Blood transfusion, anesthesia, surgery and risk of non-Hodgkin lymphoma in a population-based case-control study

The incidence of NHL has increased dramatically since at least the 1950s, and during this timeframe there has been a major increase in the use of blood transfusions, invasive surgical procedures and anesthesia, all of which can impact immune function. We evaluated these factors with NHL risk in a population-based study of 759 cases and 589 frequency-matched controls. Risk factor data were collected during in-person interviews. Unconditional logistic regression was used to estimate ORs and 95% CIs, adjusted for the matching factors. History of transfusion was associated with a 26% higher risk of NHL (95% CI 0.91-1.73), and the elevated risk was specific to transfusions first given 5-29 years before the reference date (OR = 1.69; 95% CI 1.08-2.62) and transfusions given for a medical condition (OR = 2.09; 95% CI 1.03-4.26). The total number of surgeries and dental procedures (OR = 1.53 for 26+ surgeries compared to 0-6; 95% CI 1.02-2.29) and to a lesser extent the total number of exposures to general or local/regional anesthesia (OR = 1.35 for 24+ times compared to 0-6; 95% CI 0.91-2.02) were positively associated with risk of NHL. Inclusion of transfusion and surgery or transfusion and anesthesia in the same model did not attenuate these associations. All results were broadly consistent for both DLBCL and follicular subtypes. Blood transfusions were associated with NHL risk, but appear to be a marker for underlying medical conditions. Multiple surgical procedures and/or repeated administration of anesthesia have not been previously reported to be associated with risk of NHL and these exposures warrant further evaluation.     

Smoking and non-Hodgkin lymphoma: case-control study in Italy

Tobacco smoking is a well-documented risk factor for several cancers, but the role of cigarette smoking in the etiology of non-Hodgkin lymphoma (NHL) is inadequately understood. Hepatitis C virus (HCV) has been associated with NHL, but the interaction between HCV and smoking habits has not yet been studied. Between 1999 and 2002, we conducted a case-control study on the association of HCV, smoking habits and NHL in 2 areas of northern and southern Italy. Cases were 225 consecutive patients (median age, 59 years) with a new diagnosis of NHL that were admitted to reference and general hospitals. Controls were 504 patients (median age, 63 years) admitted to the same hospitals as cases, for a wide spectrum of acute, nonneoplastic, nonimmune-, nor tobacco-related conditions. Current, heavy smokers (> or = 20 cigarettes/day) had an odds ratio (OR) of NHL of 2.10 (95% confidence interval, CI: 1.07-4.12) compared to never smokers. The association between smoking and NHL was consistent across strata of sex and age. Compared to never smokers, current smokers of > or = 20 cigarettes/day had ORs of 1.14 (95% CI: 0.37-3.56) for B-cell-low-grade, 2.10 (95% CI: 0.94-4.67) for B-cell-intermediate and high-grade, and 25.84 (95% CI: 1.95-342.17) for T-cell NHL. The effect of tobacco smoking and HCV were independent on the relative risk, leading a 4-fold elevated risk in current smokers HCV positive subjects. Tobacco smoking and hepatitis C virus (HCV) have been associated to non-Hodgkin lymphoma (NHL), but the interaction between HCV and smoking habits has not yet been studied. Our study confirms that tobacco is related to NHL, and reports on the combined effect of tobacco smoking and HCV. Infection acted together according to a multiplicative model, leading to a 4-fold elevated risk in current smokers HCV positive subjects.     

Pesticide use, immunologic conditions, and risk of non-Hodgkin lymphoma in Canadian men in six provinces

