Unhealthy thinking about body and weight 'can start ...

"Basis for eating disorders found in children as young as eight," The Guardian reports. A new UK survey of around 6,000 children found the roots of unhealthy thinking about body and weight can predate adolescence.

Researchers collected data from 6,140 boys and girls aged 14 years as part of an ongoing study into childhood health. Information had already been collected from the same group of children about a range of factors, including their body dissatisfaction, body mass index (BMI) and self-esteem, and whether there was a history of maternal eating disorders and family economic disadvantage.

The study reported childhood body dissatisfaction, weight and shape concern, and pressure to lose weight were all significantly higher in girls compared with boys. This predicted eating disorders in girls at age 14. Higher childhood self-esteem seemed to have a protective effect against teenage eating disorders, particularly in boys.

This study has both strengths and limitations. One of the biggest strengths is its size. It also assessed early risk factors in childhood before the onset of eating disorder behaviours.

However, though the study demonstrates associations, it does not prove causation. There was also a high drop-out rate – only 59% of children completed assessments at the age of 14. This means the results may not be representative.

Where did the story come from?

The study was carried out by researchers from the University College London Institute of Child Health, the London School of Hygiene and Tropical Medicine, and King's College London in the UK, and Boston Children's Hospital and Harvard Medical School in the US.

It was jointly funded by the National Institute of Health Research (NIHR) and Wellchild.

The study was published in the peer-reviewed British Journal of Psychiatry on an open-access basis. It is free to read online or download as a PDF.

Overall, the UK media reported the story accurately, although some of the limitations were not fully explained.

The Guardian included a useful quote from Lorna Garner, chief operating officer at eating disorders charity, Beat: "It is evidence that one of the causes or contributing factors towards an eating disorder or something that could trigger an eating disorder is the whole thing around body image and self-esteem.

"It doesn't cause it, but it could be a large influencing factor. It is almost as though seeds that are sown pre-teens come to fruition later.

"Knowing that is incredibly helpful because it gives everybody who is involved with wanting to prevent and manage eating disorders an indication that we need to start earlier."

What kind of research was this?

This population-based prospective cohort study aimed to investigate the prevalence of eating disorder behaviours in 14-year-old children, and how this may be associated with childhood, physical and parental risk factors.

The data source for this study was the Avon Longitudinal Study of Parents and Children, which recruited all pregnant women in Avon in the UK who were expected to have a baby between April 1 1991 and December 31 1992.

Prospective cohort studies like this one, which follow a group of people over time, are useful for looking at how different exposures may be associated with different outcomes.

They can suggest the possible causal chain of a problem, but cannot definitely prove cause and effect because unmeasured factors (confounders) could be involved in the relationship.

What did the research involve?

This research involved a group of 6,281 children who completed assessment at the age of 14. This was representative of 59% of people taking part in the cohort.

At age 14, eating disorder behaviours were assessed using the Youth Risk Behaviour Surveillance System questionnaire.

Binge eating was assessed using a two-part question where the participants were asked about how often they had eaten a very large amount of food during the past year. Those who answered "yes" were asked a second question about whether they felt out of control during these episodes.

Purging was assessed by asking how often in the past year participants made themselves sick or used laxatives to lose weight or avoid gaining weight.

Weight and shape concerns were also assessed at 14 years using three questions as part of another survey:

In the past year, how happy have you been with the way your body looks?
In the past year, how much has your weight made a difference to how you feel about yourself?
In the past year, how much have you worried about gaining a little weight (as little as 1kg)?

Pressure to lose weight (from peers, family, the media, for example) was also assessed using another scale. Childhood and parental risk factors were assessed in earlier childhood.

At the age of 10.5 years, body dissatisfaction was assessed using gender-appropriate rating scales, and body mass index (BMI) was obtained from direct assessment. Self-esteem was also assessed using another scale.

Data on family financial problems was obtained from maternal reports at regular intervals throughout childhood by means of questionnaires.

Data was also collected on maternal eating disorder when the mothers were pregnant by asking them if they ever experienced anorexia nervosa or bulimia nervosa.

The researchers used various statistical methods to investigate the association between each predictor and outcome, divided by gender.

What were the basic results?

Body dissatisfaction, weight and shape concern, and reported pressure to lose weight were all significantly higher in girls compared with boys.

Prevalence of eating disorder behaviours and cognition at 14

18% of girls and 3% of boys reported they felt quite a lot of pressure from the media to lose weight
40% of girls and 12% of boys reported dieting in the previous year
7.5% of girls and 3.5% of boys reported bingeing
7.6% of girls and 1.6% of boys reported frequent dieting
0.4% of boys and 0.5% of girls reported they binged and dieted

Predictors of eating disorder cognitions

Maternal eating disorder with a history of both anorexia and bulimia nervosa predicted greater adolescent body dissatisfaction in girls, but not in boys.
Weight and shape concern in the maternal eating disorder group was higher in 14-year-old girls compared with boys.
Family economic conditions affected both girls and boys.

Eating disorder behaviours

Maternal lifetime anorexia and bulimia and economic disadvantage predicted dieting in boys, but not in girls.
Family economic disadvantage was associated with bingeing in both boys and girls. Overall, higher self-esteem was associated with lower odds of bingeing in girls.
Higher self-esteem at eight years old was associated with lower odds of purging in boys. A high odds of purging was noticed in maternal lifetime eating disorder group children.

How did the researchers interpret the results?

Researchers said that, "We identified a strong effect of childhood body dissatisfaction on adolescent body dissatisfaction, weight and shape concern, and pressure to lose weight and dieting in girls.

"In contrast, in boys the effect of body dissatisfaction on later eating disorder outcomes was seen mainly in interaction with BMI. Boys with high BMI and high childhood body dissatisfaction had higher levels of eating disorder cognitions and behaviours, but there was no association with childhood body dissatisfaction among leaner boys."

They added that, "Maternal history of anorexia and/or bulimia nervosa was predictive of high levels of body dissatisfaction and weight and shape concern in girls, and dieting in boys. The effect was more pronounced for children of women who reported both anorexia and bulimia over their lifetime (up to child age seven years)."

Conclusion

This population-based prospective cohort study showed body dissatisfaction, weight and shape concern, and pressure to lose weight were all significantly higher in girls compared with boys.

The study reported these concerns about body image were all significantly higher in girls compared with boys. This predicted eating disorder in girls at age 14.

This study has several strengths and limitations. One of the biggest strengths is its size. It had a large population size, which is said to be representative of the overall UK population. This allowed a clear identification of gender-specific patterns. It also assessed various early risk factors in childhood before the onset of the eating disorder behaviours.

However, though the study demonstrates associations, it does not prove causation. Various health, lifestyle and personal factors may be involved in the development of an eating disorder, not all of which have been assessed here.

It is difficult to identify which factor or combination of factors could have been directly involved in the development of an eating disorder.

This is particularly relevant given that assessments on eating disorders or the child's body image and self-esteem are limited to the scope of the few questions used on the assessment questionnaires. These may not always give a reliable indication of how the child or adolescent may feel or what factors have contributed to this.

Another limitation is that despite the use of a large representative cohort, the study is not representative of all people – only 59% took part in the assessment at age 14. Assessment of the whole cohort may have given different results.

It is important to cultivate healthy eating and exercise habits from an early age, and children should be educated about the harmful effects of dieting and binge eating.

If you're concerned about your or your child's weight or body shape, you should see your GP or a dietitian before making any sudden changes to your diet.

Unhealthy thinking about body and weight 'can start in childhood'