Association between the number of live births and estimated life expectancy
We estimated the lower or higher survival time (years) due to the different parities, as shown in Figure 1. At age 40, childless women had an average 1.41 (95% CI: 0.78–2.01) lower years of life expectancy, and women with two, three, or four had an average 1.10 (95% CI: 0.63–1.74), 1.00 (95% CI: 0.54–1.74), and 1.00 (95% CI: 0.05–1.84) higher years of life expectancy, respectively, as compared with women who had one child. The corresponding lower years of life expectancy at the age of 60 years were 1.20 (95% CI: 0.66–1.71) years in unproduced women, and the corresponding higher years of life expectancy at the age of 60 years were 0.97 (95% CI: 0.56–1.52), 0.88 (95% CI: 0.48–1.52), and 0.79 (95% CI: 0.05–1.61) years in women who gave two, three, or four births, respectively.