Table 2.

Demographic Characteristics of Cases and Controls From 18 Non-Hodgkin Lymphoma Case-Control Studies Included in a Pooled Analysis of Birth Order/Sibship Size and Risk of Non-Hodgkin Lymphoma, 1983–2005

Demographic Factor	Cases		Controls
	No.	%	No.	%
Pooled total	13,535		16,427
Sex
Male	7,329	54.1	8,865	54.0
Female	6,206	45.9	7,562	46.0
Age, yearsa
<20	25	0.2	56	0.3
20–29	381	2.8	842	5.1
30–39	924	6.8	1,602	9.8
40–49	1,823	13.5	2,386	14.5
50–59	3,472	25.7	3,729	22.7
60–69	4,313	31.9	4,759	29.0
70–79	2,448	18.1	2,885	17.6
≥80	147	1.1	168	1.0
Education/SES (tertile)
Low	5,205	38.5	5,802	35.3
Medium	4,643	34.3	5,883	35.8
High	3,577	26.4	4,642	28.2
Unknown/other	110	0.8	100	0.6
Race/ethnicity
White	5,672	41.9	6,757	41.1
Black	202	1.5	327	2.0
Other/mixed	539	4.0	558	3.4
Missing data	7,122	52.6	8,785	53.5

Abbreviation: SES, socioeconomic status.

^aThe median age of cases was 58 years (range, 16–96); the median age of controls was 60 years (range, 17–89). Data on age were missing for 2 cases.