Low 25 hydroxyvitamin D has the potential to produce the following dangers: First, it may lead to severe osteoporosis. This form of vitamin D, also known clinically as active vitamin D, can be seen as a hormone. If the level of this hormone is low, it may lead to impairment of calcium absorption in the gastrointestinal tract. This can lead to a decrease in bone mass, which in turn can lead to osteoporosis. Second, it may lead to a decrease in the patient’s blood calcium level. Low levels of these hormones can reduce the absorption of calcium within the body, which in turn can lower blood calcium levels. In this case, the patient may have cramps, convulsions, peripheral pain or heart arrhythmia. Third, it may hinder the growth and development of the patient. If the patient is in adolescence, the lowered hormone level will cause the patient’s growth to slow down, and may produce a series of deformities such as chicken chest, funnel chest, rib beads and so on.