Body mass index and Hodgkin's lymphoma: UK population-based cohort study of 5.8 million individuals

Genetically determined telomere length as a risk factor for hematological malignancies: evidence from Mendelian randomization analysis

BACKGROUND

Over the past years, the exact correlation between telomere length and hematological malignancies was still not fully understood.

METHODS

We performed a two-sample Mendelian randomization study to investigate the causal relationship between telomere length and hematological malignancies. We selected genetic instruments associated with telomere length. The genetic associations for lymphoid and hematopoietic malignant neoplasms were obtained from the most recent publicly accessible FinnGen study R9 data. Inverse variant weighted (IVW) analysis was adopted as the primary method, and we also performed the weighted-median method and the MR-Egger, and MRPRESSO methods as sensitive analysis.

RESULTS

Significant associations have been observed between telomere length and primary lymphoid (IVW: OR = 1.52, P = 2.11 × 10-6), Hodgkin lymphoma (IVW: OR = 1.64, P = 0.014), non-Hodgkin lymphoma (IVW: OR = 1.70, P = 0.002), B-cell lymphoma (IVW: OR = 1.57, P = 0.015), non-follicular lymphoma (IVW: OR = 1.58, P = 1.7 × 10-3), mantle cell lymphoma (IVW: OR = 3.13, P = 0.003), lymphoid leukemia (IVW: OR = 2.56, P = 5.92E-09), acute lymphocytic leukemia (IVW: OR = 2.65, P = 0.021) and chronic lymphocytic leukemia (IVW: OR = 2.80, P = 8.21 × 10-6), along with multiple myeloma (IVW: OR = 1.85, P = 0.016).

CONCLUSION

This MR study found a significant association between telomere length and a wide range of hematopoietic malignancies. But no substantial impact of lymphoma and hematopoietic malignancies on telomere length has been detected.

Body Weight Correlates with Molecular Variances in Patients with Cancer

Overweight and obesity are identified by a high body mass index (BMI) and carry significant health risks due to associated comorbidities. Although epidemiologic data connect overweight/obesity with 13 cancer types, a better understanding of the molecular mechanisms underlying this correlation is needed to improve prevention and treatment strategies. In this study, we conducted a comprehensive analysis of molecular differences between overweight or obese patients and normal weight patients across 14 different cancer types from The Cancer Genome Atlas. Using the propensity score weighting algorithm to control for confounding factors, obesity-specific mutational features were identified, such as higher mutation burden in rectal cancer and biased mutational signatures in other cancers. Differentially expressed genes (DEG) in tumors from patients with overweight/obesity were predominantly upregulated and enriched in inflammatory and hormone-related pathways. These DEGs were significantly associated with survival rates in various cancer types, highlighting the impact of elevated body fat on gene expression profiles and clinical outcomes in patients with cancer. Interestingly, while high BMI seemed to have a negative impact on most cancer types, the normal weight-biased mutational and gene expression patterns indicated overweight/obesity may be beneficial in endometrial cancer, suggesting the presence of an "obesity paradox" in this context. Body fat also significantly impacted the tumor microenvironment by modulating immune cell infiltration, underscoring the importance of understanding the interplay between weight and immune response in cancer progression. Together, this study systematically elucidates the molecular differences corresponding to body weight in multiple cancer types, offering potentially critical insights for developing precision therapy for patients with cancer.

SIGNIFICANCE

Elucidation of the complex interplay between body weight and the molecular landscape of cancer could potentially guide tailored therapies and improve patient management amid the global obesity crisis.

Adipose tissue indices predict prognosis in hodgkin lymphoma

INTRODUCTION BACKGROUND

This study evaluated the impact of adipose tissue indices on prognosis of HL.

METHODS

Fifty-five patients with newly diagnosed Hodgkin Lymphoma were evaluated retrospectively for association with adipose tissue indices (total abdominal tissue volume, radiodensity, subcutaneous and visceral adipose tissue SUVmax value and prognostic factors for Hodgkin Lymphoma such as IPS-3, IPS-7, stage, sedimentation, progression free and overall survival.

