Prevalence of low bone mass and endocrine disorders in hip fracture patients in Southern Germany

Low bone mass and conditions leading to falls are considered to determine the risk of hip fracture. Bone mass is influenced by underlying diseases and risk factors such as malnutrition and life style habits. In order to evaluate the clinical significance of osteopenia and risk factors in the pathogenesis of hip fracture, we have studied 146 consecutive patients (27 males, 119 females, aged 53-95 years) undergoing rehabilitation shortly after hip fracture (4 cases of hip fracture resulting from traffic accidents had been excluded). We measured bone mineral density (BMD) at the hip (DXA, Hologic QDR 2,000+), evaluated vitamin D status (serum 25-OH-Vitamin D) and nutritional calcium intake (clinical dietician), and searched for endocrine disorders (physical examination and serum hormones). Femoral neck BMD was 0.543 +/- 0.084 g/cm2 in females and 0.635 +/- 0.087 g/cm2 in males (p < 0.01). For both sexes, the values were significantly lower compared to age-matched controls. 88% of the females and 69% of the males had T-Scores below -2.5, thus fulfilling the densitometric WHO criteria of osteoporosis. Nutritional calcium intake was similar in both sexes (804 +/- 330 mg/day in women, 738 +/- 295 mg/day in men), but lower compared to coxarthrosis patients (1080 +/- 436 mg/day). Vitamin D deficiency was prevalent in 69% of the women, and in 55%, of the men with hip fracture. In female hip fracture patients, the serum alkaline phosphatase was significantly higher (194 +/- 82 U/I) as compared to patients with surgery because of coxarthrosis (142 +/- 46 U/I), supporting the view that some degree of osteomalacia and high turnover was present. Primary hyperparathyroidism (pHPT) was newly detected in 1% and hyperthyroidism in 4.3% of the cases.

Hip fracture occurs at higher BMD values in men compared to women suggesting different fracture thresholds. Vitamin D deficiency and low calcium intake are common in hip fracture patients. However, before initiation of vitamin D treatment pHPT should be excluded. Determination of TSH is recommendable in all hip fracture patients.