Weight and menstrual function in patients with eating disorders and cystic fibrosis.

Many patients with eating disorders have menstrual dysfunction. In patients with anorexia nervosa, amenorrhea has been linked to weight loss. However, many patients with bulimia nervosa, even those of average or greater than average weight, also experience menstrual abnormalities, including amenorrhea. It was hypothesized that low weight per se is not responsible for menstrual dysfunction in patients with eating disorders. First, 16 patients with bulimia nervosa of average weight and 29 patients with cystic fibrosis of below average weight of similar menstrual age were compared. Of the patients with bulimia nervosa, 11 (73%) had had secondary amenorrhea at some time compared with 8 (28%) of the patients with cystic fibrosis (P less than .01). At the time of study, 6 (40%) of the patients with bulimia nervosa and 21 (78%) of the patients with cystic fibrosis were having regular cycles (P less than .01). Next 18 patients with anorexia nervosa were compared with 18 patients with cystic fibrosis matched for weight and menstrual age. Although 18 (100%) of the patients with anorexia nervosa had had secondary amenorrhea, only 6 (33%) of the patients with cystic fibrosis had amenorrhea. Although only 1 (6%) of the anorexia nervosa group was currently having regular cycles, 14 (78%) of the patients with cystic fibrosis were (P less than .0001). Closer approximation to ideal body weight was associated with regular menses only in the cystic fibrosis group. Exercise did not appear related to regularity of menstruation in any group. Body weight is not the major factor responsible for menstrual abnormalities in patients with eating disorders.