Skip to main content

Table 4 Age at First Birth and CVD – Cohort Studies (N = 14), by Year of Publication

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

Cohort Studies
First author, publication year Age at first birth No. in cohort No. study outcomes
N (%)
Point estimate (+CI) a
Base model
Point estimate (+CI) a
Final model
Adjusted for or matched on. If underlined, also adjusted in base model. Notes on study considerations and limitations.
Colditz
1987 [26]
<19 6671 b 3 (0.004)   1.3 (0.4–4.3) c D: age; SE: - BM: - HB: - R: - Very few events in the exposure category of <19. Short follow-up in a relatively young age group.
20–22 145,708 42 (0.029) 0.9 (0.6–1.2)
23–25 257,170 108 (0.042) 1 (ref)
26–29 151,206 82 (0.54) 1.1 (0.8–1.5)
≥ 30 77,091 35 (0.045) 0.8 (0.5–1.2)
Cooper
1999 [27]
15–24 7996 b 8 (0.100)   1.29 (0.5–3.0) D: age; SE: - BM: - HB: - R: - Number of outcomes very low in all exposure categories
25–29 17,698 14 (0.079) 1 (ref)
30–32 5341 3 (0.056) 0.71 (0.2–2.5)
33–43 3715 8 (0.215) 2.9 (1.2–6.9)
Otterblad- Olausson
2004 (CVD) [9]
<20 60,686 41 (0.07) 2.2 (1.5–3.1) 1.8 (1.2–2.6) D: age; SE: background SES in 1960 (parents), socio-economic position (‘90), family situation (‘90), welfare dependency (‘90) BM: - HB: - R: Parity Conducted amongst women aged 30–45, follow-up time of 5 years, resulting in low number of events. Some women still having children.
20–29 399,748 110 (0.03) 1 (ref) 1 (ref) d
Otterblad- Olausson
2004 (CHD) [9]
<20 60,686 Data not 2.8 (1.5–5.4) 2.2 (1.2–4.3)
20–29 399,748 provided 1 (ref) 1 (ref) d
Otterblad- Olausson
2004 (CeVD) [9]
<20 60,686 Data not 1.5 (0.8–2.9) 1.4 (0.7–2.7)
20–29 399,748 provided 1 (ref) 1 (ref) d
Yang CY 2006 <26 859,942 102 (0.012) 1 (ref)   D: - SE: - BM: - HB: - R: Parity No adjustment for participant age is reported (while due to study set-up women with older age at first birth were older at follow-up). Cut-off for youngest group <26
26–30 372,895 70 (0.019) 1.78 (1.3–2.4)
≥ 31 59,625 17 (0.029) 2.96 (1.8–5.0)
Continuous    1.10 (1.06–1.1) 1.08 (1.04–1.1)
Henretta
2007
Heart disease [30]
<20 991 Data not provided   0.36 (P:<.01) D: age, race, US-born, unmarried at first birth, marital status; SE: Father’s education, education, log net worth, log income; BM: - HB: - R: Birth >39, birth interval, parity No information on the number of outcomes per exposure group; no confidence intervals
≥ 20 2956
Henretta
2007
Stroke [30]
<20 991 Data not provided   −.03
P-value or CI not provided
≥ 20 2956
Sakauchi 2007
CHD [36]
<23 Data not provided 121   1.09 (0.8–1.5) D: age, study area; SE: - BM: - HB: - R: - No denominator information provided
23–25 116 1 (ref)
≥ 26 131 1.17 (0.9–1.5)
Sakauchi
2007
(CeVD) [36]
<23 Data not provided 291   1.19 (0.99–1.4)
23–25 294 1 (ref)
≥ 26 326 1.07 (0.9–1.3)
Yang L
2009, Ischemic stroke [39]
<23 11,942 68 (0.57) 1.1 (0.7–1.5) 1.0 (0.6–1.5) D: age; SE: education; BM: BMI, high blood pressure, DM; HB: alcohol, smoking, physical activity; R: - Young age at first birth category not compared to lowest risk category. Few cases for hemorrhagic stroke.
