Table 5 Detailed characteristics of studies investigating offspring educational attainment and cognition (N = 21).
Offspring educational attainment and cognition | ||||||||
|---|---|---|---|---|---|---|---|---|
Study | Design | Sample | Parental attribute (predictor) | Child attribute (outcome) | Control variables | Genetic overlap | Environmental transmission | G–E interplay |
Kendler et al. 124 | Adoption (siblings-reared-apart) | Snr 436 sibships, one member reared by biological, other by adoptive parents Age: 18–20 years | EA: highest education achieved by both parents, five-point-scale | IQ: Military Conscription Register, standardised test | Clustering of siblings within biological families | Not studied | Yes, adoptive parent EA predicted offspring IQ | |
Conley et al.82 | Within-family PGS: genetic sensitivity analysis, and genetic nurture (statistical control method) | FHS, HRS 6186 individuals from 4867 households Mean age: 39.49 years (FHS), 68.17 years (HRS) | Parental education Genetic transmission: effect of parental EA PGS Genetic nurture: effect of parental EA PGS, after adjusting for child EA PGS | EA: self-report, highest grade completed | Child sex, age | Yes, parental EA PGS predicted offspring EA (effect size not clear) | Genetic sensitivity analysis: After controlling for offspring EA PGS, parental EA was still associated with offspring EA. Genetic nurture: no evidence of genetic nurture as parental EA PGS was not associated with offspring EA after controlling for offspring EA PGS (effect size not clear) | No G × E interaction found between maternal EA and offspring PGS |
Ayorech et al.79 | Extended twin, within-family PGS | TEDS Twin analyses: 6105 twin pairs PGS analyses: 5825 individuals Age: 18 years | EA (extended twin): self-reported highest qualification Genetic transmission (within-family PGS): effect of parental EA PGS | EA: self or parent report, A levels qualification Intergenerational EA (extended twin): similarity between parental and offspring EA, two levels Intergenerational EA (within-family PGS): similarity between parental and offspring EA, four levels | PGS analyses: previous school performance (GCSE grades) | Twin analyses: yes, additive genetic effects underlying intergenerational EA were found (R2 = ~50%) PGS analyses: yes, parental EA PGS was associated with intergenerational EA | Twin analyses: yes, shared environmental effects underlying intergenerational EA were found (R2 = ~40%) PGS analyses: Not studied | |
Scheeren et al.90 | Adoption | NLnr 1792 adopted children, 424,928 biological children Age: 15 years | EA: register-based, highest education level Parental income: yearly household income | EA: level of enrolment in secondary school, four levels | Father and mother year of birth, family structure, number of children in the household, observation year, adoption age, country of adoption, gender | Not studied | Adoptive parents’ income (but not EA) predicted offspring EA | Passive rGE: family income was more strongly associated with offspring EA in biological families than adoptive families |
Bates et al.14 | Within-family PGS: genetic nurture (transmitted/non-transmitted method) | BATS 2,335 children and their genotyped parents Age: 17 years | Genetic nurture: effect of EA PGS based on non-transmitted alleles SES: ASI-2006 | EA: Queensland Core Skills Test | Sex, age at test, offspring EA PGS | Not studied | PGS for EA based on non-transmitted alleles were associated with offspring EA, but this relationship disappeared after adjusting for parental SES | No G × E interaction found between PGS and SES |
Belsky et al.86 | Within-family PGS: genetic nurture (statistical control method) | E-RISK, NLAAH 1574 & 5526 individuals Age: 18 years, late 20 s to early 30 s | Genetic nurture: effect of parental EA PGS, after adjusting for child EA PGS | EA: GCSE attainment; four levels | Genetic principal components | Not studied | Yes, parental EA PGS was associated with offspring EA after adjusting for offspring EA PGS | Passive rGE: individuals with higher PGS grew up in better-educated households |
Kong et al.83 | Within-family PGS: genetic nurture (transmitted/non-transmitted method) | deCODE 21,637 probands with at least one genotyped parent Age: not reported | Genetic transmission: effect of EA alleles PGS based on transmitted alleles Genetic nurture: effect of EA PGS based on non-transmitted alleles | EA | Sex, year of birth, the interaction between sex and year of birth, 100 principal components | Yes, EA PGS based on transmitted parental alleles was associated with offspring EA (direct effect explained 70% of the overall observed effect of EA PGS) | Yes, EA PGS based on non-transmitted parental alleles was associated with offspring PGS (genetic nurture explained explaining 22.4% of the overall effect of EA PGS) | |
