Table 2.
Associations of maternal age at pregnancy with adolescent cognitive development and emotional and behavioural problems in a birth cohort in rural Western China. Higher scores indicated better cognitive development and worse emotional and behavioural problems
| Test scores | Maternal age per year | Q1 | Q2 | Q3 | Q4 |
|---|---|---|---|---|---|
| FSIQ | |||||
| n | 1897 | 561 | 504 | 428 | 404 |
| Mean (SD) | 97.4(12.1) | 96.3(12.1) | 99.0(12.1) | 97.1(12.4) | 97.3(11.6) |
| Adjusted mean differences (95% CI) a | 0.29(0.06, 0.52) | Reference | 1.07(-0.35, 2.48) | 1.66(-0.23, 3.56) | 3.53(1.01, 6.06) |
| P value for linear trend | 0.015 | 0.009 | |||
| Total behavioural problem score | |||||
| n | 1897 | 561 | 504 | 428 | 404 |
| Mean (SD) | 49.5(25.5) | 49.6(26.0) | 48.3(24.9) | 49.3(24.7) | 51.1(26.5) |
| Adjusted mean differences (95% CI) a | -0.08(-0.63, 0.46) | Reference | -0.88(-4.18, 2.41) | -2.68(-7.10, 1.74) | -2.03(-7.93, 3.87) |
| P value for linear trend | 0.765 | 0.369 | |||
| Internalizing behavioural problem score | |||||
| n | 1897 | 561 | 504 | 428 | 404 |
| Mean (SD) | 11.3(8.0) | 11.2(8.3) | 11.1(8.0) | 11.0(7.5) | 12.0(8.2) |
| Adjusted mean differences (95% CI) a | 0.02(-0.16, 0.19) | Reference | -0.88(-4.18, 2.41) | -2.68(-7.10, 1.74) | -2.03(-7.93, 3.87) |
| P value for linear trend | 0.863 | 0.561 | |||
| Externalizing behavioural problem score | |||||
| n | 1897 | 561 | 504 | 428 | 404 |
| Mean (SD) | 8.6(7.5) | 8.5(7.5) | 8.3(7.2) | 8.7(7.3) | 9.2(7.8) |
| Adjusted mean differences (95% CI) a | -0.01(-0.17, 0.15) | Reference | -0.16(-1.12, 0.80) | -0.72(-2.00, 0.56) | -0.67(-2.38, 1.05) |
| P value for linear trend | 0.898 | 0.364 | |||
Abbreviations: CI, confidence interval; FSIQ, full-scale intelligence quotient; SD, standard deviation
aThe adjustments included parental educational attainment and occupation type, paternal age, maternal parity and mid-upper arm circumference, randomized regimen, birthweight for gestational age z score, household wealth at early adolescence, adolescent sex, height-for-age z score, school type and total behavioural problem (for cognitive outcomes) or FSIQ (for emotional and behavioural outcomes)