AimsTo investigate the effect of short‐term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes.MethodsIn a double‐blind placebo‐controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non‐diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100 000 IU vitamin D2 (ergocalciferol) or 100 000 IU vitamin D3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin (HbA1c) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C‐reactive protein levels; pulse wave velocity (PWV); anthropometric measures; and safety of the supplementation.ResultsThe mean [standard deviation (s.d.)] 25‐hydroxyvitamin D [25(OH)D]2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D2 group, and the mean (s.d.) 25(OH)D3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D3 group. There was no effect of vitamin D supplementation on HbA1c: D2 versus placebo: −0.05% [95% confidence interval (CI) −0.11, 0.02] or −0.51 mmol/mol (95% CI −1.16, 0.14; p = 0.13); D3 versus placebo: 0.02% (95% CI −0.04, 0.08) or 0.19 mmol/mol (95% CI −0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [D2 versus placebo: −0.68 m/s (95% CI −1.31, −0.05); D3 versus placebo −0.73 m/s (95% CI −1.42, −0.03)]. No important safety issues were identified.ConclusionsShort‐term supplementation with vitamin D2 or D3 had no effect on HbA1c. The modest reduction in PWV with both D2 and D3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.

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The paper reports on a comparative evaluation of 10 rapid malaria tests available in South Africa in 1998: AccuCheck (AC, developmental), Cape Biotech (CB), ICT Malaria Pf (ICT1) and Pf/Pv (ICT2), Kat Medical (KAT), MakroMal (MM), OptiMAL (OP), ParaSight-F (PS), Quorum (Q), Determine-Malaria (DM). In a laboratory study, designed to test absolute detection limits, Plasmodium falciparum-infected blood was diluted with uninfected blood to known parasite concentrations ranging from 500 to 0.1 parasites per microlitre (P/microL). The 50% detection limits were: ICT1, 3.28; ICT2, 4.86; KAT, 6.36; MM, 9.37; CB, 11.42; DM, 12.40; Q, 16.98; PS, 20; AC, 31.15 and OP, 91.16 P/microL. A field study was carried out to test post-treatment specificity. Blood samples from malaria patients were tested with all products (except AC and DM) on the day of treatment and 3 and 7 days thereafter, against a gold standard of microscopy and polymerase chain reaction (PCR). OP and PS produced fewer false-positive results on day 7 (18 and 19%, respectively) than the other rapid tests (38-56%). However, microscopy, PCR, OP and PS disagreed largely as to which individuals remained positive. The tests were further compared with regard to general specificity, particularly cross-reactivity with rheumatoid factor, speed, simplicity, their ability to detect other species, storage requirements and general presentation.

Introduction and objectivesRandomised controlled trials of vitamin D to prevent acute respiratory infection have yielded mixed results. We conducted an individual patient data (IPD) meta-analysis to identify factors that may explain this heterogeneity.MethodsWe performed an IPD meta-analysis of 25 trials of vitamin D supplementation with incidence of acute respiratory infection as a pre-specified outcome (total 11,321 participants, aged 0 to 95 years). We used one-step logistic regression with random effects adjusting for age, sex, study duration and clustering by study. Pre-specified sub-group analyses were done to determine whether effects of vitamin D on risk of acute respiratory infection varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration or dosing regimen.ResultsIPD were obtained for 10,933/11,321 (96.6%) participants. Vitamin D supplementation reduced risk of acute respiratory infection among all participants (adjusted Odds Ratio [aOR] 0.88, 95% CI: 0.81 to 0.96, P = 0.003; P for heterogeneity < 0.001). Sub-group analysis revealed a strong protective effect among individuals with baseline 25(OH) D < 25 nmol/L (aOR 0.62, 95% CI: 0.45 to 0.83, P = 0.002), not seen among those with higher levels (aOR 0.91, 95% CI: 0.78 to 1.05; Pinteraction = 0.01). A protective effect was also seen in individuals receiving daily or weekly vitamin D without additional bolus doses (aOR 0.81, 95% CI: 0.72 to 0.91, P < 0.001), but not in those receiving one or more bolus doses (aOR 0.97, 95% CI: 0.86 to 1.10, Pinteraction = 0.05). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (aOR 0.98, 95% CI: 0.80 to 1.20, P = 0.83). The body of evidence contributing to these analyses was assessed as being of high quality.ConclusionsVitamin D supplementation was safe, and it protected against acute respiratory infection overall. Very deficient individuals and those not receiving bolus doses experienced the most benefit.

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