Isolated and combined risks for anemia in children attending the nurseries of daycare centers

Objective: To identify and quantify isolated and combined risk factors for anemia, providing a comprehensive view of the likelihood of its occurrence. Methods: Cross-sectional study with 482 children aged 4 to 29 months attending the nurseries of philanthropic and public daycare centers in the city of Sao Paulo, Brazil, who participated in two surveys (2004 and 2007). Mothers were interviewed, blood was collected using digital puncture, and anthropometry was performed. Anemia was characterized by hemoglobin levels below 11 g/dL. Unconditional logistic regression was adjusted for anemia risk factors. A value of p <= 0.05 indicated statistically significant associations. Post-test odds and likelihood ratios were calculated to define post-test probabilities. Epi-Info (TM) 2000 and Stata 10.0 software packages were used for statistical analysis. Results: Prevalence of anemia was 43.6% (95% CI 39.1-48.1). The final logistic model included five categorical variables: mother's age less than 28 years (OR = 1.50; p = 0.041), per capita income below half a minimum wage (OR = 1.56; p = 0.029), exclusive breastfeeding less than 2 months (OR = 1.71; p = 0.009), decrease in weight/age z score from birth to survey (OR = 1.47; p = 0.050), and age less than 17 months (OR = 2.44; p < 0,001). Post-test probabilities in the associations of isolated and combined risk factors for anemia ranged from 54.5 to 100%. Conclusions: The probability of anemia progressively increased as the identified risk factors were added. This calculation provides a simple and rapid tool for suspicion of anemia in children both in clinical practice and population screening.