Introduction Early inflammatory changes may explain the negative impact of adiposity on bone acquisition during childhood. We aimed at estimating the effect of systemic inflammation during adolescence on forearm bone mineral density at 17 years-old.
Methods We used data from 377 girls born in 1990 and assessed at 13 and 17 years-old (EPITeen cohort). Adolescents were evaluated through physical examination, including height, weight and bone mineral density (BMD) at the forearm using dual-energy x-ray absorptiometry. Serum high-sensitivity C reactive protein (CRP) was quantified (participants over 10 mg/l were excluded). Associations between CRP and BMD were quantified using linear regression. Coefficients were adjusted for gynaecologic age, weight and height, to minimise confounding by body size.
Results Median (25th–75th percentiles) CRP concentration increased from 0.2 (0.1–0.5) mg/l at 13 to 0.6 (0.2–1.7) at 17 years-old. Mean (SD) BMD was 0.362 (0.058) g/cm2 at 13 and 0.437 (0.052) g/cm2 at 17. Adolescents in the upper quarter of CRP at 13 had similar adjusted mean BMD at that age but significantly lower BMD at 17 years-old when compared to those in the lowest quarter (−0.024, 95% CI −0.040 to −0.007). Additionally, girls in the two highest quarters of CRP variation had significantly lower BMD at 17 when compared to the lowest quarter (−0.016, 95% CI −0.031 to −0.001 and −0.027, 95% CI −0.043 to −0.010, respectively).
Conclusion Systemic inflammation in early adolescence and its increase during follow-up, predicted lower bone quality in late adolescence, providing evidence that the negative association between obesity and bone accrual is probably mediated by low-grade inflammation.