***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objective : To evaluate the effect of simultaneous zinc and vitamin A supplementation on  diarrhoea and acute lower respiratory infections in children . Study design : R and omised double blind placebo controlled trial . Setting : Urban slums of Dhaka , Bangladesh . Participants and methods : 800 children aged 12 - 35 months were r and omly assigned to one of four intervention groups : 20 mg zinc once daily for 14 days ; 200 000 IU vitamin A , single dose on day 14 ; both zinc and vitamin A ; placebo . The children were followed up once a week for six months , and morbidity information was collected . Results : The incidence and prevalence of diarrhoea were lower in the zinc and vitamin A groups than in the placebo group . Zinc and vitamin A interaction had a rate ratio ( 95 % confidence interval ) of 0.79 ( 0.66 to 0.94 ) for the prevalence of persistent diarrhoea and 0.80 ( 0.67 to 0.95 ) for dysentery . Incidence ( 1.62 ; 1.16 to 2.25 ) and prevalence ( 2.07 ; 1.76 to 2.44 ) of acute lower respiratory infection were significantly higher in the zinc group than in the placebo group . The interaction term had rate ratios of 0.75 ( 0.46 to 1.20 ) for incidence and 0.58 ( 0.46 to 0.73 ) for prevalence of acute lower respiratory infection . Conclusions : Combined zinc and vitamin A synergistically reduced the prevalence of persistent diarrhoea and dysentery . Zinc was associated with a significant increase in acute lower respiratory infection , but this adverse effect was reduced by the interaction between zinc and vitamin A. What is already known on this topic Trials of vitamin A supplementation have failed to show a beneficial effect on morbidity in children Experimental studies have shown that , in the presence of zinc deficiency , vitamin A supplementation fails to reverse vitamin A deficiency Coexistence of deficiencies of zinc and vitamin A could be a reason for the failure of vitamin A supplementation , but data in humans are limited What this paper adds Combined zinc and vitamin A supplementation is more effective in reducing persistent diarrhoea and dysentery than either vitamin A or zinc alone Zinc alone increased respiratory illnesses , but interaction between zinc and vitamin A reduced this adverse Poor micronutrient status is associated with diarrheal illness , but it is not known whether low folate and /or cobalamin status are independent risk factors for diarrhea . We measured the association between plasma folate and cobalamin  and subsequent diarrheal morbidity  in a prospect i ve cohort study of 2296 children aged 6 - 30 mo in New Delhi , India . Plasma concentrations of  folate , cobalamin , total homocysteine ( tHcy )  , and  methylmalonic acid  were determined at baseline . Whether a child had diarrhea was recorded during weekly visits in a 4-mo zinc supplementation trial . Diarrhea episodes lasting < 7 , ≥7 , and ≥14 d were classified as acute , prolonged , and persistent , respectively . There was a total of 4596 child periods with acute , 633 with prolonged , and 117 with persistent diarrhea during follow-up . Children with plasma folate concentrations in the lowest quartile had higher odds of persistent diarrhea than children in the other quartiles [ adjusted OR = 1.77 ( 95 % CI = 1.14 , 2.75 ) ; P = 0.01 ] . This effect differed between boys [ adjusted OR = 2.51 ( 95 % CI = 1.47 , 4.28 ) ] and girls [ adjusted OR = 1.03 ( 95 % CI = 0.53 , 2.01 ) ; P-interaction = 0.030 ] . We found a small but significant association between high plasma tHcy concentration and acute diarrhea [ adjusted OR = 1.14 ( 95 % CI = 1.04 , 1.24 ) ; P = 0.006 ] . Plasma cobalamin concentration was not a predictor of diarrheal morbidity . In conclusion , poor folate status was an independent predictor of persistent diarrhea in this population Background / Objectives : Zinc is an essential micronutrient and deficiency can lead to an increased risk for infectious diseases and growth retardation among children under 5 years of age . We aim ed to estimate