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Study nameRisk ratio [95% CI]RR Point estimateWeight in random-effects modelPercent of mortality from measlesPercent of mortality from diarrheaPercent of mortality from measles + diarrheaPercent of mortality from nutritional deficienciesPercent of mortality from infectious diseasesBaseline / control group VAD prevalence estimate in population studiedWhat would GiveWell predict for the effect size, given our model and these inputs?VAD prevalence estimate sourcesVAD prevalence estimate notes (see note on previous cell for sources)
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Agarwal 19951.22 [0.66, 2.25]1.224.0%9.51%18.50%28.01%11.48%74.28%62.5%0.78
Agarwal 1995; Stevens et al. 2015, WHO Global Prevalence of Vitamin A Deficiency 1995
Agarwal 1995 found that 3.2% of children participating in the study were diagnosed with xerophthalmia (see note on previous cell). Stevens et al. 2015 estimates that the prevalence of VAD among preschool-aged children in South Asia in 1991 was 47% (95% CI 14–78). Based on the relatively high xerophthalmia rates found among trial participants (see classification of xerophthalmia prevalence on Table 5, Pg. 9 of WHO Global Prevalence of Vitamin A Deficiency 1995), we roughly guess that VAD rates were halfway between Stevens et al. 2015's point estimate and upper bound for the prevalence of VAD among preschool-aged children in South Asia in 1991 (see cell formula).
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Barreto 19941.00 [0.14, 7.08]1.000.5%0.01%28.39%28.40%9.47%54.77%54.7%0.82WHO Global Prevalence of Vitamin A Deficiency 1995
The survey referenced in WHO Global Prevalence of Vitamin A Deficiency 1995 took place in 1989, and took place in the same region of Brazil as the VAS trial. It is not clear whether the children sampled for the VAD survey later participated in the VAS trial. We have not viewed documents on the original survey or investigated its methodology.
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Benn 19970.46 [0.14, 1.47]0.461.4%23.61%17.16%40.77%6.45%80.24%45%0.78
Benn et al. 1997; WHO Global Prevalence of Vitamin A Deficiency 1995; Stevens et al. 2015
Benn et al. 1997 reports that no cases of xerophthalmia among program participants at baseline were found. WHO Global Prevalence of Vitamin A Deficiency 1995 does not include any data on Guinea-Bissau, but notes "VAD likely." We use the point estimate from Stevens et al. 2015 of the prevalence of VAD among preschool-aged children in sub-Saharan Africa in 1991 as our estimate.
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Chowdhury 20020.14 [0.03, 0.63]0.140.9%9.51%18.50%28.01%11.48%74.28%47%0.83Stevens et al. 2015
We have not been able to find a full paper on Chowdhury et al. 2002. We use Stevens et al. 2015's point estimate for the prevalence of VAD in South Asia in 1991 as our estimate.
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Daulaire 19920.74 [0.55, 0.99]0.748.9%14.59%18.92%33.51%10.14%77.41%78%0.68Daulaire et al. 1992; Stevens et al. 2015.
Daulaire et al. 1992 reports a very high rate of xerophthalmia in the region. We have used the high-end estimate for VAD prevalence in South Asia in 1991 from Stevens et al. 2015 as our estimate.
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DEVTA trial 20130.96 [0.89, 1.03]0.9613.6%9.51%18.50%28.01%11.48%74.28%64.8%0.77DEVTA trial 2013
DEVTA reports that 64.8% of children in the control group who underwent biomedical visits were VAD (retinol <0.70 μmol/L) and 13.3% were severely VAD (retinol <0.35 μmol/L).
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Dibley 19960.33 [0.01, 7.99]0.330.2%14.03%20.93%34.96%2.81%74.01%56.8%0.76Dibley 1996
Measured prevalence of VAD (serum retinol concentrations <0.70μmol/L) among placebo group participants.
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Donnen 19980.60 [0.23, 1.55]0.602.0%8.50%9.57%18.07%5.08%80.84%70.9%0.81Donnen 1998
Measured prevalence of VAD (serum retinol concentrations <0.70μmol/L) among control group participants at baseline.
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Fisker 20140.93 [0.66, 1.31]0.937.9%23.61%17.16%40.77%6.45%80.24%54.7%0.74
WHO, Global prevalence of vitamin A deficiency in populations at risk 1995–2005, 2009
We use WHO's estimate of the prevalence of VAD among preschool-aged children in Guinea-Bissau, 1995-2005.
