Statistical analysis
depression, anemia
REGRESSION, ANEMIA, REGRESSIONS
The Kolmogorov-Smirnov test was used for testing the normality of the continuous outcome variables. Descriptive statistics were used to report the characteristics of the study population, with frequencies and percentages to describe categorical variables, means, and SDs to describe quantitative variables. Multivariable linear regressions (for continuous outcome) and logistic regression (for binary outcomes) were used to assess the associations between preconception Hb concentration or anemia on birth outcomes, offspring Hb concentration during the first 1000 d, and child development at 12 mo, 24 mo and 6–7 y. Associations were examined as follows: (1) unadjusted; and (2) adjusted for maternal age, ethnicity, education, SES, infant age and sex, intervention group and duration of time prior to conception, infant and young child feeding practices and child illness. Further adjustment for home environment, mother’s IQ, and depression were made in the models with child development at 12 mo and 24 mo and child intellectual development at 6–7 y as the outcomes. Effect modification by the intervention group was evaluated by including interaction terms in all models. In addition, effect modification by home environment was also evaluated by including interaction terms with maternal Hb concentration for models with child development outcomes. All analyses were conducted using Stata v17 (StataCorp, College Station, TX, USA). The significance level was adjusted for multiple testing using a Bonferroni adjustment at each domain level, including a 