disease-specific and all-cause mortality attributable to zinc deficiency . Subject/ Methods : We estimated the prevalence of zinc deficiency in Latin America , Africa and Asia , where based on zinc availability in the diet and childhood stunting rates , zinc deficiency is widespread . The relative risks of death among zinc-deficient children for diarrhea , malaria and pneumonia were estimated from r and omized controlled trials . We used the comparative risk assessment methods to calculate deaths and burden of disease ( measured in disability-adjusted life years , DALYs ) from each of these three diseases attributable to zinc deficiency in these regions . Results : Zinc deficiency was responsible for 453 207 deaths ( 4.4 % of childhood deaths ) , and 1.2 % of the burden of disease ( 3.8 % among children between 6 months and 5 years ) in these three regions in 2004 . Of these deaths , 260 502 were in Africa , 182 546 in Asia and 10 159 in Latin America . Zinc deficiency accounted for 14.4 % of diarrhea deaths , 10.4 % of malaria deaths and 6.7 % of pneumonia deaths among children between 6 months and 5 years of age . Conclusions : Zinc deficiency contributes to substantial morbidity and mortality , especially from diarrhea .  Zinc supplementation provided as an adjunct treatment for diarrhea may be the best way to target children most at risk of deficiency Background Vitamin A and zinc are crucial for normal immune function , and may play a synergistic role for reducing the risk of infection including malaria caused by Plasmodium falciparum . Methods A r and omized , double-blind , placebo-controlled trial of a single dose of 200 000 IU of vitamin A with daily zinc supplementation was done in children of Sourkoudougou village , Burkina Faso . Children aged from 6 to 72 months were r and omized to receive a single dose of 200 000 IU of vitamin A plus 10 mg elemental zinc , six days a week ( n = 74 ) or placebo ( n = 74 ) for a period of six months . Cross-sectional surveys were conducted at the beginning and the end of the study , and children were evaluated daily for fever . Microscopic examination of blood smear was done in the case of fever ( temperature ≥37.5 ° C ) for malaria parasite detection . Results At the end of the study we observed a significant decrease in the prevalence malaria in the supplemented group ( 34 % ) compared to the placebo group ( 3.5 % ) ( p < 0.001 ) . Malaria episodes were lower in the supplemented group ( p = 0.029 ) , with a 30.2 % reduction of malaria cases ( p = 0.025 ) . Time to first malaria episode was longer in the supplemented group ( p = 0.015 ) . The supplemented group also had 22 % fewer fever episodes than the placebo group ( p = 0.030 ) . Conclusion These results suggest that combined vitamin A plus zinc supplementation  reduces the risk of fever and clinical malaria episodes among children , and thus may play a key role in malaria control strategies for children in Africa Despite concerns over the neurocognitive effects of micronutrient deficiencies in infancy , few studies have examined the effects of micronutrient supplementation on specific cognitive indicators . This study investigated , in 2002 , the effects of iron-folic acid and /or zinc supplementation on the results of Fagan Test of Infant Intelligence ( FTII ) and the A-not-B Task of executive functioning among 367 Nepali infants living in Sarlahi district . Infants were enrolled in a cluster-r and omized , placebo-controlled clinical trial of daily supplementation with 5 mg of zinc , 6.25 mg of iron with 25 µg of folic acid , or zinc-iron-folic acid , or placebo . These were tested on both the tasks using five indicators of information processing : preference for novelty ( FTII ) , fixation duration ( FTII ) , accelerated performance ( ≥85 % correct ; A-not-B ) , deteriorated performance ( < 75 % correct and > 1 error on repeat-following-correct trails ; A-not-B ) , and the A-not-B error ( A-not-B ) . At 39 and 52 weeks , 247 and 333 infants respectively attempted the cognitive tests ; 213 made