Rickets is the second in a series of posts about nutritional deficiencies. Rickets, like scurvy, beriberi, pernicious anemia, and pellagra is one of the vitamin deficiencies with historically interesting names. Stay tuned on DrPullen.com for upcoming posts on these other deficiencies.
Rickets is usually thought of as vitamin D deficiency, but rickets is actually a clinical condition that can also be caused by calcium or even phosphate deficiency. The symptoms of rickets are primarily related to the bone abnormalities. These include bone pain, skeletal deformities including bow legs, pigeon chest, odd shaped skull, bumps in the rib cage and spine curvature abnormalities. Although rickets can occur in adults, it is primarily a disease of children. Children in the age range of 6-24 months are at highest risk because of their rapid bone growth. Today rickets occurs mostly in areas of famine and is usually associated with severe malnutrition.
Historically rickets was a major cause of infirmity and morbidity in much of the world. In the 1930’s as foods began to be supplemented with vitamins in the United States and much of the world as public health policy rickets became much less common. In the developed world today rickets is sometimes seen in exclusively breast fed children, as breast milk is deficient in vitamin D and in children often get little direct sunlight exposure. The American Academy of Pediatrics recommends supplementing vitamin D in exclusively breast fed infants for at least the first year of life.
Other disorders that put children at increased risk of rickets are celiac sprue, or gluten enteropathy, which can be associated with multiple other vitamin absorption issues including folate and vitamin B12, and lactose intolerance where children do not get vitamin D fortified milk. Most of the time simple supplementation of children with these disorders with vitamin D is adequate to prevent clinical manifestations of rickets.
Calcium deficiency can also cause rickets. In the third world chronic diarrhea may lead to calcium deficiency. Nutritional sources of vitamin D include oily fish, liver and fortified foods. This is why the not-so-tasty cod liver oil nutritional supplement became popular. Today most experts recommend supplementation with vitamin D3, which is more easily absorbed from the gut than vitamin D2. If you really enjoy nasty tasting oil, take cod liver oil instead. You’ll get some omega-3 fatty acids as a side benefit.
A rare x-linked disorder called Vitamin D resistant rickets is seen in the US with a frequency of about 1:20,000. In this disorder a protein that inhibits phosphate excretion is abnormal, leading to excess phosphate excretion and poor bone mineralization. X-linked disorders show up clinically in males, because they have only one copy of the X chromosome, the other being the male “Y” chromosome.
There is concern that the use of high strength sunscreens may reduce the ultraviolet B radiation exposure in the skin needed for the natural production of vitamin D. There has been more vitamin D deficiency seen in recent years that is hypothesized to be related to reduced sunlight exposure. In adults this rarely leads to clinical osteomalacia, the term for rickets used more often in adults.