HealthDay News — Fertility rates among nearby populations appear to increase after coal and oil power plant retirements, according to a study published recently in Environmental Health.

Joan A. Casey, PhD, from the University of California at Berkeley, and colleagues analyzed the changes in annual fertility rates among California mothers living within 0 to 5km and 5 to 10km of eight retired power plants (2001 to 2011). Use of the difference-in-differences method isolated the portion of the pre- vs post-retirement effects due to retirement rather than secular trends (controlled for by evaluating mothers living 10 to 20km away). 

The researchers estimated that after power plant retirement, annual fertility rates per 1000 women aged 15 to 44 years increased by 8 births within 5km and 2 births within 5 to 10km of power plants, yielding incident rate ratios of 1.2 (95% confidence interval, 1.1 to 1.4) and 1.1 (95% confidence interval, 1.0 to 1.2), respectively. There was no association in analysis for negative exposure control that used randomly selected, unretired power plants over the same time period as the original 8 power plants, suggesting that statewide temporal trends did not account for these results.

“Fertility rates among nearby populations appeared to increase after coal and oil power plant retirements. Our study design limited the possibility that our findings resulted from temporal trends or changes in population composition,” the authors write. “These results require confirmation in other populations, given known methodological limitations of ecologic study designs.”

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