Overweight and Obesity at Different Times in Life as Risk Factors for Non-Hodgkin's Lymphoma: The Multiethnic Cohort

Epidemiology and etiology of diffuse large B-cell lymphoma

As the most common non-Hodgkin lymphoma subtype, diffuse large B-cell lymphoma (DLBCL) incidence patterns generally parallel that for NHL overall. Globally, DLBCL accounts for a third of all NHLs, ranging between 20% and 50% by country. Based on United States (U.S.) cancer registry data, age-standardized incidence rate for DLBCL was 7.2 per 100,000. DLBCL incidence rises with age and is generally higher in males than females; in the U.S., incidence is highest among non-Hispanic whites (9.2/100,000). Like NHL incidence, DLBCL incidence rose in the first half of the 20th century but has largely plateaued. However, there is some evidence that incidence rates are rising in areas of historically low rates, such as Asia; there are also estimates for rising DLBCL incidence in the near future due to the changing demographics in developed countries whose aging population is growing. Established risk factors for DLBCL include those that result in severe immune deficiency such as HIV/AIDS, inherited immunodeficiency syndromes, and organ transplant recipients. Factors that lead to chronic immune dysregulations are also established risk factors, and include a number of autoimmune conditions (eg, Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis), viral infections (eg, HIV, KSHV/HHV8, HCV, EBV), and obesity. Family history of NHL/DLBCL, personal history of cancer, and multiple genetic susceptibility loci are also well-established risk factors for DLBCL. There is strong evidence for multiple environmental exposures in DLBCL etiology, including exposure to trichloroethylene, benzene, and pesticides and herbicides, with recent associations noted with glyphosate. There is also strong evidence for associations with other viruses, such as HBV. Recent estimates suggest that obesity accounts for nearly a quarter of DLBCLs that develop, but despite recent gains in the understanding of DLBCL etiology, the majority of disease remain unexplained. An understanding of the host and environmental contributions to disease etiology, and concerted efforts to expand our understanding to multiple race/ethnic groups, will be essential for constructing clinically relevant risk prediction models and develop effective strategies for disease prevention.

Association of Obesity and Type 2 Diabetes with Non-Hodgkin Lymphoma: The Multiethnic Cohort

BACKGROUND

Given the role of the immune system in non-Hodgkin lymphoma (NHL) etiology, obesity and type 2 diabetes (T2D) may impact NHL development. We examined the association of body mass index (BMI) and T2D with NHL in the multiethnic cohort (MEC).

METHODS

The MEC recruited >215,000 participants in Hawaii and Los Angeles from five racial/ethnic groups; NHL cases were identified through cancer registry linkages. T2D status, and BMI at age 21 and cohort entry were derived from repeated self-reports; for T2D, Medicare claims were also applied. HRs and 95% confidence intervals (CI) for BMI and T2D as predictors of NHL were determined using Cox regression adjusted for relevant covariates.

RESULTS

Among 192,424 participants, 3,472 (1.8%) with NHL and 68,850 (36%) with T2D after 19.2 ± 6.6 years follow-up, no significant association between T2D and NHL (HR, 1.04; 95% CI, 0.96-1.13) was observed. Stratification by BMI at cohort entry showed a significant association of T2D with NHL among individuals with normal weight only (HR, 1.18; 95% CI, 1.03-1.37). In a model with both BMI values plus T2D, only overweight (HR, 1.13; 95% CI, 1.01-1.26) and obesity (HR, 1.25; 95% CI, 0.99-1.59) at age 21 were associated with NHL incidence. Stratification by sex, race/ethnicity, and NHL subtype indicated no differences.

CONCLUSIONS

Our findings suggest an association between T2D and NHL incidence in several subgroups but not in the total population and an elevated risk related to early-life BMI.

IMPACT

Excess body weight in early life, rather than T2D, may be a predictor of NHL incidence.

GWAS-Identified Variants for Obesity Do Not Influence the Risk of Developing Multiple Myeloma: A Population-Based Study and Meta-Analysis

Multiple myeloma (MM) is an incurable disease characterized by the presence of malignant plasma cells in the bone marrow that secrete specific monoclonal immunoglobulins into the blood. Obesity has been associated with the risk of developing solid and hematological cancers, but its role as a risk factor for MM needs to be further explored. Here, we evaluated whether 32 genome-wide association study (GWAS)-identified variants for obesity were associated with the risk of MM in 4189 German subjects from the German Multiple Myeloma Group (GMMG) cohort (2121 MM cases and 2068 controls) and 1293 Spanish subjects (206 MM cases and 1087 controls). Results were then validated through meta-analysis with data from the UKBiobank (554 MM cases and 402,714 controls) and FinnGen cohorts (914 MM cases and 248,695 controls). Finally, we evaluated the correlation of these single nucleotide polymorphisms (SNPs) with cQTL data, serum inflammatory proteins, steroid hormones, and absolute numbers of blood-derived cell populations (n = 520). The meta-analysis of the four European cohorts showed no effect of obesity-related variants on the risk of developing MM. We only found a very modest association of the POC5_rs2112347G and ADCY3_rs11676272G alleles with MM risk that did not remain significant after correction for multiple testing (per-allele OR = 1.08, p = 0.0083 and per-allele OR = 1.06, p = 0.046). No correlation between these SNPs and functional data was found, which confirms that obesity-related variants do not influence MM risk.

Systematic review of perchloroethylene and non-Hodgkin's lymphoma

We conducted a systematic review of epidemiology studies that evaluated the association between perchloroethylene (PCE) and non-Hodgkin's lymphoma (NHL). This included an independent detailed assessment of a few critical aspects of study quality (i.e., study design, exposure measurement, exposure levels, and potential confounding), and a consideration of other aspects of quality less formally. Of the identified 18 cohort studies of 15 unique cohorts, 17 case-control studies of 14 unique population groups, and 3 ecological studies, none was high quality for all four critical quality elements and each study also had other major methodological study limitations. Reported risk estimates were mostly null, ranged widely from below to above 1, and often had extremely wide confidence intervals (CIs), indicating unstable risk estimates. In addition, there was no consistent evidence of dose-response. Overall, given the low quality of the available epidemiology studies, the evidence does not support an association between PCE exposure and NHL.

Second malignant neoplasms in lymphomas, secondary lymphomas and lymphomas in metabolic disorders/diseases

With inconsistent findings, evidence has been obtained in recent years that metabolic disorders are closely associated with the development of lymphomas. Studies and multiple analyses have been published also indicating that some solid tumor survivors develop a secondary lymphoma, whereas some lymphoma survivors subsequently develop a second malignant neoplasm (SMN), particularly solid tumors. An interaction between the multiple etiologic factors such as genetic factors and late effects of cancer therapy may play an important role contributing to the carcinogenesis in patients with metabolic diseases or with a primary cancer. In this review, we summarize the current knowledge of the multiple etiologic factors for lymphomagenesis, focusing on the SMN in lymphoma, secondary lymphomas in primary cancers, and the lymphomas associated to metabolic disorders/diseases, which have been received less attention previously. Further, we also review the data of coexistence of lymphomas and hepatocellular carcinoma (HCC) in patients with infection of hepatitis C virus and hepatitis B virus.

