This was an experimental-control semi-longitudinal study; an efficacy trial to assess impact of iron-folic acid supplements on cognition.

Sampling: Using accepted procedures, desired sample size was calculated(8), which came to 46 per group. Allowing for dropouts, each study group required about 60 subjects of age 9-13 years; which were available in standards V and VI per school. Thus, four schools were randomly sampled from the sampling universe of 17 schools (all municipal primary schools for girls in the morning shift), and all the consenting girls in Standards V-VI were enrolled. The schools were comparable as regards variables which could independently influence cognition; such as home enviromnent (socio-economic background; slum conditions; parents’ education) and school environment (government schools with similar syllabi and teaching facilities). Prior permission from the Primary School Board, Vadodara and informed consent from the students and their parents were taken.

Intervention: Three schools were randomly decided as experimental schools (ES) and the fourth was the control school (CS)(n=65). The participants in the three ES schools were given IFA tablets (100 mg elemental iron + 0.5 mg folic acid): either once weekly (E1: IFA-1Wkly) (n=94) or twice weekly (E2: IFA-2Wkly) (n=118) or daily (ED: IFA-Daily) (n=81) for one year. The investigators maintained regular supply of IFA, supervised the distribution and recorded compliance in all the schools. The class monitor/class teacher assisted and maintained compliance registers.

Pre-and post-intervention hemoglobin data were collected on all girls. In view of limited working school days, and the time required to conduct four cognitive tests twice in a year; a random 60% sample (n=240) was selected for the tests of cognition. Of these, data of 161 girls was available pre and post intervention; after also excluding girls who had attained menarche prior to or during the study, though they did receive IFA supplements.

At baseline, all the four groups were statistically similar having comparable cognition test scores and Hb levels (P>0.05) (Table I,II). Overall, the mean hemoglobin (Hb) was 11.3 g/dL at baseline, and more than two-third (68.3%) of the girls were anemic (Hb <12 g/dL).

Table I



Change in Mean Hemoglobin (g/dL) Levels After The Intervention

Impact on hemoglobin levels: Each of the intervention groups showed significant higher (P<0.001) Hb increment vs. the controls (Table I), with the mean Hb increment the highest (1.0 g/dL) in the IFA-2Wkly Group. The mean Hb increments among initially anemic girls in all the supplemented groups were higher than those among initially non-anemic girls, with IFA-Daily group showing highest increment (1.9 g/dL) followed closely by IFA-2Wkly (1.6 g/dL).

Impact on cognitive function: Experimental subjects showed higher increments in test scores than controls (Table II). On comparing each group with control by ‘t’ test, the increments in IFA-Daily and IFA-2Wkly were significantly higher than No-IFA, in all the four cognitive function (CF) tests; whereas IFA-1Wkly was significantly higher, only in two of the four tests. Within the intervened groups, in Digit Span and Clerical Task, IFA-Daily and IFA-2Wkly (p<0.05) had significantly better scores than IFA-1Wkly. Overall, IFA-Daily and IFA-2Wkly showed marked improvement in most tests, while IFA-1Wkly consistently showed less improvement in cognitive test scores.

Girls with good compliance showed better improvement in all four tests compared to those with poor compliance. IFA-2Wkly with good compliance was comparable to IFA-Daily in three of the four tests. In IFA-1wkly, even those with good compliance showed less impact than the comparison groups in 2Wkly and IFA-Daily regimens.

(a) Digit Span	(b) Maze Test
(c) Visual Memory Test	(d) Clerical Task
IFA-1Wkly: once weekly IFA supplementation; IFA-2Wkly: twice weekly IFA supplementation; IFA-Daily: daily IFA supplementation Fig. 1 Mean change in cognition test scores in the school girls who gained ³1g/dL vs. <1g/dL hemoglobin after the intervention.

Hemoglobin gain vs cognitive function: Fig.1 reveals that cognitive function scores were higher (though not signficant) among those who gained more than 1 g/dL Hb than those who gained less (P>0.05). Within those who gained higher level of Hb, IFA-2Wkly and IFA-Daily had better improvement in scores than IFA-1Wkly.

Fig.2 depicts the mean change in cognitive function test scores in initially anemic girls.

IFA-1Wkly: Once weekly IFA supplementation; IFA-2Wkly: twice weekly IFA supplementation; IFA-Daily: daily IFA supplementation; No-IFA: Control, no supplementation Fig. 2 Mean change in cognitive function test scores in initially anemic girls.

The findings of this study indicate that daily and twice weekly iron folate supplementation are comparable as regards significant impact on hemoglobin levels as well as cognitive functions of girls in the pubertal phase of development. The once-weekly IFA group consistently performed less satisfactorily in all the cognitive function tests. Further, those intitially anemic and those showing higher Hb gain (atleast 1 g/dL) showed better impact on cognitive function test scores; again more clearly in the daily and twice-weekly dose regimens; with daily showing best impact. This evidence indicates that a higher uptake of iron (more frequent than once-weekly) is needed to lead to cognitive improvements; and the encouraging finding is that twice weekly IFA was consistently comparable to daily IFA in this regard. This finding has important program implications as twice weekly IFA supplement will cost less and be more feasible to deliver to beneficiary girls than daily IFA.

As regards the absorption of iron and reduction of anemia from a physiological perspective, studies reviewed by Hallberg(13) on daily as well as intermittent IFA supplementation reported that six times more iron was absorbed when IFA was given daily than when given weekly and concluded that there was no mucosal block during oral iron therapy in humans. However, he further stated that, if relatively high iron doses were given for a long time to subjects with low grade anemia, then all the doses of iron, all dosage schedules, and all iron preparations will give a similar Hb response. Thus, in the long run, intermittent iron-folate therapy will perhaps have a satisfactory impact on reducing anemia at lower cost and greater compliance. From our study and from literature reviewed(4,14,15), it appears that a long-term supplementation program, whether once or twice weekly, is likely to be as effective as daily IFA with regard to improvements in hemoglobin levels.

This study underscores the importance of reducing anemia to improve cognition by showing that higher the magnitude of gain in Hb, higher the gain in CF test scores. It further indicates that to improve cognition, twice weekly IFA is superior to once weekly IFA and is likely to show a similar impact as daily IFA supplementation. Supervised supplementation, an important aspect of intermittent dosing, is feasible in school settings with active participation of class monitors and teachers.

Contributors: AS collected, analysed and interpreted the data, performed literature review and drafted the manuscript. SJK designed the study, supervised data collection, analysis. She also revised and approved the final manuscript.

Funding: None.

Competing interests: None stated.

1. Erikson KM, Jones B, Beard JL. Altered functioning of dopamine D1 and D2 receptors in brains of iron deficient rats. Physiol Pharmacol Behav 2001; 69: 409-418.