles-
cent girls, given that this is the age group and gender that experi-
ences most risk of importance of shape and weight being translated
into behavioral disturbance.
Data from the current study come from an ongoing follow-up of
twin adolescents and their parents. Although the methodology for
IMPORTANCE OF SHAPE AND WEIGHT
Time 1 data collection has been previously described (Wade,
Byrne, & Bryant-Waugh, 2008; Wilksch & Wade, 2009a), the
current study also examined a second wave of data. Female–
female twins who were registered with the Australian Twin Reg-
istry (ATR) and were between 12 and 15 years old and their
parents were approached to participate in the present study by the
ATR. Of the 719 families approached by the ATR, 411 (57.2%)
agreed to participate, 237 (32.9%) said no, and 71 (9.9%) did not
reply. Families were then approached by the researchers, who sent
self-report questionnaires to both parents, including those families
where the parents did not live together. At this stage 595 parents
returned questionnaires, representing 351 families. When ques-
tionnaires were returned from the parents, a version of the EDE
(Fairburn & Cooper, 1993) adapted for children was conducted
over the telephone with the twins, at separate times and with a
different interviewer for each child in the family. Interviews were
completed with 699 children, where 349 Twin 1 children partici-
pated, 350 Twin 2 children participated, and two Twin 1 children
and one Twin 2 child did not participate (two children had cerebral
palsy and had difficulties talking, and one withdrew), thus repre-
senting 348 complete pairs and three incomplete pairs. This sample
represents 48.8% of those families who were approached by the
ATR. All of the mothers of the complete twin pairs returned
self-report questionnaires and 247 of the fathers (71%) did so. The
mean age of the girls at Time 1 was 13.96 years (SD ? 0.80),
ranging from 12.70 years to 16.28 years (two pairs of twins had
turned 16 between the approach and data collection). The sample
was Caucasian and the socioeconomic indexes for areas
(SEIFA)—a standardized measure of socioeconomic status (SES)
with a mean of 100 (SD ? 15) that uses an amalgam of parental
occupation, education (years of school), and income from 2006
census data related to the postcode of primary residence—was
101.139 (SD ? 11.36; Farish, 2004), indicating a slightly higher
SES than the Australian average.
Zygosity assignment was based on parental responses to stan-
dard questions about physical similarity and confusion of twins by
parents, teachers, and strangers, methods that give better than 95%
agreement with genotyping (Eaves et al., 1989).
A total of 669 twins of the 699 who agreed to participate at Time
1 (96%) agreed to participate at Time 2, whereas 514 parents of the
595 parents who agreed to participate at Time 1 (86%) participated
at Time 2. Mean twin age at Time 2 was 15.10 years (SD ? 0.83),
ranging from 13.76 years to 17.56 years, where the mean duration
of time between Times 1 and 2 was 1.15 years (SD ? 0.17). As
with Time 1, the total protocol consisted of a self-report question-
naire for the parents and a telephone interview for the twins. The
current study reports on all the Time 1 measures and the interview
related to the twins’ eating from Time 2.
The Flinders University Clinical Research Ethics Committee
approved the data collection process, and written informed consent
from parents and written assent from the twins were obtained after
the procedures had been fully explained. Recruitment and assess-
ments took place between 2005 and 2008. It is important to note
that although twin data was collected, participants were treated as
individuals (with statistical corrections for data from the same
family), as influences of zygosity and other genetic factors were
not the focus of this study.
The twins completed a telephone interview related to their
eating and standardized questionnaires related to their tempera-
ment, attitudes toward weight and appearance, and their percep-
tions of family functioning (with the exception of parental dieting
behavior and total food struggles when they were aged 0 to 8
years). Parents were asked to report on their own temperament, life
events in the daughters’ lives, and their own dieting behavior. The
same protocol was used at both Times 1 and 2 (Wade, Byrne, &
Bryant-Waugh, 2008; Wilksch & Wade, 2009a).
