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Table 4 Main effects (time) and significant predictors for changes over time (within-subjects effects) in Plasmodium parasitaemia, clinical, physical and cognitive outcomes after deworming from population-averaged GEE and random effects tobit analysis

From: Effect of deworming on school-aged children’s physical fitness, cognition and clinical parameters in a malaria-helminth co-endemic area of Côte d’Ivoire

Model by outcome Predictor Change
Logistic models (binary outcomes)   OR (95% CI)
Cognition   
  Change in low performance in digit span test Time 0.27 (0.16, 0.46)*
Negative binomial model (count data) Predictor IRR (95% CI)
Plasmodium parasitaemia Time 0.84 (0.55, 1.29)
  S. mansoni 6.37 (1.94, 20.88)
  Hookworm 0.19 (0.05, 0.79)
  Anaemia status (no longer anaemic) 0.18 (0.07, 0.51)
Linear models (continuous outcomes) Predictor Coefficient (95% CI)
Clinical status §   
  Change in Hb level (g/l) Time 0.76 (−2.91, 4.43)
  Plasmodium parasitaemia (1,000+) 5.16 (0.87, 9.44)
  Change in H/A Z-score (stunting) Time −0.19 (−0.32, −0.06)*
  Age group (10–14 years) 0.14 (0.02, 0.26)
  Change in BMI/A Z-score (wasting) Time 0.30 (−0.01, 0.60)
Weight gain (kg) Time 0.88 (0.31, 1.45)*
  Sex (female) 0.73 (0.07, 1.39)
  S. mansoni intensity (++/+++) 1.06 (0.19, 1.92)
Physical fitness §   
  Change in VO2 max (ml kg−1 min−1) Time 1.01 (−0.31, 2.33)
  Sex (female) −1.40 (−2.56, −0.24)
  S. mansoni intensity (+) −1.58 (−2.99, −0.16)
  Stunting severity (↑) −2.65 (−4.52, −0.79)
  Change in hand grip strength (kg) Time 1.45 (0.71, 2.18)*
  Anaemia status (new anaemia case) −1.59 (−3.05, −0.13)
  Change in standing broad jump (cm) Time 13.84 (10.67, 17.01)*
  Anaemia status (constantly anaemic) −5.71 (−11.42, −0.00)
Tobit model (censored count data) Predictor Coefficient (95% CI)
Cognition   
  Change in code transmission score Time −0.87 (−2.25, 0.50)
  Sex (female) 2.07 (0.73, 3.41)
  Helminth infection intensity (+) 2.02 (0.52, 3.52)
  1. (+) = light intensity infection, (++/+++) = moderate or heavy intensity infection, (↑) = higher severity at follow-up.
  2. Reference groups of explanatories: age group = 5–9 years; sex = male; intestinal parasites at baseline (status or intensity) = non-infected with a particular species; Plasmodium parasitaemia at baseline = parasitaemia below 1,000 parasites/μl of blood; anaemia status = constantly not anaemic; stunting severity = unchanged severity.
  3. §Fixed explanatories for clinical and physical fitness outcomes: age, sex, socioeconomic status and anaemia.
  4. †Fixed explanatories for cognition outcomes: sex, school grade and socioeconomic status. Not predetermined predictors were kept at a significance level of 0.20.
  5. *Significant change over time (p < 0.05).
  6. The different types of models used according to the outcome variables are highlighted in bold.
  7. The study was carried out in Niablé, eastern Côte d’Ivoire between December 2012 and May 2013. Data from 219 children (112 girls, 107 boys) with complete baseline and end-of-study follow-up were considered.