Some possible signs of vitamin D deficiency include frequent infections, depression and cardiovascular disease. Dental cavities, sleep apnea and erectile dysfunction may also result from insufficient vitamin D, according to MedicineNet. Vitamin D plays an important role in reducing inflammation in the body and regulating chemicals in the brain.
People who are deficient in vitamin D are between 8 and 14 percent more likely to suffer from depression, notes MedicineNet. Vitamin D helps prevent the depletion of levels of serotonin and dopamine, two brain chemicals that are involved in regulating mood. In studies of depressed people, scientists found that the people with the lowest vitamin D levels were most likely to commit suicide.
Studies have also shown that vitamin D deficiency could increase a person's vulnerability to respiratory infections, reports MedicineNet. Researchers are investigating whether vitamin D deficiency could also leave people vulnerable to pneumonia, urinary tract infections and infections after surgery. In children, studies link vitamin D deficiency with allergies.
People who are deficient in vitamin D are more likely to have problems with their hearts and circulatory systems and may experience conditions such as high blood pressure. They are also at greater than average risk of stroke, according to MedicineNet.