RESULTS

For IPS-3, SAT SUVmax and TAAT radiodensity were significantly increased in high-risk patients (2and 3) compared to group 0 and 1. For IPS-7, total abdominal adipose volume was significantly decreased in high-risk patients, SAT SUVmax significantly increased in high-risk patients and decreased in low-risk patients. In addition, SAT SUVmax was significantly increased in patients with high sedimentation rate, with B symptoms and who passed away during follow-up. SAT SUVmax showed moderate positive correlation with sedimentation, IPS-3, IPS-7, and stage. In addition, it was observed that TAAT radiodensity and SAT SUVmax were significantly better for determining prognosis than other adipose tissue indices. Roc analysis showed that the diagnostic value of all adipose tissue indices in predicting IPS-3 and IPS-7 prognoses were statistically significant.

CONCLUSION

SAT SUVmax and TAAT radiodensity were two new and independent markers with diagnostic value in predicting prognosis.

Hodgkin Lymphoma: A disease shaped by the tumor micro- and macroenvironment

The tumor microenvironment (TMicroE) and tumor macroenvironment (TMacroE) are defining features of classical Hodgkin lymphoma (cHL). They are of critical importance to clinicians since they explain the common signs and symptoms, allow us to classify these neoplasms, develop prognostic and predictive biomarkers, bioimaging and novel treatments. The TMicroE is defined by effects of cancer cells to their immediate surrounding and within the tumor. Effects of cancer cells at a distance or outside of the tumor define the TMacroE. Paraneoplastic syndromes are signs and symptoms due to effects of cancer at a distance or the TMacroE, which are not due to direct cancer cell infiltration. The most common paraneoplastic symptoms are B-symptoms, which manifest as fevers, chills, drenching night sweats, and/or weight loss. Less common paraneoplastic syndromes include those that affect the central nervous system, skin, kidney, and hematological autoimmune phenomena including hemophagocytic lymphohistiocytosis (HLH). Paraneoplastic signs such as leukocytosis, lymphopenia, anemia, and hypoalbuminemia are prognostic biomarkers. The neoplastic cells in cHL are the Hodgkin and Reed Sternberg (HRS) cells, which are preapoptotic germinal center B cells with a high mutational burden and almost universal genetic alterations at the 9p24.1 locus primarily through copy gain and amplification with strong activation of signaling via PD-L1, JAK-STAT, NFkB, and c-MYC. In the majority of cases of cHL over 95% of the tumor cells are non-neoplastic. In the TMicroE, HRS cells recruit and mold non-neoplastic cells vigorously via extracellular vesicles, chemokines, cytokines and growth factors such as CCL5, CCL17, IL6, and TGF-β to promote a feed-forward inflammatory loop, which drives cancer aggressiveness and anti-cancer immune evasion. Novel single cell profiling techniques provide critical information on the role in cHL of monocytes-macrophages, neutrophils, T helper, Tregs, cytotoxic CD8+ T cells, eosinophils, mast cells and fibroblasts. Here, we summarize the effects of EBV on the TMicroE and TMacroE. In addition, how the metabolism of the TMicroE of cHL affects bioimaging and contributes to cancer aggressiveness is reviewed. Finally, we discuss how the TMicroE is being leveraged for risk adapted treatment strategies based on bioimaging results and novel immune therapies. In sum, it is clear that we cannot effectively manage patients with cHL without understanding the TMicroE and TMacroE and its clinical importance is expected to continue to grow rapidly.

Classic Hodgkin lymphoma in young people

Classic Hodgkin lymphoma (CHL) is a unique form of lymphoid cancer featuring a heterogeneous tumor microenvironment and a relative paucity of malignant Hodgkin and Reed-Sternberg (HRS) cells with characteristic phenotype. Younger individuals (children, adolescents and young adults) are affected as often as the elderly, producing a peculiar bimodal age-incidence profile that has generated immense interest in this disease and its origins. Decades of epidemiological investigations have documented the populations most susceptible and identified multiple risk factors that can be broadly categorized as either biological or environmental in nature. Most risk factors result in overt immunodeficiency or confer more subtle alterations to baseline health, physiology or immune function. Epstein Barr virus, however, is both a risk factor and well-established driver of lymphomagenesis in a significant subset of cases. Epigenetic changes, along with the accumulation of somatic driver mutations and cytogenetic abnormalities are required for the malignant transformation of germinal center-experienced HRS cell precursors. Chromosomal instability and the influence of endogenous mutational processes are critical in this regard, by impacting genes involved in key signaling pathways that promote the survival and proliferation of HRS cells and their escape from immune destruction. Here we review the principal features, known risk factors and lymphomagenic mechanisms relevant to newly diagnosed CHL, with an emphasis on those most applicable to young people.

