A prospective Swedish study on body size, body composition, diabetes, and prostate cancer risk

Association between body composition and the risk of mortality in the obese population in the United States

Background

Recent studies have presented the concept of the obesity paradox, suggesting that individuals with obesity have a lower risk of death than those without obesity. This paradox may arise because body mass index (BMI) alone is insufficient to understand body composition accurately. This study investigated the relationship between fat and muscle mass and the risk of mortality in individuals with overweight/obesity.

Methods

We used data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2006 and 2011 to 2018, which were linked to mortality information obtained from the National Death Index. Multiple Cox regression analyses were performed to estimate mortality risk. Subgroup analysis was conducted using propensity score-matched (PSM) data for age, sex, and race/ethnicity.

Results

This study included 16,555 participants who were overweight/obese (BMI≥25 kg/m2). An increase in appendicular skeletal muscle mass index was associated with a lower mortality risk (hazard ratio [HR]: 0.856; 95% confidence interval [CI]: 0.802-0.915). This finding was consistent with the subgroup analysis of the PSM data. Contrastingly, a high fat mass index was associated with an increased risk of mortality. Sarcopenic overweight/obesity was significantly associated with high mortality compared to obesity without sarcopenia (HR: 1.612, 95%CI: 1.328-1.957). This elevated risk was significant in both age- and sex-based subgroups. This finding was consistent with the subgroup analysis using PSM data.

Conclusion

In contrast to the obesity paradox, a simple increase in BMI does not protect against mortality. Instead, low body fat and high muscle mass reduce mortality risk.

The impact of body mass index on prostate cancer: An updated systematic review and meta-analysis

BACKGROUND

Increasing evidence suggested obesity was associated with the risk of prostate cancer. Also, the association between prostate cancer risk and obesity has received much attention in recent years, but the results are still unclear. Therefore, the current systematic review and meta-analysis aimed to evaluate the impact of body mass index (BMI) on prostate cancer.

METHODS

We systematically searched PubMed, Google Scholar, Scopus and Cochrane databases with the appropriate key terms to identify the eligible articles related to the impact of BMI on prostate cancer. The Newcastle-Ottawa checklist was used for the quality assessment of studies, and the meta-analysis was carried out using Review Manager 5.3.

RESULTS

The present review includes 23 studies that fulfilled the criteria for inclusion. In the meta-analysis, a significant difference was observed between the obese and normal weight (P < .001) and 54% of obese has a risk compared to normal weight. Heterogeneity between the fifteen studies was high (I2 = 100%). Test for overall effect: Z = 8.77 (P < .001) (odds ratio [OR] = 0.32 confidence interval [CI]: 0.25-0.42). However, there was no significant difference observed between the overweight and normal weight (P = .75). Heterogeneity between the fifteen studies is high (I2 = 100%).

CONCLUSION

Prostate cancer is a common malignancy that poses a threat to the health of men. Obesity is associated with a higher risk of death from prostate cancer based on the findings of the included studies. Furthermore, wherever possible, the impact of weight change on prostate cancer patient mortality should be investigated.

The Effect of Mixture of Heavy Metals on Obesity in Individuals ≥50 Years of Age

Little is known about the association between a mixture of heavy metals and obesity among individuals ≥50 years of age with comorbidities. Thus, we identified the associations of serum cadmium (Cd), lead (Pb), and mercury (Hg) with obesity using linear regression models; weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were conducted as secondary analyses. Of the 6434 subjects included in the analysis, 13.8% had obesity and 44.6% had abdominal obesity. In the logistic regression model, serum Hg was associated with obesity and abdominal obesity, and significant trends were observed for these heavy metal tertiles (p < 0.001). Serum Hg levels were also associated with body mass index (BMI) and waist circumference (WC). The WQS index was significantly associated with both obesity (OR = 1.43, 95% CI: 1.40-1.46) and abdominal obesity (β = 1.51, 95% CI: 1.48-1.54). The qgcomp index also found a significant association between heavy metals and both obesity (OR = 1.35, 95% CI: 1.12-1.63) and abdominal obesity (OR = 1.34, 95% CI: 1.12-1.60). Serum Hg was the most heavily weighed heavy metal in these models. In BKMR analysis, the overall effect of the mixture was significantly associated with obesity, BMI, and WC. Serum Hg showed positive trends and was observed as the most important factor associated with obesity, BMI, and WC. Our findings were largely robust to secondary analyses that used three novel mixture modeling approaches: WQS, qpcomp, and BKMR. Given increasing exposure to heavy metals, well-characterized cohorts of individuals aged ≥50 years are required to determine the mixed effects of heavy metals on obesity and related diseases.

