By STEVE CONNOR
Scientists have the strongest evidence yet that anorexia and bulimia are partly the result of an inherited predisposition to eating disorders.
A study of anorexia in men - an exceptionally rare condition - has found that their female relatives are nine times more likely than other women to suffer from the condition. This suggests that genes play a significant role in deciding whether a child of either sex will develop an eating disorder in later life.
The findings support a study by the same team, which found that female relatives of women with anorexia or bulimia were up to 12.3 times more likely to contract one of the disorders than the general female population.
"This research provides powerful evidence negating the myth that individuals with anorexia nervosa and bulimia nervosa are simply spoiled rich girls trying to be beautiful," says Dr Michael Strober, of the University of California.
Dr Strober has carried out the largest study in the world of families affected by eating disorders. It has helped to shatter the once widely held belief that anorexia and bulimia were entirely the result of social factors.
The latest research, to be published in the International Journal of Eating Disorders, studied 747 relatives of 29 men with eating disorders and 181 women with no symptoms. The scientists found 15 cases of anorexia among female relatives, 10 of them related to ill men, but no cases among male relatives. This suggests that the predisposition genes do not transmit preferentially to the same sex.
In a parallel study, the California team interviewed 1831 relatives of 504 women with eating disorders, showing sisters of anorexic or bulimic girls lived with a 12-fold increased risk of developing the condition themselves.
Herald Online Health
By STEVE CONNOR