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Eating behaviours and attitudes following prolonged exposure to television among ethnic Fijian adolescent girls
Aim - to evaluate the impact of the recent introduction of Western television on disordered eating among ethnic (indigenous) Fijian adolescent girls.
Procedure - a naturalistic experiment. These girls were not accustomed to much (if any) TV and disordered eating was rare among this group (only one documented case of AN by 1995).
2 separate samples of girls aged 16-17 were assessed using questionnaires and interviews to obtain quantitative and qualitative data. First assessment (N = 63) was 1995, within a few weeks of the introduction of TV to the area, second assessment (N = 65) 3 years later. The EAT 26 questionnaire includes questions about body image, bingeing and purging behaviours. A score of 20 or more is high. Questions were also asked about hours of TV viewing and height & weight were measured.
• Significant increase in the prevalence of 2 key indicators of disordered eating (high EAT26 score and self induced vomiting to lose weight following prolonged exposure to TV). This suggests that TV has a profound impact, particularly as eating attitudes and behaviours were traditionally so different.
• Feeling too big or fat was significantly associated with current dieting, suggesting that body dissatisfaction is related to behavioural changes.
• Exposure to idealised images of beauty in the media stimulates social comparison and potential body image disturbance or dissatisfaction.
-Aim:A variety of data suggest that Anorexia may have a genetic basis. This study aimed to explore this possibility by comparing incidence of anorexia in identical (MZ) and non-identical (DZ) twins. Since twins are raised in the same environment, similarity may be due to nature or nurture. However, if MZ twins are more similar, this implies that genes play a greater role.
-Procedures:
*45 pairs of female twins were interviewed where at least one twin had had anorexia.
*The interviews established the clinical characteristics observed as well as the occurrence of eating disorders in any close relatives.
*Records were also made of body mass and length of amenorrhoea, and questions asked about drive to be thin and body dissatisfaction.
*In order to determine whether twins were identical or not, a blood test was used.
*There were 25 MZ twins and 20 DZ twins in the study.
-Findings:There was significantly higher concordance in the MZ twins; 25 (56%) of the MZ twins were concordant for anorexia whereas only 1 (5%) of the DZ twins was.
There was significantly more anorexia in relatives studied than found in the normal population. The rate of anorexia in the population in general is 0.1%. The study found 6 cases of anorexia among first-degree relatives (4.9%) and in the second-degree relatives there were 2 cases (1.2%).
The measures of body mass, amenorrhoea, drive to be thin and body dissatisfaction indicated that these were heritable as there was greater similarity between MZ and DZ twins.
-Conclusions:The findings from all three different methods of analysis suggest that anorexia has a large genetic component. The figure of heritability may be as large as 80%; in other words, 80% of the variation in anorexia is due to genetic factors and 20% to environmental factors. This high figure may be partly explained in terms of how genetic factors interact with the environment. What is inherited is a genetic sensitivity to environmental factors.
-One difficulty with studies of anorexia is that the actual diagnosis in any individual is not that certain. Some individuals suffer both anorexia and bulimia, though not always at the same time. This means that the genetic susceptibility may be to 'develop eating disorders' rather than anorexia in particular. Gorwood et al (1988) suggest that if we want to identify the genetic causes of anorexia, we need to identify the distinct subtypes more clearly.
-Twins don't just share the same genes - they also share cultural and family values, and the environment for MZ twins is more similar than for DZ twins. Therefore, physiological and environmental factors are confounded. Indeed, the 56% concordance rate in MZs might be entirely due to their more similar upbringing than DZs.
However, Holland et al argue that MZ twins who actually look very different still have the same high concordance rates as MZ twins who look identical.
-Small sample - many twin studies involve a small sample size. Holland et al studied only 25 MZ and 20 DZ twins, and it is estimated that 15,000 pairs would be needed for a definitive, genetic study. The low occurrence of both twin births and eating disorders make this unlikely.
-McClelland & Crisp (2001) found a higher incidence of AN in social classes 1 and 2. They reject the idea that this is due to higher referral levels and suggest it's due to an avoidance response to adolescent conflict within such families. Why does this challenge the findings of Holland et al?
-There may be reasons why twins are more prone to mental illness than non-twins and therefore the findings may not be generalisable to the rest of the population. It is possible that twins may be subject to greater developmental difficulties (e.g. sense of identity) - or that they are genetically more vulnerable than other adolescents.
-Why can't the study fully explain anorexia in terms of genetics? Additionally, can the study explain the dramatic increase of cases of AN in the last 30 years?
-Method: Discussion groups were set up across the UK to explore factors that might affect the food choices of girls and young women of African and South Asian descent. The discussions were analysed using content analysis.
-Results: A number of common concerns were voiced by the women. Food choices were indeed influenced by culture, time, availability, cost, health and price.
*Pakistani/Bangladeshi women's cooking skills appeared to have been learnt from the older generation of females in the family, and they also took pride in their traditional cooking.
*All the women surveyed appeared to have low levels of western food in their diets. However, they appeared to adopt the less healthy aspects of the western diet including fried fish, pizza, chips and fatty snack foods. However, these were mainly chosen to give people a change or when preparation time available was short.
*The Pakistani/Bangladeshi women expressed the opinion that their diet had become less healthy following the adoption of the worst of the British diet!
*The women did make a link between food and health; however, cultural background and knowledge influenced this.
*Pakistani/Bangladeshi women generally appeared to have quite a good understanding of what food and methods of cooking are healthy and unhealthy. However, this knowledge did not appear to translate consistently into dietary choices.
*Zimbabwean women noted that in Zimbabwe nobody worried about being slim, but now that they were in the UK there was more pressure to be slim.
-Conclusion: many issues that affect the food choice of people who move to the UK are common within different ethnic groups.
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