Associations between early-life growth pattern and body size and follicular lymphoma risk and survival: a family-based case-control study

BACKGROUND

The influence of early-life growth pattern and body size on follicular lymphoma (FL) risk and survival is unclear. In this study, we aimed to investigate the association between gestational age, growth during childhood, body size, changes in body shape over time, and FL risk and survival.

METHODS

We conducted a population-based family case-control study and included 706 cases and 490 controls. We ascertained gestational age, growth during childhood, body size and body shape using questionnaires and followed-up cases (median=83 months) using record linkage with national death records. We used a group-based trajectory modeling approach to identify body shape trajectories from ages 5-70. We examined associations with FL risk using unconditional logistic regression and used Cox regression to assess the association between body mass index (BMI) and all-cause and FL-specific mortality among cases.

RESULTS

We found no association between gestational age, childhood height and FL risk. We observed a modest increase in FL risk with being obese 5 years prior to enrolment (OR=1.43, 95 %CI=0.99-2.06; BMI ≥30 kg/m²) and per 5-kg/m² increase in BMI 5 years prior to enrolment (OR=1.14, 95 %CI=0.99-1.31). The excess risk for obesity 5 years prior to enrolment was higher for ever-smokers (OR=2.00, 95 %CI=1.08-3.69) than never-smokers (OR=1.14, 95 %CI=0.71-1.84). We found no association between FL risk and BMI at enrolment, BMI for heaviest lifetime weight, the highest categories of adult weight or height, trouser size, body shape at different ages or body shape trajectory. We also observed no association between all-cause or FL-specific mortality and excess adiposity at or prior to enrolment.

CONCLUSION

We observed a weak association between elevated BMI and FL risk, and no association with all-cause or FL-specific mortality, consistent with previous studies. Future studies incorporating biomarkers are needed to elucidate possible mechanisms underlying the role of body composition in FL etiology.

Body size and obesity during adulthood, and risk of lympho-haematopoietic cancers: an update of the WCRF-AICR systematic review of published prospective studies

BACKGROUND

To summarise the evidence on the associations between body mass index (BMI) and BMI in early adulthood, height, waist circumference (WC) and waist-to-hip ratio (WHR), and risk of lympho-haematopoietic cancers.

METHOD

We conducted a meta-analysis of prospective studies and identified relevant studies published up to December 2017 by searching PubMed. A random-effects model was used to calculate dose-response summary relative risks (RRs).

RESULTS

Our findings showed BMI, and BMI in early adulthood (aged 18-21 years) is associated with the risk of Hodgkin's and non-Hodgkin's lymphoma (HL and NHL), diffuse large beta-cell lymphoma (DLBCL), Leukaemia including acute and chronic myeloid lymphoma (AML and CML), and chronic lymphocytic leukaemia (CLL) and multiple myeloma (MM). The summary RR per 5 kg/m2 increase in BMI were 1.12 [95% confidence interval (CI): 1.05-1.20] for HL, 1.05 (95% CI: 1.03-1.08) for NHL, 1.11 (95% CI: 1.05-1.16) for DLBCL, 1.06 (95% CI: 1.03-1.09) for ML, 1.09 (95% CI: 1.03-1.15) for leukaemia, 1.13 (95% CI: 1.04-1.24) for AML, 1.13 (95% CI: 1.05-1.22) for CML and 1.04 (95% CI: 1.00-1.09) for CLL, and were1.12 (95% CI: 1.05-1.19) for NHL, 1.22 (95% CI: 1.09-1.37) for DLBCL, and 1.19 (95% CI: 1.03-1.38) for FL for BMI in early adulthood analysis. Results on mortality showed a 15%, 16% and 17% increased risk of NHL, MM and leukaemia, respectively. Greater height increased the risk of NHL by 7%, DLBCL by 10%, FL by 9%, MM by 5% and Leukaemia by 7%. WHR was associated with increased risk of DLBCL by 12%. No association was found between higher WC and risk of MM.

CONCLUSION

Our results revealed that general adiposity in adulthood and early adulthood, and greater height may increase the risk of almost all types of lympho-haematopoietic cancers and this adds to a growing body of evidence linking body fatness to several types of cancers.

Anthropometric characteristics, physical activity and risk of hematological malignancies: A systematic review and meta-analysis of cohort studies

Overweight/obesity, adult attained height and physical activity are possible risk factors for hematological malignancies. This meta-analysis aims to evaluate the associations between these factors and hematological cancer risk in adults. Eligible cohort studies were sought in PubMed up to May 31, 2016; overall, 44 studies were included in the present analyses. Pooled relative risk estimates were calculated using random-effects models; separate analyses were conducted for non-Hodgkin lymphoma (NHL) and subtypes (diffuse large B-cell lymphoma, DLBCL; follicular cell lymphoma; small lymphocytic lymphoma/chronic lymphocytic leukemia, SLL/CLL), Hodgkin lymphoma (HL), multiple myeloma (MM), leukemia and subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, AML). Obesity was associated with increased risk of NHL, HL, MM, leukemia overall and AML in both sexes, as well as with higher DLBCL risk in women; the dose-response meta-regression analysis confirmed these associations. Less pronounced effects were observed regarding overweight, as it was associated with increased MM risk in both sexes, NHL risk in males, DLBCL and overall leukemia risk in females. Taller men presented with significantly higher risk of NHL and taller women were affected by higher risk of NHL, DLBCL, FL, CLL/SLL, MM, leukemia and AML. On the other hand, physical activity and abdominal fatness were not associated with the risk of hematological malignancies. In conclusion, this meta-analysis highlights the pivotal role of anthropometric measures in shaping the risk of hematological malignancies in adults. Additional, well-designed studies stemming from all the continents are needed for the further substantiation and generalization of the results.

Body fatness at a young age and risks of eight types of cancer: systematic review and meta-analysis of observational studies

The associations between body fatness at a young age (childhood, adolescence and young adulthood; age ≤ 30 years) and diffuse large B-cell lymphoma (DLBCL), oesophageal adenocarcinoma, gastric cardia cancer, hepatocellular carcinoma, multiple myeloma, pancreatic cancer, renal cell cancer and thyroid cancer remain inconclusive. We performed a comprehensive systematic literature review and meta-analysis of observational studies to clarify the associations between body fatness at a young age and the risks of these cancers. PubMed and Web of Science databases were searched for relevant observational studies. Fifty-six articles yielded data on 27,559 cancer cases, including 3,170 DLBCL, 1,491 oesophageal adenocarcinoma, 1,103 gastric cardia cancer, 1,067 hepatocellular carcinoma, 3,090 multiple myeloma, 7,220 pancreatic cancer, 6,212 renal cell cancer and 4,206 thyroid cancer cases. Each 5 kg m^-2 increase in body mass index at a young age was positively associated with DLBCL (relative risk [RR] 1.21, 95% confidence interval [CI] 1.09, 1.35), oesophageal adenocarcinoma (RR 1.88, 95% CI 1.37, 2.57), gastric cardia cancer (RR 1.59, 95% CI 1.15, 2.21), hepatocellular carcinoma (RR 1.31, 95% CI 1.13, 1.51), multiple myeloma (RR 1.23, 95% CI 1.15, 1.30), pancreatic cancer (RR 1.17, 95% CI 1.11, 1.24), renal cell cancer (RR 1.22, 95% CI 1.16, 1.28) and thyroid cancer (RR 1.12, 95% CI 1.07, 1.17). In summary, higher body fatness at a young age increases the risks of developing various types of cancer later in life. Prevention of overweight and obesity in children, adolescents and young adults should therefore be emphasized to reverse the obesity epidemic and thereby avoid further increases in the burden of cancer attributed to excess body fatness.

