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Background: Epidemiologic evidence suggests an inverse association between sun exposure and follicular lymphoma risk., Methods: We conducted an Australian population-based family case-control study based on 666 cases and 459 controls (288 related, 171 unrelated). Participants completed a lifetime residence and work calendar and recalled outdoor hours on weekdays, weekends, and holidays in the warmer and cooler months at ages 10, 20, 30, and 40 years, and clothing types worn in the warmer months. We used a group-based trajectory modeling approach to identify outdoor hour trajectories over time and examined associations with follicular lymphoma risk using logistic regression., Results: We observed an inverse association between follicular lymphoma risk and several measures of high lifetime sun exposure, particularly intermittent exposure (weekends, holidays). Associations included reduced risk with increasing time outdoors on holidays in the warmer months [highest category OR = 0.56; 95% confidence interval (CI), 0.42-0.76; Ptrend < 0.01], high outdoor hours on weekends in the warmer months (highest category OR = 0.71; 95% CI, 0.52-0.96), and increasing time outdoors in the warmer and cooler months combined (highest category OR = 0.66; 95% CI, 0.50-0.91; Ptrend 0.01). Risk was reduced for high outdoor hour maintainers in the warmer months across the decade years (OR = 0.71; 95% CI, 0.53-0.96)., Conclusions: High total and intermittent sun exposure, particularly in the warmer months, may be protective against the development of follicular lymphoma., Impact: Although sun exposure is not recommended as a cancer control policy, confirming this association may provide insights regarding the future control of this intractable malignancy., (©2023 The Authors; Published by the American Association for Cancer Research.)

Objectives: We aimed to examine the relationship between occupational exposure to extremely low-frequency magnetic fields (ELF-MFs) and follicular lymphoma (FL) risk., Methods: We conducted a family case-control study between 2011 and 2016 in Australia and included 681 cases. Controls were either a family member of cases (related (n=294), unrelated (n=179)) or were unrelated recruited for a similarly designed Australian multiple myeloma study (n=711). We obtained detailed job histories using lifetime work calendars. We assigned exposure to ELF-MFs using an enhanced job exposure matrix, with a lag period of 10 years. We examined associations with FL risk using logistic regression accounting for relatedness between cases and controls. We performed sensitivity analyses including by control type, by sex, complete case analyses, ELF-MF exposure percentiles in addition to quartiles, ELF-MF exposure in the maximum exposed job, a shorter lag period (1 year) and the cumulative exposure in the most recent time period (1-9 years)., Results: We observed no association with the average intensity, duration or lifetime cumulative exposure to occupational ELF-MF exposure in the primary or sensitivity analyses., Conclusions: Our findings do not support an association between occupational ELF-MF exposure and FL risk. Although the inclusion of family members as part of the larger control group may have biased our risk estimates towards the null, findings were similar in sensitivity analyses restricted to cases and unrelated controls. Further research incorporating enhanced exposure assessment to ELF-MF is warranted to inform occupational safety regulations and any potential role in lymphomagenesis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

