An Analysis of Individual Body Fat Depots and Risk of Developing Cancer: Insights From the Dallas Heart Study

Body Composition and Prostate Cancer Risk: A Systematic Review of Observational Studies

Body composition parameters are not captured by measures of body mass, which may explain inconsistent associations between body weight and prostate cancer (PC) risk. The objective of this systematic review was to characterize the association between fat mass (FM) and fat-free mass (FFM) parameters and PC risk. A search of PubMed, Embase, and Web of Science identified case-control and cohort studies that measured body composition in relation to PC risk. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS). Thirteen observational studies were included, of which 8 were case-control studies (n = 1572 cases, n = 1937 controls) and 5 were prospective cohort studies (n = 7854 incident cases with PC). The NOS score was 5.9 ± 1.1 for case-control studies and 8.4 ± 1.3 for cohort studies. The most common body composition technique was bioelectrical impedance analysis (n = 9 studies), followed by DXA (n = 2), computed tomography (n = 2), air displacement plethysmography (n = 1), and MRI (n = 1). No case-control studies reported differences in %FM between PC cases and controls and no consistent differences in FM or FFM (in kilograms) were observed. Two out of 5 cohort studies reported that higher %FM was associated with lower PC risk. Conversely, 3 cohort studies reported a greater risk of being diagnosed with advanced/aggressive PC with higher FM (expressed in kilograms, %FM, or fat distribution). Two out of 4 studies (both case-control and cohort) found that higher abdominal adipose tissue was associated with increased PC risk. In conclusion, although results were inconsistent, there is some evidence that FM may be negatively associated with total PC risk but positively associated with the risk of advanced/aggressive PC; modest evidence suggests that abdominal adipose tissue may increase the risk of PC. Future work should elucidate unique patterns of FM distribution and PC risk to triage men at risk for developing PC. This study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database as CRD42019133388.

Association of Imaging-Based Body Fat Distribution and Mammographic Density in the Multiethnic Cohort Adiposity Phenotype Study

BACKGROUND

As the stronger association of obesity with postmenopausal breast cancer in Asian than white women may be due to body fat distribution, we examined the relation of adiposity measures with percent mammographic density (PMD), a strong predictor of breast cancer incidence.

METHODS

A total of 938 women from five ethnic groups (69.1 ± 2.7 years) in the Adiposity Phenotype Study (APS) underwent DXA and MRI imaging. PMD was assessed in routine mammograms using a computer-assisted method. Spearman correlation coefficients were computed and general linear models were applied to estimate regression coefficients (β) for PMD per 0.5 SD units of adiposity measures while adjusting for known confounders, including DXA total body fat.

RESULTS

For 701 (75%) of the participants (69.1 ± 2.7 years), valid mammograms were obtained. Whereas total body fat, the trunk-to-periphery fat ratio (TPFR), visceral fat (VAT), and subcutaneous fat (SAT) were inversely correlated with PMD (P < 0.0001), the VAT/SAT ratio correlated positively (r spearman = 0.10; P = 0.01). In fully adjusted models, PMD remained inversely related to TPFR and SAT and disappeared for VAT, while it was strengthened for VAT/SAT (β = 0.51; P = 0.009). This relation was stronger in Japanese Americans than other ethnic groups.

CONCLUSIONS

This is the first study to show an association of a high VAT/SAT ratio with greater PMD, a marker of breast cancer risk after taking into account total body fat.

IMPACT

The results indicate a link between the propensity to accumulate VAT and the amount of fat in the breast (1-PMD), which may influence the relation of obesity with breast cancer incidence.

High maternal milk intake in the postnatal life reduces the incidence of breast cancer during adulthood in rats

Environmental factors during perinatal life can lead to changes in the mammary gland, making it susceptible to cancer in adulthood. Breastfeeding has a special importance since it takes place at a critical period of growth and development of the newborn. We aimed to analyze if an appropriate lactation protects the offspring against mammary carcinogenesis during adult life and explore the mechanisms involved in the protective effect. One-day-old Sprague-Dawley female rats were randomly distributed in litters of three (L3), eight (L8) or 12 (L12) pups per dam, to induce a differential consumption of breast milk. At 55 days of age, the animals were treated with a single dose of dimethylbenzanthracene to study tumor latency, incidence and progression. Histological, immunohistochemical and Western blot studies were performed. We observed lower incidence and higher latency in L3 compared to the other groups. The mitotic index and expression of proliferating cell nuclear antigen (PCNA) was significantly augmented in tumors of L12 rats compared to L3 and L8, while the apoptotic index was augmented in tumors of L3 v. L12. Cleaved caspase 8 was significantly higher in tumors from L3 compared to L12. Tumors developed in L3 have a greater number of apoptotic bodies and a greater expression of caspase 8. These results demonstrate that the animals that maintained a higher intake of maternal milk (L3) presented lower incidence and greater tumor latency. Lower consumption of breast milk (L12) would increase tumor mitosis and the expression of PCNA, explaining the higher tumor incidence observed in this group.

Relation of plasma ceramides to visceral adiposity, insulin resistance and the development of type 2 diabetes mellitus: the Dallas Heart Study

AIMS/HYPOTHESIS

Ceramides are sphingolipids that contribute to insulin resistance in preclinical studies. We hypothesised that plasma ceramides would be associated with body fat distribution, insulin resistance and incident type 2 diabetes in a multi-ethnic cohort.

