Risk factors for young adult Hodgkin lymphoma diagnosed between 13 and 50 years of age in disease-discordant twin pairs
| Exposure/twin set by response . | Ratio of exposure, discordant pairs* . | Odds ratio† . | 95% CI‡ . | P§ . |
|---|---|---|---|---|
| Appendectomy | ||||
| Total‖ | 33/11 | 3.0 | 1.5-5.9 | .002 |
| Double respondent¶ | 18/5 | 3.6 | 1.3-9.7 | .01 |
| Tonsillectomy#** | ||||
| Total‖ | 16/8 | 2.0 | 0.8-4.7 | .11 |
| Double respondent¶ | 10/3 | |||
| Smoked cigarettes, ever/never#** | ||||
| Total‖ | 21/13 | 1.6 | 0.8-3.2 | .17 |
| Double respondent¶ | 10/7 | |||
| Eczema# | ||||
| Total‖ | 14/5 | 2.8 | 1.0-7.8 | .048 |
| Double respondent¶ | 8/2 | |||
| Infectious mononucleosis | ||||
| Total‖ | 22/19 | 1.2 | 0.6-2.1 | .64 |
| Double respondent¶ | 10/9 | 1.1 | 0.4-2.7 | .82 |
| Exposure/twin set by response . | Ratio of exposure, discordant pairs* . | Odds ratio† . | 95% CI‡ . | P§ . |
|---|---|---|---|---|
| Appendectomy | ||||
| Total‖ | 33/11 | 3.0 | 1.5-5.9 | .002 |
| Double respondent¶ | 18/5 | 3.6 | 1.3-9.7 | .01 |
| Tonsillectomy#** | ||||
| Total‖ | 16/8 | 2.0 | 0.8-4.7 | .11 |
| Double respondent¶ | 10/3 | |||
| Smoked cigarettes, ever/never#** | ||||
| Total‖ | 21/13 | 1.6 | 0.8-3.2 | .17 |
| Double respondent¶ | 10/7 | |||
| Eczema# | ||||
| Total‖ | 14/5 | 2.8 | 1.0-7.8 | .048 |
| Double respondent¶ | 8/2 | |||
| Infectious mononucleosis | ||||
| Total‖ | 22/19 | 1.2 | 0.6-2.1 | .64 |
| Double respondent¶ | 10/9 | 1.1 | 0.4-2.7 | .82 |
Total number of twin pairs in which case-twin was exposed and the unaffected cotwin was unexposed/total number of twin pairs in which unaffected cotwin was exposed and the case-twin was unexposed.
Odds ratio estimated using conditional logistic regression using SAS Version 9.1.
Confidence interval estimated using conditional logistic regression.
P value estimated from the Wald test.
One hundred eighty-eight total pairs = double- and single-respondent twin pairs. Single-respondent pairs are those in whom only 1 member of the pair sent a questionnaire but answered questions about their twin's exposures (eg, proxy report for the nonresponding twin).
Ninety-three double-respondent pairs. Double respondent pair = both members of the twin pair sent back a questionnaire; answers are based on self-report.
Results are not presented for double-responding twin pairs separately since the number of exposure-discordant pairs was less than 18.
Lower 95% confidence interval for kappa 0.70 or higher.