Liu et al.84 | Within-family PGS: genetic nurture (statistical control method) | FHS, HRS 8639 individuals from three generations and 9342 individuals over age 50 Age: not reported | Genetic transmission (FHS sample): effect of parental EA PGS Genetic nurture (FHS sample): effect of parental EA PGS, after adjusting for child PGS EA (HRS sample): self-report, years of education | EA FHS: self-report, years of education completed HRS: parent report | 7 principal components HRS sample: child’s EA PGS | Yes, parental EA PGS was associated with offspring EA (FHS sample; β = 0.345), and offspring EA PGS attenuated the association between parental and offspring EA (HRS sample; from β = 0.314 to β = 0.292) | Yes, parental EA PGS was associated with offspring EA, after adjusting for offspring EA PGS (β = 0.076) | |
Young et al.17 | Relatedness disequilibrium regression | deCODE 12,035 individuals who had parents and grandparents genotyped Age: not reported | Genetic nurture: estimated variance in offspring trait explained by parental genes acting indirectly via the environment | Educational attainment: self-report, number of years of schooling | Sex, year of birth | Not studied | Yes, after accounting for shared genetic effects, parental genes explained variance in offspring EA | |
Pingault et al.13 | Within-family PGS: genetic sensitivity analysis | TEDS 3663–4693 individuals Age: 8–16 years | Maternal EA: self-report, eight levels | EA: mean of three standardised tests | Sex, age and ten principal components of ancestry, PGS for EA | Yes, association between maternal EA and offspring EA decreased after adjusting for EA PGS (from β = 0.40 to 0.33) | Under a twin-heritability scenario, the association between maternal and offspring EA was expected to be null if EA PGS captured all heritability | |
Bates et al.15 | Within-family PGS: genetic nurture (transmitted/non-transmitted method) | BATS 2335 children and their genotyped parents Age: 17 years | Genetic nurture: effect of parental EA PGS based on non-transmitted alleles SES: ASI-2006 | EA: Queensland Core Skills Test | Sex, age at test, offspring EA PGS | Not studied | PGS for EA based on non-transmitted alleles were associated with offspring EA, but this relationship disappeared after adjusting for parental SES | No G × E interaction found between PGS and SES |
Willoughby et al.88 | Within-family PGS: genetic nurture (statistical control method) | MCTFR 1223 families, 2446 offspring Age: varied | Genetic nurture: effect of parental EA PGS, on top of child EA PGS SES: composite score, family income, parent education level, parent occupation level Parental IQ: WIS | Years of education: self-report, mean age 29 High-school grade-point-average: self-report, age 17 IQ: WIS, mean age 14.4 | Height and BMI used as negative controls | Not studied | Yes, parental EA PGS was associated with offspring EA traits after adjusting for offspring EA PGS, and this association was mediated by parental SES and IQ | |
Armstrong-Carter et al.89 | Within-family PGS: genetic nurture (statistical control method) | BiBs 2077 mother–child dyads Age: 7 years | Genetic nurture: effect of maternal EA PGS, after adjusting for child EA PGS Maternal health: composite score, self-reported mental health, smoking, indirect smoke exposure, alcohol and drug use, vitamin use, sleep problems, and BMI SES: composite score, self-reported education, cohabitation status, employment, maternity leave, governmental benefits, perceived financial difficulty, and governmental index of neighbourhood-level deprivation | Academic performance: standardised national exam | Child EA PGS, maternal age, first ten principal components | Not studied | Yes, maternal EA PGS was associated with offspring academic performance, after adjusting for offspring EA PGS, and this association was mediated by maternal health and SES during pregnancy | |
Borriello et al.80 | Adoption | EGDS 195 families Age: 7 years | Mathematical achievement: standardised scores on the mathematics fluency subtest of WJ-III | Mathematical achievement: standardised scores on the mathematics fluency subtest of the WJ-III | Obstetric complications, adoption opennness, parent education level, non-mathematical cognitive skills | Yes, birth parent and offspring mathematic achievement were correlated (β = 0.17) | Yes, paternal (but not maternal) mathematic achievement was correlated with adopted-offspring mathematical achievement (β = 0.15) | No G × E interaction found |
