Maternal proximity to Central Appalachia surface mining and birth outcomes

Maternal residency in Central Appalachia counties with coal production has been previously associated with increased rates of low birth weight (LBW). To refine the relationship between surface mining and birth outcomes, this study employs finer spatiotemporal estimates of exposure.

We developed characterizations of annual surface mining boundaries in Central Appalachia between 1986 and 2015 using Landsat data. Maternal address on birth records was geocoded and assigned amount of surface mining within a 5 km radius of residence (street-level). Births were also assigned the amount of surface mining within residential ZIP code tabulation area (ZCTA). Associations between exposure to active mining during gestation year and birth weight, LBW, preterm birth (PTB), and term low birth weight (tLBW) were determined, adjusting for outcome rates before active mining and available covariates.

The percent of land actively mined within a 5 km buffer of residence (or ZCTA) was negatively associated with birth weight (5 km: β = -14.07 g; 95% confidence interval [CI] = -19.35, -8.79, P = 1.79 × 10^-7; ZCTA: β = -9.93 g; 95% CI = -12.54, -7.33, P = 7.94 × 10^-14). We also found positive associations between PTB and active mining within 5 km (odds ratio [OR] = 1.06; 95% CI = 1.03, 1.09, P = 1.43 × 10^-4) and within ZCTA (OR = 1.04; 95% CI = 1.03, 1.06, P = 9.21 × 10^-8). Positive relationships were also found between amount of active mining within 5 km or ZIP code of residence and LBW and tLBW outcomes.

Maternal residency near active surface mining during gestation may increase risk of PTB and LBW.