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Table 1 Characteristics of the study population of term born infants and their mothers

From: Investigating the association between birth weight and complementary air pollution metrics: a cohort study

Subject characteristics Number of subjects Mean birth weight (g) Standard deviation in birth weight (g) % of infants with a low birth weight (<2,500 g)
Infant’s gender     
Female 36,133 3,408.2 459.7 2.09
Male 38,283 3,527.5 473.5 1.35
Race/ethnicity of mothers     
AfricanAm 6,261 3,329.7 475.2 3.19
Asian 7,358 3,314.7 444.2 2.57
Hispanic 23,678 3,469.0 461.7 1.59
Caucasian 30,548 3,542.4 464.4 1.23
Mixed 322 3,473.2 458.2 0.93
Other 3,095 3,413.4 483.2 2.23
Missing 3,154 3,462.3 479.8 1.84
Insurance status of mothers     
Private 50,880 3,490.7 468.1 1.53
Public 20,525 3,418.5 475.9 2.2
Missing 3,011 3,460.2 450.3 1.3
Chronic hypertension in mothers     
No 74,138 3,469.8 470.3 1.7
Yes 278 3,395.9 551.7 3.96
Heart diseases in mothers     
No 74,333 3,469.7 470.6 1.7
Yes 83 3,309.7 511.1 6.02
Preeclampsia in mothers     
No 72,760 3,473.0 467.6 1.58
Yes 1656 3,319.4 570.2 7.37
Diabetes in mothers     
No 70,622 3,463.5 465.6 1.73
Yes 3794 3,582.5 544.6 1.34
Maternal weight gain during pregnancy     
Low (<15 lbs) 1286 3,376.1 491.1 3.34
Medium 57,727 3,445.9 463.2 1.79
High (>30 lbs) 15,397 3,566.1 483.5 1.24
Missing 6 2,978.8 686.4 0.08
Parity     
First delivery 60,382 3,458.3 471.4 1.81
At least second delivery 14,034 3,518.0 464.4 1.26