Pesticide exposures and immune suppression have been independently associated with the risk of non-Hodgkin lymphoma (NHL), but their joint effect has not been well explored. Data from a case-control study of men from six Canadian provinces were used to evaluate the potential effect modification of asthma, allergies, or asthma and allergies and hay fever combined on NHL risk from use of: (i) any pesticide; (ii) any organochlorine insecticide; (iii) any organophosphate insecticide; (iv) any phenoxy herbicide; (v) selected individual pesticides [1,1'-(2,2,2-trichloroethylidene)bis[4-chlorobenzene]; 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), malathion, (4-chloro-2-methylphenoxy)acetic acid (MCPA), mecoprop, and (2,4-dichlorophenoxy)acetic acid (2,4-D); and (vi) from the number of potentially carcinogenic pesticides. Incident NHL cases (n = 513) diagnosed between 1991 and 1994 were recruited from provincial cancer registries and hospitalization records and compared to 1,506 controls. A stratified analysis was conducted to calculate odds ratios (ORs) adjusted for age, province, proxy respondent, and diesel oil exposure. Subjects with asthma, allergies, or hay fever had non-significantly elevated risks of NHL associated with use of MCPA (OR = 2.67, 95% confidence interval [CI]: 0.90-7.93) compared to subjects without any of these conditions (OR = 0.81, 95% CI: 0.39-1.70). Conversely, those with asthma, allergies, or hay fever who reported use of malathion had lower risks of NHL (OR = 1.25, 95% CI: 0.69-2.26) versus subjects with none of these conditions (OR = 2.44, 95% CI: 1.65-3.61). Similar effects were observed for asthma and allergies evaluated individually. Although there were some leads regarding effect modification by these immunologic conditions on the association between pesticide use and NHL, small numbers, measurement error and possible recall bias limit interpretation of these results.     

Sun exposure may protect against non-Hodgkin lymphoma: a case-control study

Ultraviolet radiation is a hypothesised risk factor for non-Hodgkin lymphoma (NHL) but no epidemiological study has examined this association using direct measures of sun exposure in individuals. Adults aged 20-74 years living in NSW and ACT, Australia, were the study population. Cases (704 of 829 invited to take part, 85%) were diagnosed January 2000 to August 2001. Controls (694 of 1,136 invited to take part, 61%) were randomly selected from state electoral rolls and frequency-matched to cases by age, sex and state of residence. A self-administered questionnaire and telephone interview measured outdoor hours on working and nonworking days and vacations at 10, 20, 30, 40, 50 and 60 years of age. Logistic regression models of NHL and sun exposure contained the 3 matching variables, ethnicity and sun sensitivity measures as covariates. Contrary to expectations, risk of NHL fell with increasing reported sun exposure hours. Relative to 1.0 for the lowest quarter of total sun exposure hours, the odds ratios (ORs) for successively higher quarters were 0.72 (95% CI 0.53-0.98), 0.66 (0.48-0.91) and 0.65 (0.46-0.91) (p(trend)=0.01). The association of sun exposure on nonworking days with NHL was stronger; OR for highest quarter 0.47 (0.34-0.66) (p(trend)=0.0001). Risk also fell with sun exposure on vacations; OR for highest quarter 0.60 (0.43-0.85) (p(trend)=0.003). These associations appeared strongest in women and in childhood. There was little evident trend in risk with exposure on working day. Our results provide strong statistical evidence for an inverse association between sun exposure and NHL. Increasing evidence that vitamin D may protect against cancer makes UV-mediated synthesis of vitamin D a plausible mechanism whereby sun exposure might protect against NHL.     

Atopy, exposure to pesticides and risk of non-Hodgkin lymphoma

Pesticide exposure has been associated with non-Hodgkin lymphoma (NHL) risk in a number of studies, and two recent studies suggest that the increased risk may be confined to those with a history of asthma. We examined the interaction between occupational pesticide exposure and atopy on risk of NHL in an Australian population-based case-control study. Incident cases (n = 694) were diagnosed in New South Wales or the Australian Capital Territory between 2000 and 2001 and controls (n = 694) were randomly selected from electoral rolls and frequency-matched to cases by age, sex and state of residence. Occupational pesticide exposure was determined by an expert occupational hygienist's assessment of job-specific questionnaires administered by telephone. History of atopy (asthma, hay fever, eczema and food allergy) was self-reported. Logistic regression models included the three matching variables, ethnicity and sun exposure. The OR for NHL with substantial pesticide exposure and any history of asthma was 3.07 (95% CI 0.55-17.10) and with substantial pesticide exposure and no asthma history it was 4.23 (95% CI 1.76-10.16). The p-value for interaction was 0.29. A similar pattern of risk was observed for each of the pesticide subtypes; for asthma at various times of life; for hay fever, eczema, food allergy and any atopy, in men only and for follicular lymphomas only. Although this study had limited power, the findings do not suggest modification of the association between pesticide exposure and NHL risk by asthma or atopic disease more generally.     

