Woods 1998.
| Methods | Double‐blind, randomised, cross‐over, placebo‐controlled trial | |
| Participants | 12 patients (male = 5, female = 7) who believed they had previously had reactions to MSG Mean age 35.3 years (19 to 57) |
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| Interventions |
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| Outcomes | FEV1, PEF at ‐15, ‐30, ‐45, 0, 15, 30, 45 minutes; 1, 1.25, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 hours on 15 days , 18 days, 20 days (challenge visit 6, 7, 8 days) Soluble inflammatory marker activity (ECP and tryptase)(2 days, 6 days, 7 days, 8 days) Non‐specific BHR to methacholine (1 day, 5 days, 9 days) |
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| Notes | Diagnostic criteria: not reported | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "This study was conducted as a randomised, cross‐over, double‐blind, placebo‐controlled trial" "We thank Ms. Anne James, Pharmacist, for the preparation of the challenge capsules and Ms. Pam Liakakis, Respiratory Scientist, for the randomisation and administration of the capsules" Comment: Not described |
| Allocation concealment (selection bias) | Low risk | "We thank Ms. Anne James, Pharmacist, for the preparation of the challenge capsules and Ms. Pam Liakakis, Respiratory Scientist, for the randomisation and administration of the capsules" |
| Blinding (performance bias and detection bias) All outcomes | Low risk | "Each challenge dose comprised 10 size 00 opaque capsules, which were manufactured with a capsule machine filler (Sandell, Switzerland) by a pharmacist not otherwise involved in the study. All capsules were wiped clean after filling and rolled in lactose powder to prevent any MSG being detected on the outside of the capsules" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Results of all the subjects were reported |
| Selective reporting (reporting bias) | Low risk | All the results described in the method chapter were reported |
| Other bias | Low risk | "The participants had a diet that was low in other chemicals perceived to cause asthma symptoms" Comment: it minimised the influence of other materials |
BHR: bronchial hyper‐responsiveness FEV1:forced expiratory volume in the first second FVC: forced vital capacity MSG: monosodium glutamate PEF: peak expiratory flow