The Prevalence of Reduced Bone Mineral Density and the Impact of Specific Auxological Factors and Hormones on Bone Mass in Children with Endocrine Disorders

Abstract

Background/Objectives: The skeletal system reaches peak bone mass through modeling and remodeling processes, influenced by environmental, dietary, hormonal, and genetic factors. In children with endocrinopathies, disturbances in bone mass and mineralization may correlate with hormonal levels, but conditions like short stature or obesity can confound DXA results. This study aimed to assess the prevalence of decreased bone mineral density (BMD) in children with endocrine disorders and evaluate the impact of auxological and hormonal abnormalities on BMD. Methods: This study analyzed medical records of 148 children (mean age 11.85 ± 3.34 years); 73 girls and 75 boys). Conditions included obesity (22.9%), short stature (47.9%), precocious puberty (10.1%), and other diagnoses. Clinical data included primary diagnosis, height, body weight, pubertal stage, and serum concentrations of calcium, phosphate, alkaline phosphatase, 25OHD, PTH, osteocalcin, Crosslaps, TSH, fT4, IGF-1, IGF-BP3, cortisol, estradiol, testosterone, and bone age. DXA scans were performed at the total body less head (TBLH) and lumbar spine (Spine) projection. Results: Low bone mass (aBMD Z-score ≤ -2) was found in 34.46% at TBLH and 15.54% at the Spine. After height adjustment (HAZ adjustment), the prevalence of low bone mass decreased to 11.4% at TBLH and 4.1% at the Spine. In the short stature group, the normalization of Z-scores for height significantly reduced abnormal results. A positive correlation was found between DXA parameters and age, height standard deviation score (HSDS), BMI SDS, estradiol, testosterone, IGF-1, and IGF-BP3. A negative correlation existed between vitamin D and DXA parameters. Bone turnover markers (osteocalcin and Crosslaps) also negatively affected bone mass. No significant correlations were found with PTH, TSH, fT4, or cortisol. In children with growth retardation, lower aBMD_HAZ Z-scores were observed in those with decreased IGF-1. Positive correlations existed between BMI SDS, IGF-1, and adjusted aBMD Z-scores. Conclusions: Children with endocrine disorders, especially those with short stature, are at risk for bone mineralization disorders. Height normalization is crucial for accurate DXA interpretation and avoiding overdiagnosis. Positive influences on bone mass include height, BMI, IGF-1, estradiol, and testosterone, while negative factors include bone turnover markers and low vitamin D.

Keywords: IGF-1; bone mass; bone mineral density; children; dual X-ray densitometry; hormones.

Figure 1

The prevalence of bone mineralization disorders expressed as a Z-score TBLH by diagnosis, before and after height adjustment (HAZ-adjusted Z-score; BMD_HAZ Z-score).

Figure 2

The prevalence of bone mineralization disorders expressed as a Z-score Spine by diagnosis, before and after height adjustment (HAZ-adjusted Z-score; BMD_HAZ Z-score).

Figure 3

The distribution of pubertal stages according to the Tanner scale by diagnosis.

Figure 4

A comparison of aBMD_HAZ Z-score Spine (a) and TBLH (b) in growth retardation patients according to IGF-1 SDS.

Figure 4

A comparison of aBMD_HAZ Z-score Spine (a) and TBLH (b) in growth retardation patients according to IGF-1 SDS.

Figure 5

The correlation between IGF-1 SDS and aBMD_HAZ Z-score Spine among children with growth retardation.

Figure 6

The correlation between IGF-1 SDS and aBMD_HAZ Z-score TBLH among children with growth retardation.