OBJECTIVES: The aim of the present study was to describe the prevalence of childhood constipation, stool characteristics, and their relationship with toilet training and age of introduction of cow's milk. METHODS: A total of 4231 children born in 2004, from a birth cohort study, were assessed at 12, 24, and 48 months of age, when their mothers provided information on sociodemographic characteristics, bowel habits, toilet training, and age of introduction of cow's milk and other foods. RESULTS: The prevalence of constipation was 27.3% and 31.0% at 24 and 48 months of age, respectively. Among girls, at 48 months of age, it was 34.4% versus 27.4% in boys (P<0.001). The most common features of constipation were scybalous stools (47.7% and 41.0% at 24 and 48 months, respectively), evacuation difficulty (24.3% and 23.1%), and hard stools (17.8% and 34.1%). Toilet training starting before 24 months was associated with constipation at 24 months and its persistence up to 48 months. Among children who did not receive cow's milk in their first year of life, 22% had constipation at 24 months, 22.6% at 48 months, and 8.3% at 24 and 48 months. Among children who started cow's milk before 30 days of life, the respective proportions of children with constipation was 28.2%, 33%, and 12.4%. CONCLUSIONS: The prevalence of constipation increases with age and cannot be detected using only information on evacuation interval. Toilet training before 24 months and introduction of cow's milk before 1 year of age is positively associated with constipation at 24 months and its persistence up to 48 months.
OBJECTIVES: The aim of the present study was to describe the prevalence of childhood constipation, stool characteristics, and their relationship with toilet training and age of introduction of cow's milk. METHODS: A total of 4231 children born in 2004, from a birth cohort study, were assessed at 12, 24, and 48 months of age, when their mothers provided information on sociodemographic characteristics, bowel habits, toilet training, and age of introduction of cow's milk and other foods. RESULTS: The prevalence of constipation was 27.3% and 31.0% at 24 and 48 months of age, respectively. Among girls, at 48 months of age, it was 34.4% versus 27.4% in boys (P<0.001). The most common features of constipation were scybalous stools (47.7% and 41.0% at 24 and 48 months, respectively), evacuation difficulty (24.3% and 23.1%), and hard stools (17.8% and 34.1%). Toilet training starting before 24 months was associated with constipation at 24 months and its persistence up to 48 months. Among children who did not receive cow's milk in their first year of life, 22% had constipation at 24 months, 22.6% at 48 months, and 8.3% at 24 and 48 months. Among children who started cow's milk before 30 days of life, the respective proportions of children with constipation was 28.2%, 33%, and 12.4%. CONCLUSIONS: The prevalence of constipation increases with age and cannot be detected using only information on evacuation interval. Toilet training before 24 months and introduction of cow's milk before 1 year of age is positively associated with constipation at 24 months and its persistence up to 48 months.