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 between body shape index and risk of mortality in the United States

The body mass index (BMI) neither differentiates fat from lean mass nor does it consider adipose tissue distribution. In contrast, the recently introduced z-score of the log-transformed A Body Shape Index (LBSIZ) can be applied to measure obesity using waist circumference (WC), height, and weight. We aimed to investigate the association between LBSIZ and mortality. We used data from the National Health and Nutrition Examination Survey 1999–2014 and linked the primary dataset to death certificate data from the National Death Index with mortality follow-up through December 31, 2015. A multiple Cox regression analysis was performed to evaluate the hazard ratio (HR) of all-cause and cardiovascular disease (CVD) mortalities with adjustment for baseline characteristics. LBSIZ, WC, and BMI showed positive association with total fat percentage (P < 0.001); however, only WC and BMI were positively associated with appendicular skeletal mass index (ASMI) (P < 0.001). In the multiple Cox regression analysis, only LBSIZ showed a significant HR for all-cause and CVD mortalities. Under restricted cubic spline regression, mortality risk increased with LBSIZ. However, BMI and WC showed a U-shape association. In conclusion, LBSIZ is strongly associated with all-cause and CVD mortalities. Since LBSIZ is independent of BMI, LBSIZ complements BMI to identify high-risk groups for mortality even in individuals with low or normal BMI.

Association of Anthropometric Measures With the Risk of Prostate Cancer in the Multiethnic Cohort

In studies of anthropometric measures and prostate cancer risk, conducted primarily in White men, positive associations with advanced disease have been reported. We assessed body size in relation to incident prostate cancer risk in 79,950 men from the Multiethnic Cohort, with 8,819 cases identified over 22 years (1993-2015). Height was associated with increased risk of advanced prostate cancer (≥68 inches (≥ 173 cm) vs. < 66 inches (168 cm); hazard ratio (HR) = 1.24, 95% confidence interval (CI): 1.04, 1.48) and high-grade disease (HR = 1.15, 95% CI: 1.02, 1.31). Compared with men of normal weight, men overweight at baseline were at higher risk of high-grade cancer (HR = 1.15, 95% CI: 1.04, 1.26). Greater weight was positively associated with localized and low-grade disease in Blacks and Native Hawaiians (by race, P for heterogeneity = 0.0002 and 0.008, respectively). Weight change since age 21 years was positively associated with high-grade disease (for ≥ 40 pounds (18 kg) vs. 10 pounds (4.5 kg), HR = 1.20, 95% CI: 1.05, 1.37; P for trend = 0.005). Comparing highest versus lowest quartile, waist-to-hip ratio was associated with a 1.78-fold increase (95% CI: 1.28, 2.46) in the risk of advanced prostate cancer. Positive associations with the majority of anthropometric measures were observed in all 5 racial/ethnic groups, suggesting a general impact of anthropometric measures on risk across populations.

General and abdominal obesity trajectories across adulthood, and risk of prostate cancer: results from the PROtEuS study, Montreal, Canada

PURPOSE

Greater body fatness is a probable cause of advanced prostate cancer (PCa). Body fat distribution and timing of exposure may be relevant. We investigated associations between body size trajectories and PCa incidence in a population-based case-control study in Montreal, Canada.