Long-term incidence of haematological cancer after bariatric surgery or usual care in the Swedish Obese Subjects study: a prospective cohort study

BACKGROUND

Bariatric surgery in people with obesity is associated with a reduced overall cancer risk. Retrospective studies indicate that bariatric surgery specifically might reduce the risk of haematological cancers, but there is an absence of data from long-term, prospective studies. We therefore studied the association between bariatric surgery and haematological cancer in the Swedish Obese Subjects study.

METHODS

The prospective controlled Swedish Obese Subjects study was designed to compare overall mortality in people who underwent bariatric surgery (n=2007) and usual care (n=2040). Participants were recruited through campaigns in mass media and at 480 primary health-care centres all over Sweden. The inclusion criteria were an age of 37-60 years and a BMI of 34 kg/m2 or more in men and 38 kg/m2 or more in women before or at the time of the examination. Haematological cancer events, including malignant lymphoma, myeloma, myeloproliferative neoplasms, as well as acute and chronic leukaemias, were captured from the Swedish Cancer Registry. The main outcome of this study was haematological cancer incidence and mortality. This study is registered with ClinicalTrials.gov (NCT01479452) and is ongoing.

FINDINGS

A total of 4047 individuals with obesity were enrolled between Sept 1, 1987, and Jan 31, 2001. Overall, 34 participants in the surgery group and 51 participants in the usual care control group were diagnosed with haematological cancer during follow-up (hazard ratio [HR] 0·60; 95% CI 0·39-0·92; p=0·020). Moreover, there were three deaths by haematological cancer in the surgery group and 13 deaths in the control group (0·22; 0·06-0·76; p=0·017). Surgery was also associated with a reduced incidence of lymphoma (0·45; 0·23-0·88; p=0·020). A significant difference in treatment effect between men and women was found; bariatric surgery was associated with reduced incidence of haematological cancer in women (0·44; 0·26-0·74; p=0·002), but not in men (1·35; 0·58-3·17; p=0·489; interaction p=0·031).

INTERPRETATION

Bariatric surgery is associated with a reduced incidence of haematological cancer, specifically in women. Health-care providers and policy makers working in the field of cancer prevention should consider bariatric surgery a primary prevention resource for people with obesity.

FUNDING

The Swedish Research Council, the Swedish State under the agreement between the Swedish Government and the county councils, the Avtal om Läkarutbildning och Forskning agreement, the Health & Medical Care Committee of the Region Västra Götaland, the Swedish Heart Lung Foundation, Gothenburg Medical Society, and the Adlerbert Research Foundation.

TRANSLATION

For the Swedish translation of the abstract see Supplementary Material section.

Celiac Disease Is a Risk Factor for Mature T and NK Cell Lymphoma: A Mendelian Randomization Study

Celiac disease (CeD) is an immune-mediated disorder triggered by gluten ingestion that damages the small intestine. Although CeD has been associated with a higher risk for cancer, the role of CeD as a risk factor for specific malignancies, such as enteropathy-associated T-cell lymphoma (EATL), remains controversial. Using two-sample Mendelian randomization (2SMR) methods and the summarized results of large genome-wide association studies from public repositories, we addressed the causal relationship between CeD and eight different malignancies. Eleven non-HLA SNPs were selected as instrumental variables (IVs), and causality estimates were obtained using four 2SMR methods: random-effects inverse variance-weighted, weighted median estimation, MR-Egger regression, and MR pleiotropy residual sum and outlier (MR-PRESSO). We identified a significant causal relationship between CeD and mature T/NK cell lymphomas. Under a multivariate Mendelian randomization model, we observed that the causal effect of CeD was not dependent on other known lymphoma risk factors. We found that the most instrumental IV was located in the TAGAP locus, suggesting that aberrant T cell activation might be relevant in the T/NK cell malignization process. Our findings provide new insights into the connection between immune imbalance and the development of severe comorbidities, such as EATL, in patients with CeD.

Obesity and Risk for Lymphoma: Possible Role of Leptin

Obesity, which is considered a pandemic due to its high prevalence, is a risk factor for many types of cancers, including lymphoma, through a variety of mechanisms by promoting an inflammatory state. Specifically, over the last few decades, obesity has been suggested not only to increase the risk of lymphoma but also to be associated with poor clinical outcomes and worse responses to different treatments for those diseases. Within the extensive range of proinflammatory mediators that adipose tissue releases, leptin has been demonstrated to be a key adipokine due to its pleotropic effects in many physiological systems and diseases. In this sense, different studies have analyzed leptin levels and leptin/leptin receptor expressions as a probable bridge between obesity and lymphomas. Since both obesity and lymphomas are prevalent pathophysiological conditions worldwide and their incidences have increased over the last few years, here we review the possible role of leptin as a promising proinflammatory mediator promoting lymphomas.

