The subjects were from 17 countries, and all of them had European ancestry.
This time, the researchers identified eight genetic loci linked to the disorder, although Bulik says there are likely hundreds.
Anne Becker, a professor of global health and social medicine at Harvard Medical School, has conducted studies of body image and eating disorders among women in Fiji.
Becker traveled to the archipelago nation in the early 1980s, describing its strong food culture and lack of weight stigma.
And there are many other eating disorders besides anorexia whose genetic involvement has yet to be explored. “For now, this [research] actually gives an explanatory model to a lot of patients and families who have just been perplexed by this illness for a long time,” Bulik says.
New imaging technology provides insight into abnormalities in the brain circuitry of patients with anorexia nervosa (commonly known as anorexia) that may contribute to the puzzling symptoms found in people with the eating disorder.
It affects about 1 to 4 percent of women and 0.3 percent of men.
Previous studies in twins suggest it has a 50 to 60 percent heritability, meaning 50 to 60 percent of the variability of the traits associated with anorexia can be explained by genetic differences among people, with the remainder linked to the environment or other influences.
"Consequently, many patients with the disorder remain ill for years or eventually die from the disease, which has the highest death rate of any psychiatric disorder." A better understanding of the underlying neurobiology – how behavior is coded in the brain and contributes to anorexia —is likely to result in more effective treatments, according to the researchers.
Childhood personality and temperament may increase an individual's vulnerability to developing anorexia.