Eating disorder features in indigenous Aboriginal and Torres Strait Islander Australian Peoples

Aboriginal and Torres Strait Islander peoples are well known to have higher risk for a range of disorders related to poor nutrition, namely a diet high in refined carbohydrates and saturated fats. This leads to subsequent increased risk for obesity, Type 2 diabetes, cardiovascular disease and renal disease [1]. In addition there are higher rates of admissions for mental health problems and self-harm in indigenous Australians [1]. Research into mental health problems closely related to nutrition and obesity such as disordered eating and binge eating is minimal within Australia. However, international research indicates that these problems are prevalent in other indigenous cultures. A recent review of eating disorders in North American indigenous peoples found disordered eating and weight control behaviours, body dissatisfaction and eating disorders (where measured) were as frequent in First Nations or Inuit peoples as in White or other Americans [2]. One of the eight studies reviewed was a national US study of young adult women that in particular reported a higher frequency of indigenous women having problems with uncontrolled and/or 'embarrassing overeating' compared to non-indigenous [3]. The studies in this review were however confined to adolescent samples or College recruited samples [2]. Of concern, indigenous people were less likely to be referred on for further evaluation of their eating problems.

Further controlled [4] and uncontrolled [5, 6] studies in Canada and the US have found high body dissatisfaction (desire to be thinner) and increased risk for an eating disorder in indigenous peoples, particularly youth. A recent large (10,334 participants, mean age 21.93 years) national US survey [7] of adult men and women has found higher rates of current binge eating, embarrassment about excessive eating, loss of control over eating, higher weight, but not a self-reported diagnosis of an eating disorder or use of inappropriate weight control behaviours in American Indian or Native American men (n = 236) and women (n = 253).

In Australia studies of indigenous peoples are confined to adolescent samples and have been focussed on body image disturbance. An Australian report found higher levels of body dissatisfaction and a desire to build up muscle in indigenous males but lower or similar levels of body dissatisfaction in female indigenous adolescents compared to non-indigenous. Both indigenous groups had greater engagement with weight control practices [8] but indigenous females appeared less influenced by socio-cultural pressures to reduce weight [9]. The same group [10] found similarly greater body dissatisfaction in urban and rural non-indigenous adolescents but this study did not report on use of weight loss behaviours. In a national study of health, eating, weight and culture among 7889 school children in every Australian state and territory, 333 were of indigenous origin. In this study indigenous females and males perceived themselves as heavier in body weight but were more likely to be trying to gain weight and build up their bodies and to be advised by parents and family to do so [11]. These mixed reports may indicate different attitudes towards body shape, and a greater desirability for muscular strength in indigenous compared to non-indigenous Australian adolescents. However, there is no information on how, if at all, these differing attitudes indicate a problem with eating disorders and weight in older adolescents and adults.

Our aims were therefore to investigate the current 3-month prevalence of eating disorder behaviours of binge eating, restrictive dieting, and extreme weight control methods such as vomiting, and core eating disorder psychopathology of excessive weight and shape concerns, in a representative general population sample of older adolescent and adult indigenous Australians.

Two independent cross-sectional single stage interview based surveys were conducted in 2005 and in 2008. Both surveys were embedded in the respective year's Health Omnibus Survey, under the auspices of the South Australian Health Commission. The interviews were conducted by Harrison Health Research [12].

The present study to our knowledge is the first to provide data on eating disorder features in Australian indigenous peoples derived from a general population sample of older adolescents and adults. The findings support eating disorder problems of subjective and objective binge eating being at least as common if not more common (controlling for secular differences) in indigenous peoples. (Subjective binge eating is where the person perceives an episode of overeating on an amount of food that is not excessively large given the social and cultural context of eating. Objective binge eating is where the person perceives an episode of overeating on an amount of food that is excessively large given the social and cultural context of eating [14, 16].) In addition, the core cognitive feature of an eating disorder, namely weight and/or shape concern, was also as high if not higher in indigenous participants (controlling for secular differences) and levels of restrictive dieting and other compensatory weight control behaviors were similar to non-indigenous. The small numbers of people with Aboriginal or Torres Strait islander who identified their ethnicity precluded statistical comparison of rates of purging behaviors and estimate of diagnostic eating disorder prevalence. However, it can be surmised that eating disorders are likely to be at least as much a problem for indigenous as for non-indigenous Australians. Furthermore, the similar (or greater) prevalence of binge eating behaviors were not explained by secular differences in indigenous such as younger age, higher body weight, gender or income levels.

Caution must be exercised in discussing the results of eating disorder features and gender in the indigenous participants as numbers were very small and there were differences across the two years of survey. The finding that regular binge eating (objective and subjective) was as if not more common in males in 2008 is however in accord with international studies. These have found that unlike anorexia nervosa and bulimia nervosa, binge eating is as common in males as it is in females [17]. In addition in both years we found BMI to be higher in those with regular objective binge eating. This is also consistent with research indicating a higher frequency of disordered and binge eating in the overweight and obese [17, 18].

The present study was limited in that assessment was only at two time points. In addition, the survey instrument has not been validated for cross-cultural use. It also did not record details of the most common types of weight control behaviors, nor details of restrictive dieting nor the types of foods consumed during a binge and it had no assessment of excessive exercise or body composition concerns (such as a favorable regard for increased muscularity as found in previous research [11]). It would have been desirable to have included assessment of lifetime as well as current prevalence rates. It is important to note that the findings can only be generalized to indigenous Australians living in metropolitan areas with probable less income and education disadvantage than for those living in rural and remote areas. Strengths of the present study were the replication of results in a second survey within 3-years, standardized and rigorous survey methods, including random selection and interview assessment, the good response rates, wide age range and inclusion of both genders. Small numbers preclude analysis of time trends in the indigenous participants but the apparent decrease in rate of eating disorder features needs further study in larger samples and over a longer time period.

The findings are important as they highlight for indigenous Australians the problem of disordered eating and body weight concerns, eating disorder features that are commonly associated with obesity. This is consistent with the increased frequency of obesity related physical health problems such as diabetes, hypertension and the metabolic syndrome which are well recognized as contributing to shortened lifespan and greater morbidity in Aboriginal and Torres Strait Islander peoples. The poor dietary choices that likely underpin these problems can been seen in the wider context of cultural dispossession whereby traditional methods of food preparation and choices of 'plain foods' have often been displaced with pre-prepared 'fast' foods of lower nutritional value. This is exacerbated by the social disadvantage and, as indeed we found, increased health related role impairment of indigenous peoples. More research is needed to investigate the cultural and social context of food and eating and subsequent health problems in indigenous Australians.

The present study points to the need for health professionals to ask about and identify binge eating and other features of disordered eating in indigenous patients presenting with these medical problems. Not only are these important co-morbidities of obesity but they may impede weight management programs and exacerbate co-morbid medical problems such as diabetes [19] if not addressed. Furthermore, there are real concerns about the role of extreme dietary restriction and other weight control methods in exacerbating bulimic behaviors and contributing to weight gain [18]. On the other hand, psychological approaches in particular cognitive behavior therapy, are effective in reducing binge eating and other bulimic behaviors [20] and professionally lead behavioral weight management programs may attenuate eating disorder behaviors [21].

It is unclear whether concerns regarding weight and shape in indigenous participants were related to health literacy regarding physical health effects of obesity and/or societal stigma towards obesity and positive regard for thinness. However, the results indicate that it cannot be said there less is weight concern or disordered eating behaviours in indigenous people. Like others with eating disorders, it is probable that indigenous Australians would be receptive to and helped by inquiry about eating disorder symptoms and advice on appropriate help.