Introduction: There is still controversy about the levels of bone turnover markers at type 1 diabetes (T1D) onset and their dynamics at follow-up. Bonfanti et al. did not find any differences at onset, while few months afterwards beta cross laps level was significantly lower. Pater et al. found lower levels of osteocalcin and Log beta cross laps at onset which normalized after 3 and 12 months. Possible mechanisms are metabolic acidosis, decreased activity of insulin-IGF-1 system, hyperglycemia. The ability to reach peak bone mass is impaired early in the course of the disease and puts them at a higher fracture risk.
Objectives: To determine if newly diagnosed T1D patients have alterations in bone and mineral metabolism (osteocalcin, beta cross laps, bone-specific alkaline phosphatase, PTH, IGF-1, 25(OH)vitamin, Ca, Phosphorus, Mg) compared to healthy controls and to look for correlations with disease-specific parameters – HbA1c, pH and insulin dose.
Methods and Materials: A cross-sectional study of 35 patients with newly diagnosed (within one week of diagnosis) T1D (15 females) aged 10.55years ±4.58 and 52 (25 females) controls aged 9.86 years±4.60, P>0.05. Mean HbA1c 102 mmol/mol (11.57%±1.90). Statistical methods used were correlation analysis and t-test.
Results: We found significantly lower levels of serum osteocalcin -49,51 ng/ml ±41,47 in patients vs 79,21 ng/ml±40,5 in controls, P<0,001. Beta cross laps, bone specific ALP, IGF-1, their SDS and PTH tended to be lower in patients, P>0,05. 25(OH)D in both groups was in the recommended range - 64,13±28,9 vs 76,87±32,34, P>0,05. No patients had vitamin D deficiency but five (28%) had insufficiency -35,56 nmol/l±28,9. Among controls there were seven (14%) with vitamin D alterations - three had vitamin D deficiency(13,58nmol/l±3,22) and four had insufficiency (43,94nmol/l±1,47), P<0,001. Patients had significantly lower levels of serum Ca - 2,30±0,1 vs 2,40±0,1 in controls, P<0,001 but higher levels of serum Mg – 0,86±0,004 (0,78-0,91) vs 0,85±0,003 (0,75-0,96), P<0,001. No significant differences in ionized Ca and serum phosphorus. Significant negative correlation between osteocalcin and insulin dose was found, r=-0,430, P<0,05. No correlations with pH or HbA1c level.
Conclusions: Patients with newly diagnosed T1D seem to have significantly depressed bone formation. We confirm the stimulatory effect of osteocalcin on insulin secretion. No significant correlations with HbA1c and pH were found. Further studies, including imaging are needed to elucidate the exact mechanisms and evolution of the observed alterations.
15 Sep 2022 - 17 Sep 2022