METHODS

Cases (n = 1,931), aged ≤ 75 years, were diagnosed with PCa in 2005-2009; 1,994 controls were selected from the electoral list. Interviews were conducted to assess body mass index (BMI) and Stunkard's silhouette at ages 20, 40, 50, 60 years, and before interview. Current waist and hip circumferences were measured, and a predictive model estimated waist circumference in the past. BMI and waist circumference trajectories were determined to identify subgroups. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between anthropometric indicators and PCa.

RESULTS

Subjects with a current BMI ≥ 30 kg/m² had a lower risk of overall PCa (OR 0.71, 95% CI 0.59-0.85). Associations with adult BMI followed similar trends for less and more aggressive tumors, with stronger inverse relationships in early adulthood. Contrastingly, current waist circumference ≥ 102 cm was associated with elevated risk of high-grade PCa (OR 1.33, 95% CI 1.03-1.71). Men with increasing BMI or waist circumference adult trajectories had a lower risk of PCa, especially low-grade, than those in the normal-stable range. This was especially evident among men in the obese-increase group for BMI and waist circumference.

CONCLUSION

Abdominal obesity increased the risk of aggressive PCa. The inverse relationship between body size trajectories and PCa may reflect PSA hemodilution, lower detection, and/or a true etiological effect.

Effect of Sarcopenia and Body Shape on Cardiovascular Disease According to Obesity Phenotypes

Background

This study aimed to assess the effects of sarcopenia and A Body Shape Index (ABSI) on cardiovascular disease (CVD) risk according to obesity phenotypes.

Methods

We used data from the National Health and Nutrition Examination Survey 1999 to 2012. A total of 25,270 adults were included and classified into the following groups: metabolically healthy normal weight (MHNW), metabolically healthy overweight/obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obese (MUO). Sarcopenia was defined as the appendicular skeletal mass index <7 kg/m2 in men and <5.5kg/m2 in women. A multivariate logistic regression analysis was performed to evaluate the odds ratio (OR) of sarcopenia and ABSI for CVD events according to the obesity phenotype.

Results

The MHNW participants with sarcopenia had higher risk for CVD than those without sarcopenia (OR, 2.69; 95% confidence interval [CI], 1.56 to 4.64). In the analysis with MHNW participants without sarcopenia as a reference, the participants with sarcopenia showed a higher OR for CVD than those without sarcopenia in both MHO (OR in participants without sarcopenia, 3.31; 95% CI, 1.94 to 5.64) (OR in participants with sarcopenia, 8.59; 95% CI, 2.63 to 28.04) and MUO participants (OR in participants without sarcopenia, 5.11; 95% CI, 3.21 to 8.15) (OR in participants with sarcopenia, 8.12; 95% CI, 4.04 to 16.32). Participants within the second and third tertiles of ABSI had higher ORs for CVDs than the counterpart of obesity phenotypes within the first tertile.

Conclusion

These results suggest that clinical approaches that consider muscle and body shape are required.

Projecting the prevalence of obesity in South Korea through 2040: a microsimulation modelling approach

OBJECTIVE

To project the prevalence of obesity in 2040 among individuals 19 years and older in South Korea.

DESIGN, SETTING, AND PARTICIPANTS

Using the 'Population Health Model-body mass index' (BMI) microsimulation model, the prevalence of obesity in Korean adults 19 years and older was projected until 2040. The model integrated individual survey data from the Korea Health Panel Survey of 2011 and 2012, population statistics based on resident registration, population projections and complete life tables categorised by sex and age. Birth rate, life expectancy and international migration were based on a medium growth scenario. The base population of Korean adults in 2012, devised through data aggregation, was 39 842 730. The prediction equations were formulated using BMI as the dependent variable; the individual's sex, age, smoking status, physical activity and preceding year's BMI were used as predictive factors.

OUTCOME MEASURE

BMI categorised by sex.

