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. 2019 Mar 15;8(6):e011056. doi: 10.1161/JAHA.118.011056

Table 1.

Baseline Sociodemographic Characteristics and Parity of Parous Women (n=100 864) in the 45 and Up Study by Breastfeeding History and Average Breastfeeding Duration Per Childa

Variables Breastfeeding History Average Breastfeeding Duration Per Childb
Never Breastfed Ever Breastfed P Valuec >0 to 6 Months >6 to 12 Months >12 Months P Valued
No. of subjects, % 12 517 (12.4) 88 347 (87.6) 56 049 (63.4) 24 549 (27.8) 7749 (8.8)
Age group, %
45 to 54 y 26.5 37.7 <0.0001 29.5 47.3 66.9 <0.0001
55 to 64 y 42.7 34.0 36.5 29.7 28.9
≥65 y 30.8 28.3 34.0 23.0 4.2
Mean (SD) age for first child, y 24.3 (5.15) 25.1 (4.89) <0.0001 24.3 (4.66) 26.0 (4.74) 28.1 (5.29) <0.0001
Mean (SD) age for last child, y 28.9 (5.24) 30.6 (4.96) <0.0001 29.8 (4.93) 31.6 (4.64) 33.4 (4.7) <0.0001
Parity
Mean (SD) parity (no. of births) 2.4 (1.13) 2.7 (1.18) <0.0001 2.8 (1.2) 2.8 (1.15) 2.6 (1.13) <0.0001
1 child, % 19.0 8.7 <0.0001 16.7 9.5 3.9 <0.0001
2 children, % 43.7 39.8 47.7 46.4 41.5
3 children, % 23.8 31.2 24.3 29.8 35.0
≥4 children, % 13.5 20.3 11.3 14.3 19.6
Country of birth, %
Australia 72.0 77.3 <0.0001 74.0 76.1 79.7 <0.0001
Other 28.0 22.7 26.0 23.9 20.3
Highest education, %e
University and higher 11.1 23.8 <0.0001 16.3 21.3 27.0 <0.0001
High school/trade apprenticeship/certificate/diploma 33.3 38.4 37.1 37.9 39.4
≤10 y 55.6 37.8 46.6 40.8 33.6
Marital status, %f
Married/living with a partner 72.7 75.8 <0.0001 74.6 75.0 76.7 <0.0001
Single/divorced/separated/widowed 27.3 24.2 25.4 25.0 23.3
Socioeconomic status (SEIFA‐IRSD), %g
Quintile 1 (most disadvantaged) 23.2 19.7 <0.0001 21.1 19.8 18.2 <0.0001
Quintile 2 20.3 19.5 20.1 18.8 19.0
Quintile 3 22.5 21.4 21.8 21.2 20.7
Quintile 4 19.0 19.6 19.7 19.6 20.0
Quintile 5 (least disadvantaged) 15.0 19.8 17.3 20.5 22.0

SEIFA‐IRSD indicates Socio‐Economic Indexes For Area—Index of Relative Socio‐Economic Disadvantage.

a

Data are presented as means (SD) or percentages.

b

Average breastfeeding duration per child was calculated as self‐reported lifetime breastfeeding duration divided by the reported number of children.

c

Based on chi‐square test for categorical variables and Student t test for continuous variables.

d

Based on chi‐square test for categorical variables and F statistics from ANOVA for continuous variables.

e

1325 missing.

f

268 missing.

g

66 missing.