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/m 2 ) and per 5-kg/m 2 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., Competing Interests: Conflict of interest statement All authors declare that they have no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: The etiology of follicular lymphoma (FL), a common non-Hodgkin lymphoma subtype, is largely unknown., Objective: We performed a systematic review and meta-analysis of observational studies examining the relationship between occupational exposures and FL risk., Methods: We searched Ovid MEDLINE, Ovid EMBASE, and Web of Science for eligible observational studies examining job titles or occupational exposures prior to January 1, 2020. We performed a narrative synthesis and used random-effects models to generate meta-estimates of relative risk (RR) with 95% confidence intervals (95%CI) for exposures reported by three or more studies., Results: Fifty-eight studies were eligible. Ten cohort and 37 case-control studies quantified FL risk in relation to any exposure to one or more occupational groups or agents. Eight cohort and 19 case-control studies examined dose-response relationships. We found evidence of a positive association with increasing plasma concentration of dichlorodiphenyldichloroethylene (DDE; meta-RR = 1.51, 95%CI = 0.99, 2.31; I 2  = 0.0%) and polychlorinated biphenyls (PCBs; meta-RR = 1.47, 95%CI = 0.97, 2.24; I 2  = 8.6%). We observed a positive association with exposure to any solvent (meta-RR = 1.16, 95%CI = 1.00, 1.34; I 2  = 0.0%) and chlorinated solvents (meta-RR = 1.35, 95%CI = 1.09, 1.68; I 2  = 0.0%). Single studies reported a significant positive dose-response association for exposure to any pesticide, hexachlorobenzene, any organophosphate, diazinon, metolachlor, carbaryl, lindane, trichloroethylene, oils/greases, and extremely low-frequency magnetic fields. Job title-only analyses suggested increased risk for medical doctors and spray painters, and decreased risk for bakers and teachers. Overall, studies demonstrated low risk of bias, but most studies examined small numbers of exposed cases., Conclusions: Current evidence indicates a positive association between FL and occupational exposure to DDE, PCBs, any solvent and chlorinated solvents. Our findings may help guide policies and practices on the safe use of solvents and inform models of lymphomagenesis. Future studies with larger sample sizes and comprehensive quantitative exposure measures may elucidate other avoidable carcinogenic exposures., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: To investigate the relationship between follicular lymphoma (FL) risk and common modifiable lifestyle factors, specifically smoking, alcohol, body mass index (BMI), and hair dye use., Methods: We performed a systematic review and meta-analysis of observational studies published prior to 01 January 2020. We searched Ovid MEDLINE, Ovid EMBASE, and Web of Science and the reference lists of original studies and review articles. We used random-effects models to generate meta-estimates of relative risk (RR) with 95% confidence intervals (95% CI)., Results: Twenty-four cohort and ten case-control studies were eligible. Ten articles examined smoking, 11 alcohol, 13 BMI, and four hair dye use and risk of FL. The meta-estimate for current smoking was 1.11 (95% CI 0.92-1.35; I 2  = 51%) and there was no significant dose-response per 5-year increase in duration (p-trend = 0.087). Current alcohol intake was inversely associated with FL risk (meta-RR 0.87, 95% CI 0.81-0.94; I 2  = 0%) and there was a significant dose-response per 5 drinks/week increase in intake (p-trend = 0.008). There was no association with 5 kg/m 2 increase in early adulthood BMI (meta-RR 1.05, 95% CI 0.91-1.20; I 2  = 7%) or being overweight (meta-RR 0.99, 95% CI 0.92-1.07; I 2  = 0%) or obese (meta-RR 1.08, 95% CI 0.99-1.17; I 2  = 0%) as an adult. Hair dye use before 1980 was positively associated with FL risk (meta-RR 1.66, 95% CI 1.22-2.25; I 2  = 55%) and no evidence of effect after 1980., Conclusion: We found consistent evidence of an inverse association between current alcohol intake and FL risk, and a significant increased risk with hair dye use before 1980. The evidence for smoking is heterogeneous, but most studies did not support an association. Further research is required to understand the mechanisms underlying these associations and the potential for prevention strategies.

Subtype-specific incidence patterns in populations at high risk of lymphoma offer insight into lymphomagenesis. The incidence profiles for the 2 most common non-Hodgkin lymphoma subtypes were compared for 2 immunodeficient populations, adults receiving a kidney transplant 1982-2003 (n = 7,730) or diagnosed with human immunodeficiency virus (HIV) infection 1982-2004 (n = 17,175). National, population-based registries were linked and standardized incidence ratios (SIRs) were computed for each cohort and lymphoma subtype. Risk of diffuse large B-cell lymphoma was significantly increased after transplantation (SIR 17.83, 95% CI: 13.61-22.95) and after HIV infection (SIR 58.81, 95% CI: 52.59-65.56). Rates of follicular lymphoma (FL) were neither significantly increased nor decreased in transplant recipients (SIR 0.82, 95% CI: 0.10-2.96) and in people with HIV (SIR 1.25, 95% CI: 0.41-2.91). The findings argue against an infectious or other immunodeficiency-related etiology for FL and clearly differentiate it from diffuse large B-cell lymphoma.