(NaturalNews) The United Kingdom's Department of Health has warned that the health condition known as rickets is making a comeback due to more widespread vitamin D deficiency among the British population.Caused primarily by vitamin D deficiency, rickets is a childhood bone disease that can lead to skeletal deformities, fractures and other serious health problems. Improved nutrition nearly eliminated the condition from the United Kingdom in the 1950s.According to the Department of Health, however, as many as one in 100 children of Afro-Caribbean, Asian or Middle Eastern descent in the United Kingdom may now have rickets.People with darker skin are more susceptible to vitamin D deficiency, because the vitamin is typically synthesized by the body upon exposure to ultraviolet radiation from sunlight. But the same melanin that makes skin dark and protects against sunburn also decreases the body's ability to synthesize vitamin D. People who cover most of their skin for cultural or other reasons are also more susceptible to vitamin D deficiency.Doctors say that just 15 minutes of sunlight on the arms, shoulders and head every day during the summer should be enough for most people in the United Kingdom. During the winter, however, people north of the 52nd parallel are not able to synthesize vitamin D due to a lack of the right wavelength of sunlight.The northernmost point in the continental United States is just past the 49th parallel.Vitamin D deficiency is a particular concern among pregnant women"If a pregnant or breastfeeding woman is lacking in vitamin D, the baby will also have low vitamin D and calcium levels," said pediatrician Colin Michie, "which can lead babies to develop seizures in the first months of life."Health Minister Dawn Primarolo said that the Health Department encourages pregnant and breastfeeding women to take vitamin D supplements, which are often provided free by the British government.