Vitamin D and skeletal health in infancy and childhood

Abstract

During growth, severe vitamin D deficiency in childhood can result in symptomatic hypocalcaemia and rickets. Despite the suggestion from some studies of a secular increase in the incidence of rickets, this observation may be driven more by changes in population demographics than a true alteration to age, sex and ethnicity-specific incidence rates; indeed rickets remains uncommon overall and is rarely seen in fair-skinned children. Additionally, the impact of less severe vitamin D deficiency and insufficiency has received much interest in recent years, and in this review we consider the evidence relating vitamin D status to fracture risk and bone mineral density (BMD) in childhood and adolescence. We conclude that there is insufficient evidence to support the suggestion that low serum 25-hydroxyvitamin D [25(OH)D] increases childhood fracture risk. Overall, the relationship between 25(OH)D and BMD is inconsistent across studies and across skeletal sites within the same study; however there is evidence to suggest that vitamin D supplementation in children with the lowest levels of 25(OH)D might improve BMD. High quality randomised trials are now required to confirm this benefit.

The effects of different intensities of exercise and active vitamin D on mouse bone mass and bone strength

“…Calcitriol also showed a modest inhibition on bone resorption (Fig. 5a, b), as previously reported [18][19][20]. In the presence of calcitriol, the medium level of exercise, but △ p < 0.05, △△ p < 0.01 when compared to high-intensity group not the low or high level, further reduced the osteoclast surface (Fig.…”

“…Active vitamin D has been shown to improve bone health in the young and the old [13][14][15][16][17], and its derivatives have been approved to treat osteoporosis in some countries. Although the main function of natural vitamin D ingested from the diet, after being converted to the active form, is to increase intestinal absorption and kidney resorption of calcium, pharmacological doses of active vitamin D have been shown to increase bone mass and density, mainly by inhibiting osteoclastogenesis and bone resorption [18][19][20]. An alternative therapy is physical exercise.…”

Population‐based register study of children born in Sweden from 1997 to 2014 showed an increase in rickets during infancy

“…Hypocalcaemic seizure is a presenting feature for vitamin D deficiency rickets among infants and toddlers in 11.8% to 40.3% . A U.S. population study reported seven cases of seizures as a hypocalcaemic complication at age before of nine months, two of those had rickets present on radiograph .…”

Differences in childhood adiposity influence upper limb fracture site

“…However, site-specific differences in bone strength within the upper limb are unlikely, although, to our knowledge, have not been formally investigated. Vitamin D deficiency is more common in overweight and obese children, however, there is no consistent evidence to support an association between vitamin D deficiency and fracture risk in childhood [32], and similarly, it is unlikely that this would lead to site specific differences. It is possible that body weight or adiposity contribute to the likelihood of fracture depending on mechanism of injury as these did differ between children with forearm and UA fractures, although overall fracture mechanisms were similar between healthy weight and overweight/ obese children.…”