Associations between serum 25-hydroxyvitamin D and bone turnover markers in a population based sample of German children

Abstract

Severe vitamin D deficiency is known to cause rickets, however epidemiological studies and RCTs did not reveal conclusive associations for other parameters of bone health. In our study, we aimed to investigate the association between serum levels of 25(OH) vitamin D and bone turnover markers in a population-based sample of children. 25(OH)D, calcium (Ca), osteocalcin (OC), and β-Crosslaps (β-CTx) were measured in 2798 ten-year-old children from the German birth cohorts GINIplus and LISAplus. Linear regression was used to determine the association between bone turnover markers and 25(OH)D levels. 25(OH)D, OC, and β-CTx showed a clear seasonal variation. A 10 nmol/l increase in 25(OH)D was significantly associated with a 10.5 ng/l decrease (p < 0.001) in β-CTx after adjustment for design, sex, fasting status, time of blood drawn, BMI, growth rate, and detectable testosterone/estradiol. For OC alone no significant association with 25(OH)D was observed, whereas the β-CTx-to-OC ratio was inversely associated with 25(OH)D (−1.7% change, p < 0.001). When stratifying the analyses by serum calcium levels, associations were stronger in children with Ca levels below the median. This study in school-aged children showed a seasonal variation of 25(OH)D and the bone turnover markers OC and β-CTx. Furthermore a negative association between 25(OH)D and the bone resorption marker β-CTx was observed.

Children sustain high levels of skin DNA photodamage, with a modest increase of serum 25-hydroxyvitamin D3, after a summer holiday in Northern Europe

“…The crosslaps values were similar to those of healthy French and Italian children of the same age (using the same assay) and the osteocalcin values were comparable with those of healthy Italian and Danish children of the same age (different assays). One study of 2798 10‐year‐old German children showed that 25(OH)D 3 had an inverse seasonal relationship with osteocalcin and crosslaps . Our data show a positive correlation between Δ osteocalcin and crosslaps, and that there was an after‐holiday significant reduction of osteocalcin in the boys compared with an increase in the girls.…”

Dietary reference values for vitamin D

“…The serum concentration of 25(OH)D is approximately 1,000 times higher than that of 1,25(OH) 2 D. An overview of reported 25(OH)D concentrations from studies in 17 European countries (Spiro and Buttriss, ) and other recent European data ((Thiering et al., ) in Germany) show that mean/median concentrations (Section 2.4.1) range from about 20 to 95 nmol/L in adults or children.…”

Bone Turnover Markers in the Diagnosis and Monitoring of Metabolic Bone Disease

“…This circadian effect can be generally observed with most BTMs, though CTX displays the highest amplitude in circadian variation (24 ). Additionally, seasonal variation is observed in bone turnover, with a peak in bone remodeling occurring during winter months, though the degree of coupling varies with premenopausal women showing the greatest seasonal variation (25 ). Bone resorption levels drop post-prandially, which is a significant contributor to the rise in CTX occurring during the early morning, which is typically the longest period of fasting each day.…”