Midtreatment 18F-fluorodeoxyglucose positron-emission tomography in aggressive non-Hodgkin lymphoma

BACKGROUND:

The use of ¹⁸F‐fluorodeoxyglucose positron‐emission tomography (PET) scan has increased considerably in the clinical management of non‐Hodgkin lymphoma patients, and its role as a prognostic factor during chemotherapy has been established recently.

METHODS:

Between May 2003 and May 2009, 91 newly diagnosed patients with primary mediastinal large B‐cell lymphoma (PMLBCL) and diffuse large B‐cell lymphoma (DLBCL) were treated with 12 weekly cycles of rituximab‐MACOP‐B (n = 12 patients with PMLBCL), 6 cycles of rituximab‐CHOP21 (n = 65 patients with DLBCL, aged < 60 years and 1 patient with PMLBCL), or 8 weekly cycles of rituximab‐VNCOP‐B (n = 13 DLBCL patients, aged ≥ 60 years). All patients underwent a staging PET examination at baseline and a midtreatment (interim) PET examination after 6 weeks of rituximab‐MACOP‐B treatment, 3 cycles of rituximab‐CHOP21 treatment, or 4 weeks of rituximab‐VNCOP‐B treatment and again at the end of the chemo‐immunotherapy regimen.

RESULTS:

At midtreatment evaluation, 35 patients showed a persistently positive PET scan; only 6 (17%) of these patients achieved a continuous complete response (CCR). However, 56 patients presented with a negative interim PET, and 50 (89%) of these patients achieved and maintained a CCR. Comparison between the 2 PET groups indicated a statistically significant association between PET findings and event‐free survival (P = .0001) and overall survival (P = .0001).

CONCLUSIONS:

The results of this study indicated that midtreatment PET may represent a significant step forward in helping physicians make crucial decisions on further treatment. Cancer 2011. © 2010 American Cancer Society.     

Cellular telephones and non-Hodgkin lymphoma

Dramatic increase in hand-held cellular telephone use since the 1980s and excess risk of lymphoproliferative malignancies associated with radio-frequency radiation (RFR) exposures in epidemiological and experimental studies motivated assessment of cellular telephones within a comprehensive US case-control investigation of non-Hodgkin lymphoma (NHL). A questionnaire ascertained cellular telephone use in 551 NHL cases and 462 frequency-matched population controls. Compared to persons who had never used cellular telephones, risks were not increased among individuals whose lifetime use was fewer than 10 (odds ratio (OR) = 0.9, 95% confidence intervals (CI): 0.6, 1.3), 10-100 (OR = 1.0, 95 % CI: 0.7, 1.5) or more than 100 times (e.g., regular users, OR = 0.9, 95% CI: 0.6, 1.4). Among regular users compared to those who had never used hand-held cellular telephones, risks of NHL were not significantly associated with minutes per week, duration, cumulative lifetime or year of first use, although NHL was non-significantly higher in men who used cellular telephones for more than 8 years. Little evidence linked use of cellular telephones with total, diffuse large B-cell lymphoma or follicular NHL. These findings must be interpreted in the context of less than 5% of the population reporting duration of use of 6 or more years or lifetime cumulative use of 200 or more hours.     

