Rickets Pathophysiology

Rickets is a disease that directly results from a lack of Vitamin D and the improper mineral absorption that comes from response to that. If not enough Vitamin D is ingested, calcium and phosphorus cannot be absorbed. These minerals are crucial in the formation and maintenance of healthy and strong bones. Low Vitamin D levels leads to low calcium absorption in the intestines. In order to make up for this, the body will increase levels of Parathyroid Hormone (or PTH) which signals the body to increase levels of calcium. The body will them begin to reabsorb calcium from its own bones.  A disruption in the homeostasis (or equilibrium) of calcium and phosphorus causes poor calcification (or accumulation of calcium) of the cartilage in growing long bones such as the femur. This is what contributes to the bowing of the legs. The bones are weaker and less dense because not enough calcium has been brought together. Thus, it is more likely for the bones to bend.  

These legs are affected by rickets, and display bowed legs.

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Additionally, rickets can cause the widening of wrist or the splaying of bones. The bones may be widening in attempt to compensate in size for what they lack in strength. This doesn’t do much to help however, bone stability is not enhanced.

For more information, please read:

http://emedicine.medscape.com/article/985510-overview#a5
                                   or
http://www.uptodate.com/contents/overview-of-rickets-in-children

Rickets: Epidemiology

While rickets isn’t as prevalent in modern day America compared to older times or even to current day third world countries, it hasn’t been completely eradicated. The Mayo Clinic investigated the records of rickets in a county in Minnesota, and found that 768 children were diagnosed with rickets between the years 1970 and 2009. While this may seem like a small amount of children over a long period of time, remember, this study was just concerned with people in that specific Minnesotan county.  Many people don’t consume enough Vitamin D in their everyday life. Exclusively breastfed babies, premature babies, dark skinned people and people who don’t have much sun exposure are all at risk for Vitamin D deficiency, and in turn, are at risk for rickets.

Breastfeed babies can be deficient in Vitamin D if their mothers didn’t consume enough of the vitamin during pregnancy, or throughout the time they spent breast feeding. As a result, an exclusively breastfeed baby may not be receiving enough Vitamin D through milk alone. Without Vitamin, the baby’s bones can become soft and they become at risk for rickets. Many babies who are born premature can also be at risk for rickets. Their bodies may not have enough Vitamin D, or they may not be able to properly metabolize it. This problem can be solved with additional supplements to the babies diets. During the first few years of life, children’s bones grow rapidly. It is important that their bones have the nutrients they need in order to thrive.

This map demonstrates the Vitamin D deficiency among the general population (blue), and the population of pregnant women (yellow).  

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Amongst populations of people with darker skin, Vitamin D deficiency is common. As stated earlier, Vitamin D deficiency and rickets are often interrelated. Because of the darker pigmentation of the skin, it’s more difficult for the body to utilize the Vitamin D it does receive. The same idea applies to people who spend a lot of time inside. Vitamin D cannot be absorbed and used if it doesn’t reach the skin. 

Overall, rickets tends to affect younger children, while all can suffer from Vitamin D deficiency. It's important to be aware of what you're eating and what you are feeding your children. 

What is Rickets?

The term "rickets" is derived from an old English word, meaning to bend or twist, which is essentially what happens to bones with this disease. To bring it into modern terms though, the Mayo Clinic defines rickets as "the softening and weakening of bones in children, usually because of an extreme and prolonged vitamin D deficiency." A form of this disease is also present in adults, called osteomalacia. Unlike osteoporosis which results when bones weaken with age, is a result from weak bones early in childhood. We have all been taught from a young age that calcium plays a large role in the development of strong and healthy bones. What we may not have known however, is that Vitamin D is also a crucial nutrient for bone development. In order for the body to be able to use and absorb calcium, as well as phosphorus (another important mineral), the body needs Vitamin D. As the food we eat travels through our intestines, the nutrients that our body need to function are pulled out. Vitamin D aids in that process.  If the body doesn’t have enough Vitamin D, it'a likely that the body won't be able to maintain the necessary levels of calcium and phosphorus, and as a result will be unable to support normal bone development. Since our bodies can not create calcium on it's own, Vitamin D becomes even more important. Without Vitamin D, bones are more prone to deformities or fractures, often resulting in bowed legs. 

Look! The bones with normal anatomy are straight, whereas the bones affected by rickets are slanted or bowed. The lack of Vitamin D, Calcium, and Phosphorus cause the bones to be more fragile and prone to fractures.

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While rickets have nearly been eradicated from developed countries such as the United States of America, it's still a prevalent in less developed countries. It's completely and entirely preventable and with proper education and knowledge, can be eradicated fully.