The EDE was slightly modified in line with
previous recommendations for use with children (Bryant-Waugh,
Cooper, Taylor, & Lask, 1996). All diagnostic questions addressed
a 3-month time frame, and in addition, the EDE was revised with
insertion of lifetime questions, including the age range during
which the behavior occurred, in order to assess the co-occurrence
of features, as used previously with an adult sample of twins (e.g.,
Wade, Bergin, Tiggemann, Bulik, & Fairburn, 2006; Wade,
Crosby, & Martin, 2006). Three of these revisions are of relevance
to the current study. First, as the EDE does not currently assess
fasting (apart from those who have experienced concurrent binge
episodes), a 3-month and lifetime version of the “avoidance of
eating” question was included. The threshold criterion was met if
the person had gone for 8 or more waking hours without eating
anything in order to influence shape or weight on more than half
the days each week for a 3-month period. Second, lifetime occur-
rence of objective binge eating was assessed with an additional
question about whether the behavior met the threshold criterion (at
least twice a week for a 3-month period with breaks of no more
than 2 weeks). Third, lifetime questions assessing use of self-
induced vomiting, laxatives, diuretics, and excessive exercise were
included, along with questions about threshold frequency. The
threshold was defined the same as for objective binge eating with
the exception of excessive exercise, which was defined as driven
or compulsive exercise that had occurred for at least 1 hr 5 days a
week for a 3-month period with no breaks of more than 2 weeks.
Questions were asked separately for competitive sport and other
forms of exercise, where only exercise for weight or shape reasons
was included and exercise for fitness or recreation was excluded.
Abstinence from these weight control behaviors for 2 or more
weeks was assessed by a follow-up question, as was co-occurrence
with any binge eating behavior. Disordered eating was defined as
the number of lifetime disordered eating behaviors that met diag-
nostic threshold, which included objective binge episodes, fasting,
excessive exercise, self-induced vomiting, and laxative and di-
Given the difficulty of assessing lifetime importance of shape
and weight, these diagnostic items were assessed for the previous
3 months and then during any periods of disordered eating or low
weight. Our outcome variable, importance of shape and weight,
was calculated using the mean item value of the six items assessing
the importance of both shape and weight over each month for the
previous 3-month period.
Weight and height of the twins were based on the mother’s
report. The percent weight for height ratio was used in the current
study. As suggested by Cole, Flegal, Nicholls, and Jackson (2007),
underweight was considered to be less than or equal to 80% weight
WILKSCH AND WADE
for height, whereas overweight was considered to be more than or
equal to 120% weight for height.
All interviewers were postgraduate clinical psychology trainees
(n ? 16) who had been trained in use of the EDE. Each of the
interviews was taped, and corrective feedback was provided
throughout the interviewing process, where monthly group meet-
ings were held to ensure interview fidelity. Independent ratings by
the second author (Tracey D. Wade) of a subsample of 20 ran-
domly chosen interviews (five from each of the four age groups,
i.e., 12-, 13-, 14-, and 15- to 16–year-olds) yielded interrater
reliability statistics (Pearson’s correlation) of the four subscales of
the EDE (last 4 weeks) as follows: 1.00 (Dietary Restraint), .96
(Eating Concern), .98 (Weight Concern), and .99 (Shape Concern).
Candidate risk factor measures.
report questions in an interview format, whereas parents completed
the self-report measures on paper. An overview is summarized in
Table 1. The variables were drawn from nine standardized ques-
tionnaires (described below) and four questionnaires pertaining to
events that have been used in previous research examining risk
Twins answered the self-
factors for disordered eating, namely the three measures of life
events and the total food struggles.
The Ineffectiveness and Body Dissatisfaction subscales from the
Eating Disorder Inventory (EDI; Garner, Olmstead, & Polivy,
1983) use 6-point Likert scales ranging from 1 (always) to 6
(never). The Body Dissatisfaction subscale has been used reliably
with children as young as 11 years old (Meltzer et al., 2001). The
original scoring for eating disorder populations was not used (0, 0,
0, 1, 2, 3), as this was expected to be neither a sensitive enough
measure of change in a population expected to be less extreme
with respect to eating disorder behavior and psychopathology nor
to have acceptable internal consistency (Schoemaker, van Strien,
& van der Staak, 1994).