Food groups and risk of non-Hodgkin lymphoma: a multicenter, case-control study in Italy

Incidence of non-Hodgkin lymphoma (NHL) has been rising worldwide, but the reasons are undefined. Dietary habits may play a role in the etiology of NHL by influencing the metabolic pathways of several cells of the immune system. This case-control study investigated the relation between food consumption and NHL risk. Between 1999 and 2002, we conducted a hospital-based case-control study on NHL in 2 areas of Italy. Cases were 190 patients (median age 58 years) with incident NHL admitted to specialized and general hospitals. Controls were 484 patients (median age 63 years) with acute non-neoplastic conditions admitted to the same hospitals network of cases. A validated food-frequency questionnaire was used to assess habitual diet 2 years before interview. Unconditional multiple logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI), with allowance for energy intake, according to the residual model. Consumption of highest versus lowest quartile of pasta/rice (OR = 1.87, 95% CI: 1.04-3.36) and cheese (OR = 1.66, 95% CI: 0.98-2.83) were associated with a significantly increased NHL risk. Inverse association was found for vegetables (OR = 0.49, 95% CI: 0.28-0.87), fruits (OR = 0.51, 95% CI: 0.30-0.85), and egg consumption (OR = 0.59, 95% CI: 0.36-0.97). The association of pasta/rice was also supported by an increased risk of high glycemic load levels (OR = 1.86, 95% CI: 1.04-3.32). In conclusion, our results suggested that diet could affect NHL risk.     

Primary diffuse large B‐cell lymphoma of the tonsil

BACKGROUND: The purpose was to evaluate the prognostic factors and treatment outcome of Indian patients with primary diffuse large B-cell lymphoma (DLBCL) of the tonsil treated at a single institution. METHODS: In all, 121 patients with DLBCL of the tonsil, treated at the Tata Memorial Hospital, Mumbai, India, from January 1990 to December 2002, were included. The median age was 45 years and the majority of patients (68%) were males. Systemic symptoms were present in 12% of patients; 28% presented with stage I and 67% had stage II disease. Treatment consisted of a combination of chemotherapy (CTh) and radiotherapy (RT) for the majority of patients (69.4%). Among those receiving RT, 64% received an RT dose of > or =45 Gy. RESULTS: After a median follow-up of 62 months, disease-free survival (DFS) and overall survival (OS) were 66.4% and 81.6%, respectively. Significant prognostic factors included: WHO performance score > or =2 (OS: 72.1% vs 95.6%, P = .016), bulky tumors (OS: 68.5% vs 86.9%, P = .001), presence of B-symptoms (OS: 36.7% vs 79.6%, P < .001), and Ann Arbor stage. On multivariate analysis; WHO performance score > or =2 (hazard ratio [HR], 4.27; 95% confidence interval [CI], 1.20-15.12), and B symptoms (HR, 6.27; 95% CI, 2.38-16.48), retained statistical significance. CTh + RT resulted in a significantly better outcome than those treated with CTh alone (OS: 85.7% vs 70.7%, P = .008). The complete response (P = .053), DFS (P = .039), and OS (P = .014) rates were significantly better for patients receiving an RT dose > or =45 Gy. CONCLUSIONS: Tumor bulk, WHO performance score, the presence of B symptoms, and Ann Arbor stage significantly influence outcome. A combined modality treatment, consisting of CTh and RT (with an RT dose of > or =45 Gy), results in a satisfactory outcome in patients with this uncommon neoplasm.     

Presence of autoimmune disease affects not only risk but also survival in patients with B‐cell non‐Hodgkin lymphoma

