Main outcome definition and covariables

The main outcome was growth retardation including underweight, stunting or wasting defined at each visit using anthropometric indices as weight-for-age (WAZ) <-2, weight-for-length (WLZ) <-2, and length-for-age (LAZ) <-2 Z-scores respectively (7, 14). Z-score was calculated using the 2006 WHO growth standard [19].

Prior to the data analysis, a number of variables were recoded. Thus, the mother’s marital status was recoded in married, cohabitation and single/divorced/widow; the level of household income in <100,000 CFA francs and ≥100,000; the level of CD4 in <25% and ≥ 25%. The hemoglobin level was recoded according to the 2011 WHO criteria [20] as follows: not anemia (≥ 11 g / dl in children aged 0–24 months and ≥ 10 g / dl in in children aged 24–60 months), mild or moderate anemia (7 to 10.9 g / dl in children aged 0–24 months and 7–9.9 g / dl in children aged 24–60 months), and severe anemia (<7 g / dl). Sign of systemic involvement was defined at each visit by the presence of one or more of the following signs: fever, jaundice, hepatomegaly, adenopathy or parotitis. Chronic pathologies refers to a persistent pathologic condition observed or notified since the last visit (tuberculosis, sickle cell disease, malformations, chronic skin disease, etc.). Small for gestational age and gender (SGAG) defined as previously [21] as a birth weight Z-score adjusted for gestational age at delivery and gender that is more than two standard deviations below the mean (-2SD) and small birth size by any height Zscore < -2SD, in line with international recommendations [22].