Non-Hodgkin lymphoma and gluten-sensitive enteropathy: estimate of risk using meta-analyses.

OBJECTIVES: Gluten-sensitive enteropathy, including coeliac disease and dermatitis herpetiformis, is associated with non-Hodgkin lymphoma (NHL), and particularly enteropathy-associated T-cell lymphoma (EATCL). We conducted a meta-analysis to quantify the association. METHODS: Fifty-four risk estimates (range 0.28-300) were pooled using random-effects meta-analysis. Potential sources of variation were examined using sensitivity analyses and meta-regression. RESULTS: Thirty-one estimates with gluten-sensitive enteropathy diagnosed by serology then biopsy, serology alone, or recorded in medical notes accounted for half the variation in risks, giving a pooled estimate of 4.42 (95% confidence interval (CI) 3.72-5.26, I2 = 0%). Men and women had similar pooled risks. Risks were largest when these conditions were diagnosed using biopsy and lowest when self-reported. Study design, comparison population, geography or gluten-sensitive enteropathy type explained less of the variation. EATCL estimates ranged from 6 to 200; an association with diffuse large B-cell lymphoma (DLBCL) was also observed (pooled risk estimate = 1.97, 95% CI 1.23-3.15). CONCLUSIONS: Where gluten-sensitive enteropathy was diagnosed using modern techniques, NHL risk was increased fourfold. At this level, one in 2,000 persons with gluten-sensitive enteropathy develops NHL each year. In addition to EATCL, DLBCL and possibly other subtypes may be linked to these conditions, and these weaker associations could be investigated in large population-based cohorts with biological samples.

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.

Germ-line transmitted, chromosomally integrated HHV-6 and classical Hodgkin lymphoma.

A unique feature of both human herpesvirus 6A and B (HHV-6A and B) among human herpesviruses is their ability to integrate into chromosomal telomeres. In some individuals integrated viral genomes are present in the germ-line and result in the vertical transmission of HHV-6; however, little is known about the disease associations of germ-line transmitted, chromosomally integrated HHV-6 (ciHHV-6). Recent publications suggest that HHV-6 is associated with classical Hodgkin lymphoma (cHL). Here we examine the prevalence of ciHHV-6 in 936 cases of cHL and 563 controls by screening with a duplex TaqMan assay and confirming with droplet digital PCR. ciHHV-6 was detected in 10/563 (1.8%) controls and in all but one individual the virus was HHV-6B. Amongst cases 16/936 (1.7%) harboured ciHHV-6, thus demonstrating no association between ciHHV-6 and risk of cHL.

Medical history, lifestyle, family history, and occupational risk factors for mycosis fungoides and Sézary syndrome: the InterLymph Non-Hodgkin Lymphoma Subtypes Project.

BACKGROUND: Mycosis fungoides and Sézary syndrome (MF/SS) are rare cutaneous T-cell lymphomas. Their etiology is poorly understood. METHODS: A pooled analysis of 324 MF/SS cases and 17217 controls from 14 case-control studies from Europe, North America, and Australia, as part of the International Lymphoma Epidemiology Consortium (InterLymph) Non-Hodgkin Lymphoma (NHL) Subtypes Project, was carried out to investigate associations with lifestyle, medical history, family history, and occupational risk factors. Multivariate logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: We found an increased risk of MF/SS associated with body mass index equal to or larger than 30 kg/m(2) (OR = 1.57, 95% CI = 1.03 to 2.40), cigarette smoking for 40 years or more (OR = 1.55, 95% CI = 1.04 to 2.31), eczema (OR = 2.38, 95% CI = 1.73 to 3.29), family history of multiple myeloma (OR = 8.49, 95% CI = 3.31 to 21.80), and occupation as crop and vegetable farmers (OR = 2.37, 95% CI = 1.14 to 4.92), painters (OR = 3.71, 95% CI = 1.94 to 7.07), woodworkers (OR = 2.20, 95% CI = 1.18 to 4.08), and general carpenters (OR = 4.07, 95% CI = 1.54 to 10.75). We also found a reduced risk of MF/SS associated with moderate leisure time physical activity (OR = 0.46, 95% CI = 0.22 to 0.97). CONCLUSIONS: Our study provided the first detailed analysis of risk factors for MF/SS and further investigation is needed to confirm these findings in prospective data and in other populations.