Body fatness associations with cancer: evidence from recent epidemiological studies and future directions

This narrative review highlights current evidence linking greater body fatness to risk of various cancers, with focus on evidence from recent large cohort studies and pooled analyses of cohort studies as well as Mendelian randomization studies (which utilized genetic variants associated with body mass index to debrief the causal effect of higher body fatness on cancer risk). This review also provides insights into the biological mechanisms underpinning the associations. Data from both observational and Mendelian randomization studies support the associations of higher body mass index with increased risk of many cancers with the strongest evidence for digestive system cancers, including esophageal, stomach, colorectal, liver, gallbladder, and pancreatic cancer, as well as kidney, endometrial, and ovarian (weak association) cancer. Evidence from observational studies suggests that greater body fatness has contrasting effects on breast cancer risk depending on menopausal status and on prostate cancer risk depending on disease stage. Experimental and Mendelian randomization studies indicate that adiponectin, insulin, and sex hormone pathways play an important role in mediating the link between body fatness and cancer risk. The possible role of specific factors and pathways, such as other adipocytokines and hormones and the gut microbiome in mediating the associations between greater body fatness and cancer risk is yet uncertain and needs investigation in future studies. With rising prevalence of overweight and obesity worldwide, the proportion of cancer caused by excess body fatness is expected to increase. There is thus an urgent need to identify efficient ways at the individual and societal level to improve diet and physical activity patterns to reduce the burden of obesity and accompanying comorbidities, including cancer.

Management of Hematologic Malignancies in the Era of COVID-19 Pandemic: Pathogenetic Mechanisms, Impact of Obesity, Perspectives, and Challenges

The COVID-19 pandemic brought about an unprecedented societal and healthcare system crisis, considerably affecting healthcare workers and patients, particularly those with chronic diseases. Patients with hematologic malignancies faced a variety of challenges, pertinent to the nature of an underlying hematologic disorder itself as well as its therapy as a risk factor for severe SARS-CoV-2 infection, suboptimal vaccine efficacy and the need for uninterrupted medical observation and continued therapy. Obesity constitutes another factor which was acknowledged since the early days of the pandemic that predisposed people to severe COVID-19, and shares a likely causal link with the pathogenesis of a broad spectrum of hematologic cancers. We review here the epidemiologic and pathogenetic features that obesity and hematologic malignancies share, as well as potential mutual pathophysiological links predisposing people to a more severe SARS-CoV-2 course. Additionally, we attempt to present the existing evidence on the multi-faceted crucial challenges that had to be overcome in this diverse patient group and discuss further unresolved questions and future challenges for the management of hematologic malignancies in the era of COVID-19.

The Impact of Obesity on Hodgkin’s Lymphoma Patients Treated With Uniform Chemotherapy Protocol at Princess Noorah Oncology Center, National Guard Health Affairs, Jeddah, Saudi Arabia: Retrospective Matched Cohort

Background

Hodgkin's lymphoma (HL) is a disease that affects lymphocytes, mostly B cells, and it is commonly diagnosed by the presence of Reed-Sternberg cells. The influence of obesity on the disease course of HL is still controversial. This study’s aim was to investigate the treatment outcomes in obese patients suffering from HL and compare them to the outcomes of non-obese patients.

Methods

This study is a single-center retrospective cohort study that included 280 patients admitted between 2009 and 2020 with different subtypes of HL who received the chemotherapy regimen of Adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) at Princess Norah Oncology Center, National Guard Hospital, Jeddah, Saudi Arabia. Based on WHO criteria, the participants were divided into two groups (obese with a BMI that exceeds 30 kg/m2 versus non-obese with any BMI less than 29,9 kg/m2). All demographic data including age, gender, BMI, body surface area (BSA), and HL subtype (nodular sclerosis, mixed cellularity, lymphocyte depletion) were recorded. In addition, the presence of diabetes mellitus (DM), previous cancer, smoking, staging of HL, number of cycles of ABVD, dose intensity of ABVD, and outcomes (emergency visits, death during therapy, primary resistance, relapse) were collected from the participant files.

