Effect of Deworming on Indices of Health, Cognition, and Education Among Schoolchildren in Rural China: A Cluster-Randomized Controlled Trial

Abstract

Abstract. Soil-transmitted helminths (STHs) infect over one billion people worldwide. There is concern that chronic infection with STHs among school-aged children may detrimentally affect their development, including their health, cognition, and education. However, two recent Cochrane reviews examining the impact of deworming drugs for STH on nutrition, hemoglobin, and school performance found that randomized controlled trials (RCTs) in the literature provide an insufficient evidence base to draw reliable conclusions. This study uses a cluster-RCT to add to existing evidence by assessing the impact of a deworming intervention on nutrition, cognition, and school performance among schoolchildren in rural China. The intervention, implemented by local health practitioners in a setting with a baseline infection prevalence of 41.9% (95% confidence interval [CI] = 39.8%, 43.9%) and infection intensity of 599.5 eggs per gram of feces among positive-tested schoolchildren (95% CI = 473.2, 725.8), consisted of distributing a 400-mg dose of albendazole accompanied with educational training about STH infection, treatment, and prevention. The intervention was conducted twice over the course of the study-at baseline in May 2013 and later in November 2013. We found that the deworming intervention reduced both infection prevalence and infection intensity, but these declines in infection were not accompanied by an impact on outcomes of nutrition, cognition, or school performance. Our interpretation is that the impact of deworming was attenuated by the light infection intensity in our sample population. Evidence from future RCTs is needed to assess the effect of deworming on key outcomes in areas with moderate and severe worm infections.

Does Mass Deworming Affect Child Nutrition? Meta-Analysis, Cost-Effectiveness, and Statistical Power

“…For studies that were included in Taylor-Robinson et al (2015), effect sizes and standard errors are taken directly from that meta-analysis, except for the updates described to Awasthi and Pande (2001), Hall et al (2006), andSur et al (2005). The full sample additionally includes several studies that were not included in the TMSDG meta-analysis: Gateff, Lemarinier and Labusquiere (1972), Gupta and Urrutia (1982), Joseph et al (2015), Liu et al (2016), , Ndibazza et al (2012), Ostwald et al (1984), Stephenson et al (1993), Willett, Kilama and Kihamia (1979), and Wiria et al (2013). The point estimate squares are sized according to the weight each study is given in the fixed effect meta-analysis (calculated according to the precision of the study).…”

“…The full sample includes 22 estimates from 20 studies, twice as many as TMSDG. In particular, the full sample includes four studies not identified in TMSDG or unpublished when their review was compiled (Gateff, Lemarinier and Labusquiere 1972;Ostwald et al 1984;Joseph et al 2015;Liu et al 2016); data extracted from six studies discussed by TMSDG but not included in their meta-analysis for the MDA child weight outcome (Willett, Kilama and Kihamia 1979;Ndibazza et al 2012;Wiria et al 2013;Stephenson et al 1993;Gupta and Urrutia 1982); and improved estimates from three studies that are included in the TMSDG meta-analysis (Sur et al 2005;Hall et al 2006;Awasthi and Pande 2001). Note that we classify Stephenson et al (1993) as an MDA trial; the Cochrane authors classify it in this way in their 2012 Review but change the classification system in the 2015 update; we retain the 2012 classification in this analysis.…”

Mass deworming for improving health and cognition of children in endemic helminth areas: A systematic review and individual participant data network meta‐analysis

“…Lanka (Ebenezer et al, 2013), Kenya Miguel & Kremer, 2004;, Vietnam (Hall, Hanh, Farley, Quynh andValdivia, 2006, Le Huong, Brouwer, Nguyen, Burema &Kok, 2007;), China (Liu et al, 2017;Yap et al, 2014), Cote d'Ivoire (Rohner et al, 2010), Bangladesh (Rousham and Mascie-Taylor, 1994), Indonesia (Wiria et al, 2013), Nigeria (Kirwan et al, 2009), Uganda (Ndibazza et al, 2012) and the Philippines (Solon et al, 2003) (Tables 2 and S7).…”

“…Since we considered that the fortified soup and unfortified soup were not randomised, we collapsed across the fortified and unfortified soup conditions, calculating an overall effect for all children randomised to anthelminthics versus placebo (n = 178). Liu et al (2017): We used IPD data provided by the authors. Croke et al (2016) used published mean changes.…”

More Evidence on the Effects of Deworming: What Lessons Can We Learn?

“…In this month's issue, Liu and others present new evidence on the effects of deworming children from a cluster-randomized trial conducted in rural China 1. This was a useful, well-conducted study.…”