Medical history, lifestyle, family history, and occupational risk factors for diffuse large B-cell lymphoma: the InterLymph Non-Hodgkin Lymphoma Subtypes Project.

BACKGROUND: Although risk factors for diffuse large B-cell lymphoma (DLBCL) have been suggested, their independent effects, modification by sex, and association with anatomical sites are largely unknown. METHODS: In a pooled analysis of 4667 cases and 22639 controls from 19 studies, we used stepwise logistic regression to identify the most parsimonious multivariate models for DLBCL overall, by sex, and for selected anatomical sites. RESULTS: DLBCL was associated with B-cell activating autoimmune diseases (odds ratio [OR] = 2.36, 95% confidence interval [CI] = 1.80 to 3.09), hepatitis C virus seropositivity (OR = 2.02, 95% CI = 1.47 to 2.76), family history of non-Hodgkin lymphoma (OR = 1.95, 95% CI = 1.54 to 2.47), higher young adult body mass index (OR = 1.58, 95% CI = 1.12 to 2.23, for 35+ vs 18.5 to 22.4 kg/m(2)), higher recreational sun exposure (OR = 0.78, 95% CI = 0.69 to 0.89), any atopic disorder (OR = 0.82, 95% CI = 0.76 to 0.89), and higher socioeconomic status (OR = 0.86, 95% CI = 0.79 to 0.94). Additional risk factors for women were occupation as field crop/vegetable farm worker (OR = 1.78, 95% CI = 1.22 to 2.60), hairdresser (OR = 1.65, 95% CI = 1.12 to 2.41), and seamstress/embroider (OR = 1.49, 95% CI = 1.13 to 1.97), low adult body mass index (OR = 0.46, 95% CI = 0.29 to 0.74, for <18.5 vs 18.5 to 22.4 kg/m(2)), hormone replacement therapy started age at least 50 years (OR = 0.68, 95% CI = 0.52 to 0.88), and oral contraceptive use before 1970 (OR = 0.78, 95% CI = 0.62 to 1.00); and for men were occupation as material handling equipment operator (OR = 1.58, 95% CI = 1.02 to 2.44), lifetime alcohol consumption (OR = 0.57, 95% CI = 0.44 to 0.75, for >400 kg vs nondrinker), and previous blood transfusion (OR = 0.69, 95% CI = 0.57 to 0.83). Autoimmune disease, atopy, and family history of non-Hodgkin lymphoma showed similar associations across selected anatomical sites, whereas smoking was associated with central nervous system, testicular and cutaneous DLBCLs; inflammatory bowel disease was associated with gastrointestinal DLBCL; and farming and hair dye use were associated with mediastinal DLBCL. CONCLUSION: Our results support a complex and multifactorial etiology for DLBCL with some variation in risk observed by sex and anatomical site.

Medical history, lifestyle, family history, and occupational risk factors for marginal zone lymphoma: the InterLymph Non-Hodgkin Lymphoma Subtypes Project.

BACKGROUND: Marginal zone lymphoma (MZL), comprised of nodal, extranodal, and splenic subtypes, accounts for 5%-10% of non-Hodgkin lymphoma cases. A detailed evaluation of the independent effects of risk factors for MZL and its subtypes has not been conducted. METHODS: Data were pooled from 1052 MZL cases (extranodal [EMZL] = 633, nodal [NMZL] = 157, splenic [SMZL] = 140) and 13766 controls from 12 case-control studies. Adjusted unconditional logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Novel findings for MZL subtypes include increased risk for B-cell activating autoimmune conditions (EMZL OR = 6.40, 95% CI = 4.24 to 9.68; NMZL OR = 7.80, 95% CI = 3.32 to 18.33; SMZL OR = 4.25, 95% CI = 1.49 to 12.14), hepatitis C virus seropositivity (EMZL OR = 5.29, 95% CI = 2.48 to 11.28), self-reported peptic ulcers (EMZL OR = 1.83, 95% CI = 1.35 to 2.49), asthma without other atopy (SMZL OR = 2.28, 95% CI = 1.23 to 4.23), family history of hematologic cancer (EMZL OR = 1.90, 95% CI = 1.37 to 2.62) and of non-Hodgkin lymphoma (NMZL OR = 2.82, 95% CI = 1.33 to 5.98), permanent hairdye use (SMZL OR = 6.59, 95% CI = 1.54 to 28.17), and occupation as a metalworker (NMZL OR = 3.56, 95% CI = 1.67 to 7.58). Reduced risks were observed with consumption of any alcohol (EMZL fourth quartile OR = 0.48, 95% CI = 0.28 to 0.82) and lower consumption of wine (NMZL first to third quartile ORs < 0.45) compared with nondrinkers, and occupation as a teacher (EMZL OR = 0.58, 95% CI = 0.37 to 0.88). CONCLUSION: Our results provide new data suggesting etiologic heterogeneity across MZL subtypes although a common risk of MZL associated with B-cell activating autoimmune conditions was found.

