Osteopenia

Osteopenia is a decrease in bone mineral density that can be a precursor condition to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis. More specifically, osteopenia is defined as :
 * T score less than -1.0 and greater than -2.5

Like osteoporosis, it occurs more frequently in post-menopausal women as a result of the loss of estrogen. It can also be exacerbated by lifestyle factors such as lack of exercise, excess consumption of alcohol, smoking or prolonged use of glucocorticoid medications such as those prescribed for asthma.

This disease can occur in young women who are athletes. It is associated with female athlete triad syndrome as one of the three components, the other two being amenorrhea and disordered eating. Female athletes tend to have lower body weight, lower fat percentage, and higher incidence of asthma than their less active peers. The low estrogen levels (stored in body fat) and/or use of corteosteroids to treat asthma can significantly weaken bone over long periods of time. Distance runners in particular are also discouraged from consuming milk products when training, which would result in lower calcium absorption than other groups.

It is also a sign of normal aging, in contrast to osteoporosis which is present in pathologic aging.