Body composition measurements and risk of hematological malignancies: A population-based cohort study during 20 years of follow-up

High body mass index (BMI) is associated with development of hematological malignancies (HMs). However, although BMI is a well-established measurement of excess weight, it does not fully reflect body composition and can sometimes misclassify individuals. This study aimed at investigating what body composition measurements had highest association with development of HM. Body composition measurements on 27,557 individuals recorded by healthcare professionals as part of the Malmö Diet and Cancer study conducted in Sweden between 1991–1996 were matched with data from national registers on cancer incidence and causes of death. Cox regression models adjusted for age and sex were used to test the association between one standard deviation increments in body composition measurements and risk of HM. During a median follow-up of 20 years, 564 persons developed an HM. Several body composition measurements were associated with risk of developing an HM, but the strongest association was found for multiple myeloma (MM). Waist circumference (HR 1.31, p = 0.04) and waist-hip ratio (HR 1.61, p = 0.05) had higher risk estimates than BMI (HR 1.18, p = 0.07) for MM. In conclusion, our study shows that measurements of abdominal adiposity better predict the risk of developing HM, particularly MM, compared to BMI.

Anthropometric factors and non-Hodgkin's lymphoma risk: systematic review and meta-analysis of prospective studies

The associations between anthropometric factors and non-Hodgkin's lymphoma (NHL) risk remain inconclusive. A meta-analysis was performed to clarify these associations. PubMed and Web of Science were searched for relevant prospective observational studies. A random-effects model was used to generate the summary relative risks (RRs) with 95% confidence intervals (CIs). A total of 22 prospective cohort studies, with over 20,000 NHL cases, were included in the present meta-analysis. The summary RRs of NHL risk were 1.06 (95% CI 1.03, 1.09) for each 5 kg/m² increase in body mass index (BMI), 1.11 (95% CI 1.07, 1.16) for each 5 kg/m² increase in BMI in early adulthood (age 18-21 years), 1.05 (95% CI 1.01, 1.09) for each 10 kg increase in weight, 1.21 (95% CI 1.15, 1.28) for each 10 kg increase in weight in early adulthood (age 18-21 years), and 1.13 (95% CI 1.10, 1.17) for each 10 cm increase in height. No association was found for waist circumference (WC) and waist-to-hip ratio. By subtypes, all anthropometric factors (but not WC) were associated with an increased risk of diffuse large B-cell lymphoma. Chronic lymphocytic leukemia/small lymphocytic lymphoma was positively associated with BMI in early adulthood and with height, whereas follicular lymphoma was only positively associated with height. In summary, BMI and weight in early adulthood may be more relevant to NHL development than current BMI and weight. These findings emphasize the importance of maintaining a healthy weight throughout the life-course, starting from early life, for NHL prevention. Increased NHL risk with taller stature, which may reflect cumulative exposure to hormones/growth factors and nutrition status in early life, further supports the relevance of early life exposure in the etiology of NHL.

Dietary Fat Consumption and Non-Hodgkin's Lymphoma Risk: A Meta-analysis

OBJECTIVE

Many studies suggest that high-fat diets are linked to the etiology of non-Hodgkin's lymphoma (NHL). However, the findings are inconsistent and therefore the association between fat and non-Hodgkin's lymphoma remains unclear. In this study, we aim to quantitatively assess the association between fat consumption and the risk for NHL.

METHODS

We reviewed 221 published cohort and case-control studies that reported relative risk (RRs) and corresponding 95% confidence intervals (CIs) of NHL and fat intake using PubMed, Cochrane, EMBASE, and Google Scholar databases. A random-effects model computed summary risk estimates.

RESULTS

Based on our literature search, 10 of 221 studies (two cohort and eight case-control studies) were relevant to this meta-analysis. There was a significant association between total fat consumption and increased risk of NHL (RR = 1.26; 95% CI: 1.12-1.42); in addition, subgroup analysis showed a significant correlation with diffuse large B-cell lymphoma (RR = 1.41; 95% CI: 1.08-1.84) but not with follicular lymphoma (RR = 1.21; 95% CI: 0.97-1.52), small lymphocytic lymphoma/chronic lymphocytic leukemia (RR = 0.91; 95% CI: 0.68-1.23), nor with T cell lymphoma (RR = 1.12; 95% CI: 0.60-2.09). The funnel plot revealed no evidence for publication bias.

CONCLUSION

Total fat consumption, particularly animal fat, increases the risk for NHL.

Body size in early life and risk of lymphoid malignancies and histological subtypes in adulthood

Risk of adult lymphoid malignancy is associated with recent adiposity. Some have reported apparent associations with adiposity in childhood or early adulthood, but whether these associations are independent of recent adiposity is unknown. Birth weight, body size at age 10 years, clothes size at age 20 years, and recent body mass index (BMI) were recorded in 745,273 UK women, mean age 60.1 (SD 4.9) at baseline, without prior cancer. They were followed for 11 years, during which time 5,765 lymphoid malignancies occurred. Using Cox regression, a higher risk of lymphoid malignancy was strongly associated with higher recent BMI (RR=1.33, 95%CI 1.17-1.51, for BMI 35+ vs <22.5 kg/m(2)), and this association remained essentially unchanged after adjustment for birth weight and body size at 10. Higher lymphoid malignancy risk was also associated with large size at birth, at age 10, and at age 20 years, but after adjustment for recent BMI, the significance of the associations with large size at birth and at age 10 years was sufficiently reduced that residual confounding by adult BMI could not be excluded; a weak association with large size at 20 years remained (adjusted RR =1.17, 95%CI 1.10-1.24 for large size at age 20 vs. medium or small size). We found no strong evidence of histological specificity in any of these associations. In conclusion, our findings suggest a possible role of adiposity throughout adulthood in the risk of lymphoid malignancy, but the independent contribution of body size at birth and during childhood appears to be small.

Adolescent weight and height are predictors of specific non-Hodgkin lymphoma subtypes among a cohort of 2,352,988 individuals aged 16 to 19 years

BACKGROUND

The age-adjusted annual incidence of non-Hodgkin lymphoma (NHL) has risen worldwide. This trend may be affected by the secular increase in height and the sharp upswing in adolescent overweight; these drive increased insulinlike growth factor 1 and chronic inflammation, which may play an etiologic role. This study examined the association of the body mass index (BMI) and height of adolescents with NHL subtypes, which have been insufficiently evaluated.

METHODS

Health-related data on 2,352,988 Israeli adolescents, aged 16 to 19 years, who were examined between 1967 and 2011 were linked to the Israel National Cancer Registry to derive the NHL incidence up to December 31, 2012 (4021 cases). Cox proportional hazards modeling was used to estimate the multivariate-adjusted hazard ratio (HR) for NHL subtypes associated with the BMI and height of adolescents.