Rationale and Design of the International Lymphoma Epidemiology Consortium (InterLymph) Non-Hodgkin Lymphoma Subtypes Project.

BACKGROUND: Non-Hodgkin lymphoma (NHL), the most common hematologic malignancy, consists of numerous subtypes. The etiology of NHL is incompletely understood, and increasing evidence suggests that risk factors may vary by NHL subtype. However, small numbers of cases have made investigation of subtype-specific risks challenging. The International Lymphoma Epidemiology Consortium therefore undertook the NHL Subtypes Project, an international collaborative effort to investigate the etiologies of NHL subtypes. This article describes in detail the project rationale and design. METHODS: We pooled individual-level data from 20 case-control studies (17471 NHL cases, 23096 controls) from North America, Europe, and Australia. Centralized data harmonization and analysis ensured standardized definitions and approaches, with rigorous quality control. RESULTS: The pooled study population included 11 specified NHL subtypes with more than 100 cases: diffuse large B-cell lymphoma (N = 4667), follicular lymphoma (N = 3530), chronic lymphocytic leukemia/small lymphocytic lymphoma (N = 2440), marginal zone lymphoma (N = 1052), peripheral T-cell lymphoma (N = 584), mantle cell lymphoma (N = 557), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (N = 374), mycosis fungoides/Sézary syndrome (N = 324), Burkitt/Burkitt-like lymphoma/leukemia (N = 295), hairy cell leukemia (N = 154), and acute lymphoblastic leukemia/lymphoma (N = 152). Associations with medical history, family history, lifestyle factors, and occupation for each of these 11 subtypes are presented in separate articles in this issue, with a final article quantitatively comparing risk factor patterns among subtypes. CONCLUSIONS: The International Lymphoma Epidemiology Consortium NHL Subtypes Project provides the largest and most comprehensive investigation of potential risk factors for a broad range of common and rare NHL subtypes to date. The analyses contribute to our understanding of the multifactorial nature of NHL subtype etiologies, motivate hypothesis-driven prospective investigations, provide clues for prevention, and exemplify the benefits of international consortial collaboration in cancer epidemiology.

A population-based study of venous thrombosis in pregnancy in Scotland 1980-2005.

OBJECTIVES: Data on time trends in the incidence of pregnancy-related venous thromboembolism (VTE) are sparse. This report charts the incidence of pregnancy-related VTE over the period 1980-2005 in Scotland, and discusses the results in relation to potential risk factors. STUDY DESIGN: 1475301 maternity discharges from Scottish hospitals recorded on the Scottish Morbidity Record 2 (SMR2) were included. Incidences of pregnancy-related VTE, antenatal deep venous thromboembolism (DVT), postnatal DVT and pulmonary embolism (PTE) were derived relative to the number of deliveries, and risk factors were analysed using Poisson regression. RESULTS: Over the period, VTE incidence rose from 13.7 to 18.3 per 10000 deliveries, antenatal DVTs from 8.8 to 12.2 per 10000 deliveries and PTE from 1.5 to 3.0 per 10000 deliveries. Postnatal DVTs, on the other hand, declined from 4.2 to 2.7 per 10000 deliveries. Risk factors were: age over 35 years; three or more previous pregnancies; previous VTE; obstetric haemorrhage; and preeclampsia. Antenatal DVT risk was highest in the most deprived areas, where events started increasing before those in less deprived areas. Postnatal DVT risk was increased following caesarean delivery, especially when unplanned, although after 1996, events following emergency caesarean decreased. CONCLUSION: During the 26-year period, pregnancy-related VTEs increased, with the greatest rise for antenatal DVTs. Postnatal DVTs, on the other hand, declined over the period, particularly following emergency section. Thromboprophylaxis use following emergency delivery may have led to the postpartum reduction. To continue to prevent events, risk assessment and intervention are required, particularly antenatally.