RESULTS

The median BMI for Korean adults in 2040 was expected to be 23.55 kg/m² (23.97 and 23.17 kg/m² for men and women, respectively). According to the Korean BMI classification, 70.05% of all adults were expected to be 'preobese' (ie, have BMIs 23-24.9 kg/m²) by 2040 (81.23% of men and 59.07% of women) and 24.88% to be 'normal'.

CONCLUSIONS

We explored the possibility of applying and expanding on the concept of microsimulation in the field of healthcare by combining data sources available in Korea and found that more than half of the adults in this study population will be preobese, and the proportions of 'obesity' and 'normal' will decrease compared with those in 2012. The results of our study will aid in devising healthy strategies and spreading public awareness for preventing this condition.

Systematic review and meta-analysis of the associations between body mass index, prostate cancer, advanced prostate cancer, and prostate-specific antigen

PURPOSE

The relationship between body mass index (BMI) and prostate cancer remains unclear. However, there is an inverse association between BMI and prostate-specific antigen (PSA), used for prostate cancer screening. We conducted this review to estimate the associations between BMI and (1) prostate cancer, (2) advanced prostate cancer, and (3) PSA.

METHODS

We searched PubMed and Embase for studies until 02 October 2017 and obtained individual participant data from four studies. In total, 78 studies were identified for the association between BMI and prostate cancer, 21 for BMI and advanced prostate cancer, and 35 for BMI and PSA. We performed random-effects meta-analysis of linear associations of log-PSA and prostate cancer with BMI and, to examine potential non-linearity, of associations between categories of BMI and each outcome.

RESULTS

In the meta-analyses with continuous BMI, a 5 kg/m2 increase in BMI was associated with a percentage change in PSA of - 5.88% (95% CI - 6.87 to - 4.87). Using BMI categories, compared to normal weight men the PSA levels of overweight men were 3.43% lower (95% CI - 5.57 to - 1.23), and obese men were 12.9% lower (95% CI - 15.2 to - 10.7). Prostate cancer and advanced prostate cancer analyses showed little or no evidence associations.

CONCLUSION

There is little or no evidence of an association between BMI and risk of prostate cancer or advanced prostate cancer, and strong evidence of an inverse and non-linear association between BMI and PSA. The association between BMI and prostate cancer is likely biased if missed diagnoses are not considered.

Relationship of self-reported body size and shape with risk for prostate cancer: A UK case-control study

INTRODUCTION

Previous evidence has suggested a relationship between male self-reported body size and the risk of developing prostate cancer. In this UK-wide case-control study, we have explored the possible association of prostate cancer risk with male self-reported body size. We also investigated body shape as a surrogate marker for fat deposition around the body. As obesity and excessive adiposity have been linked with increased risk for developing a number of different cancers, further investigation of self-reported body size and shape and their potential relationship with prostate cancer was considered to be appropriate.

OBJECTIVE

The study objective was to investigate whether underlying associations exist between prostate cancer risk and male self-reported body size and shape.

METHODS

Data were collected from a large case-control study of men (1928 cases and 2043 controls) using self-administered questionnaires. Data from self-reported pictograms of perceived body size relating to three decades of life (20's, 30's and 40's) were recorded and analysed, including the pattern of change. The associations of self-identified body shape with prostate cancer risk were also explored.

RESULTS

Self-reported body size for men in their 20's, 30's and 40's did not appear to be associated with prostate cancer risk. More than half of the subjects reported an increase in self-reported body size throughout these three decades of life. Furthermore, no association was observed between self-reported body size changes and prostate cancer risk. Using 'symmetrical' body shape as a reference group, subjects with an 'apple' shape showed a significant 27% reduction in risk (Odds ratio = 0.73, 95% C.I. 0.57-0.92).

