Women with extremely low body fat, including runners and dancers, as well as women with eating disorders, are prone to develop hypothalamic amenorrhea, a condition in which their menstrual periods cease, triggering such serious problems as infertility and osteoporosis.
Now, a study led by researchers at Beth Israel Deaconess Medical Center offers the first definitive proof that a lack of leptin contributes to hypothalamic amenorrhea and that treatment with a synthetic form of the hormone can restore fertility and reduce the risk of bone fractures. The findings were reported online April 4 in the Proceedings of the National Academy of Sciences.
“Our findings now prove that leptin is the missing link in women with significantly diminished body fat,” explains senior author Christos Mantzoros, an HMS professor of medicine and director of the Human Nutrition Unit at Beth Israel Deaconess. Without leptin, menstrual periods cease, the body becomes chronically energy-deprived, and women experience bone loss and an increased risk of bone fractures.
The study followed 20 women, 18 to 35 years of age, with hypothalamic amenorrhea. Over 36 weeks, the women received either daily subcutaneous injections of a synthetic form of leptin or a placebo. Within a month of treatment, hormone levels in women receiving replacement leptin had risen significantly, with many again ovulating and menstruating. Mantzoros says the team will next examine whether synthetic leptin affects bone density and bone mineral content, factors key to preventing stress fractures and osteoporosis.