Fish oil supplemented for 9 months does not improve glycaemic control or insulin sensitivity in subjects with impaired glucose regulation: a parallel randomised controlled trial.

The effects of fish oil (FO) supplementation on glycaemic control are unclear, and positive effects may occur only when the phospholipid content of tissue membranes exceeds 14% as n-3 PUFA. Subjects (n 36, thirty-three completed) were paired based on metabolic parameters and allocated into a parallel double-blind randomised trial with one of each pair offered daily either 6 g of FO (3·9 g n-3 PUFA) or 6 g of maize oil (MO) for 9 months. Hyperinsulinaemic-euglycaemic-euaminoacidaemic (HIEGEAA) clamps (with [6,6 2H2 glucose]) were performed at the start and end of the intervention. Endogenous glucose production (EGP) and whole-body protein turnover (WBPT) were each measured after an overnight fast. The primary outcome involved the effect of oil type on insulin sensitivity related to glycaemic control. The secondary outcome involved the effect of oil type on WBPT. Subjects on FO (n 16) had increased erythrocyte n-3 PUFA concentrations >14%, whereas subjects on MO (n 17) had unaltered n-3 PUFA concentrations at 9%. Type of oil had no effect on fasting EGP, insulin sensitivity or total glucose disposal during the HIEGEAA clamp. In contrast, under insulin-stimulated conditions, total protein disposal (P=0·007) and endogenous WBPT (P=0·001) were both increased with FO. In an associated pilot study (n 4, three completed), although n-3 PUFA in erythrocyte membranes increased to >14% with the FO supplement, the enrichment in muscle membranes remained lower (8%; P<0·001). In conclusion, long-term supplementation with FO, at amounts near the safety limits set by regulatory authorities in Europe and the USA, did not alter glycaemic control but did have an impact on WBPT.

Antithyroid drug regimen for treating Graves' hyperthyroidism.

BACKGROUND: Antithyroid drugs are widely used in the therapy of hyperthyroidism. There are wide variations in the dose, regimen or duration of treatment used by health professionals. OBJECTIVES: To assess the effects of dose, regimen and duration of antithyroid drug therapy for Graves' hyperthyroidism. SEARCH STRATEGY: We searched seven databases and reference lists. SELECTION CRITERIA: Randomised and quasi-randomised trials of antithyroid medication for Graves' hyperthyroidism. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data and assessed risk of bias. Pooling of data for primary outcomes, and select exploratory analyses were undertaken. MAIN RESULTS: Twenty-six randomised trials involving 3388 participants were included. Overall the quality of trials, as reported, was poor. None of the studies investigated incidence of hypothyroidism, changes in weight, health-related quality of life, ophthalmopathy progression or economic outcomes. Four trials examined the effect of duration of therapy on relapse rates, and when using the titration regimen 12 months was superior to six months, but there was no benefit in extending treatment beyond 18 months. Twelve trials examined the effect of block-replace versus titration block-regimens. The relapse rates were similar in both groups at 51% in the block-replace group and 54% in the titration block-group (OR 0.86, 95% confidence interval (CI) 0.68 to1.08) though adverse effects (rashes (10% versus 6%) and withdrawing due to side effects (16% versus 9%)) were significantly higher in the block-replace group. Three studies considered the addition of thyroxine with continued low dose antithyroid therapy after initial therapy with antithyroid drugs. There was significant heterogeneity between the studies and the difference between the two groups was not significant (OR 0.58, 95% CI 0.05 to 6.21). Four studies considered the addition of thyroxine alone after initial therapy with antithyroid drugs. There was no significant difference in the relapse rates between the groups after 12 months follow-up (OR 1.15, 95% CI 0.79 to 1.67). Two studies considered the addition of immunosuppressive agents. The results which were in favour of the interventions would need to be validated in other populations. AUTHORS' CONCLUSIONS: The evidence suggests that the optimal duration of antithyroid drug therapy for the titration regimen is 12 to 18 months. The titration (low dose) regimen had fewer adverse effects than the block-replace (high dose) regimen and was no less effective. Continued thyroxine treatment following initial antithyroid therapy does not appear to provide any benefit in terms of recurrence of hyperthyroidism. Immunosuppressive therapies need further evaluation.