Dark-skinned people having a high body-mass index and not taking vitamin D supplements were associated with vitamin D deficiency.[66][67] Vitamin D plays an important role in regulating the human immune system and chronic deficiencies in vitamin D can make humans susceptible to specific types of cancers and many kinds of infectious diseases.[35][68][69] Vitamin D deficiency increases the risk of developing tuberculosis fivefold and also contributes to the development of breast, prostate, and colorectal cancer.[70] The most prevalent disease to follow vitamin D deficiency is rickets, the softening of bones in children potentially leading to fractures and deformity.