Body Mass Index and Risk of Leukemia in Older Women

Obesity and Leukemia: Biological Mechanisms, Perspectives, and Challenges

PURPOSE OF REVIEW

To examine the epidemiological data on obesity and leukemia; evaluate the effect of obesity on leukemia outcomes in childhood acute lymphoblastic leukemia (ALL) survivors; assess the potential mechanisms through which obesity may increase the risk of leukemia; and provide the effects of obesity management on leukemia. Preventive (diet, physical exercise, obesity pharmacotherapy, bariatric surgery) measures, repurposing drugs, candidate therapeutic agents targeting oncogenic pathways of obesity and insulin resistance in leukemia as well as challenges of the COVID-19 pandemic are also discussed.

RECENT FINDINGS

Obesity has been implicated in the development of 13 cancers, such as breast, endometrial, colon, renal, esophageal cancers, and multiple myeloma. Leukemia is estimated to account for approximately 2.5% and 3.1% of all new cancer incidence and mortality, respectively, while it represents the most frequent cancer in children younger than 5 years. Current evidence indicates that obesity may have an impact on the risk of leukemia. Increased birthweight may be associated with the development of childhood leukemia. Obesity is also associated with worse outcomes and increased mortality in leukemic patients. However, there are several limitations and challenges in meta-analyses and epidemiological studies. In addition, weight gain may occur in a substantial number of childhood ALL survivors while the majority of studies have documented an increased risk of relapse and mortality among patients with childhood ALL and obesity. The main pathophysiological pathways linking obesity to leukemia include bone marrow adipose tissue; hormones such as insulin and the insulin-like growth factor system as well as sex hormones; pro-inflammatory cytokines, such as IL-6 and TNF-α; adipocytokines, such as adiponectin, leptin, resistin, and visfatin; dyslipidemia and lipid signaling; chronic low-grade inflammation and oxidative stress; and other emerging mechanisms. Obesity represents a risk factor for leukemia, being among the only known risk factors that could be prevented or modified through weight loss, healthy diet, and physical exercise. Pharmacological interventions, repurposing drugs used for cardiometabolic comorbidities, and bariatric surgery may be recommended for leukemia and obesity-related cancer prevention.

The Effect of Obesity and Body Mass Index on Hematologic Malignancies

A thorough examination of the available literature has revealed a well-established association of obesity and high body mass index (BMI) with an increased risk of various types of cancers, including hematologic malignancies. Specifically, the studies reviewed indicate a clear correlation between obesity and an increased risk of leukemias, lymphomas, multiple myeloma, myelodysplastic syndrome, and myeloproliferative diseases. Despite the established association of obesity and high BMI with hematologic malignancies, the underlying mechanisms remain largely undetermined. The development of hematologic malignancies may be influenced by several mechanisms associated with obesity and high BMI, including chronic inflammation, hormonal imbalances, adiposopathies, and metabolic dysregulation. Furthermore, there is mounting evidence indicating that obesity and high BMI may have a negative impact on the response to treatment and overall survival in patients with hematologic malignancies. This article aims to increase awareness and summarize the current state of research on the impact of obesity on hematologic malignancies, including the mechanisms by which obesity may influence the development and progression of these diseases. In addition, the current review highlights the need for effective weight management strategies in patients with hematologic malignancies to improve outcomes and mitigate the risk of complications.

Obesity-induced inflammation exacerbates clonal hematopoiesis

Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.

Anthropometric factors and risk of myeloid leukaemias and myelodysplastic syndromes: a prospective study and meta-analysis

There is insufficient evidence linking excess body weight to risk of myeloid malignancies. We investigated this association using data from the Cancer Prevention Study-II (CPS-II), and a meta-analysis of published cohort studies. Among 152 090 CPS-II participants, 387 acute myeloid leukaemias (AML), 100 chronic myeloid leukaemias (CML) and 170 MDS were identified over 21 years of follow-up. In CPS-II, body mass index (BMI) was weakly associated with risk of CML (hazard ratio [HR] = 1·04, 95% confidence interval [CI]: 0·99-1·09 per 1 unit increase in BMI), AML (HR = 1·01, 95% CI: 0·98-1·03) and MDS (HR = 1·03, 95% CI: 0·99-1·07). After controlling for other anthropometric factors, no clear association was observed for height, BMI at age 18 years or weight change. In the meta-analysis (n = 7117 myeloid leukaemias), BMI 25-29·9 kg/m² (HR_pooled  = 1·36, 95% CI: 1·12-1·59) and BMI ≥30 kg/m² (HR_pooled  = 1·43, 95% CI: 1·18-1·69) were associated with higher risk of myeloid leukaemia overall, compared to a BMI <25 kg/m² . Likewise, BMI ≥25 kg/m² was positively associated with both AML and CML risk individually in the meta-analysis. These results underscore the need for large studies to detect associations with rare cancers, and show a modest, but positive association between excess body weight and myeloid malignancy risk.

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.

Complex karyotype including ring chromosome 11 in a patient with acute myeloid leukemia: case report

CONTEXT

Complex karyotypes in acute myeloid leukemia (AML) are characterized by an overall low response rate with frequent relapses after clinical treatment.

CASE REPORT

Here, we describe the case of a 61-year-old obese female with clinically diagnosed AML who presented a complex karyotype involving an uncommon abnormality: ring chromosome 11. Immunophenotypic analysis confirmed the diagnosis. Classical and molecular cytogenetic analyses, using GTG banding and FISH (fluorescence in situ hybridization), revealed the presence of complex structural rearrangement involving r(11), add(12)(p13), der(5) and der(13).

