Supplementation with omega-3 fish oil has no effect on bone mineral density in adults with knee osteoarthritis: a 2-year randomized controlled trial.

UNLABELLED: This study aimed to determine the effect of fish oil on bone mineral density (BMD). There were no differences in the 2-year BMD measures between high and low dose groups after adjusting for baseline BMD. This randomized controlled trial did not demonstrate any efficacy of omega-3 fatty acids on bone loss in adults. INTRODUCTION: The purpose of this study is to investigate whether supplementation with high dose omega-3 fish oil could have an impact on BMD. METHODS: In a multicentre, double-blind randomized controlled trial (RCT) (ACTRN 12607000415404), 202 Australian participants aged ≥40 with knee osteoarthritis (mean age, 61.0 ± 10.0 years; 49 % female) were randomized to receive either high dose (4.5 g eicosapentaenoic acid and docosahexaenoic acid daily) or low dose (0.45 g/day) omega-3 fish oil for 2 years. BMD was assessed at baseline and 2 years by dual energy X-ray absorptiometry. RESULTS: In subjects with baseline and 2-year assessments, mean standardized BMD at baseline for low or high dose group was 1198 ± 198 and 1157 ± 169 mg/cm(2), respectively, for the lumbar spine and was 1035 ± 165 and 1017 ± 174 mg/cm(2), respectively, for the femoral neck. There were no differences in the 2-year BMD measures between high and low dose groups after adjusting for baseline BMD in the complete case regression analyses (lumbar spine 3.7, 95 % confidence interval (CI) -7.9 to 15.3 mg/cm(2) and femoral neck -5.5, 95 % CI -14.9 to 3.9 mg/cm(2)). The findings did not change with additional adjustments of age, gender, study centre and uses of bone-related drugs during the study period as well as using the intention-to-treat analysis or limiting to older participants (≥55 years at the baseline) (all P ≥ 0.25). Mild adverse events such as headache and gastrointestinal intolerance were common but did not occur more frequently in either group. There were no serious adverse events related to the intervention. CONCLUSION: A 2-year supplementation with high-dose omega-3 fish oil did not alter bone loss among men and women with knee osteoarthritis.

Abnormal bone mineral metabolism after long-term anticonvulsant treatment.

OBJECTIVE: To present a case of anticonvulsant-induced disturbances of bone mineral metabolism associated with long-term phenytoin treatment. CASE SUMMARY: An 87-year-old woman was hospitalized with generalized acroparesthesia. Her medical history was significant for grand mal epilepsy, which had been treated with phenytoin for more than ten years. On admission she was found to be hypocalcemic, and her alkaline phosphatase concentration was markedly elevated. DISCUSSION: Further investigations revealed that the patient's serum concentration of 25-hydroxycalciferol was well below the expected range. Phenytoin treatment was withdrawn, and calcitriol supplementation commenced. Ten weeks later she was normocalcemic, and the calcitriol dosage was reduced. Radiologic investigations at this time revealed an ununited hip fracture, as well as widespread evidence of bone demineralization. CONCLUSIONS: Minor elevations of liver enzymes observed in association with anticonvulsant treatment may reflect hepatic microsomal enzyme induction. Marked elevation of serum alkaline phosphatase, particularly when seen in concert with hypocalcemia, may be markers of anticonvulsant-induced bone disease. Under these circumstances, further radiologic investigations and measurement of the vitamin D serum concentration should be undertaken.