RESULTS

Adolescent overweight and obesity were associated with an HR of 1.25 (95% confidence interval [CI], 1.13-1.37; P = 1.14 × 10(-5) ) for NHL in comparison with normal weight. There was a graded association of height with NHL (P = 4.29 × 10(-9) ), with the tallest adolescents (≥ 95th percentile vs 25th to < 50th percentiles [US Centers for Disease Control and Prevention]) exhibiting an HR of 1.28 (95% CI, 1.04-1.56). Marginal zone lymphoma, primary cutaneous lymphoma (PCL), and diffuse large B-cell lymphoma (DLBCL) showed the strongest associations for overweight/obesity, and DLBCL and PCL showed the strongest associations for height.

CONCLUSIONS

The findings of this large cohort study add to the growing body of evidence showing that higher body weight and taller stature during adolescence are associated with an increased risk of NHL and may modestly contribute to its increasing incidence. Further studies are needed to elucidate the mechanisms linking anthropometric measures and NHL risk.

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

BACKGROUND

Follicular lymphoma (FL) has been linked with cigarette smoking and, inconsistently, with other risk factors.

METHODS

We assessed associations of medical, hormonal, family history, lifestyle, and occupational factors with FL risk in 3530 cases and 22639 controls from 19 case-control studies in the InterLymph consortium. Age-, race/ethnicity-, sex- and study-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression.

RESULTS

Most risk factors that were evaluated showed no association, except for a few modest or sex-specific relationships. FL risk was increased in persons: with a first-degree relative with non-Hodgkin lymphoma (OR = 1.99; 95% CI = 1.55 to 2.54); with greater body mass index as a young adult (OR = 1.15; 95% CI = 1.04 to 1.27 per 5 kg/m(2) increase); who worked as spray painters (OR = 2.66; 95% CI = 1.36 to 5.24); and among women with Sjögren syndrome (OR = 3.37; 95% CI = 1.23 to 9.19). Lower FL risks were observed in persons: with asthma, hay fever, and food allergy (ORs = 0.79-0.85); blood transfusions (OR = 0.78; 95% CI = 0.68 to 0.89); high recreational sun exposure (OR = 0.74; 95% CI = 0.65 to 0.86, fourth vs first quartile); who worked as bakers or millers (OR = 0.51; 95% CI = 0.28 to 0.93) or university/higher education teachers (OR = 0.58; 95% CI = 0.41 to 0.83). Elevated risks specific to women included current and longer duration of cigarette use, whereas reduced risks included current alcohol use, hay fever, and food allergies. Other factors, including other autoimmune diseases, eczema, hepatitis C virus seropositivity, hormonal drugs, hair dye use, sun exposure, and farming, were not associated with FL risk.

CONCLUSIONS

The few relationships observed provide clues suggesting a multifactorial etiology of FL but are limited in the extent to which they explain FL occurrence.

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.

Non-Hodgkin Lymphoma, Body Mass Index, and Cytokine Polymorphisms: A Pooled Analysis from the InterLymph Consortium

BACKGROUND

Excess adiposity has been associated with lymphomagenesis, possibly mediated by increased cytokine production causing a chronic inflammatory state. The relationship between obesity, cytokine polymorphisms, and selected mature B-cell neoplasms is reported.

METHOD

Data on 4,979 cases and 4,752 controls from nine American/European studies from the InterLymph consortium (1988-2008) were pooled. For diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), joint associations of body mass index (from self-reported height and weight) and 12 polymorphisms in cytokines IL1A (rs1800587), IL1B (rs16944, rs1143627), IL1RN (rs454078), IL2 (rs2069762), IL6 (rs1800795, rs1800797), IL10 (rs1800890, rs1800896), TNF (rs1800629), LTA (rs909253), and CARD15 (rs2066847) were investigated using unconditional logistic regression. BMI-polymorphism interaction effects were estimated using the relative excess risk due to interaction (RERI).

RESULTS

Obesity (BMI ≥ 30 kg/m(2)) was associated with DLBCL risk [OR = 1.33; 95% confidence interval (CI), 1.02-1.73], as was TNF-308GA+AA (OR = 1.24; 95% CI, 1.07-1.44). Together, being obese and TNF-308GA+AA increased DLBCL risk almost 2-fold relative to those of normal weight and TNF-308GG (OR = 1.93; 95% CI, 1.27-2.94), with a RERI of 0.41 (95% CI, -0.05-0.84; Pinteraction = 0.13). For FL and CLL/SLL, no associations with obesity or TNF-308GA+AA, either singly or jointly, were observed. No evidence of interactions between obesity and the other polymorphisms were detected.

CONCLUSIONS

Our results suggest that cytokine polymorphisms do not generally interact with BMI to increase lymphoma risk but obesity and TNF-308GA+AA may interact to increase DLBCL risk.

IMPACT

Studies using better measures of adiposity are needed to further investigate the interactions between obesity and TNF-308G>A in the pathogenesis of lymphoma.

Body mass index and other anthropometric parameters in patients with diffuse large B-cell lymphoma: physiopathological significance and predictive value in the immunochemotherapy era

Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma, accounting for 30-40% of newly diagnosed cases. Obesity is a well-defined risk factor for DLBCL. However, the impact of body mass index (BMI) on DLBCL prognosis is controversial. Recent studies suggest that skeletal muscle wasting (sarcopenia) or loss of fat mass can be detected by computed tomography (CT) images and is useful for predicting the clinical outcome in several types of cancer including DLBCL. Several hypotheses have been proposed to explain the differences in DLBCL outcome according to BMI or weight that include tolerance to treatment, inflammatory background and chemotherapy or rituximab metabolism. In this review, we summarize the available literature, addressing the impact and physiopathological relevance of simple anthropometric tools including BMI and tissue distribution measurements. We also discuss their relationship with other nutritional parameters and their potential role in the management of patients with DLBCL.

Obesity and non-Hodgkin lymphoma survival in an ethnically diverse population: the Multiethnic Cohort study

PURPOSE

Obesity increases mortality for several malignancies, but for non-Hodgkin lymphoma (NHL), the association between body mass index (BMI) and survival is unclear. We examined the association of pre-diagnostic BMI with overall and NHL-specific survival in the multiethnic cohort (MEC) study of African Americans, Native Hawaiians, Japanese Americans, Latinos, and Caucasians.

METHODS

MEC participants free of NHL at cohort entry and diagnosed with NHL during follow-up were included in the analyses (n = 1,331). BMI was based on self-reported weight and height at cohort entry and after 6.1 years of cohort entry. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95 % confidence intervals (CI) with BMI as time-varying exposure in relation to all-cause and NHL-specific mortality while adjusting for known confounders.

RESULTS

The mean age at NHL diagnosis was 70.5 (range 45-89) years. After a mean follow-up of 4.3 ± 3.5 years, 667 deaths including 450 NHL-specific deaths occurred. In multivariable models, obese patients (BMI ≥30.0 kg/m(2)) had higher all-cause (HR 1.46, 95 % CI 1.13-1.87) and NHL-specific (HR 1.77, 95 % CI 1.30-2.41) mortality compared with patients with high-normal BMI (22.5-24.9 kg/m(2)). For overweight patients (BMI = 25.0-29.9 kg/m(2)), the respective HRs were 1.21 (95 % CI 0.99-1.49) and 1.36 (95 % CI 1.06-1.75). Cases with low-normal BMI (<22.5 kg/m(2)) experienced a significant 45 % higher all-cause and a 40 % higher NHL-specific mortality. After stratification by NHL type, the adverse effect of BMI was stronger for chronic lymphocytic leukemia/small lymphocytic lymphoma than for diffuse large B cell lymphoma and follicular lymphoma.

