Osteoporosis in type 1 diabetes mellitus : correlation with biomarkers of bone metabolism

الملخص EN

Type I diabetes mellitus (DM) has been associated with decreased bone mineral density (BMD).

However, the natural history and etiopathogenesis of osteoporosis in type I diabetes are not clear.

The aim of this study was to assess BMD in a group of female patients with type I diabetes compared with non-diabetic control subjects and to evaluate the possible association of BMD with diabetes duration, glycemic control, diabetic microvascular complications and biomarkers of bone metabolism.

This study was conducted on 45 type I diabetes mellitus females (Group I) with age ranged between 20-35 years.

They were subdivided into 2 subgroups according to the absence (Group Ia, n=23) or presence (Group Ib, n=22) of microvascular diabetic complications (neuropathy, nephropathy and retinopathy).

Twenty age and sex-matched healthy subjects were also included as a control group (Group II). BMD at lumber spine (L2-L4) was measured by DEXA.

Disease variables and biochemical markers of bone metabolism (serum osteocalcin, insulin-like growth factor-I {IGF-I} and insulin-like growth factor binding protein-3 {IGFBP-3}) were also measured. Our results showed that BMD was significantly lower at lumber spine (L2-L4) in females with type I diabetes compared with age-matched control subjects (P<0.001).

Moreover, BMD was significantly lower in the group of diabetic patients with microvascular complications when compared to the uncomplicated group (P<0.001).

Our results also showed a highly significant decrease in serum osteocalcin, IGF-I and IGFBP-3 in patients with type I diabetes compared to control subjects (P<0.01, <0.001 and <0.01 respectively).

Furthermore, the group of type I diabetes mellitus with microvascular complications showed a significant lower levels of these parameters when compared to uncomplicated group (P<0.05).

Our data showed that BMD in diabetic subjects had a significant negative correlation with the duration of the disease and metabolic control (HbA1c) (r= -0.47, r= -0.43, P<0.05 respectively) and a significant positive correlation with the biomarkers of bone metabolism (osteocalcin, IGF-I and IGFBP-3) (r= 0.44, 0.41 and 0.52, P<0.05 respectively). In conclusion, the present study demonstrated lower BMD in young women with type I diabetes mellitus compared to age-matched control subjects.

This difference may impact future fracture risk.

These data suggest that screening may be important in this group of patients; in addition, these women should be counseled regarding life style intervention that may improve bone health.