Research ArticleSOCIAL SCIENCES

The evolution of infant mortality inequality in the United States, 1960–2016

See allHide authors and affiliations

Science Advances  17 Jul 2020:
Vol. 6, no. 29, eaba5908
DOI: 10.1126/sciadv.aba5908
  • Fig. 1 Mortality rates and fitted values.

    (A) shows results for infant mortality rates, (B) shows results for neonatal mortality rates, and (C) shows results for postneonatal mortality rates (mortality rates defined in the notes to Table 1). The lines in each figure show fitted values estimated from population weighted county-level regressions each year using Eq. 1 and are shown for 1960, 1970, 1980, 1990, 2000, 2010, and 2016. Table 2 shows parameter estimates for each regression. Data points in the figures show mean mortality rates for each poverty ventile for 1960 and 2016 only to improve readability of the figures. Data on mortality rates are from the CDC, and data on poverty rates are from the U.S. Census Bureau.

  • Fig. 2 Mortality-poverty gradient estimates.

    (A) shows results for infant mortality, (B) shows results for neonatal mortality, and (C) shows results for postneonatal mortality. The lines in each figure show parameter estimates of the effect of increasing one unit in the poverty ventile distribution on the given mortality rate, estimated in each year using Eq. 1. The shaded areas show the 95% confidence intervals based on SEs clustered at the poverty ventile level. Table 2 reports parameter estimates and SEs. Data on mortality rates are from the CDC, and data on poverty rates are from the U.S. Census Bureau.

  • Fig. 3 Mortality rates, fitted values, and gradients, by gender.

    Both panels show results for infant mortality. Because of data limitations, the first available year of data for these figures is 1970. The lines in (A) and the gradients in (B) are based on estimates from weighted county-level regressions each year using Eq. 1. Table 2 reports parameter estimates for each regression. In (A), data points show mean mortality rates for each poverty ventile for 1970 and 2016 only to improve readability of the figures. In (B), we omit the confidence intervals to increase readability of the figure as the confidence intervals overlap in each year. Data on mortality rates are from the CDCs, and data on poverty rates are from the U.S. Census Bureau.

  • Fig. 4 Counterfactual and actual mortality rates, by year.

    (A) shows results for infant mortality rates, (B) shows results for neonatal mortality rates, and (C) shows results for postneonatal mortality rates (mortality rates defined in the notes to Table 1). The solid lines show actual mortality rates. The dashed lines show counterfactual mortality rates, defined as the mortality rate that would exist if (i) the mortality gradient remained at the 1960 value reported in Table 2 and (ii) each poverty ventile experienced a reduction in mortality rates over time equal to the actual reduction experienced by the least poor ventile. Table S1 reports the counterfactual estimates in each year. Data on mortality rates are from the CDC, and data on poverty rates are from the U.S. Census Bureau.

  • Table 1 Mean poverty rates and mortality rates, by poverty ventile, 1960 and 2016.

    Poverty ventiles (equally sized groups representing 5% of the population) are defined in each year based on county-level data using population estimates from the CDC and poverty rates from the U.S. Census Bureau. Means are calculated as the population-weighted average across all counties in each poverty ventile and are reported for 1960 and 2016. Columns 2 and 3 report the average poverty rate. The remainder of the columns report 1-year mortality rates (expressed as deaths per 1000 births). Columns 4 and 5 show the infant mortality rate (deaths before age 1), columns 6 and 7 report neonatal mortality rate (deaths from 0 to 28 days), and columns 8 and 9 report postneonatal mortality rate (deaths from 29 to 364 days). Data for mortality rates are from the CDC, and data for poverty rates are from the U.S. Census Bureau.

    Poverty ventilePoverty rateInfant mortality rateNeonatal mortality ratePostneonatal mortality rate
    19602016196020161960201619602016
    (1)(2)(3)(4)(5)(6)(7)(8)(9)
    16.75.820.44.016.02.84.31.2
    28.87.421.84.216.83.14.91.1
    310.38.621.94.816.63.35.31.5
    411.99.623.85.018.43.55.41.6
    512.510.524.25.017.73.36.51.7
    613.011.323.35.417.53.95.81.5
    713.712.223.95.618.13.85.81.9
    814.612.924.05.217.93.36.11.9
    915.813.724.05.118.23.35.71.8
    1016.714.325.06.118.74.06.32.2
    1117.615.224.46.518.14.16.32.4
    1219.215.826.16.619.64.56.42.1
    1321.316.224.56.217.94.36.61.9
    1423.616.627.36.920.14.57.22.4
    1526.016.926.65.719.33.97.31.8
    1629.517.726.66.119.04.07.62.0
    1732.918.828.17.319.64.78.52.6
    1838.120.129.56.919.64.39.92.5
    1947.322.432.17.020.54.411.62.6
    2061.827.838.27.622.34.716.02.9
  • Table 2 Mortality-poverty gradient estimates.

    (A) shows results for infant mortality, (B) shows results for neonatal mortality, and (C) shows results for postneonatal mortality. Each coefficient and SE (shown in brackets) is from a separate regression and represents the effect on the given mortality rate of increasing one unit on the poverty ventile distribution, estimated using Eq. 1. Gender-specific mortality rates are available in 1970 and later years only. SEs are clustered at the poverty ventile level. Data on mortality rates are from the CDC, and data on poverty rates are from the U.S. Census Bureau.

    Sample1960197019801990200020102016
    (A) Infant mortality
    Entire sample0.5810.3740.2610.2100.1410.1450.153
    [0.111][0.052][0.025][0.026][0.031][0.014][0.014]
    N3096310431043128313431363137
    Females0.3380.2480.1870.1320.1330.145
    [0.053][0.025][0.025][0.030][0.018][0.017]
    N304631033128313231363134
    Males0.4060.2760.2340.1500.1560.160
    [0.058][0.030][0.030][0.037][0.015][0.016]
    N304331043127313431353135
    (B) Neonatal mortality
    Entire sample0.2180.2120.1390.1150.0670.0660.083
    [0.031][0.020][0.016][0.022][0.020][0.008][0.008]
    N3096310431043128313431363137
    Females0.1810.1300.0980.0560.0640.074
    [0.024][0.016][0.019][0.019][0.012][0.012]
    N304631033128313231363134
    Males0.2380.1480.1320.0780.0670.091
    [0.023][0.020][0.027][0.024][0.009][0.009]
    N304331043127313431353135
    (C) Postneonatal mortality
    Entire sample0.3630.1620.1230.0950.0740.0790.070
    [0.086][0.038][0.012][0.008][0.013][0.007][0.008]
    N3096310431043128313431363137
    Females0.1580.1180.0890.0760.0700.072
    [0.035][0.013][0.009][0.012][0.009][0.009]
    N304631033128313231363134
    Males0.1680.1270.1010.0720.0880.069
    [0.044][0.012][0.009][0.015][0.008][0.009]
    N304331043127313431353135

Supplementary Materials

  • Supplementary Materials

    The evolution of infant mortality inequality in the United States, 1960–2016

    Nick Turner, Kaveh Danesh, Kelsey Moran

    Download Supplement

    This PDF file includes:

    • Data Sources
    • Tables S1 to S7
    • Figs. S1 and S2

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article