Caesar 2012.

Study characteristics
Methods	Study design: parallel randomised controlled trial Prevention or treatment trial: treatment Concomitant treatments explicitly allowed or forbidden: "Any subject with fever received paracetamol." Investigation of ability to distinguish between zinc and placebo: NR Duration of follow‐up: 7 days Duration of intervention: 7 days Duration of run‐in or washout period: none How participants were identified as having colds/URTI at baseline (treatment trial): "Diagnosis of common cold were based on cough and runny nose with clear or mucopurulent secretions of less than 10 days, with or without mild fever of <39 degrees, good general condition and no thoracic abnormalities on physical examination." Outcomes measured: decreased cold severity, side effects
Participants	Setting: outpatient Country: Indonesia Zinc NR 20 mg/d powder Number: 57 Percentage female: 54% Age, (n (%)): 3 to 5 years (mean not given) Placebo powder Number: 57 Percentage female: 56% Age, (n (%)): 3 to 5 years (mean not given) Overall Number: 114 Percentage female: 55% Age, (n (%)): 3 to 5 years (mean not given) Inclusion criteria: "We included subjects aged 3–5 years who lived in Yogyakarta, suffered from the common cold for less than 2 days, had good general appearance, had parents willing to participate by signing the proxy consent and had an active phone number to maintain contact." Exclusion criteria: "Those suffering from a common cold with complications such as pneumonia, acute otitis media, sinusitis, exacerbation of asthma, as well as immunocompromised status such as HIV infection, malignancy or on steroid therapy for more than 4 weeks were excluded." Group differences: no apparent difference in baseline characteristics (Table 1) Condition studied: common cold Description of recruitment: participants were recruited by consecutive sampling from primary health care centres in Gedongtengen, Umbulharjo I and Kotagede II, Yogyakarta. Diagnostic criteria for condition: diagnosis of common cold was based on cough and runny nose with clear or mucopurulent secretions of less than 10 days with or without fever < 39 °C, good general condition, and no thoracic abnormalities on physical examination. Number of study centres: 1 Number of withdrawals: none Total number screened/eligible/randomised: 120/114/114
Interventions	Zinc NR 20 mg/d powder Study description of intervention and administration: "The treatment group received zinc powder (1x20mg) for seven days, while control group received placebo powder." "Any subject with fever received paracetamol." Form of product (tablet, lozenge, syrup, intranasal, other (specify)): powder Type of zinc (zinc sulfate, zinc gluconate, zinc acetate, other (specify)): NR Frequency of dose: 1x day Dose per day (elemental zinc in mg): 20 mg Duration of treatment: 7 days Placebo powder Study description of intervention and administration: "The treatment group received zinc powder (1x20mg) for seven days, while control group received placebo powder." Form of product (tablet, lozenge, syrup, intranasal, other (specify)): powder Frequency of dose: 1 x day Duration of treatment: 7 days
Outcomes	Global severity of cold symptoms (0 to 3 rating) Outcome type: dichotomous outcome Reported as: number of participants with event (n, N) Notes: only given in terms of the number whose cold severity decreased (see Tables 1 and 2) Adverse events Outcome type: dichotomous outcome Reported as: number of participants with event (n, N)
Identification	Author's name: Cahalafa Shinta Caesar Institution: Department of Child Health, Gadjah Mada University Medical School Email: cahalafa@gmail.com Address: Department of Child Health, School, Gadjah Mada University Medical School, Jalan Kesehatan No 1 Sekip, Yogyakarta 55284, Indonesia Trial registration identifier: NR Year study recruitment began: 2009
Notes	Declaration of interest: "The authors declare that they have no conflict of interest in this research." Funding source: NR Contact with study authors for additional information: none Other: study does not have any outcomes that correspond to the predetermined outcomes for this review. Closest outcome is proportion of participants with decreased cold severity. Primary healthcare centres in Gedongtengen, Umbulharjo I and Kotagede II, Yogyakarta.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: Stated to be randomised. "Subjects were collected by consecutive sampling." No other details.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: no details about allocation.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "A pharmacist from an outside primary health care center held the key, so subjects and researchers were blinded until the end of the study." Judgement comment: stated to be double‐blind and although there are no descriptions of the constitution of the placebo powder it is likely that participants and personnel were blinded. We assume that researchers were also personnel, but not clear.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Judgement comment: it is not explicitly stated that the nurses assessing the cold symptoms were blinded to treatment group, however the key was held by a pharmacist from an outside primary healthcare centre.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no participants were lost to follow‐up.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no protocol or trial registration available.
Other bias	Low risk	Judgement comment: no other apparent source of bias.