Table I.
Selected characteristics of the NCI-SEER, Connecticut and NSW NHL case–control studies
| NCI-SEER | Connecticut | NSW | |
| Location | Residents of the Iowa, Detroit, Los Angeles and Seattle SEER registries | Residents of the Connecticut SEER registry | Residents of the Australian State of NSW or the Australian Capital Territory via the NSW Central Cancer Registry |
| Time period | 1998–2000 | 1996–2000 | 2000–2001 |
| Age range (years) | 20–74 | 21–84 | 20–74 |
| Eligibility criteria | Excluded known HIV-positive individuals | Excluded males | Excluded known HIV-positive individuals and organ transplant recipients |
| Histopathologic classification system | ICD-O-2 | REAL | WHO + ICD-O-3 |
| Control selection | <65 years: random digit dialing | <65 years: random digit dialing | Electoral rolls |
| ≥65 years: medicare files | ≥65 years: medicare files | ||
| Matching variables | Age (5 year groups), sex, race and SEER area | Age (5 year groups) | Age (5 year groups), sex, state or territory |
| Study population (participation)a | Cases: n = 1321 (76%) | Cases: n = 601 (72%) | Cases: n = 694 (85%) |
| Controls: n = 1057 (52%) | Controls: n = 717 (<65 years: 69%; ≥65 years: 47%) | Controls: n = 694 (61%) | |
| Risk factor information | Self-administered questionnaire, in-person interview | Self-administered questionnaire, in-person interview | Self-administered questionnaire, telephone interview |
| DNA source | Venous blood or mouthwash buccal cell sample | Venous blood or mouthwash buccal cell sample | Venous blood sample |
| Restrictions for this analysis | Excluded participants who provided a buccal cell sample | Included participants of European or Asian ethnicity (97% of participants) | |
| Genotyped for this analysisb | Cases: n = 1001 | Cases: n = 436 | Cases: n = 524 |
| Controls: n = 834 | Controls: n = 517 | Controls: n = 474 |
HIV, human immunodeficiency virus; ICD-O-2/3, International Classification of Diseases for Oncology, second/third revision; REAL, Revised European American Lymphoma system; WHO, World Health Organization.
Participation was defined as the percentage interviewed among those approached.
Study participants who did not provide a biologic specimen, did not have sufficient material for DNA extraction or sufficient DNA for genotyping or whose genotyped sex was discordant from the questionnaire data were excluded from this analysis. As described in Materials and Methods, the final analytic population further excluded participants with a low sample completion rate (NCI-SEER: 11 cases, 6 controls; Connecticut: 2 controls; NSW: 4 cases, 9 controls).