Results

Regarding therapy outcomes, 24.1% of obese patients were admitted to the hospital after receiving the first cycle of ABVD as compared to 75.9% of non-obese patients. However, there was no significant statistical difference between obese and non-obese patients in their hospital admission (p value=0.500). In addition, non-obese patients had a higher chance of being admitted to the hospital after receiving the chemotherapy dose with an odds ratio of 1.22 compared to obese patients. For the emergency visits, 20.8% of obese patients were admitted to ER as a complication of the chemotherapy regimen, whereas 79.3% of non-obese patients were admitted to ER after receiving the chemotherapy. The P-value was statistically not significant (0.396), but the odds of ER admissions after ABVD cycles were 1.28 times higher in non-obese patients compared to obese.

Conclusion

The study outcomes showed a higher odds of hospital admission and ER admission as complications of the chemotherapy regimen in non-obese HL patients as compared to obese patients.

Incidence, mortality, risk factors, and trends for Hodgkin lymphoma: a global data analysis

Background

Hodgkin lymphoma is a lymphatic malignancy commonly found in cervical lymph nodes. This study evaluated the worldwide incidence, mortality, associated risk factors, and temporal trends of Hodgkin lymphoma by sex, age, and country.

Methods

The age-standardised Hodgkin lymphoma incidence and mortality were retrieved from the GLOBOCAN, CI5 volumes I-XI, WHO mortality database, the NORDCAN and SEER Program. The age-standardised prevalence of smoking, alcohol drinking, obesity, and hypertension was also extracted for each country. Trends were tested using Average Annual Percentage Change (AAPC) from Joinpoint regression analysis.

Results

The Hodgkin lymphoma incidence and mortality were 0.98 and 0.26 per 100,000 in 2020. A higher incidence was observed in high-income countries, while higher mortality was found in low-income countries. Incidence and mortality were associated with GDP per capita, prevalence of smoking, obesity, and hypertension at the population level. Despite the decreasing mortality trend, there was an increasing incidence, especially among females, younger population, and subjects from Asian countries.

Conclusions

There was an increasing trend in Hodgkin lymphoma incidence, especially among subjects who were female, younger population, and from Asian countries. Further studies are needed to investigate the reasons for these epidemiologic trends.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01281-9.

Trends in pediatric lymphoma incidence by global region, age and sex from 1988-2012

BACKGROUND

Global variation in lymphoma incidence by type and age at diagnosis, region, sex, and Human Development Index (HDI) categories has not been reported, may shed light on potential biologic mechanisms and identify areas for targeted interventions.

METHODS

Using the Cancer Incidence in Five Continents data from 1988 to 2012, we identified Hodgkin (HL), non-Hodgkin (NHL), and Burkitt lymphoma (BL) diagnosed in children aged 0-19 years. We estimated incidence rates (IRs; cases/million) and average annual percent change in incidence (AAPC; 95 % CI) by geographic region, sex, and HDI for each age group (0-9years and 10-19 years).

RESULTS

There were 42,440 NHL, 38,683 H L, and 7703 included. Southern European (SE) 10-19-year-olds (yo) had the highest IR of NHL (19.6 cases/million) in 2008-2012. HL IRs for 0-9yo were <6 cases/million and >25 cases/million for 10-19yo in European regions and Oceania (OC). BL IRs were generally <5cases/million. Northern Europe (NE), SE, and OC 10-19yo had significantly increased APPCs in incidence for all lymphomas with the largest increases in BL (NE AAPC: 7.69 %; 95 % CI: 5.27, 10.16; SE AAPC: 5.21 %; 95 % CI: 3.26, 7.19; OC AAPC: 3.97 %; 95 % CI: 3.26, 4.70). BL incidence increased among males of all ages by approximately 2 %. NHL and BL incidence increased significantly among 10-19yo in very high HDI countries by approximately 3 %.

CONCLUSIONS

Southern and Northern Europe and Oceania displayed increased incidence of all lymphomas studied from 1988 to 2012. BL incidence significantly increased in 8 of 15 global regions, males, and higher HDI countries over the study period. Mechanisms underlying these increases remain to be elucidated.

Body mass index and waist circumference in relation to the risk of 26 types of cancer: a prospective cohort study of 3.5 million adults in Spain

BACKGROUND

A high body mass index (BMI) has been associated with increased risk of several cancers; however, whether BMI is related to a larger number of cancers than currently recognized is unclear. Moreover, whether waist circumference (WC) is more strongly associated with specific cancers than BMI is not well established. We aimed to investigate the associations between BMI and 26 cancers accounting for non-linearity and residual confounding by smoking status as well as to compare cancer risk estimates between BMI and WC.

