Prevalence of obesity and comorbid eating disorder behaviors in South Australia from 1995 to 2015.

BACKGROUND

Obesity and eating disorders are often studied and treated separately. While the increases in obesity prevalence are well known, examination of its co-occurrence with eating disorders, a problem also of public health concern, is important because eating disorder behaviors are known to contribute to obesity onset and maintenance, and vice versa.

METHODS

Data from large cross-sectional representative statewide community samples of people in the years of 1995 (n=3001), 2005 (n=3047) and 2015 (n=3005) were analyzed. Data were collected using a structured, self-report interview that included demographic, health-related, weight, height and eating disorder behavior questions. Eating behavior questions assessed binge eating, very strict dieting/fasting and purging, and were derived from the Eating Disorder Examination. Logistic regression analyses were conducted comparing prevalence of obesity, eating disorder behaviors and their co-occurrence.

RESULTS

The prevalence of obesity or binge eating, or obesity with comorbid binge eating, each increased significantly from 1995 to 2005 (P<0.001 for each comparison) and continued to increase significantly from 2005 to 2015 (P<0.001 for each comparison). The highest increases from 1995 to 2015 were in the prevalence of obesity with comorbid binge eating (7.3-fold), or obesity with comorbid very strict dieting/fasting (11.5-fold). The prevalence of very strict dieting/fasting also increased significantly from 1995 to 2015 (3.8-fold). The prevalence of purging, or obesity with comorbid purging, did not change significantly from 1995 to 2015.

CONCLUSION

There were statewide increases during the 20 years from 1995 to 2015 in the independent prevalence of obesity, binge eating and very strict dieting/fasting, and even higher increases in the prevalence of obesity with comorbid binge eating, and obesity with comorbid very strict dieting/fasting. These findings support the need for more integrated approaches to both the prevention and treatment of obesity and eating disorder behaviors, namely binge eating and very strict dieting/fasting.