Domingue et al.85 | Adoption (PGS study) | WLS 855 adopted and 20,939 biological offspring Age: not reported | Genetic transmission: association between parental EA PGS and EA of biological offspring Genetic nurture: association between parental EA PGS and EA of adoptive offspring | Educational attainment: parent-reported, highest grade of school attended | Child sex, age, ten principal components | Yes, parental EA PGS was associated with EA of biological offspring (effect size not clear) | Yes, parental EA PGS was associated with EA of adoptive offspring (effect size not clear) | Passive rGE implied: higher association in biological families than adoptive families |
de Zeeuw et al.75 | Within-family PGS: genetic nurture (transmitted/non-transmitted method) | NTR 5900 offspring from 2649 families Age: 10–12, 25–64 years | Genetic transmission: effect of EA and ADHD ADHD PGS based on transmitted alleles Genetic nurture: effect of EA and ADHD PGS based on non-transmitted alleles | Childhood academic achievement: nationwide standardised test at age 12 Adult EA: self-report, highest degree; four levels | Sex, birth year (EA), interaction between sex and birth year (EA), ten principal components, genotyping platform | EA PGS based on transmitted parental alleles were associated with offspring academic achievement in childhood and EA in adulthood (R2 = 5.7–7.6%) but there was no association with ADHD PGS | EA PGS based on non-transmitted parental alleles were associated with offspring EA in adulthood (R2 = 1.7%), but not academic achievement in childhood (which was also not associated with non-transmitted PGS for ADHD) | |
Halpern-Manners et al.81 | Adoption | EGDS 340 families Age: first-graders (6–7 years) | Adoptive and birth parent education attainment: self-report, highest level of education completed by adoptive or birth parents | Early educational achievement: WJ-III | Obstetric complications, adoption opennness, child sex, child and adoptive parents’ ethnicity, adoptive parents’ age, type of adoption agency | Yes, birth parent EA was associated with offspring EA (effect size not clear) | Yes, adoptive parent EA was associated with offspring EA (effect size not clear) | No G × E interaction |
Torvik et al.45 | Children-of-twins and siblings | MoBa 34,958 children Age: 8 years | Educational attainment: self-report, highest level completed | Academic problems: maternal report, three-point scale | Yes, there were shared genetic effects between parental EA and offspring academic problems (effect size not clear) | Yes, after accounting for genetic relatedness, parental EA was associated with offspring academic problems (effect size not clear) | ||
Ellingson et al.71 | Sibling comparison | CNLSY 10,251 children of 4827 mothers Age: 4–14 years | Smoking during pregnancy: self-report, mean number of packs smoked per day | Cognitive functioning: PPVT-R (math, reading and reading Recognition subtests) and digit span test | Maternal age at birth, EA, intelligence, delinquency, offspring sex, birth order, ethnicity, household income, geographic location | Not studied | Exposed children had poorer reading recognition than their unexposed siblings, but there were no other group differences | |
Kuja-Halkola et al.67 | Sibling comparison, children-of-twins | Snr 2,754,626 children Age: up to 20 years | Maternal smoking during pregnancy: self-report | Academic achievement: class 9 records General cognitive ability: Military Conscription Register, nine levels | Maternal age at childbirth, child sex, birth year | Yes, there were shared genetic effects between maternal smoking during pregnancy and offspring EA traits (effect size not clear) | No, exposed children did not differ from their unexposed siblings, and after accounting for genetic relatedness, maternal smoking was not associated with offspring EA traits | |
Wertz et al.78 | Within-family PGS: genetic nurture (statistical control method) | E-RISK 860 mothers and their children Age: 18 years | Genetic nurture: effect of maternal EA PGS, after adjusting for child PGS Parenting behaviour: mother, child and interviewer report, cognitive stimulation, warmth and sensitivity, household chaos, and safety and tidiness of the family home | EA: self-report, highest educational attainment, 18 years | Sex, first ten principal components, offspring EA PGS | Yes, controlling for offspring EA PGS attenuated the association between parenting behaviours and offspring EA (from β range = 0.33–0.52 to β range = 0.30–0.48) | Genetic nurture: yes, maternal EA PGS was associated with offspring EA after adjusting for offspring EA PGS (β = 0.11), and this effect was mediated by parenting behaviours including cognitive stimulation, household chaos and a safe, tidy home (but not parental warmth) | Evocative rGE: mother and offspring PGS for EA predicted cognitive stimulation and warm, sensitive parenting |