METHODS

Prospective cohort study with population-based electronic health records from Catalonia, Spain. We included 3,658,417 adults aged ≥ 18 years and free of cancer at baseline between 2006 and 2017. Our main outcome measures were cause-specific hazard ratios (HRs) with 99% confidence intervals (CIs) for incident cancer at 26 anatomical sites.

RESULTS

After a median follow-up time of 8.3 years, 202,837 participants were diagnosed with cancer. A higher BMI was positively associated with risk of nine cancers (corpus uteri, kidney, gallbladder, thyroid, colorectal, breast post-menopausal, multiple myeloma, leukemia, non-Hodgkin lymphoma) and was positively associated with three additional cancers among never smokers (head and neck, brain and central nervous system, Hodgkin lymphoma). The respective HRs (per 5 kg/m2 increment) ranged from 1.04 (99%CI 1.01 to 1.08) for non-Hodgkin lymphoma to 1.49 (1.45 to 1.53) for corpus uteri cancer. While BMI was negatively associated to five cancer types in the linear analyses of the overall population, accounting for non-linearity revealed that BMI was associated to prostate cancer in a U-shaped manner and to head and neck, esophagus, larynx, and trachea, bronchus and lung cancers in an L-shaped fashion, suggesting that low BMIs are an approximation of heavy smoking. Of the 291,305 participants with a WC measurement, 27,837 were diagnosed with cancer. The 99%CIs of the BMI and WC point estimates (per 1 standard deviation increment) overlapped for all cancers.

CONCLUSIONS

In this large Southern European study, a higher BMI was associated with increased risk of twelve cancers, including four hematological and head and neck (only among never smokers) cancers. Furthermore, BMI and WC showed comparable estimates of cancer risk associated with adiposity.

Early Radiation-Induced Sarcoma in an Adolescent Treated for Relapsed Hodgkin Lymphoma with Nivolumab

Radiation-induced sarcoma (RIS) has been reported as a late secondary malignancy following radiotherapy for various types of cancer with a median latency of 10 years. We describe an early RIS that developed in an adolescent within three years of treatment (including PD-L1 check-point inhibitor Nivolumab) of a relapsed classic Hodgkin lymphoma (HL) and was diagnosed post-mortem. The patient died of the progressive RIS that was misleadingly assumed to be a resistant HL based on the positive PET/CT scan. Repetitive tumor biopsies are warranted in cases of aggressive and multi-drug resistant HL to validate imaging findings, ensure correct diagnosis and avoid overtreatment.

Socioeconomic deprivation and regional variation in Hodgkin's lymphoma incidence in the UK: a population-based cohort study of 10 million individuals

OBJECTIVES

Hodgkin's lymphoma (HL) is the the most common cancer in teenagers and young adults. This nationwide study conducted over a 25-year period in the UK investigates variation in HL incidence by age, sex, region and deprivation to identify trends and high-risk populations for HL development.

DESIGN

Population-based cohort study.

SETTING

Clinical Practice Research Datalink (CPRD) electronic primary care records linked to Hospital Episode Statistics and Index of Multiple Deprivation data were used.

PARTICIPANTS

Data on 10 million individuals in the UK from 1992 to 2016 were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Poisson models were used to explore differences in HL incidence by age, sex, region and deprivation. Age-specific HL incidence rates by sex and directly age-standardised incidence rates by region and deprivation group were calculated.

RESULTS

A total of 2402 new cases of HL were identified over 78 569 436 person-years. There was significant variation in HL incidence by deprivation group. Individuals living in the most affluent areas had HL incidence 60% higher than those living in the most deprived (incidence rate ratios (IRR) 1.60, 95% CI 1.40 to 1.83), with strong evidence of a marked linear trend towards increasing HL incidence with decreasing deprivation (p=<0.001). There was significant regional variation in HL incidence across the UK, which persisted after adjusting for age, sex and deprivation (IRR 0.80-1.42, p=<0.001).

CONCLUSIONS

This study identified high-risk regions for HL development in the UK and observed a trend towards higher incidence of HL in individuals living in less deprived areas. Consistent with findings from other immune-mediated diseases, this study supports the hypothesis that an affluent childhood environment may predispose to development of immune-related neoplasms, potentially through fewer immune challenges interfering with immune maturation in early life. Understanding the mechanisms behind this immune dysfunction could inform prevention, detection and treatment of HL and other immune diseases.