We also excluded 481 women with foreign addresses outside the United States, U.S. military, U.S. protectorate, Hawaiian, Alaskan, or missing addresses at the time of randomization or their event, all of which precluded estimation of PM exposures; a total of 26,450 women were included in the PM10 analyses.
Subjects with missing addresses were excluded from the analysis.
As almost a third of cases were missing an address at delivery our assessment of mobility could be biased if these missing data are related to migration out of the region.
Of the 113,905 women, a total of 1362 (1.2%) cases were excluded from the analysis because they were diagnosed at autopsy or through death certificate only (n = 705), had unknown race (n = 647) or missing residential address at diagnosis (n = 10).
Briefly, children ≥ 12 years of age by December 2010 (n = 2,153) were excluded to minimize confounding due to tobacco or alcohol consumption, along with children whose parents answered the English or French versions of the study questionnaire (n = 26), and children with missing residential addresses at baseline questionnaire (n = 42) (see Supplemental Material, Figure S1).
b) We address missing data at single measurements of a repeated measurement study by using the multiple imputation and data augmentation techniques.
We excluded from analysis cases in persons without a valid address because we assumed the address was missing completely at random.
Second, although the multiple imputation method was employed reasonably to address the missing age at menarche, additional 'measurement error' is unavoidable.
20 Missing data on the questionnaire-based cost categories (informal care and production loss) and on the EQ-5D-based health utility scores were replaced using multiple imputation, which is generally used to address data missing at random.
