Knowing the target for neglected tropical disease programs: identifying systematic differences between school-attending and non-school-attending children in Amhara region, Ethiopia.

School-age children are often targeted by neglected tropical disease (NTD) programs. In areas where school attendance is low, the population of school-age children may not be homogeneous, with differences between school-attending and non-school-attending children. We aimed to identify whether systematic differences between school-attending and non-school-attending children exist in Amhara National Regional State in Ethiopia, where school attendance is approximately 60%. Methods: We conducted a cross-sectional, cluster random survey of school-age children aged 6-15 years. Potential differences between school and non-school children recorded were: demographics, trachoma clinical signs and intestinal parasitic infections, anthropometric measurements, knowledge and behaviors regarding trachoma control and hygiene activities and household characteristics. Stool specimens were collected. Principal Findings: 2,711 school-age children were recruited of whom 2,468 (91.0%) from 106 communities in 20 districts provided assent and all data. Reported school attendance was 58.5% (95% confidence interval (CI): 54.5-62.4). School-attending children were older (odds ratio (OR)=1.42, 95% CI: 1.33-1.51), more likely to be female (OR=1.42, 95% CI: 1.15-1.76), live with their birth parents (OR=2.49, 95% CI: 1.30-4.77), present with less trachomatous inflammation-follicular (TF; OR=0.55, 95% CI: 0.37-0.81), have lower body-mass-index-for age (OR=1.86, 95% CI: 1.36-2.55), reside in households with higher socio-economic status (OR=1.94, 95% CI: 1.46-2.56), have heard about trachoma (OR=3.87, 95% CI: 2.70-5.54), report more frequent face washing (OR=2.74, 95% CI: 1.76-4.25), hand washing after defecation (OR=3.49, 95% CI: 2.16-5.64) and latrine use (OR=2.29, 95% CI: 1.80-2.92). Adjusting for age and sex, there were no significant differences in presentation of TF or intestinal parasitic infections between school-attending and non-school-attending children. Conclusions: Systematic differences exist between school-attending and non-school-attending children. Control strategies for NTDs should include interventions specifically targeted to school-attending and non-school-attending children, as they are different populations and consequently require unique approaches to maximize coverage to each group.