an attempt to solve both the tests . The likelihood of females completing the A-not-B Task was lower compared to males when cluster r and omization was controlled [ odds ratio=0.67 ; 95 % confidence interval 0.46 - 0.97 ; p<0.05 ] . All of the five cognitive outcomes were modelled in linear and logistic regression . The results were not consistent across either the testing sessions or the information-processing indicators . Neither the combined nor the individual micronutrient supplements improved the performance on the FTII or the A-not-B Task ( p>0.05 ) . These findings suggest that broader interventions ( both in terms of scope and duration ) are needed for infants who face many biological and social stressors Controversy exists about the effect of zinc on growth and the GH-IGF system .  Zinc supplementation has been shown to stimulate linear growth in zinc-deficient children . However the mechanism of this effect has not been well characterized . Furthermore , the effect of zinc supplementation on non-zinc-deficient short children is unknown . We investigated the effect of zinc supplementation on endogenous GH secretion , serum IGF-I and IGFBP-3 concentrations , IGF-I and IGFBP-3 generation in response to exogenous GH , bone formation markers , and linear growth of non-zinc-deficient children with idiopathic short stature . We analyzed prospect ively serum zinc , IGF-I , IGFBP-3 , alkaline phosphatase , osteocalcin , and GH response to clonidine test  , and performed a somatomedin generation test before and 6 weeks after zinc supplementation in 22 ( 16 M , 6 F ) prepubertal children with idiopathic short stature .  Serum IGF-I increased from 67.4+/-70.6 to 98.2+/-77.3 ng/ml ( p < 0.001 ) , IGFBP-3 from 2326+/-770 to 2758+/-826 ng/ml ( p < 0.001 ) , alkaline phosphatase from 525+/-136 to 666+/-197 U/l ( p < 0.0001 ) , and osteocalcin from 16.8+/-10.6 to 25.8+/-12.8 ng/ml ( p < 0.05 ) after zinc supplementation despite there being no difference in GH response to clonidine after zinc supplementation ( peak GH 11.6+/-6.9 vs 13.4+/-7.8 ng/ml , GH area under the curve during clonidine test 689+/-395 vs 761+/-468 , NS ) . Percent change in IGF-I and IGFBP-3 during the somatomedin generation test was not significantly affected by zinc supplementation ( 118 % vs 136 % and 57 % vs 44 % , respectively ) . There was no significant correlation between percentage increase in zinc levels and percentage increase in parameters tested . Height SDS or weight SDS did not improve significantly in 17 patients who continued on zinc supplementation for at least 6 months ( 6 - 12 months ) ( -2.59 vs -2.53 SDS and -1.80 vs -1.67 SDS , respectively ) . Zinc supplementation increased basal IGF-I , IGFBP-3 , alkaline phosphatase and osteocalcin without changing GH response to clonidine . Zinc supplementation did not affect sensitivity to exogenous GH as tested by IGF-I and IGFBP-3 generation test . These results suggest a direct stimulatory effect of zinc on serum IGF-IGFBP-3 , alkaline phosphatase and osteocalcin . Despite improvements in the above parameters , zinc supplementation to children with idiopathic short stature with normal serum zinc levels did not significantly change height or weight SDS during 6 - 12 months follow-up Summary Background In north India , vitamin A deficiency ( retinol < 0·70 μmol/L ) is common in pre-school children and 2–3 % die at ages 1·0–6·0 years . We aim ed to assess whether periodic vitamin A supplementation could reduce this mortality . Methods Participants in this cluster-r and omised trial were pre-school children in the defined catchment areas of 8338 state-staffed village child 
    Output:
    
There was a medium to large positive effect on zinc status .
We found no clear evidence of benefit or harm of supplementation with regard to haemoglobin or iron status .
Supplementation had a negative effect on copper status .
AUTHORS ' CONCLUSIONS In our opinion , the benefits of preventive zinc supplementation outweigh the harms in areas where the risk of zinc deficiency is relatively high .