Multivariable GEE modeling of self-reported total HrQoL scores adjusting for measured covariates^a.

In each case, the initial model of PedsQL SF15 score included the following explanatory variables: sex, age group, village type (high- vs. lower-endemicity), socioeconomic standing, current Schistosoma infection, current hookworm infection, anemia, presence of growth stunting, and nutritional wasting. Generalized multivariable linear modeling, adjusted for covariance at the village level using GEE estimation (SPSS) used stepwise backward removal of non-significant variables to create ‘best fit’ parsimonious models (based on information criteria) retaining explanatory variables with P-values<0.1. Multiply-adjusted parameter estimates are reported (with 95% CI and corresponding P-values) for covariates remaining in the final models. Scale for the HrQoL scale output variable was set at 100, so that the parameter estimates reflect percentage changes in overall HrQoL as estimated by the PedsQL instrument.

Abbreviations: GEE, Generalized Estimating Equations; HrQoL, Health-related quality of life; Sh, Schistosoma haematobium; CI, Confidence Interval; SES, socio-economic standing.

Reference group for comparison was top 50% SES.

Stunting: height-for-age Z score (HAZ) ≤−2.

Wasting: BMI-for-age Z score (BAZ) ≤−2.