CONCLUSIONS

Change in self-reported body size throughout early to mid-adulthood in males is not a significant risk factor for the development of prostate cancer. Body shape indicative of body fat distribution suggested that an 'apple' body shape was protective and inversely associated with prostate cancer risk when compared with 'symmetrical' shape. Further studies which investigate prostate cancer risk and possible relationships with genetic factors known to influence body shape may shed further light on any underlying associations.

Measures of body fatness and height in early and mid-to-late adulthood and prostate cancer: risk and mortality in The Pooling Project of Prospective Studies of Diet and Cancer

BACKGROUND

Advanced prostate cancer etiology is poorly understood. Few studies have examined associations of anthropometric factors (e.g. early adulthood obesity) with advanced prostate cancer risk.

PATIENTS AND METHODS

We carried out pooled analyses to examine associations between body fatness, height, and prostate cancer risk. Among 830 772 men, 51 734 incident prostate cancer cases were identified, including 4762 advanced (T4/N1/M1 or prostate cancer deaths) cases, 2915 advanced restricted (same as advanced, but excluding localized cancers that resulted in death) cases, 9489 high-grade cases, and 3027 prostate cancer deaths. Cox proportional hazards models were used to calculate study-specific hazard ratios (HR) and 95% confidence intervals (CI); results were pooled using random effects models.

RESULTS

No statistically significant associations were observed for body mass index (BMI) in early adulthood for advanced, advanced restricted, and high-grade prostate cancer, and prostate cancer mortality. Positive associations were shown for BMI at baseline with advanced prostate cancer (HR = 1.30, 95% CI = 0.95-1.78) and prostate cancer mortality (HR = 1.52, 95% CI = 1.12-2.07) comparing BMI ≥35.0 kg/m2 with 21-22.9 kg/m2. When considering early adulthood and baseline BMI together, a 27% higher prostate cancer mortality risk (95% CI = 9% to 49%) was observed for men with BMI <25.0 kg/m2 in early adulthood and BMI ≥30.0 kg/m2 at baseline compared with BMI <25.0 kg/m2 in early adulthood and BMI <30.0 kg/m2 at baseline. Baseline waist circumference, comparing ≥110 cm with <90 cm, and waist-to-hip ratio, comparing ≥1.00 with <0.90, were associated with significant 14%-16% increases in high-grade prostate cancer risk and suggestive or significant 20%-39% increases in prostate cancer mortality risk. Height was associated with suggestive or significant 33%-56% risks of advanced or advanced restricted prostate cancer and prostate cancer mortality, comparing ≥1.90 m with <1.65 m.

CONCLUSION

Our findings suggest that height and total and central adiposity in mid-to-later adulthood, but not early adulthood adiposity, are associated with risk of advanced forms of prostate cancer. Thus, maintenance of healthy weight may help prevent advanced prostate cancer.

The Association between Z-Score of Log-Transformed A Body Shape Index and Cardiovascular Disease in Korea

BACKGROUND

In order to overcome the limitations of body mass index (BMI) and waist circumference (WC), the z-score of the log-transformed A Body Shape Index (LBSIZ) has recently been introduced. In this study, we analyzed the relationship between the LBSIZ and cardiovascular disease (CVD) in a Korean representative sample.

METHODS

Data were collected from the Korea National Health and Nutrition Examination VI to V. The association between CVD and obesity indices was analyzed using a receiver operating characteristic curve. The cut-off value for the LBSIZ was estimated using the Youden index, and the odds ratio (OR) for CVD was determined via multivariate logistic regression analysis. ORs according to the LBSIZ value were analyzed using restricted cubic spline regression plots.

RESULTS

A total of 31,227 Korean healthy adults were analyzed. Area under the curve (AUC) of LBSIZ against CVD was 0.686 (95% confidence interval [CI], 0.671 to 0.702), which was significantly higher than the AUC of BMI (0.583; 95% CI, 0.567 to 0.599) or WC (0.646; 95% CI, 0.631 to 0.661) (P<0.001). Similar results were observed for stroke and coronary artery diseases. The cut-off value for the LBSIZ was 0.35 (sensitivity, 64.5%; specificity, 64%; OR, 1.29, 95% CI, 1.12 to 1.49). Under restricted cubic spline regression, LBSIZ demonstrated that OR started to increase past the median value.

