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Rickets—a common health problem in the nineteenth and early twentieth centuries—might be making a comeback where you would least expect it: in a modern, industrialized European nation. A recent University of Toronto study (Scientific Reports, Nov. 17, 2017), focused on a mysterious increase in cases of rickets among British children in the last several decades. Rickets had been on the decline in Britain since the 1960s, but hospitalizations of British children due to rickets began to rise starting in the mid-1990s. The researchers found that the incidence of rickets almost doubled between 1997 and 2011, going from 0.56 cases per 100,000 children to 1.01 cases.
What Is Rickets?
Rickets is essentially a manifestation of a vitamin D deficiency, although it can occur due to a genetic condition. It mainly affects children and adolescents in developing countries, but it rarely can affect adults, in whom it is referred to as osteomalacia.
Rickets causes the bones to soften and become weak. Its most obvious symptom is a bowing of the legs, which occurs mainly in toddlers (older children may develop knock knees), short height, and low weight. Other symptoms include:
- Pain in the bones
- Bones that fracture easily
- Knobs on the bones between the ribs and sternum (breastbone)
- A visible horizontal groove across the chest where the diaphragm is attached to the ribs
- A soft skull that may cause an infant’s “soft spots” (fontanels) to close more slowly than is normal.
- Deformities of the cranium, spine and/or pelvis
- Thickened ankles and wrists
- Muscle spasms
- Low calcium levels
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Low Calcium and Vitamin D a Major Cause of Rickets
The most common cause of rickets is malnutrition—that’s one reason why it’s much more likely to occur in areas of the world where drought and famine are common. A lack of calcium is key, because calcium is a major component of bones—without it, bones become weaker. Vitamin D is also crucial because it helps the body absorb calcium from food. Vitamin D is synthesized by the body with exposure to sunlight, and Haris Majeed, co-author of the University of Toronto study, and a master’s student in medical imaging at U of T’s Faculty of Medicine, points to lack of sunlight as a factor in the study findings.
People need about six hours of sunshine per month in order to produce sufficient vitamin D, but since the mid-1990s, increasing cloud cover has deprived Britain of about four hours of sunshine per month during the summer. “Nobody thought of the sun,” says Majeed. “Climatologists knew that the UK receives lower summer sunshine than other parts of the world, but no one ever thought of the effect it had on specific health implications, such as rickets.” As to the reason for Britain’s even cloudier summers, Majeed contends that long-term climate variability in sea surface temperatures played a role. “Sea surface temperatures are getting warmer over the North Atlantic, and are known to fluctuate every 60 to 80 years,” he says. “After the mid-1990s, North Atlantic sea surface temperatures entered a warm phase, decreasing average summer atmospheric pressures and causing more rain, and less sunshine, in the UK.”
In the United States, people who live in Northern latitudes frequently have low vitamin D levels due to a lack of summer sunshine, although the U.S. hasn’t seen the same increase in rickets as the UK. This may be due to the fact vitamin D is added to milk, orange juice, many cereals, and soy products. This fortification makes up for the fact that natural food sources of vitamin D are fairly limited (it’s mostly found in oily fish, such as mackerel, salmon and trout, cod liver oil, flaxseeds, and eggs). If you live above the 35th parallel, or are housebound most of the time, a simple blood test can check your vitamin D levels (it’s also worth having the test if you are dark-skinned, since dark skin doesn’t produce as much vitamin D with exposure to sunlight). If you come up low, discuss with your doctor what you can do to boost them. The recommended daily amount of vitamin D for people aged up to 70 years is 600 International Units (IU); people age 70 and older are advised to get 800 IU. If taking a supplement, choose one that contains vitamin D3, as this is more easily absorbed.
Other Causes of Rickets
While the most common cause of rickets is malnutrition, it also can develop in people with celiac disease or ulcerative colitis, which prevent the body from absorbing nutrients. Kidney problems also can underpin rickets if they affect the way the kidneys process phosphorous, which is important for bone strength.
Premature birth raises the risk for rickets in children, as does exclusive breastfeeding, since breast milk does not contain much vitamin D. If you are pregnant and deficient in vitamin D this can result in your baby developing rickets.
Certain medications have also been linked to a greater risk of rickets—these include some anti-seizure drugs, as well as drugs used to treat HIV/AIDS.
- If you intend trying for a baby, or are pregnant, ensure that you get sufficient calcium and vitamin D.
- If you exclusively breastfeed, be sure to give your baby vitamin D drops as advised by your pediatrician.
- Try to get 10 to 15 minutes of sun each day—exposing your forearms to the sunlight (without sunscreen) should be enough. If you have children, ensure they also get sufficient sun exposure each day—but don’t get any more than 10 to 15 minutes without applying sunscreen to protect against skin cancer.
- If you (and/or your child) don’t like the foods that are naturally high in vitamin D, substitute them with fortified milk (look for soy or other milks with added vitamin D if you don’t drink cows’ milk), cereals, and juices.
- If taking a vitamin D supplement, choose one that contains vitamin D3, as this is more easily absorbed.
• If rickets occurs due to an underlying medical condition, be sure to follow your (or your child’s) doctor’s advice for managing the condition.