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

Rheumatoid arthritis and cancer risk in the Million Women Study

BACKGROUND

Most previous studies of rheumatoid arthritis (RA) and cancer risk have lacked information on potential confounding factors. We investigated RA-associated cancer risks in a large cohort of women in the UK, taking account of shared risk factors.

METHODS

In 1996-2001, women aged 50-64, who were invited for routine breast screening at 66 National Health Service (NHS) screening centres in England and Scotland, were also invited to take part in the Million Women Study. Participants provided information on sociodemographic, lifestyle and health-related factors, including RA, and were followed up for cancers and deaths. Cox regression yielded RA-associated hazard ratios (HRs) of 20 cancers, adjusted for 10 characteristics including smoking status and adiposity.

RESULTS

Around 1.3 million women (half of those invited) were recruited into the study. In minimally adjusted analyses, RA was associated with the risk of 13 of the 20 cancers. After additional adjustment for lifestyle factors, many of these associations were attenuated but there remained robust evidence of RA-associated increases in the risk of lung (HR 1.21, 95% confidence interval 1.15-1.26), lymphoid (1.25, 1.18-1.33), myeloid (1.12, 1.01-1.25), cervical (1.39, 1.11-1.75) and oropharyngeal (1.40, 1.21-1.61) cancers, and decreases in the risk of endometrial (0.84, 0.77-0.91) and colorectal (0.82, 0.77-0.87) cancers.

CONCLUSIONS

After taking account of shared risk factors, RA is positively associated with lung and certain blood and infection-related cancers, and inversely associated with colorectal cancer. These findings are consistent with existing hypotheses around immune response, susceptibility to infections, and chronic inflammation. The inverse association observed for endometrial cancer merits further investigation.

Clinical Risk and Overall Survival in Patients with Diabetes Mellitus, Hyperglycemia and Glioblastoma Multiforme. A Review of the Current Literature

The relationship between type 2 diabetes mellitus (DM2) and hyperglycemia with cancer patients remains controversial also in the setting of patients with glioblastoma multiforme (GBM), the most common and aggressive form of astrocytoma with a short overall survival (OS) and poor prognosis. A systematic search of two databases was performed for studies published up to 19 August 2020, reporting the OS of patients with DM2 or high blood sugar level and GBM and the clinical risk of diabetic patients for development of GBM. According to PRISMA guidelines, we included a total of 20 papers reporting clinical data of patients with GBM and diabetes and/or hyperglycemia. The aim of this review was to investigate the effect of DM2, hyperglycemia and metformin on OS of patients with GBM. In addition, we evaluated the effect of these factors on the risk of development of GBM. This review supports accumulating evidence that hyperglycemia, rather than DM2, and elevated BMI are independent risk factors for poor outcome and shorter OS in patients with GBM. GBM patients with normal weight compared to obese, and diabetic patients on metformin compared to other therapies, seems to have a longer OS. Further studies are needed to understand better these associations.

Childhood body mass index is associated with the risk of adult hematologic malignancies in men-The best Gothenburg cohort

Hematologic malignancies are common and the incidence is increasing. Adult obesity has been associated with hematologic malignancies (HM), but the importance of body mass index (BMI) in childhood and during puberty has not been evaluated. The aim of the present study was to evaluate the relative contribution of BMI and height in childhood and during puberty for the risk of adult HM. 37 669 men born in 1946 to 1961 who had weight and height measured at 8 (childhood) and 20 (young adult age) years of age available from the BMI Epidemiology Study were included in the study. Pubertal BMI change was calculated as BMI at 20 years of age minus BMI at 8 years of age. Information on HM was retrieved from Swedish registers (459 cases of HM). Hazard ratios (HR) and 95% confidence intervals (CI) were estimated by Cox regressions. Childhood BMI (HR 1.11 per SD increase [95% CI 1.02-1.23]), but not pubertal BMI change, was associated with hematologic malignancies in a linear manner. Childhood BMI was, independent of childhood height, associated with the diagnostic entities Non-Hodgkin lymphoma (HR 1.14 [95% CI 1.00-1.30]) and its largest subgroup diffuse large B-cell lymphoma (HR 1.31 [95% CI 1.03-1.67]). Childhood height was associated with multiple myeloma (HR 1.30 [95% CI 1.04-1.64]) independent of childhood BMI. We conclude that childhood but not puberty is the critical developmental period regarding future risk of HM and we suggest that elevated childhood BMI is a determinant of Non-Hodgkin lymphoma and diffuse large B-cell lymphoma.

Epidemiology of Follicular Lymphoma

Follicular lymphoma (FL) is a common indolent lymphoma subtype in Western countries. FL incidence increases with age, and shows considerable variation by race/ethnicity and geography. In the United States and France, FL incidence has been stable since 2000, whereas in other Western and Asian countries it has been increasing. Five-year relative survival rates have been increasing in Western and Asian countries. Progress on identifying FL-specific risk factors has accelerated with the implementation of the InterLymph nested classification and the availability of larger epidemiologic studies and pooled analyses. Identification of risk factors for FL requires further research.