21–25 9905 49 (0.49) 1 (ref) 1 (ref)
≥ 26 17,444 48 (0.28) 0.6 (0.4–0.9) 0.7 (0.4–1.1)
Yang L <21 11,942 28 (0.23) 2.0 (1–4) 1.8 (0.8–4.1)
2009
hemorrhagic stroke
21–25 9905 11 (0.11) 1 (ref) 1 (ref)   
≥ 26 17,444 19 (0.11) 1.1 (0.5–2.3) 1.2 (0.5–2.6)
Grundy
2010 [29]
Women
<20 862,007 b 572 (0.07) 1.47 (1.3–1.6) 1.22 (1.1–1.3) D: age, year, region residence, log population size, marital status; SE: level of education; BM: - HB: - R: parity  
20–24 3,200,462 1567 (0.05) 1 (ref) 1 (ref)
25–29 1,670,417 574 (0.03) 0.67 (0.6–0.7) 0.81 (0.7–0.9)
≥ 30 646,983 224 (0.03) 0.60 (0.5–0.7) 0.78 (0.7–0.9)
Grundy
2010
Men [29]
<23 1,164,183 b 2190 (0.19) 1.39 (1.3–1.5) 1.23 (1.2–1.3)
23–28 3,238,174 4804 (0.15) 1 (ref) 1 (ref)
29–34 1,313,342 1772 (0.13) 0.88 (0.8–0.9) 0.93 (0.9–0.99)
≥ 35 473,472 571 (0.12) 0.87 (0.8–0.95) 0.93 (0.9–1.01)
Chang
2011
CVD [25]
15–19 844 144 (17.1) 1.00 (ref) 1.00 (ref) d D: age at entry; SE: education, occupation; BM: BMI, HT HB: drinking, smoking R: -
For CVD there was a mention of a fourth model in which the authors additionally corrected for reproductive variables and marital status, which did not change the findings.
Extensive adjustment in final model. Few CHD events.
20–22 1646 230 (14.0) 0.74 (0.6–0.9) 0.74 (0.6–0.9)
≥ 23 787 104 (13.2) 0.75 (0.6–0.96) 0.76 (0.6–0.98)
Chang
2011
CHD [25]
15–19 844 12 (1.42) 1.00 (ref) 1.00 (ref) d
20–22 1646 24 (1.46) 0.88 (0.4–1.8) 0.89 (0.4–1.8)
≥ 23 787 11 (1.40) 0.93 (0.4–2.1) 0.90 (0.4–2.1)
Chang
2011
Stroke [25]
15–19 844 87 (10.3) 1.00 (ref) 1.00 (ref) d
20–22 1646 142 (8.6) 0.76 (0.6–0.99) 0.78 (0.6–1.02)
≥ 23 787 68 (8.6) 0.80 (0.6–1.1) 0.84 (0.6–1.2)
Gallagher
2011
CHD [28]
<20 12,460 43 (0.35)   0.93 (0.7–1.3) D: age; SE: - BM: - HB: - R: - Young age at first birth category not compared to lowest risk category.
20–24 72,570 239 (0.33) 1 (ref)
25–29 124,044 101 (0.08) 0.75 (0.6–0.95)
≥ 30 45,041 37 (0.08) 0.85 (0.6–1.2)
Gallagher
2011
Ischemic stroke [28]
<20 12,460 75 (0.60)   1.23 (0.96–1.6)
20–24 72,570 309 (0.43) 1 (ref)
25–29 124,044 141 (0.11) 0.88 (0.7–1.1)
≥ 30 45,041 50 (0.11) 0.95 (0.7–1.3)
Gallagher
2011
Hemorrhagic
Stroke [28]
<20 12,460 178 (1.43)   1.09 (0.9–1.3)
20–24 72,570 850 (1.17) 1 (ref)
25–29 124,044 423 (0.34) 0.84 (0.7–0.9)
≥ 30 45,041 132 (0.29) 0.81 (0.7–0.97)
Webb
2011 [10]
N/A 1,021,417 b 46 (0.0045)   1 (ref) D: age, decade; SE: - BM: - HB: - R: - Few events in <20 category. Nulliparous group includes young women who did not have children yet.
