In-born errors of vitamin D metabolism can also cause vitamin D deficiency and rickets; these children cannot convert inactive vitamin D to active vitamin D and suffer the same symptoms as children with a nutritional deficiency.
Bone growth may also be limited by vitamin D deficiency, resulting in a condition called rickets (osteomalacia), which leads to soft and/or deformed bones and is caused by an inability to absorb calcium due to lack of vitamin D.
Specific diseases causing an increased risk for fractures include Paget's disease, rickets, osteogenesis imperfecta, osteoporosis, bone cancer and tumors, and prolonged disuse of a nonfunctional body part such as after a stroke.
The bone deformities are similar to, or are the same as, those that occur in typical rickets; however, calcium deficiency rickets is treated by increasing the amount of calcium in the diet.
Rickets results from a lack of vitamin D rich foods in a child's diet, insufficient sunlight exposure, or digestive system problems that result in poor vitamin D absorption.
Rickets, scurvy and "marasmus" may be instanced as diet diseases in children.
Thus the liability to tubercular infection is far commoner in the midst of a depraved population than in one fulfilling the primary laws of nature; rickets is a disease of great cities rather than of rural districts; and syphilis is more disastrous and protracted in its course in the depraved in health than in the robust.
The most important disease hitherto undescribed was rickets, first made known by Arnold de Boot, a Frisian who practised in Ireland, in 1649, and afterwards more fully in the celebrated work of Francis Glisson (1597-1677) in 1651.
Owing to this influence it has been used in rickets and osteomalacia.
Similarly Karl Hoffmann of Wiirzburg wasted his appreciations of the newer schools of developmental biology in fanciful notions of human diseases as reversions to normal stages of lower animals; scrofula being for him a reversion to the insect, rickets to the mollusc, epilepsy to the oscillaria, and so forth.