Reproductive factors, menopausal hormone therapy, and risk of non-Hodgkin, diffuse large B-cell and follicular lymphomas: a UK case-control study.

BACKGROUND

Most non-Hodgkin lymphoma (NHL) subtypes occur more among men than women. Since sex hormones may influence immune function, female hormones may be involved. To investigate the relationship between NHL subtypes and reproductive factors, findings from a UK population-based case-control study (1998-2003) are presented.

METHODS

Female cases (n = 389) and controls (n = 394) aged 16-69 reported their reproductive histories. Odds ratios (ORs) and 95% confidence intervals (CI) were computed using unconditional logistic regression.

RESULTS

No associations were found for age at menarche, parity, or age at first child. Among postmenopausal women, hormone therapy (HT) users had risks of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) below one compared to non-users (OR = 0.7, 95% CI 0.5,1.2; OR = 0.6, 95% CI 0.4,1.0, respectively). Estimates agree with other reports: meta-analyses gave pooled ORs of 0.8 (95% CI 0.6,0.9) for DLBCL and 1.0 (95% CI 0.8,1.2) for FL. In our study, ORs decreased with years of HT use: less and more than 5 years being 0.9 (95% CI 0.5,1.5) and 0.6 (95% CI 0.3,1.1) for DLBCL (p-trend = 0.22), and 0.8 (95% CI 0.4,1.4) and 0.4 (95% CI 0.2,0.9) for FL (p-trend = 0.06).

CONCLUSION

For greater power to investigate the association of hormones with DLBCL, FL, and rarer NHL subtypes, pooling data through the International Lymphoma Epidemiology Consortium (InterLymph) is warranted.