Concern over mistakes, parental expectations, and parental crit-
icism were measured using the Multidimensional Perfectionism
Scale (MPS; Frost, Marten, Lahart, & Rosenblate, 1990). Items
were rated on a 5-point Likert scale ranging from 1 (strongly
agree) to 5 (strongly disagree). Convergent validity for the entire
MPS has been supported with the Perfectionism subscale of the
Summary and Description of the Self-Report Measures Used in the Analyses
Variable Scale Content
Eating Disorder Inventory (EDI; Garner, Olmstead, & Polivy, 1983),
Multidimensional Perfectionism Scale (MPS; Frost et al., 1990)
Concern over mistakesb
Sensitivity to punishmentb,d
Sensitivity to Punishment and Sensitivity to Reward Questionnaire
(SPSRQ; Torrubia et al., 2001), Sensitivity to Punishment subscale
Sensitivity to rewardb,d
SPSRQ, Sensitivity to Reward subscale5 items
Vancouver Obsessional Compulsive Inventory (Thordarson et al.,
2004), “Just Right” subscale
Attitudes toward weight and
Multidimensional Media Influence Scale (Cusumano & Thompson,
Perceived Sociocultural Pressure Scale (Stice et al., 1996)
EDI, Body Dissatisfaction subscale
Perceived pressure to be thina
Weight-related peer teasinga
Total perinatal eventsc
Total life eventsc
McKnight Risk Factor Survey (McKnight Investigators, 2003)
Indexes of Pregnancy and Perinatal Complications (Foley et al., 2001)
12 yes–no items
6 yes–no items
Family Environment Scale (Moos & Moos, 1986), Conflict subscale
Parental Bonding Inventory (Parker et al., 1979), Care scale
Dutch Eating Behavior Questionnaire—Revised (van Strien et al.,
1986), Restraint subscale
Total food struggles during 0–8
years of agec
— 3 yes–no items
(Kotler et al., 2001)
aMeasure administered to twins only.
the measure used only.
bMeasure administered to twins and parents.
cMeasure administered to parents only.
dSubset of the items from
IMPORTANCE OF SHAPE AND WEIGHT
EDI in a population with anorexia nervosa (r ? .59; Garner et al.,
The sensitivity to punishment and reward items were taken
from the Sensitivity to Punishment and Sensitivity to Reward
Questionnaire (SPSRQ; Torrubia, Avila, Molto, & Caseras,
2001), where both subscales have been found to have accept-
able internal reliability and test–retest reliability (Torrubia et
al., 2001). The measure was developed from Gray’s (1981)
model of personality, which has described two motivational
systems, the behavioral inhibition system (BIS) and the behav-
ioral activation system (BAS), that control aversive and appet-
itive behaviors, respectively. The first subscale, Sensitivity to
Punishment, has been found to correlate positively with Ey-
senck Personality Questionnaire (EPQ; Eysenck & Eysenck,
1978) dimension of Neuroticism (r ? .69 in boys and r ? .47
in girls) as well as the State–Trait Anxiety Inventory (Spiel-
berger, Gorsuch, & Lushene, 1970), with correlations of .68 and
.59 for boys and girls, respectively (Torrubia et al., 2001). The
second subscale, Sensitivity to Reward, is positively associated
with the EPQ Impulsiveness scale, with a correlation of .43 (and
a correlation of –.02 with the Punishment subscale). Thus the
subscales are suggested to map on to the anxiety (BIS) and
impulsivity (BAS) constructs from Gray’s model. Although the
internal consistency for each scale at Time 1 was generally
adequate, the five-item Sensitivity to Reward subscale was not
highly reliable with twins or their parents. It should be noted
that the SPSRQ was abbreviated from its original 48-item
version to a 10-item version in order to reduce the burden of
measure completion. The five items that had previously been
found to load most strongly on each factor were selected
(Torrubia et al., 2001).
Obsessionality was measured using the “Just Right” subscale of
the Vancouver Obsessional Compulsive Inventory (Thordarson et
al., 2004). It contains a 5-point Likert-type scale ranging from not
at all to very much. The internal consistency has been found to be
good, ranging from .90 to .96, and good convergent and discrimi-
nant validity have been achieved (Thordarson et al., 2004).
