|Parameter||Base scenarioa||Low scenarioa||High scenarioa|
|IQR, interquartile range.
aBase scenario estimates are based on OR of 1.15; low and high scenario estimates are based on ORs of 1.07 and 1.16, respectively. For calculations, please see “Methods.”
bMedian RR estimated using the MEDIAN function in Excel (Microsoft).
cLost economic productivity due to reduced cognitive potential was measured as an indirect cost of PM2.5-attributable PTB. PTB-associated IQ loss was calculated using data from a systematic review that estimates an 11.9-point IQ decrement on average in PTB children (95% CI: 10.5, 13.4). See “Methods.”
dTwo types of direct costs of PTB were estimated: costs for treatment of PTB-associated medical conditions in the first 5 years of life, and costs after the first 5 years of life due to PTB-associated developmental disability. See “Methods.”
|Range of relative risks||1.000–1.352||1.000–1.159||1.000–1.429|
|Median relative risk (IQR)b||1.003 (1.000–1.045)||1.002 (1.000–1.021)||1.043 (1.011–1.089)|
|Percentage with RR above 1 (RR = 1 indicates risk unchanged)||63.4%||63.4%||91.7%|
|Attributable preterm births (n)||15,808||7,532||29,968|
|Lost economic productivity, PM2.5-attributable preterm birthsc||$4.33 billion||$2.06 billion||$8.22 billion|
|Additional medical care, PM2.5-attributable preterm birthsd||$760 million||$362 million||$1.44 billion|
|Total costs, PM2.5-attributable preterm births||$5.09 billion||$2.43 billion||$9.66 billion|