Assessment of child feeding practices using a summary index: stability over time and association with child growth in urban Madagascar.

BACKGROUND Previous studies investigating the association between an infant and child feeding index (ICFI) and length-for-age were based on a cross-sectional design and on the assumption that data collected with brief recalls could provide information about more enduring processes. OBJECTIVES The objectives were to test the stability of the individual ICFI values over time and to investigate how they relate to length-for-age z score (LAZ) and weight-for-length z score (WLZ) at the end of the study. DESIGN This prospective cohort study included 363 children aged 6-17 mo who were visited 3 times over 6 mo. A cross-sectional ICFI (CS-ICFI) was constructed for each visit by using data on feeding practices and data from quantitative 24-h recalls. A longitudinal ICFI (L-ICFI) was constructed with use of the 3 CS-ICFIs. The stability of the CS-ICFI was assessed by using the variance of the repeatability coefficient (s(2)r). RESULTS Stability of the CS-ICFI was shown by the value of 0.704 (95% CI: 0.625, 0.805) of the s(2)r, which differed significantly from 1 (P < 0.0001). There was no significant association between the CS-ICFIs and LAZ or WLZ at visit 3. In contrast, when moving from low to high L-ICFI, there was a highly significant 0.5 z score difference in mean LAZ at visit 3 (P = 0.0008). The L-ICFI was not associated with WLZ. CONCLUSIONS The ICFI constructed by using data collected with brief recalls can provide information about feeding in the long term. However, the absence of association with LAZ suggests a lack of precision that can be reduced by using an ICFI based on repeated measurements.