The Internalization subscale of the Multidimensional Media
Influence Scale (Cusumano & Thompson, 2001) was used to
measure thin-ideal internalization. Each item was answered using
a 5-point Likert scale, and previous investigation has found the
scale to correlate significantly and positively with body dissatis-
faction in 8- to 11-year-old girls (Cusumano & Thompson, 2001).
The Perceived Sociocultural Pressure Scale (Stice, Ziemba,
Margolis, & Flick, 1996) was used to assess participants’ felt
pressure from friends, family, media, and dating partners to have
a thin body/not get fat (two items for each source of pressure).
Each question was assessed using a 5-point Likert scale ranging
from 1 (none) to 5 (a lot). Ratings have been found to relate to
retrospective reports of the perceived pressure from parents to lose
weight during childhood (r ? .51; Stice et al., 1996).
Conflict between the parents was measured using the Conflict
subscale from the Family Environment Scale (Moos & Moos,
1986) with nine items using a 4-point Likert scale. Items were
adapted to refer to parents rather than family, for example, “My
parents rarely become openly angry with each other.” A previous
investigation of 11- to 16-year-old girls has found this form of the
measure to have good internal reliability (? ? .81) and to be
significantly correlated with the Shape Concern and Weight Con-
cern subscales of the EDE (Wade & Lowes, 2002), where more
conflict is associated with higher concern.
Parental care was assessed using the Parental Bonding Inventory
(PBI; Parker, Tupling, & Brown, 1979) Care scale. The PBI has
been widely investigated over the last 3 decades and has been
shown to have good test–retest reliability and to have a robust
factorial structure in various populations, including adolescents
Parental dietary restriction was measured using the Dutch Eat-
ing Behavior Questionnaire—Revised (van Strien, Frijters, Berg-
ers, & Defares, 1986), Restraint subscale. Each item has a 5-point
Likert scale ranging from 1 (never) to 5 (very often). High internal
reliability has been previously been found for use of this measure
with a sample of 13- to 17-year-old girls (Stice, 2001).
SPSS Version 15. Logistic regressions were used to investigate
any differences between twins who participated at Time 1 only
compared to those who participated at both Time 1 and Time 2.
Prior to analyses, candidate risk factors were standardized for ease
Validity of the outcome variable.
validity of the importance variable, we calculated correlations with
other Time 1 variables. In addition, we used a linear mixed-models
approach to investigate if Time 1 importance of shape and weight
predicted any eating disordered behavior at Time 2 (the number of
eating disordered behaviors), controlling for Time 1 disordered
eating. Given that Twin 1 and Twin 2 are correlated observations,
linear mixed models can correct for within-family shared variance
that is inherent in family research.
Risk factors for the outcome variable.
whether the candidate risk factors accounted for significant vari-
ance in Time 2 importance of shape and weight scores. This was
achieved by running a series of univariate linear mixed-model
analyses, where Time 1 importance of shape and weight scores
were controlled for in each analysis. There was no correction for
Type I error in these analyses as we went on to examine predictor
variables in a multivariate analysis.
All candidate risk factors found to approach univariate signifi-
cance (p ? .10) in predicting Time 2 importance of shape and
weight were entered in a multivariate analysis to reveal which
predictors remained robust when combined with related variables.
For each linear mixed-models analysis, restricted maximum like-
lihood (REML) estimates are reported, which can be interpreted in
the same way as regression coefficients.
All analyses were conducted using
In order to investigate the
Participation at Time 2 was not related to Time 1 disordered
eating behaviors, weight for height ratio, or zygosity but was
related to age, where those who participated at Time 1 only (M
age ? 13.63, SD ? 0.74) were younger than those who partici-
pated at both assessments (M ? 13.96, SD ? 0.79), odds ratio ?
1.79, 95% CI [1.05, 3.05], p ? .031.
WILKSCH AND WADE
Of the 696 twins for whom importance of shape and weight data
were available at Time 1, a total of 55 twins (7.9%) recorded
threshold importance of shape and weight, and at Time 2, 58
(8.7%) recorded threshold importance of shape and weight. Eleven
of these participants had clinically significant importance of shape
and weight at both Time 1 and Time 2, whereas 44 met this
criterion at Time 1 only and 47 at Time 2 only.
