Researchers from Spain noted that, similar to girls, boys with anorexia can develop debilitated bones as a result of the eating disorder. They also noted that anorexic boys, like girls with the disorder, can "catch-up" with their peers in bone strength if they return to normal weights.
Dr. Josefina Castro of the Hospital Clinic Universities, demonstrated "that young boys with a relatively short duration of anorexic disorder can already have a reduction of bone mineral density, and that with total weight recovery it can be reversed if they are still in their adolescence. In the study, the researchers measured bone mineral density (BMD)--a measure of bone strength--in 25 boys aged 10 to 15 years diagnosed with anorexia. The investigators then repeated BMD measurements in 15 of the boys up to 2 years later, and noted how much weight they had gained.
Castro and her colleagues found that 40% of the boys had reduced bone mineral density. This proportion is similar to that seen in girls with the disorder, with previous studies documenting loss of bone strength in 41% to 45% of adolescent anorexic girls.
The bone mineral density in boys was associated with how long they had the eating disorder, with the longer the period of weight loss, the lower the bone mineral density. Boys were also more likely to have weakened bones if they consumed lower amounts of calcium, and had relatively little physical activity.
According to the follow-up measurements, boys who only regain part of the needed weight experienced a continued decrease in bone mineral density. However, boys who regained their normal weight experienced a rapid increase in bone mineral density--at twice the rate seen in non-anorexic boys--allowing them to catch up with their peers.
The same effect has been observed in female adolescent anorexics, although studies indicate that female adult anorexics are unable to fully regain bone mass after recovering a normal weight.
Castro said that since anorexia is relatively rare in boys, it can be difficult for them to accept they have the disorder. For example, during inpatient or day hospital treatment programs, male patients are usually surrounded by girls. Castro added that her findings demonstrate the importance of studying bone mass in boys, as well as girls, given that they can regain any losses while still in adolescence.