Bone mineral density of both genders in Type 1 diabetes according to bone composition

Abstract

Aims

This study is an investigation of the impact of Type 1 diabetes on bone mineral density (BMD) with regard to bone composition.

Material and methods

Thirty male and 30 premenopausal female patients with Type 1 diabetes (IDD) were retrospectively compared with an equal number of healthy individuals, matched on a person-to-person basis and to the reference population mean. BMD was measured at the L2–L4 vertebrae and femoral neck (FN) by dual energy X-ray absorptiometry (DXA).

Results

BMD absolute values were significantly lower in the diabetic than in the healthy males at vertebrae and FN (P<.05). The vertebral BMD values of diabetic women did not significantly differ, whereas those of FN were significantly lower compared with those of the healthy participants. FN age-adjusted BMD values (Z scores) were significantly lower than those of the healthy persons and the population reference mean in both genders (P=.01, <.001 for males and <.01 for females), whereas regarding the vertebrae, only in the diabetic males (P<.05 and <.01 respectively). The percentages of osteopenia and osteoporosis were significantly higher in the male compared to the female diabetic patients (P<.001). No significant correlations existed between the BMD values and diabetes duration, glycosylated hemoglobin (HbA1c) concentration, or age of diabetes onset. Similar results were obtained when applying stepwise multiple regression analysis to explain the BMD value variance.

Conclusions

Young males with Type 1 diabetes exhibit significantly lower BMD values of trabecular and mixed cortical–trabecular bone, compared with matched healthy persons. Premenopausal females with Type 1 diabetes present significantly lower BMD values of mixed bone only. Blood glucose control and diabetes duration do not appear to influence BMD behavior.

Introduction

Diabetes mellitus and osteoporosis are chronic diseases with great socioeconomic consequences, mainly due to the late complications and consequent disabilities. The potential effects of diabetes mellitus on bone metabolism remain a very controversial issue, and disagreement exists with regard to the clinical implications of diabetic osteopenia, wherever the latter exists, and the mechanisms of its occurrence. The issue is further complicated by the contribution of specific factors, such as duration of disease and the degree of metabolic control (Lopez-Ibarra et al., 2001, Olmos et al., 1994). Substances common to the pathophysiology of diabetes and osteoporosis, such as cytokines and growth factors with their binding proteins, have been implicated in the pathogenesis of diabetic osteopenia (Hadjidakis et al., 1999, Jehle et al., 1998, Jilka et al., 1992, Kemink et al., 2000, Manolagas & Jilka, 1995, Tagaki et al., 1997, Terada et al., 1998).

The metabolic processes of bone tissue depend on its composition, which varies with the anatomic area, with the trabecular bone being metabolically more active than the cortical one. Type 1 diabetes usually involves age periods, such as adolescence and early adulthood, during which bone mass is accrued. Dual energy X-ray absorptiometry (DXA) represents a sensitive and reliable method for clinical densitometry (Kanis & Glüer, 2000). Previous studies have addressed the issue of bone metabolism in cohorts with Type 1 diabetes of relatively narrow age spectra or without gender discrimination. Most of these studies reported diminished bone mineral density (BMD) values in Type 1 diabetic patients relative to normal individuals (Auwerx et al., 1988, Lopez-Ibarra et al., 2001, McNair et al., 1981). However, either lack of significant difference or even increased BMD values in Type 1 diabetic patients have also been reported (Forst et al., 1995, Gallagher et al., 1993).

The purpose of our study is to explore the changes of BMD in diabetic persons of both genders in areas with different bone tissue composition [vertebrae, femoral neck (FN): mixed cortical–trabecular]. The comparison was accomplished on a strict person-to-person matching basis.