Validity of the Outcome Variable
The correlations between the outcome variable at Time 1 and
the candidate risk factors are presented in Table 2. It can be seen
that, for twin reports, shape and weight importance was moder-
ately correlated with the temperament variables, strongly corre-
lated with the appearance attitude variables and weight-related
teasing, and weakly correlated with family factors. The correla-
tions between paternal and maternal perinatal and adverse life
events were high (.85 and .83, respectively, for Twin 1 and .84 and
.83, respectively, for Twin 2) as would be expected. Correlations
among the remaining independent variables at Time 1 were all less
than .60, with the exception of the correlation between thin-ideal
internalization and perceived pressure to be thin (.68) and body
dissatisfaction (.60) for Twin 1 and thin-ideal internalization and
perceived pressure to be thin (.61) for Twin 2.
Time 1 importance of shape and weight scores was a significant,
positive predictor of the presence of any Time 2 lifetime diagnostic
threshold level of disordered eating behaviors when controlling for
these behaviors at Time 1, REML estimate ? .05, 95% CI [.03,
.07], p ? .001. Table 3 provides frequency information on the
presence of disordered eating behaviors at both assessment points
for those with and without threshold levels of importance of shape
and weight at Time 1. It can be seen that 32% of those with Time
1 threshold levels of importance of shape and weight met diag-
nostic criteria for at least one lifetime disordered eating behavior at
Time 2, whereas only 3.6% of those without Time 1 threshold
levels of importance of shape and weight met criteria for a lifetime
disordered eating behavior at Time 2. There was a correlation of
.34 between Time 2 importance of shape and weight and disor-
Risk Factors for the Outcome Variable
ticipants with threshold importance of shape and weight at Time 1
still met this criterion at Time 2, whereas 44 participants did not.
Of those with Time 1 threshold importance of shape and weight
(and controlling for Time 1 disordered eating behaviors), 32.1%
met criterion for at least one disordered eating behavior at Time 2
compared to just 3.6% of those with nonthreshold levels of shape
and weight importance at Time 1.
Univariate linear mixed models.
ratio was investigated as a potential covariate but was not found to
be significantly related to growth in importance of shape and
weight scores, REML estimate ? .03, 95% CI [–.08, .13], p ? .65.
Seven of the measured variables were found to be significant
predictors of Time 2 importance of shape and weight scores, when
controlling for Time 1 importance of shape and weight scores (see
Table 4). Six of these were twin variables, whereas paternal
sensitivity to reward was the only significant parent variable
It should be noted that only eight par-
Percent weight for height
Correlations Between Time 1 Importance of Shape and Weight and Time 1 Candidate
Mother report Father report
Twin 1Twin 2 Twin 1 Twin 2
Sensitivity to punishment
Sensitivity to reward
Concern over mistakes
Attitudes toward weight and appearance
Pressure to be thin
N perinatal events
N adverse life events
N food struggles
?p ? .01.
A dash indicates that the scale was not administered to these participants.
IMPORTANCE OF SHAPE AND WEIGHT
Multivariate linear mixed models.
ness of candidate risk factors found to approach univariate signif-
icance (p ? .10), a multivariate mixed-model analysis was con-
ducted (again with Time 1 importance of shape and weight scores
controlled for). In total, nine variables were entered into the model.
Table 4 reveals that father’s sensitivity to reward scores was the
only unique predictor of the outcome variable.
To examine the unique-
Understanding Importance of Shape and Weight
This study prospectively investigated variables that contribute to
increased risk of the development of the core cognitive psychopa-
thology of eating disorders (i.e., importance of shape and weight)
Frequency of Lifetime Disordered Eating Behaviors, Weight Status at Time 1 and Time 2, and Their Association With Clinically
Significant Importance of Shape and Weight at Time 1
Presence of threshold behavior
Time 1 importance of shape and weight ? 4Time 1 importance of shape and weight ? 4
Time 1 (n ? 56)
n (% age)
Time 2 (n ? 53)
n (% age)
Time 1 (n ? 643)
n (% age)
Time 2 (n ? 616)
n (% age)
Any threshold ED behavior
Objective bulimic episodes
Fasting (avoidance of eating)
% weight for height ? 80
% weight for height ? 120
ED ? eating disordered.
