Characteristics of 1,697 study participants stratified by the presence or absence of any soil-transmitted helminth (STH) infection during the first 3 years of life.

P values were calculated using Chi-squared or Student's t tests, as appropriate. Ethnicity ‘other’ represents: mothers; 1,245 Mestizo/6 Indigenous; fathers 1264 Mestizo/6 Indigenous. Socioeconomic status represents tertiles of z scores obtained using a factor analysis. Overcrowding is defined as the number of people living in the household per sleeping room. STH infections were detected using direct saline, Kato-Katz and formol-ether concentration methods. SD – standard deviation. Infection intensities were estimated using the Kato-Katz method. STH infection intensity categories were: A. lumbricoides (light- T. trichiura (light - *Treatments with any of: albendazole, mebendazole, oxantel/pyrantel, piperazine, nitazoxanide, and flubendazole. Numbers of missing values (brackets) were: gestational age (312), maternal ethnicity (6), paternal ethnicity (54), paternal educational level (140), household overcrowding (304), maternal STH infection (9), and paternal STH infection (1100).