CONCLUSIONS

Pre-diagnostic BMI may be a suitable prognostic marker for NHL patients.

Prediagnostic serum tocopherol levels and the risk of non-hodgkin lymphoma: the multiethnic cohort

BACKGROUND

Compromised immunity and chronic inflammation are thought to contribute to the development of non-Hodgkin lymphoma (NHL). Because tocopherols protect cells through antioxidant mechanisms, they may play a role in NHL etiology.

METHODS

This nested case-control study within the Multiethnic Cohort examined the association of prediagnostic serum tocopherols levels measured in 271 NHL cases and 538 matched controls by high-pressure liquid chromatography/photodiode array detection with NHL risk. Conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

We observed U-shaped associations with NHL for total and α-tocopherols [Ptrend < 0.01 for polynomial terms (3 df)]. The ORs (95% CI) for total tocopherols, which consisted primarily of α-tocopherol, were 0.41 (0.25-0.68), 0.52 (0.32-0.85), 0.39 (0.23-0.65), and 0.78 (0.47-1.29) for the second to fifth quintiles as compared with the first. The risk estimates were similar for α-tocopherol but nonsignificant for β- and γ-tocopherol combined and for γ-tocopherol. Adjustment for serum lipids strengthened the nonlinear associations for total and α-tocopherols. Serum total tocopherol levels were higher for vitamin E supplement users at cohort entry than nonusers (21.32 ± 9.04 vs. 17.72 ± 7.43 μg/mL; P < 0.0001), but supplement use was not associated with NHL risk. No heterogeneity in risk estimates was detected by sex, ethnicity, vitamin E supplement use, or NHL subtype.

CONCLUSIONS

Circulating tocopherols, at levels likely reflecting adequate dietary intakes, may be protective against NHL, whereas higher intakes from supplementation may not be beneficial.

IMPACT

The association between serum tocopherol levels and NHL risk provides possible new insights into the etiology of NHL.

A prospective analysis of body size during childhood, adolescence, and adulthood and risk of non-Hodgkin lymphoma

The etiology of non-Hodgkin lymphoma (NHL) is poorly understood. Obesity is associated with inflammation, a cytokine milieu conducive to lymphocyte proliferation, and has been associated with NHL risk in some epidemiologic studies. To prospectively examine NHL risk in relation to adult and earlier life obesity, we documented 635 incident NHL diagnoses among 46,390 men in the Health Professionals Follow-up Study and 1,254 diagnoses among 116,794 women in the Nurses' Health Study over 22 to 32 years of follow-up. Using multivariable Cox proportional hazards models, we estimated cohort-specific incidence rate ratios (RR) and 95% confidence intervals (CI) for risk of NHL and major histologic subtypes associated with cumulative average middle and young adult (ages, 18-21 years) body mass index (BMI) and adolescent and childhood somatotype. NHL risk was modestly increased in men (but not women) with a cumulative average middle adult BMI ≥ 30 kg/m(2) (vs. 15-22.9 kg/m(2); RR, 1.28; 95% CI, 0.92-1.77; Ptrend = 0.05). In meta-analyses across cohorts, higher young adult BMI was associated with increased risk of all NHL (pooled RR per 5 kg/m(2), 1.19; 95% CI, 1.05-1.37), diffuse large B-cell lymphoma (DLBCL), and follicular lymphoma (all Ptrend ≤ 0.02). Adolescent somatotype was also positively associated with all NHL, DLBCL, and follicular lymphoma in pooled analyses (all Ptrend ≤ 0.03), whereas childhood somatotype was positively associated with NHL overall among women only (Ptrend < 0.01). These findings in two large prospective cohorts provide novel evidence that larger body size in childhood, adolescence, and young adulthood predicts increased risk of NHL, and particularly of DLBCL and follicular lymphoma.

Invited commentary: are dietary intakes and other exposures in childhood and adolescence important for adult cancers?

In this issue of the Journal, Nimptsch et al. (Am J Epidemiol. 2013;178(2):172-183) report significant associations between female adolescents' poultry consumption in high school and subsequent reduced risk of colorectal adenomas in adulthood. Consumption of red meat or fish was not related to risk, but replacement with poultry reduced the risk of later adenomas. Most epidemiologic studies of adult diseases lack exposure data from the distant past. By focusing on a cancer precursor lesion and using a variety of methods to assess data quality, the investigators address concerns about the quality of distant recall. These findings add to the growing evidence that links childhood and adolescent lifestyle and environmental exposures with subsequent risk of cancers arising in adulthood. Highlights of the literature on this topic and methodological challenges are summarized. Future studies would benefit from incorporating measures of lifestyle, diet, environmental exposures, and other risk factors from early in life and from validation and other data quality checks of such measurements. Sources of historical data on children's and adolescents' exposures should be sought and evaluated in conjunction with subsequent exposures in relationship to adult-onset cancers.

Switching to a low-fat diet attenuates the intensified doxorubicin cardiotoxicity associated with high-fat feeding

PURPOSE

A high-fat diet has been shown to exacerbate the cardiotoxicity associated with the chemotherapy drug doxorubicin (DOX); however, it is unknown whether switching from a high-fat diet to a low-fat diet can attenuate the intensified DOX cardiotoxicity. The purpose of this study was to investigate the effects of a low-fat diet on DOX-induced cardiotoxicity in rats previously fed a high-fat diet.

METHODS

Male rats were randomly assigned to consume a Western diet or a low-fat diet for 6 weeks. Western diet-fed rats were then further randomized to switch to the low-fat diet (WD-LF) or continue with the Western diet (WD). One week later, WD-LF and WD received 1 mg/kg DOX per day for 10 consecutive days and continued with their diets (WD-LF + DOX, WD + DOX). LF was further randomized to receive 1 mg/kg DOX per day for 10 consecutive days (LF + DOX) or saline injections as a control (LF + SAL). Four weeks following the first injection, cardiac function was analyzed, and left ventricles were analyzed for cardiotoxicity indices.

RESULTS

When compared to LF + SAL and LF + DOX, WD + DOX exhibited an enhanced cardiotoxicity as evidenced by reduced septal wall thickness, fractional shortening, and sarco-endoplasmic reticulum Ca(2+) ATPase expression as well as increased left ventricular cavity dimensions, lipid peroxidation, and β-myosin heavy-chain expression. This exacerbated cardiotoxicity was not observed in WD-LF + DOX.

CONCLUSIONS

Switching to a low-fat diet 1 week prior to, during, and following DOX treatment attenuated the exacerbated cardiotoxicity observed in the previously Western diet-fed rats.

Body mass index, height and risk of lymphoid neoplasms in a large United States cohort

Results from epidemiologic studies examining associations between body size and risk of non-Hodgkin lymphoma (NHL) are inconsistent, and etiology may vary by histologic subtype of disease. Using Cox proportional hazards regression, multivariable relative risks (RRs) and 95% confidence intervals (CIs) were computed for associations of body mass index (BMI) and height with NHL in the prospective American Cancer Society Cancer Prevention Study-II Nutrition Cohort. From 1992 to 2007, 2074 incident cases of NHL were identified among 152 423 men and women. Obese individuals (BMI ≥ 30 kg/m(2)) had 23% higher incidence of NHL (95% CI 1.08-1.40) compared to those with normal weight (BMI 18.5-< 25 kg/m(2)). Height was positively associated with NHL (RR = 1.25, 95% CI 1.10-1.43, sex-specific quintile 5 vs. 1). BMI associations were strongest for diffuse large B-cell lymphoma. Height was most strongly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma and to a lesser extent with multiple myeloma. These findings provide further evidence that body size may play a role in the etiology of NHL, which is of public health importance given the rapid rise in obesity worldwide.