CONCLUSIONS

Molecular cytogenetic analysis is suitable for better identification and characterization of chromosomal rearrangements in AML. Case reports like this, as well as population-based studies, are necessary for understanding the karyotypic changes that occur in humans.

Influence of body mass index on incidence and prognosis of acute myeloid leukemia and acute promyelocytic leukemia: A meta-analysis

Previous studies have demonstrated an association between high body mass index (BMI) and acute myeloid leukemias (AML), particularly acute promyelocytic leukemia (APL). However, the effect of obesity and overweight on the incidence of AML is not supported by all studies, and the relationship between obesity and prognosis of AML and APL has not been established. Thus, we conducted a meta-analysis to determine the role of BMI on the risk and clinical outcome of AML, including APL. Twenty-six eligible studies enrolling 12,971 AML (including 866 APL) patients were retrieved and analyzed. Overweight and obesity was associated with an increased incidence of AML (relative risk [RR], 1.23; 95% confidence interval [CI], 1.12–1.35; P < 0.001). High BMI did not significantly affect overall survival (OS) (hazard ratio [HR], 0.97; 95% CI, 0.92–1.03; P = 0.323) or disease-free survival (HR, 0.98; 95% CI, 0.88–1.10; P = 0.755) in patients with non-APL AML. By contrast, APL patients with high BMI had shorter OS (HR, 1.77; 95% CI, 1.26–2.48; P = 0.001) and a higher risk of differentiation syndrome (HR, 1.53; 95% CI, 1.03–2.27, P = 0.04). Overall, our findings suggest that patients with overweight or obesity have a higher incidence of AML, and high BMI is a predictor of adverse clinical outcomes in APL.

Higher body mass index in 16-19 year-old Jewish Adolescents of North African, Middle Eastern and European Origins is a Predictor of Acute Myeloid Leukemia: a cohort of 2.3 million Israelis

PURPOSE

Studies evaluating adolescent risk factors for developing acute myeloid leukemia (AML) are virtually nonexistent. We assessed adolescent predictors of AML in adults, with a main focus on adolescent BMI.

METHODS

The study included 2,310,922 16-19-year-old Jewish Israeli adolescents (mean age 17.3 ± 0.4, 59.5% male), called up for an obligatory health examination. Sociodemographic and health data, including measured weight and height, were gathered. Body mass index (BMI) was examined both as a continuous variable and grouped according to the World Health Organization (WHO) classification and US-CDC percentiles. Bone-marrow-biopsy-verified AML cases diagnosed up to 31 December 2012 were identified by linkage to the Israel national cancer registry. Multivariable-adjusted Cox proportional-hazards models were used to model time to diagnosis.

RESULTS

During 47 million person years of follow-up, 568 AML cases were identified (crude incidence rate 1.21/100,000 person years). There was a multivariable-adjusted hazard ratio (HR) of 1.041 (95% CI 1.015-1.068, p = 0.002) per unit BMI. The association was evident in those of Middle Eastern, North African, and European origin. A graded association was evident across the overweight and obese WHO grouping. With the US-CDC grouping, excess risk was evident in overweight but not in obese adolescents, although a test for trend in percentiles was significant (p = 0.004). Borderline associations were noted for origin (p = 0.065) (higher in the predominantly Ashkenazi European origin), sex (higher in women: HR = 1.24 (95% CI 0.99-1.55), and stature (HR = 1.013, 95% CI 1.000-1.026, per cm).

CONCLUSIONS

Higher BMI in adolescence was associated with increased AML incidence in adulthood in this multiethnic population.

Adipocytes impair leukemia treatment in mice

Obesity is associated with increased cancer incidence and mortality. We have previously found that obesity in children is associated with a 50% increased recurrence of acute lymphoblastic leukemia (ALL) in high-risk patients. We have therefore developed novel in vivo and in vitro preclinical models to study the mechanism(s) of this association. Obesity increased relapse after monotherapy with vincristine (P = 0.03) in obese mice injected with syngeneic ALL cells. This occurred although the drug was dosed proportionally to body weight, equalizing blood and tissue drug levels. In coculture, 3T3-L1 adipocytes significantly impaired the antileukemia efficacy of vincristine, as well as three other chemotherapies (P < 0.05). Interestingly, this protection was independent of cell-cell contact, and it extended to human leukemia cell lines as well. Adipocytes prevented chemotherapy-induced apoptosis, and this was associated with increased expression of the two prosurvival signals Bcl-2 and Pim-2. These findings highlight the role of the adipocyte in fostering leukemia chemotherapy resistance, and may help explain the increased leukemia relapse rate in obese children and adults. Given the growing prevalence of obesity worldwide, these effects are likely to have increasing importance to cancer treatment.

Tobacco use, body mass index, and the risk of leukemia and multiple myeloma: a nationwide cohort study in Sweden

In a prospective cohort study of more than 330,000 Swedish construction workers, we explored the effect of tobacco smoking, oral moist snuff use, and body mass index (BMI) on the risk of developing leukemia (excluding chronic lymphocytic leukemia) and multiple myeloma (MM). Study subjects were participants of a health surveillance system within the building industry. Record linkage to the nationwide Swedish cancer registry, migration registry, and cause of death registry made a comprehensive follow-up available. A total of 372 incident cases of leukemia and 520 subjects with MM was ascertained. An increase in risk of acute myelogenous leukemia (AML) was observed in current smokers (incidence rate ratio, 1.50; 95% confidence interval, 1.06-2.11). Furthermore, there was an indication of a possible association between smoking intensity and risk of acute lymphocytic leukemia. Results on snuff use as well as BMI showed no association. This study confirms the role of smoking as a risk factor for AML and gives no support to the hypothesis of a role of snuff use or BMI level on the risk of leukemia or MM.