Aims

To better understand how blood pressure (BP) is related to cognitive function and academic attainment in childhood. More specifically, to investigate: (a) the relationship between BP and cognitive function (ages 4, 5, 9, 10, 11, 13 and 15 years) and academic attainment (reception, year 2, year 6, year 9 and year 11) in children, (b) the association between parental hypertension (HT) and cognitive functioning and academic attainment in offspring, (c) the contribution of vascular health (flow-mediated dilatation and pulse wave velocity) to BP-related cognitive functioning and academic attainment, (d) the impact of BP in pregnancy on offspring cognitive performance and academic attainment (e) how these four risk factors (i.e., children's BP, parental history of HT, vascular health and BP in pregnancy) jointly relate to cognitive performance and academic attainment, (f) if these potential risk factors predict future as well as current cognitive functioning and academic attainment.

Hypotheses

a) Paediatric BP will be inversely related to cognitive performance and academic attainment, after controlling for potential confounders.

b) Children with one or more parents diagnosed with HT will be more likely to show poorer cognitive performance and academic attainment than those without a parental history, after controlling for potential confounders.

c) Poorer vascular health (as measured by flow-mediated dilatation and pulse wave velocity) will confer additional risk, compared to elevated BP and parental history of HT, for reduced cognitive performance and academic attainment.

d) Higher maternal BP during pregnancy will be related to reduced cognitive performance and academic attainment in offspring, after controlling for potential confounders.

e) Parental history of HT, higher maternal BP during pregnancy and poorer vascular health will each confer greater risk for poorer cognitive performance and academic attainment than when paediatric BP is considered in isolation.

f) Risk for HT (based on elevated paediatric BP and/or parental history of HT) will be related to cognitive performance and academic attainment both cross-sectionally and longitudinally.

Exposure variables

a) Paediatric BP at ages 4-15: valid measurements of BP taken and expressed as BP percentiles accounting for age, sex, and height. All children with will be included in analyses.

b) Parental HT status: Based on latest evidence of a HT diagnosis (ideally verified by antihypertensive medication) and may review latest BP measurements if necessary. Latest evidence of diabetes diagnosis will highlight secondary HT.

c) Vascular measures: Brachial artery flow-mediated dilatation and pulse wave velocity.

d) Maternal BP in pregnancy and gestational HT.

e) HT Risk: based on paediatric BP (elevated BP >=90th BP Percentile) and parental history for HT (scored as presence of 2, 1, or 0 risk factors).

Outcome variables

a) Cognitive performance: including the following: (i) Aged 4: IQ (WPPSI- R) measures and short-term memory (digit span), (ii) Aged 5: short-term memory (digit span, non-word repetition, initial consonant recognition), (iii) Aged 9: maths and reading ability, (iv)Aged 10: working memory (counting span task) and inhibition (stop signal task), (v) Aged 11: attention (TEACh), (vi) Aged 13: CDR executive function tasks (simple RT, choice RT, digit vigilance), and (vii) Aged 15: WASI measures and inhibition (stop signal task).

b) Perception of ability: including (i) mother's perception of child's ability, (ii) child's perception of school ability/performance, reading and maths ability, (iii) teacher's perception of child's ability.

c) Academic attainment : including (i) External data for Entry and Key stage 1-4, (ii) Pupil Level Annual School Census, and (iii) Key stage 3 grades and qualifications.

To minimise confounding, the following variables form the basis of exclusion or statistical control as they are known to affect one or more of the exposure or outcome variables:

Covariates

a) Study child measures, including : (i) core variables: birth weight, sex, gestation, parity, (ii) age at clinic visit or school assessment, (iii) alcohol consumption, (iv) smoking habits, (v) pubertal development and menstruation (vi) body mass index, (vii) head circumference at 6 months, (viii) clinic anxiety: heart rate and tester rating where possible, (ix) depression, and (x) blood lead level.

b) Parent/caregiver measures (depending on the analysis it might be more applicable to use biological or caregivers information, if different), including: (i) core variables: Mothers age at delivery, ethnicity, parity, marital status, housing tenure, maternal and paternal social class in pregnancy, maternal education during pregnancy, smoking in pregnancy), (ii) mothers alcohol consumption during pregnancy, (iii) mothers and fathers/partners current/most recent occupation, (iv) mothers and fathers/partners current/most recent education, (v) father/partner living with study child, (vi) female caregiver is biological mother, (vii) current partner is biological father, (viii) household income, (ix) Mothers WASI IQ score at TF3, (x) diabetes during pregnancy, (xi) diabetes medical diagnosis in biological mother and father.

Exclusions:

a) Study child measures, including: (i) chronic health conditions (e.g., seizure disorder, obstructive sleep apnoea, chronic disease such as diabetes), (ii) prescription medication, (iii) use of illicit drugs, (iv) acute illness at time of assessment (e.g., infection), (v) demeanour inappropriate at clinic assessment, (vi) presence of special education needs and learning disabilities, (vii) attendance at non-mainstream school, (viii) presence of mental health problems/ symptoms, (ix) uncorrected visual or hearing problems or other problems that may affect cognitive/ academic performance, (x) first language not English.

b) Parent/caregiver measures, including: (i) illicit drug use during pregnancy, (ii) excessive alcohol consumption during pregnancy, (iii) HT status information from both biological parents not available (only for analyses using parental history of HT).