Table 3

Possible causalities between malnutrition and learning capacities

 Causality between two variables Three conditions for a causality Possible causality (Condition 1)Bivariate analysis:Crude covariational relationship (Condition 2) Multivariate analysis: Covariational relationship through controlling for third variables (Condition 3) Temporal precedence Causal path A: on mathematical proficiency (Step 1)From not being stunted to attendance rate Yes P=0.003* Mann-Whitney U test* Yes P=0.041* Ordinal regression¶ Yes While stunting is chronic undernutrition that occurs generally before 3 years of age,24 school attendance takes place after enrolment at 5 or 6 years of age at primary schools. Thus, clearly, school attendance follows becoming stunted. Yes (Step 2)From attendance rate to mathematical proficiency Yes P=0.013* Spearman’s correlation† Yes P=0.014* Ordinal regression‡ Yes Without attending schools, children cannot take mathematics examinations. Thus, clearly, mathematical proficiency follows attendance. Yes Causal path B: on national language proficiency (Step 1)From not being thin to attendance rate No P=0.141 Mann-Whitney U test* Yes P=0.020* Ordinal regression¶ Not necessarily Thinness is acute undernutrition that can occur after attendance at school, too. Thus, school attendance does not necessarily follow becoming thin. No (Step 2)From attendance rate to national language proficiency No P=0.104 Spearman’s correlation (rs)† No P=0.483 Ordinal regression§ Yes Without attending schools, children cannot take national language examinations. Thus, national language proficiency follows attendance. No
• *See figure 2.

• †See figure 3.

• ‡Coefficient estimate for not being stunted in multiple regression model with attendance rate (%) and other all background variables as dependent and independent variables, respectively.

• §Coefficient estimate for not being thin in multiple regression model with attendance rate (%) and other all background variables as dependent and independent variables, respectively.

• ¶See table 2.

• ** * P <0.05