Case-control study of risk factors for recurrent low hemoglobin level among primary and middle school students

ObjectiveTo explore the risk factors of recurrent low hemoglobin(RLH) level among students from 6 to 13 years old, and to formulate strategies and policies in this regard.

MethodsSurveillance on hemoglobin concentration was conducted among 71 742 students aged from 6 to 13y between 2013-2014 based on the annual physical examination for primary and middle school in Minhang District.Of those students, 670 were diagnosed with low hemoglobin level according to WHO criteria.A 1 ︰ 1 matched case-control study was conducted based on gender, age and school type.Questionnaire surveys for data collection were analyzed using Cox′s proportional hazards regression.

ResultsFactors as pregnancy anemia(OR=2.32, 95%CI:1.49-3.63), non-pregnancy anemia(OR=4.65, 95%CI:1.22-17.69), maternal anemia(OR=2.51, 95%CI:1.50-4.21), drinking strong tea(OR=2.56, 95%CI:1.27-5.13) and dietary bias(OR=1.94, 95%CI:1.45-2.59) were risk factors of recurrent low hemoglobin level.Chewing pencils(OR=1.80, 95%CI:1.25-2.59) or toys(OR=1.79, 95%CI:1.10-2.86) and wasting(OR=3.37, 95%CI:1.11-10.21)might be the risk factors.

ConclusionThe risk factors of recurrent low hemoglobin level among students aged from 6 to 13 years are related to maternal anemia status and their dietary habits.We should strengthen education for women of child-bearing age, and help to develop healthy eating practices for their babies.Emaciated students should be focused on in this regard.