Characteristics of included studies [ordered by study ID]
Foo 1996
|
| Methods | Randomised controlled trial, blinding not mentioned
Units of comparison: Villages
Duration: One year
Location: Sarawak |
|
| | Participants | 101 women (15-50 years) and 65 young children (<= 6 years)
Goitre prevalence: (women) 83% (but large consumption of goitrogenic food) |
|
| | Interventions | 1. Iodised salt (47.1±9.7 ppm iodine - unclear if iodate or iodide used) (N=48 women, 33 children)
2. Iodised water (138.6±43.2 µg/l) (N=53 women, 32 children) |
|
| | Outcomes | 1. Urinary iodine excretion
2. Goitre palpation (women only) |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
Hintze 1988
|
| Methods | Randomised controlled trial - not blinded
Units of comparison: Individuals
Duration: Four years
Location: Germany |
|
| | Participants | 334 children (166 female, 168 male), 10 years at the beginning of the study
Goitre prevalence: 30.5% |
|
| | Interventions | 1. Iodised salt (iodate, 20 ppm iodine) (N=146)
2. Plain salt (N=188) |
|
| | Outcomes | 1. Goitre (palpation)
2. Neck circumference
3. Urinary iodine excretion |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
l'Ons 2000
|
| Methods | Prospective controlled study, randomisation unclear, participants were blind to the intervention
Units of comparison: Schools
Duration: Four months
Location: South Africa |
|
| | Participants | 112 school children (7-16 years) (102 at follow-up)
Goitre prevalence: 9.5-28.2% |
|
| | Interventions | 1. Iodised salt (first 2 batches 18 and 12 ppm iodine, last batch (last 4-5 weeks) 53 ppm (unclear if iodide or iodate)) (N=39)
2. Plain salt (N=63) |
|
| | Outcomes | 1. Goitre (palpation)
2. Urinary iodine excretion |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
Romano 1991
|
| Methods | Randomised trial - blinding not mentioned
Units of comparison: Individuals
Duration: Nine months of pregnancy
Location: Italy |
|
| | Participants | 35 pregnant women (27.1±3.8 years)
Goitre prevalence: unknown for the given sample, 41% in the 8-15 year olds in the area |
|
| | Interventions | 1. Iodised salt (20 ppm iodide, i.e. 15.27 ppm iodine) (N=17)
2. Control - plain salt, but not specifically distributed (N=18) |
|
| | Outcomes | 1. Thyroid volume (ultrasono-graphy)
2. Urinary iodine excretion
3. Serum TSH levels |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
Sooch 1965
|
| Methods | Prospective controlled study, randomisation and blinding unclear
Units of comparison: Geographical regions
Duration: Five years
Location: Himalayan endemic goitre belt, Punjab |
|
| | Participants | Over 20,000 villagers, includes specific investigations of school children 5-16 years, boys versus girls, men versus women
Goitre prevalence: 37.6-47% |
|
| | Interventions | 1. Iodised salt (20 ppm KI, i.e. 15.27 ppm iodine) (N over 6000)
2. Plain salt (N over 7000)
3. Iodised salt (25 ppm KIO3, i.e. 14.83 ppm iodine) (N over 6000) |
|
| | Outcomes | 1. Goitre (visual and palpation)
2. [131]I uptake by the thyroid and subsequent excretion |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
Zhao 1999
|
| Methods | Randomised controlled trial, participants not blinded, outcome assessment blinded
Duration: 18 monthsLocation: China |
|
| | Participants | 205 children 8-10 years (50% male)
Goitre prevalence: 26.1-26.5% |
|
| | Interventions | 1. Iodised salt (42.25 g/kg KIO3, 25 ppm iodine) (N=69)
2. Market iodised salt (iodine content varied, 13-47 ppm) (N=68)
3. Market iodised salt (iodine content varied, 13-47 ppm) plus oral iodised oil 400 mg (N=68) |
|
| | Outcomes | 1. Goitre (palpation)
2. Thyroid volume (ultrasonography)
3. Urinary iodine concentration |
|
| | Notes | |
|
| | Risk of bias |
| | Item | Authors' judgement | Description |
| | Allocation concealment? | Unclear | B - Unclear |
|
|
Characteristics of excluded studies [ordered by study ID]
|
| Study | Reason for exclusion |
|---|
| | Carella 2002 | The objective of the trial is to investigate whether the addition of iodized salt to daily diet in thyroidectomized patients for nontoxic goitre could influence the effectiveness of nonsuppressive L-thyroxine (L-T4) therapy on thyroid remnant size after thyroid surgery, was not for preventing IDDs. |
| | Hess 2002 | The comparison in this controlled trial is iodised salt plus iron versus iodised salt alone - so this is not assessing the effects of iodised salt. |
| | Kimball 1937 | Not a prospective controlled study but a case-control study comparing goitre rates in children having used iodised salt and those not having used iodised salt. |
| | Marine 1917/20 | Possibly a prospective controlled study, but the intervention was not iodised salt but a syrup of hydriodic acid or ferrous iodide. |
| | Saowakhontha 1994 | Prospective controlled study comparing iodised fish sauce, iodised salt, iodised water and placebo. The outcome assessed was urinary iodine excretion only, and the values given seem very implausible, by several orders of magnitude. |
| | Scrimshaw 1953 | The intervention was potassium iodide or potassium iodate given as tablets and not in salt. |
| | Simescu 2002 | It's not a randomised controlled trial, but a 'random selection' cross-sectional study and no control group. Also, the intervention was iodised oil combined with iodised salt. |
| | van den Briel 2000 | Although the abstract suggests involvement of iodised salt, the primary intervention of this randomised controlled trial was in fact iodised oil. |
| | Yang 1997 | The comparison in this controlled trial is iodised salt plus sodium selenite versus iodised salt alone - so this is not assessing the effects of iodised salt. |
| | Zhao 2002 | Duplicate publication with Zhao 1999. |
|
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