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Table 6 Mediation analysis of the estimated effect1 (95% confidence interval, CI) of maternal energy and nutrient intake (per SD increment) on birth outcomes through toenail arsenic2 (ln(μg/g)) (n = 1057), with no energy adjustment

From: Mediating role of arsenic in the relationship between diet and pregnancy outcomes: prospective birth cohort in Bangladesh

  Natural direct effect (95% CI) Natural indirect effect (95% CI) Total effect (95% CI) Percent Mediated (%)3
GA (week)
 Energy4 0.11 (0.01, 0.20)* 0.01 (− 0.01,0.01) 0.11 (0.00, 0.22) *  
 Protein −0.66 (− 0.77, − 0.54) * −0.01 (− 0.041, 0.02) −0.68 (− 0.80, − 0.56) *
 Fat −0.34 (− 0.45, − 0.23) * −0.02 (− 0.04, − 0.00) * −0.36 (− 0.47, − 0.25) * 6% (1–9%)
 Carbohydrate 0.47 (0.36, 0.58) * 0.02 (0.00, 0.03) * 0.49 (0.38, 0.60) * 3% (1–6%)
 Fiber −0.22 (− 0.33, − 0.10) * −0.03 (− 0.05, − 0.01) * −0.24 (− 0.36, − 0.13) * 10% (4–13%)
GWG (g/week)
 Protein −21.2 (− 29.7, − 12.6) * −1.4 (− 3.6, 0.5) −22.5 (− 31.1, − 14.0) *
 Fat −9.5 (− 19.8, − 18.0) * −1.4 (− 3.2, 0.0) −11.3 (− 18.9, − 3.6) * 12% (0–17%)
 Carbohydrate 11.7 (4.1, 19.4) * −1.4 (− 0.5, 2.3) 12.6 (5.0, 20.3) *
 Fiber −11.7 (− 19.4, − 4.1) * −1.4 (− 2.7, 0.0) −13.1 (− 20.7, − 5.4) * 10% (0–13%)
BW (gram)
 Protein −22.8 (−50.4, 4.8) − 2.9 (− 3.6, 9.4) − 19.9 (− 46.7, 6.9)
 Carbohydrate 23.9 (− 0.79, 48.6) − 1.3(− 4.7, 2.1) 22.6 (− 1.9, 47.0)
  1. 1The natural direct effect, natural indirect effect, and total effects reflect the change in gestational age (GA, week), gestational weight gain rate (GWG, g/week), or birth weight (BW, gram) per standard deviation (SD) increase in intake and are measured based on intake change from mean minus 1 SD to mean. Model was adjusted for BMI at the time of enrollment, exposure to environmental tobacco smoke, age, education level, household income level, newborn sex, birth delivery location, birth delivery type, physical activity level during pregnancy, and daily hours spent cooking over an open fire
  2. 2Absolute intake and unadjusted toenail arsenic concentration
  3. 3Percent mediated = (Natural indirect effect/total effect)*100%
  4. 4Controlled for exposure-mediator interaction
  5. *p < 0.01