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Table 2 Characteristics of Included Studies, by Year of Publication – Cohort Studies (N = 14)

From: Age at first birth and risk of later-life cardiovascular disease: a systematic review of the literature, its limitation, and recommendations for future research

First author, publication year Duration of study + years of FU Location of study Exclusion criteria Cohort size Number of cases
(% of cohort)
Age at entry Endpoint category a Specific endpoint
CHD CVA CVD
Colditz
1987 [26]
En: ‘76
F: until ‘82
FU: 6 y
USA Diagnoses of CHD at entry, non-married. (Note: only registered nurses, 98% white) 119,963 women. 700,809 person years 308 (2.6%) 30–55 at entry C    Incident cases non-fatal myocardial infarction or fatal CHD.
Cooper
1999 [27]
En: ‘34-‘39
F: until ‘90–‘91.
FU: 51–57 y
Minne-sota, USA Enrolled white college students. In FU excluded if missing information age CVD event, or missing CVD data in questionnaire 867. (714 self-administered FU, 153 proxy respondents (family members)) 45 (35 non-fatal, 10 fatal) (5.2%) Under 25 at entry, 63–81 at FU C    Non-fatal and fatal CHD
Otterblad- Olausson
2004 [9]
En:‘85 census. FU: From ‘90-‘95.
FU: 5 y
Sweden Women who had first infant before the age of 30 between 1964 and 1989 are included. Exclusion: women who emigrated or died between census and follow up. 460,434 women 151 (total circulatory) (0.05%), no data reported for CHD and cerebrovascular. Born ‘50 – ‘64 → 21 to 35 at census. M M M Total circulatory, CHD, cerebrovascular mortality.
Yang CY
2006 [38]
En: ‘78/‘87
F: until ‘03 FU: 16–25 y
Taiwan Included women with a first and singleton childbirth between 1978 and 1987. 1,292,462 women, 27,402,995 person years 189 (0.01%) ?   M   Subarachnoid hemorrhage mortality
Henrettab
2007 [30]
En: ‘31/‘41
F: ‘92/‘02a
USA First two follow up years excluded. People who didn’t survive until follow up excluded. 4335 women Heart disease: 13.2%, stroke: 8.9% (parous women) Birth cohort ‘31-‘41. Age at FU: 51–61 through 61–71 E E   Presence of disease in 1994: heart, stroke. Self-reported.
Sakauchi
2007 [36]
En:‘88/‘90
F: until ‘03. FU: 13–15 y
Japan Previous history of cancer. Missing target question item. 63,600 women at baseline, 817,669 person years CHD: 458 (0.7%)
Cerebrovascular: 1151 (1.8%)
40 to 79 at entry. M M   CHD mortality, cerebrovascular mortality
Yang L
2009 [39]
En: ‘91-‘92
F: until ‘04. FU: avg. 12.9 y
Sweden Prior CVD. Missing information on OC use or smoking. Baseline self-reported natural menopause or HRT use. 45,729 Stroke: 285 (0.6%);
Ischemic: 193 (0.4%) Hemorrhagic: 72 (0.2%)
30–49   C   Ischemic and Hemorrhagic stroke.
Grundy
2010 [29]
En: ‘35/‘68
F:’ from ‘80 to ‘03.
FU: 23 y
Norway Analysis restricted to ages above 45 (largely completed childbearing for women). Men and women who died before this age were excluded 744,784 women (7.2 million person years) 785,317 men (7.36 million person years) 3605 women (0.5%)
12,640 men (1.6%)
Register data born ‘35-‘68. Mortality at 45–68    M Death from circulatory diseases
Chang
2011 [25]
En: ‘85
FU: until ‘05
FU: 20 y
Kangwha, Korea Ever on OC. Missing info on age menarche, MP, BMI, BP, AFB, gravidity or parity. 3257 women. 48,313 person years 478 (14.7%) PostMP, 55 or older at entry M M M CVD mortality, CHD mortality, stroke mortality
Gallagher
2011 [28]
En: ‘89-‘91
F: until ‘00
FU: 10/12 y
China None mentioned 267,400 women. 2,565,433 person years CVD: 4349 (1.6%), Stroke: 2776 (0.9%), CHD: 494 (0.2%). 30–60 at entry M M   CHD, ischemic and hemorrhagic stroke mortality.
Webb
2011 [10]
En: ‘70
F: until ‘06 FU: max 37 y
England and Wales Included women estimated to have reached age 13 during ‘70s-‘90s, sampled members of census ‘71, ‘81 and ‘91. 1,913,595 person years 133 (0.007%) 13–49 M    Heart disease mortality
Merritt
2015 [32]
En: ‘92/‘00
F: Until ‘10.
FU: mean 12.9 y
10 western European countries DM, myocardial infarction, angina, stroke, cancer. Report of a prevalent disease that could influence important confounders. Missing lifestyle questionnaire, vital status or date of death. Women reported never having menstruated or missing information on all reproductive variables. 322,972 women Circulatory: 2404 (0.7%); Cerebrovascular: 808 (0.3%);
CHD: 732 (0.2%)
25–70 at entry M M M Total circulatory, cerebrovascular, and CHD mortality
Barclay
2016 [22]
En: ‘32 - ‘60
F: ‘90 - ‘12
FU: 22 y
Sweden This is a sibling study: ID for both parents needed, no multiple births, no only children, no childless individuals, no variance on either mortality or AFB. 12,635 women, 27,183 men 4503 women (35.6% 10,067 men (37.0%) People enter cohort in ‘90 or after age 45. Ages 45–80 throughout follow-up.    M Circulatory deaths
Parikh
2016 [35]
En: ‘91
F: until ‘10
FU: median 12 years
USA Missing reproductive and CHD risk factor information, missing follow up, prevalent or unknown history of CHD. 72,982 4607(6.3%) Mean age at start of study 63.2 E    Coronary Heart Disease events
  1. En entry in to study, F follow-up until, FU follow up time in years, OC oral contraceptives, MP menopause, BMI Body mass index, BP blood pressure, AFB age at first birth;
  2. aThis column provides an overview of study endpoint category (coronary heart disease (CHD), cerebrovascular disease (CVA), cardiovascular disease (CVD)) and whether it concerns events (E), mortality (M) or a combination (C) of events and mortality
  3. bThe data used for this article are drawn from a cohort study. However, the data on stroke and heart disease are cross sectional on presence of heart disease in 1994