The association between early life and adult body mass index and physical activity with risk of non-Hodgkin lymphoma: impact of gender

PURPOSE

To evaluate the association of body mass index (BMI) and physical activity (PA) during adulthood and at the age of 18 years with risk of non-Hodgkin lymphoma (NHL).

METHODS

We enrolled 950 newly diagnosed NHL patients and 1146 frequency-matched clinic-based controls. Height, weight, and PA (recent adult and at the age of 18 years) were self-reported. Odds ratios (ORs), 95% confidence intervals, and tests for trend were estimated using unconditional logistic regression adjusted for age, gender, and residence.

RESULTS

BMI at the age of 18 years was associated with an increased NHL risk (OR, 1.38 for highest vs. lowest quartile; p-trend = .0012), which on stratified analysis was specific to females (OR, 1.90; p-trend = .00025). There was no association of adult BMI with NHL risk. Higher PA in adulthood (OR, 1.03; p-trend = .85) or at the age of 18 years (OR, 0.88; 95% confidence interval, 0.72-1.07) was not associated with risk, but there was an inverse association for adult PA that was specific to females (OR, 0.71; p-trend = .039). Only BMI at the age of 18 years remained significantly associated with NHL risk when modeled together with PA in adulthood or at the age of 18 years. There was little evidence for heterogeneity in these results for the common NHL subtypes.

CONCLUSIONS

Early adult BMI may be of greatest relevance to NHL risk, particularly in females.

Exploring risk factors for follicular lymphoma

Follicular lymphoma (FL) is an indolent malignancy of germinal center B cells with varied incidence across racial groups and geographic regions. Improvements in the classification of non-Hodgkin lymphoma subtypes provide an opportunity to explore associations between environmental exposures and FL incidence. Our paper found that aspects of Western lifestyle including sedentary lifestyle, obesity, and diets high in meat and milk are associated with an increased risk of FL. Diets rich in fruits and vegetables, polyunsaturated fatty acids, vitamin D, and certain antioxidants are inversely associated with FL risk. A medical history of Sjogren's syndrome, influenza vaccination, and heart disease may be associated with FL incidence. Associations between FL and exposure to pesticides, industrial solvents, hair dyes, and alcohol/tobacco were inconsistent. Genetic risk factors include variants at the 6p21.32 region of the MHC II locus, polymorphisms of the DNA repair gene XRCC3, and UV exposure in individuals with certain polymorphisms of the vitamin D receptor. Increasing our understanding of risk factors for FL must involve integrating epidemiological studies of genetics and exposures to allow for the examination of risk factors and interactions between genes and environment.

Current understanding of lifestyle and environmental factors and risk of non-hodgkin lymphoma: an epidemiological update

The incidence rates of non-Hodgkin lymphoma (NHL) have steadily increased over the last several decades in the United States, and the temporal trends in incidence can only be partially explained by the HIV epidemic. In 1992, an international workshop sponsored by the United States National Cancer Institute concluded that there was an “emerging epidemic” of NHL and emphasized the need to investigate the factors responsible for the increasing incidence of this disease. Over the past two decades, numerous epidemiological studies have examined the risk factors for NHL, particularly for putative environmental and lifestyle risk factors, and international consortia have been established in order to investigate rare exposures and NHL subtype-specific associations. While few consistent risk factors for NHL aside from immunosuppression and certain infectious agents have emerged, suggestive associations with several lifestyle and environmental factors have been reported in epidemiologic studies. Further, increasing evidence has suggested that the effects of these and other exposures may be limited to or stronger for particular NHL subtypes. This paper examines the progress that has been made over the last twenty years in elucidating the etiology of NHL, with a primary emphasis on lifestyle factors and environmental exposures.

Erythrocyte membrane fatty acid composition, serum lipids, and non-Hodgkin's lymphoma risk in a nested case-control study: the multiethnic cohort

PURPOSE

Composition of dietary fatty acid intake, which influences cytokine production, may contribute to the development of non-Hodgkin's lymphoma (NHL). Serum lipid levels may serve as biomarkers of inflammation associated with NHL risk.

METHODS

We conducted a case-control analysis (275 cases and 549 controls) nested within the Multiethnic Cohort Study (whites, Japanese Americans, Latinos, African Americans, and Native Hawaiians) to examine the association of prediagnostic, erythrocyte membrane phospholipid fatty acid composition, and serum cholesterol and triglyceride (TG) concentrations with the risk of NHL. Conditional logistic regression was used to calculate odds ratios (OR) and 95 % confidence intervals (CI) by tertiles of biomarker concentrations.

RESULTS

Higher total saturated fatty acids (SFA) were associated with an increase in NHL risk (OR(T3 vs. T1) = 1.57 [95 % CI: 1.03-2.39]; p(trend) = 0.01), whereas no associations were detected for total n-3 or n-6 polyunsaturated fatty acids. Inverse associations were observed for total cholesterol (TC; OR (T3 vs. T1) = 0.51 [95 % CI: 0.35-0.74]; p(trend) < 0.0001) and high-density lipoprotein cholesterol (HDL-C; OR (T3 vs. T1) = 0.47 [95 % CI: 0.31-0.71]; p(trend) = 0.0001) but not for low-density lipoprotein cholesterol or TG. Adjustment for the use of lipid-lowering medication did not modify the results substantially.

CONCLUSIONS

This prospective biomarker investigation offers supportive evidence for an adverse effect of higher erythrocyte membrane SFA levels on NHL risk, but preclinical effects cannot be excluded. Inverse relations between prediagnostic, circulating TC and HDL-C and NHL risk may be due to reverse causation or a result of protective actions of these lipids and lipoproteins.

Epidemiologic overview of malignant lymphoma

Malignant lymphoma encompasses a wide variety of distinct disease entities. It is generally more common in developed countries and less common in developing countries. The East Asia region has one of the lowest incidence rates of malignant lymphoma. The incidence of malignant lymphoma around the world has been increasing at a rate of 3-4% over the last 4 decades, while some stabilization has been observed in developed countries in recent years. The reasons behind this lymphoma epidemic are poorly understood, although improving diagnostic accuracy, the recent AIDS epidemic, an aging world population and the increasing adoption of cancer-causing behaviors are suggested as contributing factors. Etiologies of malignant lymphoma include infectious agents, immunodeficiency, autoimmune disease, exposure to certain organic chemicals, and pharmaceuticals. The distribution of many subtypes exhibit marked geographic variations. Compared to the West, T/natural killer (NK) cell lymphomas (T/NK-cell lymphoma) and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) are relatively more common, whereas other B-cell lymphomas, particularly follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, are less common in Asia. Some subtypes of T/NK-cell lymphomas defined by Epstein-Barr virus association are predominantly Asian diseases, if not exclusively so. Both ethnic and environmental factors play roles in such diversity. In this review, we discuss the geographic distribution and etiology of malignant lymphoma, as well as the trend.

