word of mouth. All study controls were frequency matched to cases by 5-year age group, sex, and race. Questions about family history and smoking history were obtained using the same questionnaires in each study. The family history study case interview response rate was 67.7%, and biospecimens, including blood, buccal cells through buccal brush or mouthwash collection, and normal tissue from paraffin-embedded tissue, were collected for 53.5% of these cases. The control participation rate was 93.1% of those completing the eligibility screeners, with 50.3% providing biospecimens. The women’s epidemiology of lung diseases study had an interview participation rate for cases of 54.2%, for controls of 69.6%, with biospecimens collected for 98.6% of subjects. The EXHALE study is still recruiting and, to date, 87.3% of subjects have provided a biospecimen. Volunteer controls were selected for the EXHALE study that focuses on using admixture mapping to identify novel genes for lung cancer. It is unlikely that unknown genotype influences volunteer participation or participation in any of the studies. Because 92% of all cases had NSCLC, the results are restricted to 1058 NSCLC cases and 1314 controls providing a biospecimen. Thirty-nine percent of the cases and 34% of the controls included were African Americans.
