Table 3

Low birthweight (LBW) singleton births among mothers 15 to 55 years old, stratified by the census block group (BG), census tract (CT), and zip code (ZC) area based socioeconomic measures for births in areas with the least and most resources: proportion, odds ratio (OR), and relative index of inequality (RII) for Massachusetts (1989–1991; n=239564) and Rhode Island (1987–1993; n=84995)*

Proportion %: least resourcesProportion %: most resourcesOR: least/most (95% CI)RII (95% CI)
Health outcomeArea based socioeconomic measureBGCTZCBGCTZCBGCTZCBGCTZC
*See appendix for cut off points used for each variable.
% LBW (<2500 g) singleton: MAWorking class (categorical)6.36.45.63.53.53.61.85 (1.73 to 1.98)1.87 (1.74 to 2.01)1.35 (1.23 to 1.48)2.13 (1.98 to 2.29)2.11 (1.97 to 2.26)1.91 (1.77 to 2.05)
Unemployed (quintile)6.56.86.23.93.53.51.72 (1.61 to 1.84)1.99 (1.86 to 2.12)1.58 (1.46 to 1.70)2.09 (1.95 to 2.24)2.37 (2.21 to 2.53)2.19 (2.04 to 2.36)
Median household income (quintile)6.66.76.33.33.33.32.06 (1.93 to 2.19)2.07 (1.94 to 2.20)1.61 (1.52 to 1.71)2.51 (2.34 to 2.69)2.48 (2.32 to 2.66)2.41 (2.24 to 2.59)
Poverty (categorical)7.47.57.63.73.63.72.08 (1.98 to 2.19)2.16 (2.05 to 2.28)1.90 (1.80 to 2.00)2.69 (2.51 to 2.89)2.74 (2.55 to 2.93)2.61 (2.43 to 2.80)
Gini (quintile)6.16.56.23.94.03.71.59 (1.49 to 1.69)1.66 (1.56 to 1.76)1.57 (1.47 to 1.67)1.80 (1.68 to 1.93)1.88 (1.76 to 2.01)2.07 (1.93 to 2.22)
Wealth (categorical)4.95.05.13.83.63.71.32 (1.23 to 1.42)1.41 (1.31 to 1.51)1.23 (1.15 to 1.31)1.79 (1.62 to 1.98)1.79 (1.63 to 1.96)1.80 (1.64 to 1.98)
Crowding (quintile)6.77.16.33.93.73.51.76 (1.69 to 1.84)2.01 (1.89 to 2.14)1.59 (1.47 to 1.71)2.42 (2.25 to 2.60)2.55 (2.38 to 2.73)2.39 (2.22 to 2.57)
Low education (categorical)6.96.96.23.63.63.51.97 (1.86 to 2.08)1.99 (1.88 to 2.12)1.61 (1.51 to 1.72)2.48 (2.31 to 2.66)2.43 (2.27 to 2.60)2.33 (2.17 to 2.50)
High education (categorical)6.06.16.03.63.73.91.71 (1.61 to 1.82)1.67 (1.57 to 1.78)1.40 (1.32 to 1.50)2.15 (2.00 to 2.31)2.11 (1.97 to 2.26)1.83 (1.71 to 1.97)
Townsend index (quintile)7.07.26.13.33.33.42.19 (2.05 to 2.34)2.24 (2.10 to 2.39)1.57 (1.46 to 1.68)2.85 (2.65 to 3.06)2.79 (2.60 to 2.99)2.50 (2.32 to 2.69)
Index of Local Economic Resources (quintile)6.76.96.33.43.43.32.05 (1.93 to 2.19)2.09 (1.97 to 2.22)1.62 (1.53 to 1.72)2.59 (2.42 to 2.78)2.55 (2.39 to 2.73)2.36 (2.20 to 2.54)
Factor 1 (quintile)6.66.96.13.33.43.32.03 (1.91 to 2.16)2.11 (1.99 to 2.25)1.59 (1.49 to 1.70)2.61 (2.43 to 2.81)2.65 (2.47 to 2.83)2.49 (2.31 to 2.68)
Factor 2 (quintile)6.36.56.13.43.53.61.93 (1.81 to 2.06)1.91 (1.79 to 2.04)1.50 (1.40 to 1.59)2.33 (2.17 to 2.51)2.27 (2.12 to 2.43)2.04 (1.90 to 2.19)