Metabolic factors and blood cancers among 578,000 adults in the metabolic syndrome and cancer project (Me-Can)

We investigated associations between metabolic factors and blood cancer subtypes. Data on body mass index (BMI), blood pressure, blood glucose, total cholesterol, and triglycerides from seven prospective cohorts were pooled (n = 578,700; mean age = 44 years). Relative risks of blood cancers were calculated from Cox regression models. During mean follow-up of 12 years, 2,751 incident and 1,070 fatal cases of blood cancers occurred. Overall, higher BMI was associated with an increased blood cancer risk. In gender-specific subgroup analyses, BMI was positively associated with blood cancer risk (p = 0.002), lymphoid neoplasms (p = 0.01), and Hodgkin's lymphoma (p = 0.02) in women. Further associations with BMI were found for high-grade B-cell lymphoma (p = 0.02) and chronic lymphatic leukemia in men (p = 0.05) and women (p = 0.01). Higher cholesterol levels were inversely associated with myeloid neoplasms in women (p = 0.01), particularly acute myeloid leukemia (p = 0.003), and glucose was positively associated with chronic myeloid leukemia in women (p = 0.03). In men, glucose was positively associated with risk of high-grade B-cell lymphoma and multiple myeloma, while cholesterol was inversely associated with low-grade B-cell lymphoma. The metabolic syndrome score was related to 48 % increased risk of Hodgkin's lymphoma among women. BMI showed up as the most consistent risk factor, particularly in women. A clear pattern was not found for other metabolic factors.

Anthropometric factors, physical activity, and risk of non-Hodgkin's lymphoma in the Women's Health Initiative

BACKGROUND

Incidence rates of non-Hodgkin's lymphoma (NHL) increased substantially in the United States and worldwide during the latter part of the 20th century, but little is known about its etiology. Obesity is associated with impaired immune function through which it may influence the risk of NHL; other factors reflecting energy homeostasis (height, abdominal adiposity, and physical activity) may also be involved.

METHODS

We examined the association of anthropometric factors and physical activity with risk of NHL and its major subtypes in a large cohort of women aged 50-79 years old who were enrolled at 40 clinical centers in the United States between 1993 and 1998. Over a mean follow-up period of 11 years, 1123 cases of NHL were identified among 158,975 women. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Height at baseline was positively associated with risk of all NHL and with that of diffuse large B-cell lymphoma (HRs(q4vs.q1) 1.19, 95% CI 1.00-1.43 and 1.43, 95% CI 1.01-2.03, respectively). Measures of obesity and abdominal adiposity at baseline were not associated with risk. Hazard ratios for NHL were increased for women in the highest quartile of weight and body mass index at age 18 (HRs(q4vs.q1) 1.29, 95% CI 1.01-1.65 and 1.27, 95% CI 1.01-1.59, respectively). Some measures of recreational physical activity were modestly associated with increased risk of NHL overall, but there were no clear associations with specific subtypes.

CONCLUSION

Our findings regarding anthropometric measures are consistent with those of several previous reports, suggesting that early life influences on growth and immune function may influence the risk of NHL later in life.

Obesity and the risk for a hematological malignancy: leukemia, lymphoma, or myeloma

Studies on obesity and the risk for hematological malignancies are reviewed. The paper includes a discussion of the metabolic effects of obesity and their possible role in linking increased body fat to neoplasia.

The aggregate of epidemiological studies indicates a significantly elevated risk for cancer in people with a high body mass index (BMI); a “dose–response” effect exists with increasing risk as BMI increases from the normal to overweight to obese categories. Successful sustained weight loss decreases future risk. The relationship of being overweight to the risk for leukemia in the aggregate has been supported in several large cohort studies and two meta-analyses of cohort and case–control studies. One meta-analysis found an elevated risk for each of the four major subtypes of leukemia. A significant association between the risk for non-Hodgkin's lymphoma and elevated BMI was supported by a meta-analysis of 13 cohort and nine case–control studies. The risk for diffuse large B-cell lymphoma may be especially significant. A high BMI increases the risk for myeloma, as judged by a meta-analysis of 11 cohort and four case–control studies. The biological relationship of obesity to the risk for cancer (biological plausibility) is unresolved. The two major causal final pathways could be “inductive” or “selective.” The metabolic, endocrinologic, immunologic, and inflammatory-like changes resulting from obesity may increase the cell mutation rate, dysregulate gene function, disturb DNA repair, or induce epigenetic changes, favoring the induction of neoplastic transformation (inductive). Alternatively, obesity may create an environment in which pre-existing clones that are dormant are permitted (selected) to emerge.

Associations between anthropometry, cigarette smoking, alcohol consumption, and non-Hodgkin lymphoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Prospective studies of lifestyle and non-Hodgkin lymphoma (NHL) are conflicting, and some are inconsistent with case-control studies. The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was used to evaluate risk of NHL and its subtypes in association with anthropometric factors, smoking, and alcohol consumption in a prospective cohort study. Lifestyle was assessed via questionnaire among 142,982 male and female participants aged 55-74 years enrolled in the PLCO Trial during 1993-2001. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards regression. During 1,201,074 person-years of follow-up through 2006, 1,264 histologically confirmed NHL cases were identified. Higher body mass index (BMI; weight (kg)/height (m)(2)) at ages 20 and 50 years and at baseline was associated with increased NHL risk (P(trend) < 0.01 for all; e.g., for baseline BMI > or =30 vs. 18.5-24.9, hazard ratio = 1.32, 95% confidence interval: 1.13, 1.54). Smoking was not associated with NHL overall but was inversely associated with follicular lymphoma (ever smoking vs. never: hazard ratio = 0.62, 95% confidence interval: 0.45, 0.85). Alcohol consumption was unrelated to NHL (drinks/week: P(trend) = 0.187). These data support previous studies suggesting that BMI is positively associated with NHL, show an inverse association between smoking and follicular lymphoma (perhaps due to residual confounding), and do not support a causal association between alcohol and NHL.

Association of anthropometric characteristics with the risk of malignant lymphoma and plasma cell myeloma in a Japanese population: a population-based cohort study

BACKGROUND

Although Asian and Western populations differ markedly in anthropometric characteristics and the incidence of malignant lymphoma and plasma cell myeloma, few studies have evaluated the associations between these variables among Asian populations.

METHODS

We conducted a large-scale, population-based prospective study in a Japanese cohort that included 45,007 men and 49,540 women ages 40 to 69 years at baseline. During an average follow-up period of 13 years, 257 cases of malignant lymphoma and 88 of plasma cell myeloma were identified. Hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated with the use of a Cox regression model adjusted for potential confounders.

RESULTS

Compared with the 1st quartile, categorization in the 4th quartile for height showed a positive association with lymphoid neoplasm risk (HR, 1.38; 95% CI, 1.00-1.91), and the association was significant among men (HR, 1.72; 95% CI, 1.11-2.66). A similar trend was observed for subcategories of malignant lymphoma, plasma cell myeloma, and non-Hodgkin lymphoma, albeit the associations were weak due to the small number of subjects in each category. In contrast, weight and body mass index were not associated with risk of lymphoid neoplasm.