<20 159,716 16 (0.0100) 1.25 (0.7–2.2)
≥ 20 732,462 71 (0.0097) 0.93 (0.6–1.4)
<20 159,716 16 (0.0100) 1.35 (0.8–2.3)
≥ 20 732,462 71 (0.0097) 1 (ref)
Merritt
2015
(FTP)
(CVD) [32]
<21 39,201 304 (0.78)   1.15 (0.99–1.3) D: age, site; SE: education; BM: BMI; HB: physical activity, smoking (duration and intensity); R: menopausal status. Extensive adjustment in final model and no unadjusted model for comparison.
21–23 71,322 497 (0.70) 1.11 (0.98–1.3)
24–25 52,056 359 (0.69) 1.05 (0.9–1.2)
26–30 75,927 557 (0.73) 1 (ref)
≥ 31 27,027 237 (0.88) 1.06 (0.9–1.2)
Merritt
2015
(FTP)
(CeVD) [32]
<21 39,201 97 (0.25)   1.14 (0.9–1.5)
21–23 71,322 150 (0.21) 0.96 (0.8–1.2)
24–25 52,056 122 (0.23) 1 (ref)
26–30 75,927 199 (0.26) 0.97 (0.8–1.2)
≥ 31 27,027 79 (0.29) 0.90 (0.7–1.2)
Merritt
2015
(FTP)
(CHD) [32]
<21 39,201 105 (0.27)   1.14 (0.9–1.5)
21–23 71,322 140 (0.20) 0.96 (0.7–1.2)
24–25 52,056 106 (0.20) 1 (ref)
26–30 75,927 166 (0.22) 0.99 (0.8–1.3)
≥ 31 27,027 74 (0.27) 1.10 (0.8–1.5)
Barclay
2016
Women [22]
15–19 2998 1148 (38.3) 1.18 (1.1–1.3) 1.25 (1.1–1.4) D: birth cohort [2]; SE: (sibling fixed effect model) age of person’s mother at time of their own birth, attained socioeconomic status, educational attainment, marital status; BM: - HB: - R: Completed parity  
20–24 5232 1894 (36.2) 1.11 (1.02–1.2) 1.23 (1.1–1.4)
25–29 3052 1022 (33.5) 1 (ref) 1 (ref)
30–34 1010 322 (31.9) 0.94 (0.8–1.1) 0.89 (0.7–1.1)
35+ 343 120 (35.0) 1.14 (0.9–1.4) 1.09 (0.8–1.5)
Barclay
2016
Men [22]
15–19 1469 661 (45.0) 1.45 (1.3–1.6) 1.37 (1.2–1.6)
20–24 9380 3595 (38.3) 1.11 (1.1–1.2) 1.10 (1.03–1.2)
25–29 9533 3395 (35.6) 1 (ref) 1 (ref)
30–34 4590 1623 (35.4) 0.98 (0.9–1.04) 1.03 (0.9–1.1)
35+ 2211 793 (35.9) 0.98 (0.9–1.1) 0.97 (0.9–1.1)
Parikh
2016 [35]
Nullipara 10,462 Data not provided. Total cases: 4607   1.00 (0.9–1.1) D: age at enrollment; SE: income, education, neighborhood SES variables; BM: history of high cholesterol requiring pills, hypertension, diabetes; HB: smoking; nr of still births, nr of miscarriages, breastfed for >1 month Extensive adjustment in final model
<20 8780 1.65 (1.5–1.8) 1.27 (1.1–1.4)
20–24 29,803 1.25 (1.2–1.4) 1.14 (1.1–1.2)
≥ 25 23,937 1 (ref) 1 (ref)
  1. D demographics, SE Socio-economic, BM Biomedical, HB Health behavior, R Reproductive, AFB age at first birth, AFP age at first pregnancy, HT hypertension, DM diabetes mellitus, CHD coronary heart disease, CeVD cerebrovascular disease, SES socio-economic status, BMI body mass index, FTP full term pregnancy
  2. aRisk estimates used: Relative risk: Yang C, Yang L, Barclay. Rate ratio: Colditz, Cooper, Otterblad, Webb. Hazard ratio: Chang, Gallagher, Merritt, Sakauchi. Odds ratio: Grundy, Parikh. Log odds ratio: Henretta
  3. bPerson years rather than individuals in group. Percentage is based on N / person years
  4. cAuthors indicate that a multivariate model yielded the same/similar results
  5. dFor intermediate models, see original publications
  6. The bold data indicate significant results