METHODS

A total of 1557 participants in the Dallas Heart Study without type 2 diabetes underwent measurements of metabolic biomarkers, fat depots by MRI and plasma ceramides by liquid chromatography-mass spectrometry. Diabetes outcomes were assessed after 7 years. Associations of body fat and insulin resistance with ceramides at baseline and of ceramides with incident diabetes outcomes were analysed.

RESULTS

The cohort had a mean age of 43 years, with 58% women, 45% black participants and a mean BMI of 28 kg/m². Total cholesterol levels were associated with all ceramides, but higher triacylglycerols and lower HDL-cholesterol and adiponectin were associated only with saturated fatty acid chain ceramides (p < 0.0003). After adjusting for clinical characteristics and total body fat, visceral adipose tissue was positively associated with saturated fatty acid ceramides (per SD, β = 0.16 to 0.18) and inversely associated with polyunsaturated fatty acid ceramides (β = -0.14 to -0.16, p < 0.001 for all). Lower-body subcutaneous fat showed an opposite pattern to that for visceral fat. HOMA-IR was positively associated with saturated (β = 0.08 to 0.09, p < 0.001) and inversely with polyunsaturated ceramides (β = -0.06 to -0.07, p < 0.05). Ceramides were not associated with incident type 2 diabetes after adjustment for clinical factors.

CONCLUSIONS/INTERPRETATION

Plasma ceramides demonstrate a biologically complex relationship with metabolic and imaging indicators of dysfunctional adiposity. The role of ceramides in a shared pathway of metabolic dysfunction linking visceral adiposity and insulin resistance requires further investigation.

Waist, neck circumferences, waist-to-hip ratio: Which is the best cardiometabolic risk marker in women with severe obesity? The SOON cohort

A centralized deposit of adiposity increases the risk of cardiometabolic diseases. Several anthropometric markers can be used to characterize fat distribution. In the case of severe obesity, several markers, such as hip and waist circumference, are prone to measurement error. Conversely, neck circumference is easy to obtain. The aim was to determine the best surrogate marker of obesity-related cardiometabolic diseases from: body mass index (BMI), waist, hip and neck circumferences and waist-to-hip ratio.

The association between fat mass and the risk of breast cancer: A systematic review and meta-analysis

BACKGROUND & AIMS

Several cohort and case-control studies examined the association between fat mass (FM) and the risk of breast cancer; however, findings are conflicting. The purpose of the present study was to systematically review this association and conducted a meta-analysis, if possible.

METHOD

A systematic search of PubMed/Medline, Scopus, Web of Science and Embase databases was conducted for cohort and case-control studies, between January 2000 and 31 March 2018 with no language limitations. Multivariate adjusted relative risk (RR) estimates with 95% confidence intervals (CI) for each category of FM were pooled to examine the association.

RESULTS

Finally, 12 papers were considered for quantitative synthesis. The pooled RR for the highest vs. the lowest FM (%) of cohort studies was 1.44 (95% CI: 1.33, 1.56; I²: 63.3%, p = 0.008). The overall effect size for adjusted case-control studies showed no significant association (1.49, 95% CI: 0.77, 2.90; I²: 93.2%; p = 0.001). After stratification by menopause, it was revealed that the association between FM and the risk of breast cancer in post menopausal women (2.29, 95% CI: 1.12, 4.68; I²: 92%, p = 0.0001) was significant, while there was no significant association in pre-menopausal women (0.68, 95% CI: 0.18, 2.58; I²: 81.3%; p = 0.02).

CONCLUSION

Cohort studies showed that higher FM is positively associated with the risk for breast cancer. However, only case-control studies on post-menopausal women showed a positive link. Due to limited studies and high heterogeneity, findings should be interpreted with caution. More cohort studies are needed to clarify this association.

Cardiovascular and Metabolic Heterogeneity of Obesity: Clinical Challenges and Implications for Management

The prevalence of obesity has increased globally over the last 2 decades. Although the body mass index has been a convenient and simple index of obesity at the population level, studies have shown that obesity defined by body mass index alone is a remarkably heterogeneous condition with varying cardiovascular and metabolic manifestations across individuals. Adipose tissue is an exquisitely active metabolic organ engaged in cross-talk between various systems; perturbation of adipose tissue results in a pathological response to positive caloric balance in susceptible individuals that directly and indirectly contributes to cardiovascular and metabolic disease. Inadequate subcutaneous adipose tissue expansion in the face of dietary triglycerides leads to visceral and ectopic fat deposition, inflammatory/adipokine dysregulation, and insulin resistance. Conversely, preferential fat storage in the lower body depot may act as a metabolic buffer and protect other tissues from lipotoxicity caused by lipid overflow and ectopic fat. Translational, epidemiological, and clinical studies over the past 30 years have clearly demonstrated a strong link between visceral and ectopic fat and the development of a clinical syndrome characterized by atherogenic dyslipidemia, hyperinsulinemia/glucose intolerance, hypertension, atherosclerosis, and adverse cardiac remodeling/heart failure. This relationship is even more nuanced when clinical entities such as metabolically healthy obesity phenotype and the obesity paradox are considered. Although it is clear that the accumulation of visceral/ectopic fat is a major contributor to cardiovascular and metabolic risk above and beyond the body mass index, implementation of fat distribution assessment into clinical practice remains a challenge. Anthropometric indexes of obesity are easily implemented, but newer imaging-based methods offer improved sensitivity and specificity for measuring specific depots. Lifestyle, pharmacological, and surgical interventions allow a multidisciplinary approach to overweight/obesity that may improve outcomes and align with a public health message to combat the growing epidemic of obesity worldwide and to build healthier lives free of cardiovascular diseases.