Table 2

Validity characteristics of included studies

Random-isation Described/Allocation Concealment

Researcher/Outcome Assessor/Participants Masked to intervention

Change in iron status OR 12+ wks?*

All those randomised included in outcomes?/Reason for dropouts reported?

Potential for funding bias**

Study data useable in meta-analysis?


Beard 2005

Partially/Unclear

Unclear/Unclear/Yes

Yes (SF, 29 wks)

No/Partially

Moderate

Yes


Bruner 1996

Yes/Unclear

Yes/Unclear/Yes

Yes (Hb & SF)

No/Yes

High

No (no raw data, only regression)


Elwood 1970

No/Unclear

Unclear/Yes/Yes

Unclear (p-values not presented)

No/Partially

High

Yes


Gopaldas 1985

Partially/Unclear

No/No/Yes

Anaemic & Iron repl: Yes (Hb)

Yes/Yes (no drop-outs)

High

Yes


Groner 1986

No/Unclear

Yes/Yes/Yes

Yes (Hb)

No/Yes

Moderate

Yes


Kashyap 1987

Partially/Unclear

Unclear/Unclear/Yes

Anaemic & Iron repl: Yes (Hb, 17 wks)

No/Partially

Moderate

Yes


Kordas 2005

Yes/Unclear

Yes/Yes/Yes

Yes (21 wks)

No/Partially

Moderate

No (only z-scores)


Lambert 2002

No/Unclear

Yes/Unclear/Yes

Yes (SF, not Hb)

No/No

Moderate

No (no variance data)


Lynn & Harland 1998

Yes/Unclear

Yes/Yes/Yes

Iron Defic & Iron repl: Yes (16 wks)

Unclear/No

High

Yes


Murray-Kolb 2007

Yes/Unclear

No/Yes/Yes

Anaemic & Iron repl: Yes (SF, not Hb, 16 wks),Iron defic: No (not SF or Hb)

No/Partially

Moderate

No (reported only as z-scores)


Pollitt 1989

No/Unclear

Unclear/Unclear/Yes

Anaemic, Iron defic & Iron repl: Yes (Hb, SF, 16 wks)

No/No

Moderate

Yes


Soemantri 1985

No/Unclear

Unclear/Unclear/Unclear

Anaemic: Yes (Hb, 13 wks)

Iron repl: No (Hb)

Unclear/No

Moderate

No (no variance or SD data)


Soemantri 1989

No/Unclear

Unclear/Unclear/Yes

Anaemic & Iron repl: Yes (Hb, 13 wks)

No/No

Moderate

Yes


Sungthong 2004

Yes/Yes

Yes/Yes/Yes

Yes (SF & Hb, 16 wks)

No/Yes

Low

Yes


* Iron status was said to have changed if there were statistically significant differences in Hb or SF between iron and placebo groups at the end of the study or, where no data were provided, if the intervention period was at least 12 weeks long.

** Potential for funding bias was assessed as follows: low (when funders were clearly not industry-related, no authors worked for industry and there was no suggestion that products were donated by industry); high (when non-industry funding was reported, or when funding was not mentioned); moderate in all other studies.

Falkingham et al. Nutrition Journal 2010 9:4   doi:10.1186/1475-2891-9-4

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