Although autoimmune diseases (AIDs) are known to predispose to non‐Hodgkin lymphoma (NHL), their association with NHL prognosis has rarely been investigated. We examined associations between autoimmunity and B‐cell NHL onset by comparing AID history (determined by self‐report and medication review and supplemented by chart review where possible) among 435 adult B‐NHL patients in Hadassah‐Hebrew University Medical Center, diagnosed 2009‐2014, and 414 age‐and‐sex frequency‐matched controls. We examined AIDs as a whole, B‐ and T‐cell–mediated AIDs, and autoimmune thyroid diseases. Among cases, we used Kaplan‐Meier and Cox regression models to assess the association of AID with overall survival and relapse‐free survival, adjusting for prognostically important patient and disease characteristics such as Ki67% staining, International Prognostic Index, rituximab treatment, and histological subgroup. Autoimmune diseases were associated with B‐NHL (odds ratio [OR] = 1.95; 95% confidence interval (CI), 1.31‐2.92), especially AIDs mediated by B‐cell activation (OR = 5.20; CI, 1.90‐14.3), which were particularly associated with marginal zone lymphoma (OR = 19.3; CI, 4.59‐80.9). We found that time to relapse for all B‐NHL patients with AIDs was significantly shorter (mean of 49.21 mo [±3.22]) than among patients without AID (mean of 59.74 mo [±1.62]), adjusted hazard ratio [HR_adj] = 1.69 (CI, 1.03‐2.79). Specifically, in patients with diffuse large B‐cell lymphoma, of whom 91.8% had received rituximab, a history of B‐cell–mediated AIDs was associated with shorter relapse‐free survival and overall survival, HR_adj = 8.34 (CI, 3.01‐23.1) and HR_adj = 3.83 (CI, 1.20‐12.3), respectively. Beyond confirming the well‐known association between AIDs and B‐NHL, we found that AID is an adverse prognostic factor in B‐cell lymphoma, associated with a shortened time to relapse, suggesting that there are specific therapeutic challenges in the subgroup of patients suffering from both these diseases. Further work is required to address mechanisms of resistance to standard treatment in the setting of AID‐associated B‐NHL. In the era of immunotherapy, these findings have particular relevance.     

Sun exposure and malignant lymphoma: a population-based case-control study in Germany

Although some causes for malignant lymphoma are known their etiology is not well understood so far. We analyze the relationship between sun exposure and malignant lymphoma in a multicenter, population-based case-control study. Patients with malignant lymphoma (n = 710, 18-80 years) were prospectively recruited in 6 study regions in Germany. For each case, a gender, region and age-matched control was drawn from population-registers. In personal interviews, lifetime holidays spent in sunny climate, outdoor leisure activities and sunbed or sunlamp use were recorded. On basis of job task-specific supplementary questionnaires, an occupational physician assessed the cumulative working time outside. Odds ratios (OR) and 95%-confidence-intervals (CI) were calculated using conditional logistic regression analysis, adjusted for smoking and alcohol consumption. To increase statistical power, patients with specific lymphoma subentities were additionally compared with the entire control group using unconditional logistic regression. We observed a reduced overall lymphoma risk among subjects having spent vacations at sunny climates or frequently used sunbeds or sunlamps. The analysis of lymphoma subentities revealed similar results with the exception of T-NHL and follicular lymphoma which were positively associated with outdoor leisure activities. While cumulative working time outside appeared unrelated to NHL overall and most subentities, it was negatively associated with follicular lymphoma and weakly positively to HL. This data suggest that exposure to natural and artificial ultraviolet radiation may reduce the OR for lymphoma in this study population.     

t(2; 18) and t(18;22) Variant Chromosomal Translocations in B Cell Malignancies

Variant translocations (2;18 and 18;22) are described in this review. The chromosomal and molecular findings of these translocations of BCL2 and their effect on possible BCL2 gene activation is discussed. Unanswered questions still remain and these include why this is so rare compared to the 25% incidence recorded for translocations in Burkitt's lymphoma. Further studies are obviously still needed in order to determine the true frequency of these findings and their distribution in the various B-cell disorders.     

Clinical impact of t(14;18) in diffuse large B-cell lymphoma

Objective: Recent studies have suggested that t(14;18) is present in a significant proportion of diffuse large B-cell lymphomas (DLBCLs). However, the prognostic significance of this translocation and its relationship with BCL-2 protein expression remains controversial. Our study aimed to investigate the predictive power of t(14;18) and BCL-2 protein expression in the prognosis of DLBCLs. Methods: Biopsy specimens from 106 DLBCLs were analyzed using interphase fluorescence in situ hybridization (FISH). Immunophenotypic analysis of CD20, CD3, CD10, BCL-6, MUM1 and BCL-2 was performed by immunohistochemistry. SPSS 13.0 software was used for statistical analysis. Results: The t(14;18) was identified in 27 of 106 cases (25.5%). The percentages of tumor cells expressing CD10, BCL-6, MUM1 and BCL-2 were 21.7%, 26.4%, 56.6% and 73.6%, respectively. The presence of this translocation was significantly correlated with the expression of CD10 and immunophenotypic subtype (p<0.001). No association was observed between BCL-2 protein expression and the presence of t(14;18). Multivariate analysis confirmed that both t(14;18) and BCL-2 expression were significantly associated with survival. Moreover, patients with t(14;18) had worse prognosis, compared with those with BCL-2 expression (for overall survival: hazard ratio, 4.235; 95%CI, 2.153-8.329, p<0.001 vs. hazard ration, 2.743; 95%CI, 1.262-5.962, p=0.011). Conclusions: The t(14;18) is a useful prognostic tool for the evaluation of DLBCL immunophenotype and prognosis. The prognosis of GCB (germinal centre-like B cell) DLBCL patients should be made with the consideration of the presence of this translocation, and the detection of t(14;18) should be included as a routine diagnostic test in these cases.     

