Low bone turnover and low bone density in a cohort of adults with Down syndrome

Abstract

Summary Increased incidence of osteoporosis in Down syndrome has been reported, but etiology is not established. We report low bone turnover markers and bone mineral density (BMD) in a cohort of people with Down syndrome without consistent clinical risk factors. Our results should guide future studies and treatments for this common problem. Introduction To better understand the etiology for osteoporosis in Down syndrome (DS), we measured bone density by dual-energy X-ray absorptiometry (DXA) and circulating biochemical markers of bone formation and resorption in a cohort of 30 community-dwelling DS adults. Methods Seventeen males and 13 females followed in the University of Arkansas Down Syndrome Clinic were evaluated by DXA to estimate BMD and underwent phlebotomy to measure serum procollagen type-1 intact N-terminal propeptide (P1NP) to evaluate bone formation, and serum C-terminal peptide of type-I collagen (CTx) to evaluate bone resorption. Results Seven of 13 DS females and 12 of 17 DS males had low bone mass at one of measured sites (z≤−2.0). When data were grouped by age, males had apparent osteopenia earlier than females. The mean P1NP in the normal group was 19.2±5.2 ng/ml vs. 2.2±0.9 ng/ml in the DS group (P= 0.002). Serum CTx levels in the normal group were 0.4± 0.1 ng/ml vs. 0.3±0.1 ng/ml (P=0.369). Conclusions Low BMD in adults with DS is correlated with a significant decrease in bone formation markers, compared to controls without DS, and is independent of gender. These data suggest that diminished osteoblastic bone formation and inadequate accrual of bone mass, with no significant differences in bone resorption, are responsible for the low bone mass in DS. These observations question the use of antiresorptive therapy in this population and focus attention on increasing bone mass by other interventions.

Effect of whole-body vibration training on bone mass in adolescents with and without Down syndrome: a randomized controlled trial

“…To our knowledge, the analysis and study of biochemical markers of bone formation and resorption in adolescents with DS remain unknown. Nevertheless, in a cohort of 30 community-dwelling DS adults, McKelvet et al [10] stated that low BMD was correlated with a significant decrease in bone formation markers, compared to controls without DS, and pointed out that diminished osteoblastic bone formation and inadequate accrual of bone mass were responsible for the low bone mass in that particular population. It would be possible to hypothesize that the low BMD and BMC values in our study can be due to increased bone resorption and/or decreased bone formation.…”

“…exercise and nutrition). In fact, a recent study has questioned the use of antiresorptive therapy in DS population and focused attention on increasing bone mass by other interventions like weight-bearing training [10].…”

Treatment with anti‐Sclerostin antibody to stimulate mandibular bone formation

“…Patients with Down syndrome have low bone mass with reduced osteoblast activity and bone turnover . Craniofacial analyses of humans with Down syndrome reveal several skeletal abnormalities, including small atrophic mandibles with significantly reduced alveolar height .…”

Bone mineral density from early to middle adulthood in persons with Down syndrome

“…; Mckelvey et al . ) and non‐DS adults with ID in western populations (Da Silva et al . ; Geijer et al .…”