Background Hypovitaminosis D as the possible main risk factor for inducing osteoporosis.
Objectives To determine the prevalence o of hypovitaminosis D as the possible main risk factor for inducing osteoporosis in an attempt to differentiate between the association of the two conditions and the direct causal relationship.
Methods Retrospectively, we reviewed the records of 131 adult patients with hypovitaminosis D who underwent DXA scanning. Results of the scan were interpreted according to the T or the Z scores for patients above and below 50 years of age respectively. A score of -2.5 or less in one or more of the examined sites indicated the presence of osteoporosis. Other Data of interest were age, nationality, 25 (OH) D3, PTH (assayed by CMIA, Abbot), and serum calcium. The study does not include data of patients who are concurrently or recently been on corticosteroids therapy, or patients with autoimmune diseases and others with chronic renal failure.
Results The majority of the patients were Arab Individuals (77%) from various Arab states. The rest were Asian and non Asian individuals. All are residents of Abu Dhabi, UAE. 68 were females. 28 (21.5%) were deficient (<12 ng/ml) vs. 103 insufficient (12-30 ng/ml) for the vitamin. 60 individuals had normal outcome of DXA (46%), 47 with osteopenia (36%) and 24 (18.5%) had osteoporosis. The mean age of the latter was (51.2±17.5 vs. 46.4 years ±12) in l patients with normal outcome, p=0.15. Osteoporosis in males was determined in 5/63 (8%) vs. 19/68 (28%) in females, p=0.005,whereas more males expressed normal outcome on DXA compared to females (60.5% vs. 32.5%, p=0.001. However, the mean age of patients with osteoporosis was comparable in males and females respectively, (43.4±23.4 vs. 53.3±15.8 yrs, p=0.27). Age was also non –discriminatory in osteoporotics below and above the age of 50 years (41.5% vs. 58.5%, respectively, p=0.386). The mean values of 25(OH)D3,serum calcium and PTH were not different in patients with osteoporosis and others with normal outcome (17.8±5.47 vs.18.3±5.95 ng/mlfor 25 (OH) D3, 9.41±0.44 vs. 9.38±0.372 mg% for serum calcium and 105±65.1 vs.94.3±53.7 pg/ml for PTH, and 97.6±7.8 vs, 73.2±17.9 U/l foralkaline phosphatase) respectively, P=NS. 67.5% had secondary hyperparathyroidism vs. 32.5% with blunted PTH response. Secondary hyperparathyroidism occurred in 15/21 (71.5%) in patients with osteoporosis vs. 38/54 (70.5%), in those with normal outcome, p=1.00. Four in the deficient group (14%) and 20 (19.5%) among the insufficient had osteoporosis, p=0.78.
Conclusions Osteoporosis tends to occur in the minority of patients with hypovitaminosis D irrespective to the degree of the inadequacy of the vitamin. In these patients, osteoporosis appears to be gender- related and associated with low body mass index. Future work should compare these findings to others in patients with osteoporosis but with normal vitamin D status.
Disclosure of Interest None declared