Children with dark skin , like aleanie , who is african-american , appear to be at even greater risk for rickets because they do not synthesize vitamin d through the skin as easily as those with light skin .
Physicians have known for more than a century that exclusive breast-feeding may be associated with vitamin d deficiency and rickets , and that the condition is easily prevented and treated with inexpensive vitamin drops or cod liver oil .
In theory , rickets is easy to cure : official advice is to get more sunshine and , for pregnant women and young children , to take vitamin d supplements ( though only around a fifth of mothers heed it ) .