Univariate Predictors (Standardized Time 1 Scores) of Twins’ Importance of Shape and Weight Scores at Time 2, After Controlling
for Twins’ Importance of Shape and Weight at Time 1
Time 1 variable
Univariate analyses Multivariate analyses
Sensitivity to punishment
Sensitivity to reward
.16 [.04, .27]
.13 [.02, .24]
.11 [.01, .22]
—— .12 [?.06, .30]
?.01 [?.15, .14]
.00 [?.12, .13]
.16 [.03, .29] (F)
.07 [?.07, .21]
.06 [?.05, .16]
?.05 [?.06, .16]
.09 [?.04, .22]
.16 [.03, .29]
Concern over mistakes
Attitudes toward weight and appearance
Pressure to be thin
N perinatal events
N adverse life events
N food struggles
.10 [?.01, .20]
.06 [?.05, .16]
.02 [?.09, .13]
.02 [?.09, .13]
.07 [?.06, .20]
.03 [?.11, .16]
.15 [.03, .26]
.14 [.02, .26]
.15 [.03, .27]
.08 [?.10, .26]
.03 [?.15, .21]
.06 [?.11, .24]
.11 [?.01, .23]
.07—— .05 [?.12, .22] .56
.01 [?.09, .12]
.02 [?.09, .12]
?.04 [?.17, .09]
.06 [?.07, .19]
.06 [?.04, .16]
.05 [?.06, .15]
.02 [?.09, .13]
.04 [?.06, .15]
.07 [?.04, .18]
?.02 [?.13, .09]
.07 [?.06, .19]
.02 [?.11, .15]
A dash indicates that the scale was not administered to these participants. REML ? restricted maximum likelihood; CI ? 95% confidence interval; F ?
Significant predictors of Time 2 importance of shape and weight in bold. Multivariate analysis included only those univariate items where p ? .10.
WILKSCH AND WADE
in early adolescent twins. The significance and validity of the
importance variable is indicated from its cross-sectional relation-
ship with other variables and its relationship to the growth of
disordered eating. With respect to this first investigation, we found
that the most consistent patterns of significant correlations be-
tween the importance variable and the independent variables was
with twin reports of temperament, attitudes toward weight and
appearance, weight-related teasing, and some of the family factor
variables. The correlations were in the expected directions, where
higher importance of shape and weight was associated with more
ineffectiveness, anxiety, impulsivity, obsessionality, perfection-
ism, thin-ideal internalization, perceived pressure to be thin, body
dissatisfaction, weight-related teasing, and parental criticism and
conflict and with lower levels of perceived care from parents. With
respect to the second investigation, importance of shape and
weight at Time 1 was shown to contribute significantly to the
development of disordered eating between Times 1 and 2. Overall,
these results support the validity of our importance measure.
Univariate Predictors of Importance of Shape
Our univariate explorations of associations between growth of
importance of shape and weight and our independent variables
present a slightly different picture from the correlations, in part
because we are using a different outcome variable (Time 2 impor-
tance when controlling for Time 1 importance), and in part because
the correlations between family member observations is now con-
trolled for in our mixed-model analyses. Seven variables were
significantly positively associated with Time 2 importance of
shape and weight scores: three twin temperament variables (i.e.,
ineffectiveness; sensitivity to punishment, or anxiety; and sensi-
tivity to reward, or impulsivity); all three of the attitudes toward
weight and appearance measures; and one parent variable, fathers’
sensitivity to reward, or impulsivity. This latter finding is consis-
tent with previous findings from a twin study showing that broth-
ers’ novelty seeking was associated with lifetime bulimia nervosa
in their sisters when controlling for sisters’ novelty seeking (Wade
et al., 2004).
Thin-ideal internalization, body dissatisfaction, and perceived
pressure to be thin, feature in Stice’s (2001) dual pathway model
of bulimic symptoms. In addition, prevention work targeting thin-
ideal internalization and perceived pressure to be thin has pro-
duced significant benefits for ratings of importance of shape and
weight in controlled trials with early adolescents, providing further
support of a potential link between these variables (Wade, David-
son, & O’Dea, 2003; Wilksch & Wade, 2009b).