SEP Index (quintile)6.66.96.13.23.43.22.11 (1.98 to 2.26)2.09 (1.96 to 2.23)1.60 (1.51 to 1.71)2.64 (2.45 to 2.83)2.55 (2.38 to 2.73)2.42 (2.25 to 2.61)
SEP1 (categorical)7.67.46.83.33.53.62.40 (2.19 to 2.64)2.21 (2.03 to 2.41)1.65 (1.47 to 1.85)2.46 (2.28 to 2.65)2.54 (2.36 to 2.73)2.36 (2.18 to 2.57)
Median value6.66.96.23.53.53.61.972.011.592.462.482.36
% LBW (<2500 g) singleton: RIWorking class (categorical)6.66.86.93.63.45.01.91 (1.65 to 2.22)2.06 (1.71 to 2.48)1.40 (1.15 to 1.69)2.22 (1.98 to 2.49)2.30 (2.06 to 2.58)1.98 (1.77 to 2.21)
Unemployed (quintile)7.07.26.84.74.23.51.51 (1.37 to 1.67)1.75 (1.59 to 1.93)2.00 (1.77 to 2.27)1.79 (1.61 to 1.99)2.18 (1.95 to 2.43)2.11 (1.89 to 2.35)
Median household income (quintile)7.57.56.73.53.73.62.28 (2.05 to 2.53)2.10 (1.90 to 2.32)1.93 (1.68 to 2.23)2.71 (2.43 to 3.03)2.63 (2.36 to 2.93)2.35 (2.10 to 2.63)
Poverty (categorical)7.67.77.64.04.13.61.97 (1.82 to 2.13)1.96 (1.81 to 2.14)2.17 (1.95 to 2.43)2.52 (2.26 to 2.81)2.52 (2.26 to 2.81)2.44 (2.18 to 2.72)
Gini (quintile)6.36.66.64.44.54.31.48 (1.34 to 1.64)1.51 (1.37 to 1.66)1.59 (1.33 to 1.89)1.64 (1.47 to 1.83)1.63 (1.47 to 1.81)1.89 (1.69 to 2.11)
Wealth (categorical)5.65.75.73.03.74.51.93 (1.55 to 2.41)1.55 (1.28 to 1.87)1.27 (1.08 to 1.49)2.06 (1.68 to 2.51)2.17 (1.82 to 2.58)1.75 (1.51 to 2.03)
Crowding (quintile)7.07.36.54.43.93.21.63 (1.52 to 1.74)1.95 (1.76 to 2.16)2.15 (1.76 to 2.62)2.20 (1.97 to 2.47)2.42 (2.17 to 2.70)2.08 (1.86 to 2.33)
Low education (categorical)7.17.36.83.93.74.01.91 (1.73 to 2.10)2.08 (1.85 to 2.33)1.74 (1.56 to 1.94)2.50 (2.24 to 2.80)2.47 (2.21 to 2.76)1.99 (1.78 to 2.22)
High education (categorical)6.36.46.33.83.84.21.70 (1.48 to 1.96)1.75 (1.53 to 2.01)1.53 (1.31 to 1.77)2.11 (1.87 to 2.37)2.26 (2.01 to 2.54)1.75 (1.56 to 1.96)
Townsend index (quintile)7.27.56.63.83.73.31.98 (1.78 to 2.20)2.11 (1.91 to 2.33)2.05 (1.68 to 2.50)2.57 (2.30 to 2.87)2.71 (2.43 to 3.02)2.42 (2.16 to 2.72)
Index of Local Economic Resources (quintile)7.47.46.83.73.73.92.07 (1.87 to 2.29)2.09 (1.90 to 2.31)1.80 (1.64 to 1.98)2.46 (2.20 to 2.75)2.53 (2.27 to 2.82)2.26 (2.02 to 2.53)
Factor 1 (quintile)7.37.56.43.73.73.52.04 (1.85 to 2.26)2.07 (1.87 to 2.30)1.91 (1.61 to 2.26)2.57 (2.30 to 2.87)2.63 (2.36 to 2.93)2.34 (2.08 to 2.63)
Factor 2 (quintile)7.07.16.33.74.24.01.96 (1.76 to 2.18)1.76 (1.59 to 1.95)1.61 (1.45 to 1.80)2.40 (2.15 to 2.68)2.22 (1.99 to 2.47)1.87 (1.68 to 2.09)
SEP Index (quintile)7.57.56.73.53.54.02.21 (1.98 to 2.46)2.21 (1.99 to 2.45)1.74 (1.54 to 1.97)2.71 (2.42 to 3.03)2.65 (2.38 to 2.96)2.23 (1.99 to 2.50)
SEP1 (categorical)7.87.97.73.33.35.12.51 (2.03 to 3.10)2.49 (1.99 to 3.12)1.55 (1.28 to 1.88)2.42 (2.16 to 2.71)2.48 (2.22 to 2.78)2.04 (1.81 to 2.30)
Median value7.17.36.73.73.74.01.962.061.742.422.472.08