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Herrera 19921.06 [0.82, 1.37]1.069.8%24.54%16.73%41.27%3.44%64.93%53%0.75
Herrera 1992; Stevens et al. 2015, WHO Global Prevalence of Vitamin A Deficiency 1995
Herrera et al. 1992 reports that 3% of preschool-aged children initially enrolled were diagnosed with xerophthalmia. Stevens et al. 2015 estimates that the prevalence of VAD among preschool-aged children in Sub-Saharan Africa in 1991 was 45% (95% CI 29–60). Based on the relatively high xerophthalmia rates found among trial participants (see classification of xerophthalmia prevalence on Table 5, Pg. 9 of WHO Global Prevalence of Vitamin A Deficiency 1995), we roughly guess that VAD rates were halfway between Stevens et al. 2015's point estimate and upper bound for the prevalence of VAD among preschool-aged children in sub-Saharan Africa in 1991 (see cell formula).
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Pant 19960.57 [0.37, 0.88]0.576.2%14.59%18.92%33.51%10.14%77.41%47%0.81Stevens et al. 2015
No information on baseline or control group rates of xerophthalmia or serum retinol concentrations available in Pant 1996. No serum retinol surveys from Nepal reported in WHO Global Prevalence of Vitamin A Deficiency 1995. We use the point estimate for the prevalence of VAD among preschool-aged children in South Asia in 1991 from Stevens et al. 2015 as our estimate.
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Rahmathullah 19900.46 [0.30, 0.71]0.466.3%9.51%18.50%28.01%11.48%74.28%47%0.83Stevens et al. 2015
No information on baseline or control group rates of xerophthalmia or serum retinol concentrations available in Rahmathullah 1990. Rahmathullah 1990 does not state when the trial took place, but we would guess it occurred in the late 1980s. We use the point estimate for the prevalence of VAD among preschool-aged children in South Asia in 1991 from Stevens et al. 2015 as our estimate.
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Ross 1993 HEALTH0.30 [0.12, 0.74]0.302.1%10.62%33.61%44.23%6.56%83.79%73%0.62Ross et al. 1993
Ross et al 1993 reports measuring serum retinol levels at baseline.
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Ross 1993 SURVIVAL0.81 [0.67, 0.97]0.8111.5%10.62%33.61%44.23%6.56%83.79%57%0.70Ross et al. 1993
Ross et al 1993 reports measuring serum retinol levels at baseline.
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Sommer 19860.73 [0.54, 1.00]0.738.7%7.63%17.78%25.41%5.57%64.57%60%0.81Sommer et al. 1986
We have not seen any data on rates of vitamin A deficiency in Indonesia in the early 1980s. Given a high rate of xerophthalmia, we roughly guess that VAD rates may have been around 60%.
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Venkatarao 19960.37 [0.10, 1.37]0.371.1%9.51%18.50%28.01%11.48%74.28%47%0.83Stevens et al. 2015
No information on baseline or control group rates of xerophthalmia or serum retinol concentrations available in Venkatarao 1990. We use the point estimate for the prevalence of VAD among preschool-aged children in South Asia in 1991 from Stevens et al. 2015 as our estimate.
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Vijayaraghavan 19901.02 [0.57, 1.82]1.024.3%9.51%18.50%28.01%11.48%74.28%47%0.83Stevens et al. 2015
No information on baseline or control group rates of xerophthalmia or serum retinol concentrations available in Vijayaraghavan 1990. We use the point estimate for the prevalence of VAD among preschool-aged children in South Asia in 1991 from Stevens et al. 2015 as our estimate.
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West 19910.70 [0.56, 0.88]0.7010.5%14.59%18.92%33.51%10.14%77.41%63%0.74
Stevens et al. 2015, WHO Global Prevalence of Vitamin A Deficiency 1995
West 1991 found that 3.0% of children participating in the study were diagnosed with xerophthalmia (see note on previous cell). Stevens et al. 2015 estimates that the prevalence of VAD among preschool-aged children in South Asia in 1991 was 47% (95% CI 14–78). Based on the relatively high xerophthalmia rates found among trial participants (see classification of xerophthalmia prevalence on Table 5, Pg. 9 of WHO Global Prevalence of Vitamin A Deficiency 1995), we roughly guess that VAD rates were halfway between Stevens et al. 2015's point estimate and upper bound for the prevalence of VAD among preschool-aged children in South Asia in 1991 (see cell formula).
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Lin 2008Not estimableNot estimable0%N/AN/A
Lin 2008 has no weight in the meta-analysis, so we have not attempted to find information on baseline VAD rates.
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Overall-random effects13.51%20.16%33.67%8.53%75.13%58.92%
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