Cigarette smoking and colorectal cancer risk in Germany: a population-based case-control study

Studies have shown fairly consistent positive relationships between smoking and risk of colorectal adenomas, but have yielded inconsistent results for colorectal cancer. Issues relating to the duration, cumulative dose of smoking and the effect of smoking cessation on colorectal cancer risk still need clarification. In a population-based case-control study in Germany, we recruited 540 incident cases of colorectal cancer and 614 controls matched to cases by sex, 5-year age groups and county of residence from January 2003 to June 2004. Subjects were aged>or=30 years, and provided information on risk factors of colorectal cancer, including lifetime cigarette smoking habits, in personal interviews. Odds ratios (OR) and 95% confidence intervals (CI) were computed using conditional logistic regression models, adjusting for potential confounders. Compared with nonsmokers, there was an increased risk for smoking for >or=30 years (OR: 1.25, 95% CI: 0.90-1.75) and a significant risk increase for >or=40 pack-years of smoking (OR: 1.92, 95% CI: 1.13-3.28). Stratification by sex yielded higher risk estimates among females than that among males, with adjusted ORs of 3.5 (95% CI: 1.29-9.52) and 1.15 (0.69-1.91) for women and men, respectively, following >or=30 pack-years of smoking (pinteraction=0.18). Among smokers, risk reduction was observed after >or=20 years of quitting smoking and was significant for >or=40 years (OR: 0.46; 95% CI: 0.21-0.98), when compared to current smokers (p for linear trend=0.05). This study supports the hypothesis that smoking for a long duration at a high cumulative dose increases the risk for colorectal cancer, particularly among women, and suggests that there is risk reduction after longterm smoking cessation.     

Dose dense (CEOP-14) vs dose dense and rituximab (CEOP-14+R) in high-risk diffuse large cell lymphoma

To assess efficacy and toxicity of rituximab and dose chemotherapy in high-risk diffuse large cell lymphoma, we conducted a controlled clinical trial to assess efficacy and toxicity of a dose-dense regimen CEOP-14 (cyclophosphamide, epirubicin, vincristine, and prednisone every 14 d) compared to CEOP-14 plus rituximab. One hundred and ninety-six patients were randomized to received CEOP-rituximab (cyclophosphamide 1500mg/m², epirubicin 120 mg/m², vincristine, and prednisone at standard dose and rituximab at 375 mg/m²) compared with the same chemotherapy administered every 14 d (CEOP-14). In an intent-to-treat analysis all patients were available for efficacy and toxicity. Complete response in CEOP-14 was observed in 73 cases (74%) and in 75 patients (76%) in the CEOP-R regimen (76%) (p=0.8). With a median follow-up of 53.4 mo, median has not been reached in time to tumor-progression (TTP) and overall survival (OS). Actuarial curves at 5 yr showed that TTP and OS in patients treated with CEOP-R were 74% and 67%, respectively, that were not statistical different when compared to CEOP-14, 72% and 65%, respectively (p=0.8). Acute toxicity was mild and well tolerated. The use of a dense-dose regimen is useful and well tolerated in patients with very high risk diffuse large cell lymphoma. The addition of rituximab did not improve outcome in these setting of patients.     

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/m², 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/m². 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.