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. Author manuscript; available in PMC: 2018 Oct 1.
Published in final edited form as: Environ Int. 2017 Jul 22;107:173–180. doi: 10.1016/j.envint.2017.07.012

Table 5.

Linear models with and without surrogate study variable for the association between PM2.5 over pregnancy and birth weight for gestational age z-score.

Model β 95% CI P-value
1* −0.001 −0.013, 0.011 0.92
2# −0.015 −0.022, −0.008 <0.0001

β represents the change in birth weight z-score per 1 unit increase in PM2.5 (μg/m3) during thethird trimester of pregnancy

Adjusted for maternal education (≤ high school or > higher school), race/ethnicity (white/non-Hispanic or non-white and/or Hispanic), age at birth (continuous), and pre-pregnancy BMI (continuous).

*

Model 1: Includes study variable (ACCESS, PROGRESS, PRISM)

#

Model 2: Includes surrogate study variable, Surrogate Site 1 (PROGRESS and ACCESS) and Surrogate Site 2 (PRISM).