Mortality ascertainment of participants in the National Wilms Tumor Study using the National Death Index: comparison of active and passive follow-up results

Table 2 Demographic characteristics and NDI* match counts of the known decedents (1979–2001) as ascertained in April 2005

	Total	Match	% Match	OR*†	95% CI*†
Sex
Female	413	364	88.1	1.00
Male	376	345	91.8	1.49	(0.90, 2.48)
Ethnicity
Caucasian, non-Hispanic	551	507	92.0	1.00
African American	147	131	89.1	0.67	(0.35, 1.25)
Asian	13	12	92.3	1.19	(0.13, 11.10)
Hispanic	72	55	76.4	0.30	(0.14, 0.63)
Unknown/Other	6	4	66.7	0.31	(0.05, 1.99)
SSN
Unknown	606	532	87.8	1.00
Known	183	177	96.7	4.04	(1.54, 10.58)
Place of birth
United States	623	568	91.2	1.00
Foreign	23	13	56.5	0.12	(0.04, 0.34)
Unknown	143	128	89.5	1.02	(0.54, 1.94)
Age at death
0–4 years	245	231	90.9	1.00
5–9 years	329	291	88.4	0.61	(0.33, 1.10)
10–19 years	156	141	90.4	0.60	(0.28, 1.32)
20+ years	50	46	92.0	0.35	(0.09, 1.37)
Total	789	709	89.9

* NDI, National Death Index; OR, odds ratio; CI confidence interval.
† Odds ratios and 95 percent confidence intervals adjusted for sex, ethnicity, presence of SSN, year of death, location of birth, age at death group, location of treatment institution, institutional compliance and NWTS recorded cause of death.