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

Previous epidemiological studies describe a positive association between body mass index (BMI) and Hodgkin’s lymphoma, mainly in obese vs. normal weight individuals. We examined the shape of this relationship in individuals aged 16 years or older, using primary care data from the United Kingdom’s Clinical Practice Research Datalink. Cox models were fitted with linear, non-linear (spline) and categorical BMI. Models were adjusted for potential confounders and effect modification was investigated. Five point eight two million patients were included, 927 of whom developed Hodgkin’s lymphoma during 41.6 million years of follow-up. Each 5 kg/m² increase in BMI was associated with a 10% increase in Hodgkin’s lymphoma (95% confidence intervals: 2–19). Analysis of non-linearity suggested a J-shaped association with incidence increasing with BMI above 24.2 kg/m². Seven point four per cent of adult Hodgkin’s lymphoma cases were estimated to be attributable to excess weight. Our findings suggest a pattern of increasing risk beyond the World Health Organisation healthy weight category in the general population.

Mendelian randomization provides support for obesity as a risk factor for meningioma

Little is known about the causes of meningioma. Obesity and obesity-related traits have been reported in several epidemiological observational studies to be risk factors for meningioma. We performed an analysis of genetic variants associated with obesity-related traits to assess the relationship with meningioma risk using Mendelian randomization (MR), an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations. We considered 11 obesity-related traits, identified genetic instruments for these factors, and assessed their association with meningioma risk using data from a genome-wide association study comprising 1,606 meningioma patients and 9,823 controls. To evaluate the causal relationship between the obesity-related traits and meningioma risk, we consider the estimated odds ratio (OR) of meningioma for each genetic instrument. We identified positive associations between body mass index (odds ratio [OR_SD] = 1.27, 95% confidence interval [CI] = 1.03–1.56, P = 0.028) and body fat percentage (OR_SD = 1.28, 95% CI = 1.01–1.63, P = 0.042) with meningioma risk, albeit non-significant after correction for multiple testing. Associations for basal metabolic rate, diastolic blood pressure, fasting glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, systolic blood pressure, total cholesterol, triglycerides and waist circumference with risk of meningioma were non-significant. Our analysis provides additional support for obesity being associated with an increased risk of meningioma.

Influence of obesity-related risk factors in the aetiology of glioma

BACKGROUND

Obesity and related factors have been implicated as possible aetiological factors for the development of glioma in epidemiological observation studies. We used genetic markers in a Mendelian randomisation framework to examine whether obesity-related traits influence glioma risk. This methodology reduces bias from confounding and is not affected by reverse causation.

METHODS

Genetic instruments were identified for 10 key obesity-related risk factors, and their association with glioma risk was evaluated using data from a genome-wide association study of 12,488 glioma patients and 18,169 controls. The estimated odds ratio of glioma associated with each of the genetically defined obesity-related traits was used to infer evidence for a causal relationship.

RESULTS

No convincing association with glioma risk was seen for genetic instruments for body mass index, waist-to-hip ratio, lipids, type-2 diabetes, hyperglycaemia or insulin resistance. Similarly, we found no evidence to support a relationship between obesity-related traits with subtypes of glioma-glioblastoma (GBM) or non-GBM tumours.

CONCLUSIONS

This study provides no evidence to implicate obesity-related factors as causes of glioma.

The aetiology of B-cell lymphoid malignancies with a focus on chronic inflammation and infections

B-cell malignancies are a heterogeneous group of lymphoproliferative disorders with different molecular characteristics and clinical course. It is increasingly recognized that the group displays considerable heterogeneity also regarding aetiologic factors. Here, we summarize the latest developments in the aetiology of B-cell lymphoid malignancy subtypes focusing on immune perturbation. Severe immune suppression constitutes a strong and well-established risk factor for aggressive subtypes (e.g. diffuse large B-cell and Burkitt lymphoma), but appears unrelated to risk of common low-grade subtypes (e.g. follicular and mantle cell lymphoma). Inflammation and infections are known co-factors amongst the immunosuppressed; however, immune stimulation is now recognized as a crucial determinant of lymphomagenesis also amongst immunocompetent individuals. This is best exemplified in marginal zone lymphomas where local chronic inflammation and infection in the stomach, ocular adnexa and salivary glands have been directly linked with the development of oligoclonal and monoclonal malignant B-cell populations. Aggressive subtypes (e.g. diffuse large B-cell lymphoma) are increasingly linked with features of systemic immune stimulation including autoimmune/inflammatory disease and subclinical cytokine elevations. Lifestyle factors (e.g. high body mass index, cigarette smoking) are associated with risk of diffuse large B-cell and follicular lymphoma, respectively, possibly mediated through inflammation. Recent genome-wide association studies further underline the importance of immune function by linking several subtypes to variations in the human leucocyte antigen (HLA) class genes. In the future, improved knowledge of mechanistic pathways of inflammation/infections in lymphoma development may translate to active measures of prevention or treatment, as is already the case for some low-grade lymphoma subtypes.