MAVIS 2005 Low.

Methods	Mineral And Vitamin Intervention Study (MAVIS) Randomised, double‐blind placebo‐controlled trial with parallel group design (two intervention groups).
Participants	Country: Scotland Number of participants randomised: 910, 479 men and 431 women, aged 65 or over who did not take vitamins or minerals. Inclusion criteria: all people aged 65 or over who were registered with the practices were eligible, irrespective of chronic illness, unless their doctors considered them too unwell. Exclusion criteria: use of vitamin, mineral, or fish oil supplements in the previous three months (one month in the case of water soluble vitamins) or vitamin B12 injection in the past three months.
Interventions	Participants were randomly assigned to receive: group 1: multivitamin and multimineral supplement (800 µg vitamin A (acetate), 60 mg vitamin C, 5 µg vitamin D3, 10 mg vitamin E (D, L alpha‐tocopheryl acetate), 1.4 mg thiamin (mononitrate), 1.6 mg riboflavin, 18 mg niacin (nicotinamide), 6 mg pantothenic acid (calcium D‐pantothenate), 2 mg pyridoxine (hydrochloride), 1µg vitamin B12, 200 µg folic acid, 14 mg iron (fumurate), 150 µg iodine (potassium iodide), 0.75 mg copper (gluconate), 15 mg zinc (oxide), and 1 mg manganese (sulphate); or group 2: matched sorbitol placebo, one tablet daily for one year. Tablets were purchased from a commercial supplier.
Outcomes	The primary outcome measures were: number of contacts with primary care (doctor and other primary care workers, in person or by phone) for infection, number of self reported days of infection, and health related quality of life measured by the EuroQol and SF‐12. The secondary outcome measures were: number of antibiotic prescriptions in primary care, number of days that antibiotics were prescribed, number of hospital admissions (including those related to infection), number of days in hospital with infection, number of infection related and all outpatient visits, adverse events reported by participants, and compliance with trial drugs (from diaries submitted monthly in all participants and tablet count at six and 12 months in a random sample of 10% of participants).
Notes	Compliance with treatment was assessed by self‐report and was consistent with tablet counting. There were no differences between the groups for compliance with drug taking. Compliance in participants still taking tablets and returning information in diaries was over 91% throughout the trial. Only 13% (n = 121) of the participants were lost to follow‐up or reported stopping taking tablets. At least 1 diary was provided by 99% (901) of participants, 6 diaries by 93% (846), and 12 diaries by 89% (808). Losses to follow‐up was equal in the active and the placebo (n = 22) groups. Fourteen participants in the active group and 18 participants in the placebo group withdrew.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Sequence generation was achieved using computer random number generation.
Allocation concealment (selection bias)	Low risk	Allocation was controlled by a central and independent randomisation unit, so that intervention allocations could not have been foreseen in advance of, or during, enrolment.
Blinding (performance bias and detection bias) All outcomes	Low risk	The trial was described as blinded, the parties that were blinded, and the method of blinding was described, so that knowledge of allocation was adequately prevented during the trial.
Incomplete outcome data (attrition bias) All outcomes	Low risk	The numbers and reasons for dropouts and withdrawals in all intervention groups were described.
Selective reporting (reporting bias)	Low risk	Pre‐defined, or clinically relevant and reasonably expected outcomes are reported on.
Other bias	Low risk	The trial appears to be free of other components that could put it at risk of bias.