CONCLUSIONS

Height was positively associated with risk of lymphoid neoplasm in a Japanese population.

IMPACT

Our data suggested that early life exposure to growth-related hormones, such as insulin-like growth factors and growth hormones, or genetic factors relating to height may affect the risk of lymphoid neoplasm.

Association between obesity and the risk of malignant lymphoma in Japanese: a case-control study

Although marked differences in anthropometric characteristics and malignant lymphoma (ML) incidence suggest that the association between obesity and ML risk in Asian and non-Asian populations may differ, few studies have investigated this association in Asian populations. Here, we conducted a sex- and age-matched case-control study in a Japanese population using 782 cases and 3,910 noncancer controls in the hospital-based Epidemiological Research Program at Aichi Cancer Center Hospital. Odds ratios (ORs) and 95% confidence intervals (CIs) for anthropometric characteristics were estimated using a conditional logistic regression model that incorporated smoking and alcohol intake. Recent body weight and body mass index (BMI) showed marginally significant association with ML risk (ORs [95% CIs] per 5-unit increase in recent weight and BMI; 1.04 [0.99-1.09] and 1.11 [0.98-1.27], respectively). On the other hand, weight and BMI in early adulthood exhibited a strong association with ML risk (ORs [95% CIs] per 5-unit increase in early adulthood weight and BMI; 1.11 [1.05-1.18] and 1.33 [1.13-1.55], respectively). Further, in women, a BMI of 25.0-29.9 kg/m(2), defined as obesity in Asian populations, during early adulthood was significantly associated with ML risk compared to the normal range of 18.5-22.9 kg/m(2). By histological ML subtype, the point estimates of ORs for obesity relative to normal weight in early adulthood were over unity for non-Hodgkin lymphoma (NHL) as a whole and significant for diffuse large B-cell lymphoma (DLBCL). In conclusion, our study in Japanese subjects suggested that early adulthood obesity is associated with the risk of NHL, particularly DLBCL.

Physical activity and hematologic cancer prevention

This chapter presents the epidemiologic evidence on the association between physical activity and hematologic cancers and related hypothesized biologic mechanisms. Some preliminary indications of a protective role for physical activity for non-Hodgkin's lymphoma, leukemia, multiple myeloma, and Hodgkin's lymphoma exist, but the level of epidemiologic evidence is still insufficient to make any definitive conclusions regarding the nature of these associations. Several plausible biologic mechanisms underlying the possible associations between physical activity and hematologic cancers have been proposed, including enhancement of immune function, reduction in obesity, improvement of antioxidant defense systems, impact on metabolic hormones, and anti-inflammatory effects. Future studies should improve the estimation of physical activity by using more reliable, valid, and comprehensive measurement tools, assessing all components of physical activity (type, intensity, and time period), and conducting intervention studies to evaluate the effect of physical activity on various biomarkers of cancer in order to provide further insight into plausible biologic mechanisms underlying the possible association between physical activity and hematologic cancers.

Body size, recreational physical activity, and B-cell non-Hodgkin lymphoma risk among women in the California teachers study

Nutritional status and physical activity are known to alter immune function, which may be relevant to lymphomagenesis. The authors examined body size measurements and recreational physical activity in relation to risk of B-cell non-Hodgkin lymphoma (NHL) in the prospective California Teachers Study. Between 1995 and 2007, 574 women were diagnosed with incident B-cell NHL among 121,216 eligible women aged 22-84 years at cohort entry. Multivariable-adjusted relative risks and 95% confidence intervals were estimated by fitting Cox proportional hazards models for all B-cell NHL combined and for the 3 most common subtypes: diffuse large B-cell lymphoma, follicular lymphoma, and B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma. Height was positively associated with risk of all B-cell NHLs (for >1.70 vs. 1.61-1.65 m, relative risk = 1.50, 95% confidence interval: 1.16, 1.96) and chronic lymphocytic leukemia/small lymphocytic lymphoma (relative risk = 1.93, 95% confidence interval: 1.09, 3.41). Weight and body mass index at age 18 years were positive predictors of B-cell NHL risk overall. These findings indicate that greater height, which may reflect genetics, early life immune function, infectious exposures, nutrition, or growth hormone levels, may play a role in NHL etiology. Adiposity at age 18 years may be more relevant to NHL etiology than that in later life.

Common immune-related risk factors and incident non-Hodgkin lymphoma: the multiethnic cohort

Severe immune dysfunction is an established risk factor of lymphoma, but the role of moderate alterations of immunity is not clear and prospective investigations are needed. We examined several immune-related disorders and medications in relation to non-Hodgkin lymphoma (NHL) in the Multiethnic Cohort. Over 215,000 subjects of African American, Caucasian, Japanese American, Latino and Native Hawaiian ancestry aged 45-75 years completed a questionnaire, including information on medical history, in 1993-1996. After exclusions, we performed Cox regression among 193,050 cohort members including 939 incident NHL cases while adjusting for sex, age, ethnicity, education, body mass index and alcohol intake. Self-reported diabetes was not associated with NHL overall, but was positively associated with risk among Japanese Americans [hazard ratio (HR) = 1.55; 95% confidence interval (CI): 1.10-2.17]. Participants with a history of blood transfusion were at increased risk with HR = 1.39 (95% CI: 1.06-1.84) in men and HR = 1.22 (95% CI: 0.94-1.58) in women, especially for the diffuse large B-cell lymphoma subtype. History of asthma or other allergies was associated with elevated risk only among Latinos (HR = 1.46; 95% CI: 1.07-2.00) who also showed a significant relation between current use of antihistamines and NHL (HR = 1.80; 95% CI: 1.09-2.97). Use of nonsteroidal anti-inflammatory drugs was not associated with NHL. Our findings from this large prospective study support a moderate risk for NHL related to blood transfusions, current long-term antihistamine use and diabetes, but the associations were limited to certain ethnic groups and require further replications.

Estimating the number of U.S. incident cancers attributable to obesity and the impact on temporal trends in incidence rates for obesity-related cancers

BACKGROUND

Reaching the American Cancer Society challenge goal for the nation to reduce cancer incidence by 25% by 2015 will be influenced in part by the epidemic of obesity. The purpose of this study was to estimate the impact of obesity on the number obesity-attributable incident cancers in the U.S. in 2007 and on trends on cancer incidence rates.

METHODS

Using estimated relative risks (RRs) for obesity vs. normal weight/height from published meta-analyses and/or large cohort studies, and the prevalence of obese adults from the latest national surveys, attributable risk percent (ARP) and numbers of obesity-attributed incident cancers in 2007 were estimated. Using the ARPs, the impact of obesity trends on trends in incidence rates for certain obesity-related cancers was estimated for the calendar years (1976-1980 through 2001-2004) for which cancer rates and obesity prevalence rates were available.

RESULTS

An estimated 33,966 new cancers (4% of all estimated cancers) in males and 50,535 (7% of all estimated cancers) in females diagnosed in 2007, or 6% of all cancers, may be potentially attributable to obesity. Without the impact of rising obesity rates, incidence rates might have declined (instead of remaining stable) from 1988-1994 to 2001-2004 for uterus, breast and certain other cancers.

CONCLUSIONS

Obesity may contribute to about 6% of U.S. incident cancers, apparently has affected recent trends in incidence rates for certain cancers, and is important because of increasing prevalence in the U.S. population.