Sensitivity to punishment (anxiety) and ineffectiveness are pos-
tulated to be critical causal influences on eating disorders; Slade
(1982) has suggested that premorbid personal ineffectiveness,
when allied with weight sensitivity triggered by adolescence, can
result in coping strategies that focus on the importance of control-
ling weight, shape, and eating in order to manufacture some sense
of personal success. Pallister and Waller (2008) have suggested
that similar underlying vulnerability and harm avoidance cogni-
tions might account for associations between anxiety and disor-
However, these results do differ from studies that examine
growth of disordered eating as opposed to cognition, where life
events (e.g., Favaro et al., 2006; Kotler et al., 2001; Loth, van den
Berg, Eisenberg, & Neumark-Sztainer, 2008) and family environ-
ment (Jacobi, Schmitz, & Agras, 2008) have been found to be
significantly associated with growth of disordered eating. Twin
studies have consistently found that the environment contributes
more to the cognitive substrates of disordered eating than the
behavioral substrates (e.g., Wade & Bulik, 2007; Wade et al.,
1999, 1998), thus providing some indication that we may not
necessarily expect that the same risk factors for eating disordered
behavior will apply to cognitions. Future prospective studies
should examine both the cognitive and behavioral substrates of
disordered eating so that direct comparisons of risk factor profiles
can be conducted.
Multivariate Predictors of Importance of Shape
The only variable to be significant in the multivariate context
was the father’s sensitivity to reward (impulsivity). Fathers’ scores
on this measure had comparatively low internal consistency (? ?
.68); thus some caution is required in interpreting this finding.
Questions related to reward seeking in the forms of praise (“Do
you often do things to be praised?”), attention (“Do you like being
the center of attention at a party or a social meeting?”), and
advancement (“Do you sometimes do things for quick gains?”).
There have been very few prospective investigations of a possible
causal role of parental (and in particular, paternal) temperament
styles in increasing risk of disordered eating in their children. The
importance of paternal variables in terms of contribution to risk for
eating disorders has recently been highlighted across a variety of
longitudinal studies, including maladaptive paternal behavior
(Johnson et al., 2002), low levels of paternal care (Wade, Treloar,
& Martin, 2008), paternal eating attitudes (Westerberg et al.,
2008), and importance of weight to the father (Field et al., 2008).
Somewhat surprisingly, none of the attitudes toward weight and
appearance variables were implicated in this analysis; although our
correlational data did not indicate multicollinearity between our
independent variables, it was these three variables that were most
highly correlated, sharing between 36% and 46% of their variance.
Attitudes toward weight and appearance should be examined more
closely in future validity research in order to identify one variable
that can best represent this construct in a multivariate analytic
This study had a number of limitations. First, we had only a
moderate Time 1 response rate (48.8%), although it is commen-
surate with other large Australian twin studies (Wade, Bergin, et
al., 2006). Consistent with research with adults in the ATR (Heath
et al., 2001; Wade, Bergin, et al., 2006), response rates were not
influenced by body mass index or level of eating pathology,
suggesting those with disordered eating did not avoid participating.
Second, the prospective time frame of the current study was
comparatively short, and more adolescents will develop high levels
of importance of shape and weight as they progress toward adult-
hood. Related to this limitation is our finding that there was some
instability in our importance variable in young adolescents, given
that only 15% of girls who had threshold shape and weight
IMPORTANCE OF SHAPE AND WEIGHT
importance at Time 1 also met threshold at Time 2. Third, using
the current design we cannot identify whether paternal impulsivity
increases genetic or environmental risk (or both) for importance of
shape and weight in the daughter, and it will be of interest to
examine this question in further research.
The current study provides further support for the core role of
threshold levels of importance of shape and weight in the devel-
opment of disordered eating behaviors. Although a number of
“well-established” eating disorder risk factors (e.g., thin-ideal in-
ternalization) were supported as risk factors for the growth of
shape and weight concern, support also emerged for less investi-
gated variables, most notably fathers’ sensitivity to reward (im-
pulsivity). Although our study is not without limitations, it does
highlight the importance of conceptualizations of disordered eating
that extend beyond an exclusively individual focus.
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Received October 28, 2008
Revision received May 11, 2009
Accepted May 13, 2009 ?
IMPORTANCE OF SHAPE AND WEIGHT