- Vitamin D deficiency is the major cause of rickets around the world.
- Nutritional rickets continues to be reported in the United States and in other developed nations, especially in minority ethnic groups and immigrants.
- Vitamin D deficiency in childhood and rickets continue to be public health problems in the Middle East, North Africa, and some parts of Asia.
- The recommended adequate intake of vitamin D by the National Academy of Sciences to prevent vitamin D deficiency in normal infants, children, and adolescents is 200 IU/d.
- It is recommended that all infants (breast-fed or not) who are ingesting less than 500 mL/d of vitamin D-fortified formula or milk have a minimum intake of 200 IU of vitamin D per day beginning during the first 2 months of life.
- Other organizations and individuals recommend a daily intake of 400 to 2000 IU of vitamin D daily as a preventive dose, for infants through 18 years of age.
- Vitamin D supplementation is critically important for breast-fed infants and for infants and children living in an inner-city area and those with increased skin pigmentation.
Rickets is defined as the failure of osteoid to calcify in a growing person. Osteomalacia is the failure of osteoid to calcify in the adult.1 Osteoid is the collagen-containing organic matrix of the bones. Rickets results from vitamin D deficiency or the abnormal metabolism of vitamin D. Vitamin D deficiency is the major cause of rickets around the world.2,3 Less commonly, deficiency of calcium or phosphorus may produce rickets. In this chapter, we will focus on vitamin D-deficient (nutritional) rickets and will mention some important characteristics of other causes of rickets.
Vitamin D (cholecalciferol or vitamin D3) is formed in the skin under the stimulus of ultraviolet (UV) light. UV light was the only significant source of vitamin D until ergosterol (vitamin D2), contained in fish liver oil, was introduced as a dietary supplement in 1918.4
Rickets became a public health problem when the factories of the industrial revolution triggered a massive migration to overcrowded cities and produced so much contamination that UV light rays were blocked. Rickets was probably the first childhood disease caused by environmental pollution. Early in the 20th century, vitamin D was named as the factor responsible for causing rickets. Fish liver oil and exposure to sunlight were recognized to have a role in the prevention and treatment of rickets.5
After vitamin D was discovered, many public health initiatives were implemented. Education of the population on the importance of sunlight exposure and fortification of dairy and other food products with vitamin D resulted in the eradication of rickets from North America.4 In the last two or three decades, we have seen a resurgence of rickets, with vitamin D deficiency and several other factors contributing to the resurgence. Nutritional rickets continues to be reported in the United States and other ...