Benzene and the risk of non-Hodgkin lymphoma: a review and meta-analysis of the literature.

Benzene, an accepted leukemogen, has been suggested to cause other hemato- and lymphopoietic cancers. Here we review the published literature for non-Hodgkin lymphoma (NHL) and occupational exposure to benzene. Six cohorts, sixteen case-control studies and two studies of other designs were identified through keyword searches of bibliographic databases. Twenty-two of twenty-four studies found no association between NHL and ever exposed to benzene compared to never; a random-effects meta-analysis gave a pooled risk estimate of 1.11 (95% confidence interval 0.94-1.30). Our finding of no effect agrees with one of two previous meta-analyses. The other meta-analysis examined if high benzene exposure increased NHL risk but a lack of consistent exposure categories within the same metric should have precluded pooling risks by exposure level. Instead, we reviewed whether dose-response relationships existed. The best available data came from six studies where exposure was estimated from historical measurements and on the whole, no trends in risks of NHL with rising cumulative, average, peak, or duration of benzene exposure were found. NHL is a heterogeneous group of malignancies and although less well-studied, benzene was not associated with any NHL subtype. In conclusion, benzene at either low or high doses does not increase the risk of NHL.

Occupational exposure to gasoline and the risk of non-Hodgkin lymphoma: a review and meta-analysis of the literature.

AIMS: Gasoline comprises over 500 chemicals, including the known or suspected carcinogens benzene, 1,3-butadiene, ethylbenzene and methyl tert-butyl ether (MTBE). To assess whether work in the production, distribution and use of gasoline is associated with non-Hodgkin lymphoma (NHL), we reviewed the published literature on this topic. METHOD: English-language peer-reviewed articles were identified by keyword searches of bibliographic databases. Twenty-two cohorts and thirteen case-control studies examined the risk of NHL among persons employed in the downstream petroleum industry. RESULT: No positive associations were found with the exception of one study. The pooled risk estimate from a random-effects meta-analysis was 1.02 (95% confidence interval (CI) 0.94-1.12). Although there were no estimates available, exposure is likely to have varied by occupation, location and time period; there was no evidence however that risk estimates varied by any of these factors. NHL is a heterogeneous disease, yet no data were reported for NHL subtypes. CONCLUSION: In summary, there is no suggestion across an extensive literature that exposure to gasoline at the levels workers' experience in an occupational setting increases the risk of NHL.

Melanocortin 1 receptor (MC1R), pigmentary characteristics and sun exposure: findings from a case-control study of diffuse large B-cell and follicular lymphoma.

The relationship between skin cancer and non-Hodgkin lymphoma (NHL) suggests common genetic, host or environmental causes. Ultraviolet radiation (UVR), pigmentary characteristics have been linked with both malignancies, and for skin cancer, the melanocortin 1 receptor (MC1R) which influences pigmentation has also been implicated. This paper reports on the relationship between MC1R, skin, hair and eye colour, time spent outdoors, and diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Persons carrying MC1R homozygote variant alleles at R151C, R160W, D294H and D84E were more likely to have fair skin, red hair and to spend less time outdoors than those who did not. The variant allele at V92M was associated with FL (odds ratio (OR)=1.61, 95% confidence interval (CI) 1.08-2.39) and the r:wild type genotype with DLBCL (OR=0.58, 95% CI 0.38-0.89). Interactions between MC1R genotypes and skin colour influenced DLBCL risk; the RR genotype increased risk in individuals with medium or dark skin, based on 5 cases and no controls, but decreased risk among those of fair skin. On the whole, DLBCL and FL risk were not related to genetic variation in MC1R, pigmentation or time spent outdoors.