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. 2019 Oct 3;9(10):e026449. doi: 10.1136/bmjopen-2018-026449

Table 2.

Summary results of meta-analysis of associations of parental factors and cognitive, motor and language developments

Risk factor Cognitive Motor Language
No of studies Adjusted*
SMD (95% CI)
P value I2 (%) No of studies Adjusted*
SMD (95% CI)
P value I2 (%) No of studies Adjusted*
SMD (95% CI)
P value I2 (%)
Mother's education
No education (<1 years) 15 −0.12 (–0.24 to –0.008) 0.05 50.8 18 −0.07 (–0.13 to –0.01) 0.03 18.2 5 −0.06 (–0.21 to –0.09) 0.49 35.5
Primary (1- <6 years) Reference Reference Reference
Secondary (6- <10 years) 17 0.14 (0.05 to 0.24) <0.01 59.7 19 0.12 (0.06 to 0.18) <0.01 51.8 5 0.13 (0.04 to 0.21) 0.04 0.0
Higher (≥10 years) 17 0.36 (0.19 to 0.48) <0.01 65.8 19 0.26 (0.14 to 0.38) <0.01 70.6 5 0.21 (0.09 to 0.33) 0.03 0.0
Father's education
No education (<1 years) 13 −0.005 (–0.08 to 0.07) 0.91 0.0 17 −0.08 (–0.11 to –0.04) <0.01 0.0 4 0.02 (–0.15 to 0.20) 0.80 30.0
Primary (1- <6 years) Reference Reference Reference
Secondary (6- <10 years) 15 0.06 (0.015 to 0.11) 0.02 0.0 17 0.08 (0.03 to 0.13) <0.01 30.3 4 0.09 (0.02 to 0.16) 0.08 0.0
Higher (≥10 years) 15 0.15 (0.08 to 0.21) <0.01 0.0 17 0.18 (0.10 to 0.26) <0.01 42.3 4 0.22 (0.11 to 0.32) 0.03 17.9
Mother's age (years)
<15 5 −0.06 (–0.13 to 0.25) 0.57 0.0 5 0.12 (–0.06 to 0.30) 0.25 0.0 2 n/a n/a n/a
15- <20 years 18 −0.007 (–0.06 to 0.05) 0.80 10.7 20 −0.02 (–0.11 to 0.08) 0.75 83.6 6 0.01 (–0.09 to 0.11) 0.85 37.0
20–34 years Reference Reference Reference
≥35 years 18 −0.01 (–0.06 to 0.04) 0.58 0.0 20 −0.006 (–0.07 to 0.05) 0.85 50.1 6 0.02 (–0.05 to 0.09) 0.59 0.0
Mother's height
<145 cm 11 −0.10 (–0.20 to –0.004) 0.07 0.0 13 −0.11 (–0.19 to –0.03) 0.02 21.5 5 −0.11 (–0.31 to 0.09) 0.35 0.0
145- <150 cm 13 −0.11 (–0.19 to –0.02) 0.03 27.1 15 −0.07 (–0.16 to 0.03) 0.17 71.1 5 −0.06 (–0.13 to 0.06) 0.52 0.0
150- <155 cm 13 −0.09 (–0.14 to –0.04) <0.01 3.3 15 −0.04 (–0.09 to 0.009) 0.14 31.5 5 −0.05 (–0.12 to 0.02) 0.22 0.0
>155 cm Reference Reference Reference
Mother's BMI (kg/m2)
<18.5 11 −0.11 (-0.20 to -0.02) 0.03 12.7 13 −0.02 (-0.11 to 0.07) 0.69 51.4 3 n/a n/a n/a
18.5- <25 Reference Reference Reference
25- <30 12 0.03 (-0.04 to 0.09) 0.44 23.3 14 0.04 (-0.03 to 0.11) 0.31 64.6 4 −0.04 (-0.21 to 0.13) 0.70 61.0
≥30 12 −0.02 (-0.17 to 0.14) 0.82 46.3 14 −0.02 (-0.14 to 0.10) 0.77 63.6 4 −0.14 (-0.34 to 0.06) 0.26 35.9
Mother's haemoglobin level (g/L)
Normal (≥110 g/L)) Reference Reference Reference
Mild anaemia (100–109 g/L) 4 −0.06 (-0.15 to 0.03) 0.28 0.0 11 0.06 (0.008 to 0.11) 0.04 29.7 1 n/a n/a n/a
Moderate anaemia
(70–99 g/L)
4 −0.06 (-0.19 to 0.06) 0.39 0.0 6 −0.01 (-0.06 to 0.04) 0.68 16.3 1 n/a n/a n/a

*Adjusted for child’s gender and age, mother’s education and household wealth.

BMI, body mass index; SMD, standardised mean difference.