Table 1:
Characteristics of studies included in the systematic review
| Study | Country | Age at baseline/Follow-up Time1 | Study Period | Sample source | Study design | Type of HDP exposure | Type of Dementia outcome | Sample size of exposed or cases | Sample size of non-exposed or controls | Confounder control |
|---|---|---|---|---|---|---|---|---|---|---|
| Abheiden et al., 2015 | Netherlands | Maternal age, not reported, mean follow up age 64–67 years (± 10 years | Not reported | Hospital-based | Case-control | GH, PE, E (SR) | AD (EA) | 104 (AD) | 129 (no AD) | Age and BMI at time of survey |
| Basit et al., 2018 | Denmark | 95.4% <45 years at start of follow-up/mean follow-up 21.1 years (IQR: 11.3–23.4 years) | Exposure: 1978–2015 Outcome: 1994–2017 | Population-based | Retrospective cohort | Time-varying PE, E, HELLP (MVR) | AD, vascular dementia, and other/unspecified dementia (MVR) | 50,068 HDP | 1,127,937 no HDP | Maternal birth year, and time dependent parity, region of most recent delivery, and mid-life cardiovascular disease, stroke, chronic kidney disease, hypertension, and diabetes |
| Theilen et al., 2016 | United States | Maternal age 26.0 ± 5.9 years/total follow-up of 73 years (mean not reported) | Exposure and Outcome 1939–2012 | Population-based | Retrospective cohort | GH, PE, HELLP, E (MVR) | Death from AD (MVR) | 60,580 HDP | 123,140 no HDP | Neonatal sex, gestational age at delivery, maternal and paternal education, maternal race–ethnicity, and maternal marital status at baseline |
| Nelander et al.,2015 | Sweden | Maternal age not reported, age at end of follow-up was 82 years ± 6 years. | Exposure <1958 Outcome 1998–2010 | Population-based | Ambispective cohort | GH, PE (SR) | All-cause dementia (MVR) | 419 HDP | 2646 no HDP | Maternal age, education, smoking, and BMI at time of interview |
| Fields et al., 2017 | United States | Mean maternal age 24 years (IQR 22, 260/mean follow up age 59 (IQR 56–63 years) | Exposure 1976–1982 Outcome 2016–2017 | Population-based | Retrospective cohort | PE (MVR) | MCI/Dementia (EA) | 40 HDP | 40 no HDP | Maternal age and parity at baseline. |
| Andolf et al., 2020 | Sweden | Not reported | Exposure 1973–1993 Outcome Up to 2013 | Population-based | Retrospective cohort | GH, PE (MVR) | AD, VaD, Other Dementia (MVR) | 20,096 GH 52,671 PE | 1,055,942 no HDP | Maternal education, parity, ethnicity, & neonatal sex (baseline) and cardiovascular disease (follow-up) |
AD: Alzheimers disease; BMI: body mass index; E: Eclampsia HDP: Hypertensive disorder of pregnancy; GH: Gestational hypertension; HELLP: haemolysis, elevated liver enzymes, and low platelets; MVR: medical or vital records; PE: Preeclampsia; SR: self-report; EA: expert assessed; VaD: Vascular Dementia
1
Note mean/median age at baseline and mean/median age at follow-up or follow-up years is approximate, as most studies reported by HDP status, not overall.