CONCLUSION

The findings of this study suggest that the LBSIZ might be more strongly associated with CVD risks compared to BMI or WC. These outcomes would be helpful for CVD risk assessment in clinical settings, especially the cut-off value of the LBSIZ suggested in this study.

Utility of the Z-score of log-transformed A Body Shape Index (LBSIZ) in the assessment for sarcopenic obesity and cardiovascular disease risk in the United States

Body mass index (BMI) has limited accuracy for predicting cardiovascular diseases (CVD) and is not capable of identifying sarcopenic obesity, the combination of sarcopenia (an age-associated decline in muscle mass and physical function) and obesity. To overcome this, the z-score of the log-transformed A Body Shape Index (LBSIZ) was recently introduced as a measure of obesity using waist circumference, height, and weight. We aimed to investigate the association of LBSIZ with sarcopenic obesity and CVD, and propose appropriate cut-off values using the National Health and Nutrition Examination Survey 1999–2016 data. Of 92,062 participants, 40,468 adults (≥20 years) were included. Overall area under curve (AUC) of LBSIZ was 0.735 (95% confidence interval [CI]: 0.716–0.754) for sarcopenic obesity, and 0.695 (95% CI: 0.687–0.703) for CVD. The subgroup analysis of ethnicity/race showed similar results. Waist circumference (WC), BMI, conicity index, body roundness index (BRI), Clinica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE), new BMI, and waist to height ratio (WHtR) showed a negative association with sarcopenic obesity, while LBSIZ and conicity index showed a positive association. The AUC of LBSIZ was significantly higher for sarcopenic obesity than that of conicity index (p < 0.001). The AUC of LBSIZ was significantly higher for CVD than those of parameters including WC, BMI, BRI, CUN-BAE, new BMI, and WHtR (p < 0.001). The AUC for conicity index alone was comparable to that of LBSIZ for CVD. Overall LBSIZ cut-off was 0.35 for both sarcopenic obesity (sensitivity, 65.3%; specificity, 71.5%) and CVD (sensitivity, 63.3%; specificity, 66.6%). These results may be useful not only to identify sarcopenic obesity, but also to conduct CVD risk assessment in the clinical setting.

Body fat distribution on computed tomography imaging and prostate cancer risk and mortality in the AGES-Reykjavik study

BACKGROUND

The World Cancer Research Fund classifies as "strong evidence" the link between obesity and the risk of advanced prostate cancer. In light of the different hormonal profiles associated with where adipose is stored, this study investigated the role of objectively measured body fat distribution and the risk of clinically relevant prostate cancer.

METHODS

This was a prospective study of 1832 men in the Age, Gene/Environment Susceptibility-Reykjavik study. From 2002 to 2006, participants underwent baseline computed tomography imaging of fat deposition, bioelectric impedance analysis, and measurement of body mass index (BMI) and waist circumference. Men were followed through linkage with nationwide cancer registries for the incidence of total (n = 172), high-grade (Gleason grade ≥8; n = 43), advanced (≥cT3b/N1/M1 at diagnosis or fatal prostate cancer over follow-up; n = 41), and fatal prostate cancer (n = 31) through 2015. Cox regression was used to evaluate the association between adiposity measures and prostate cancer outcomes.

RESULTS

Among all men, visceral fat (hazard ratio [HR], 1.31 per 1-standard deviation [SD] increase; 95% confidence interval [CI], 1.00-1.72) and thigh subcutaneous fat (HR, 1.37 per 1-SD increase; 95% CI, 1.00-1.88) were associated with risk of advanced and fatal disease, respectively. Among men who were leaner based on BMI, visceral fat was associated with both advanced and fatal disease. BMI and waist circumference were associated with a higher risk of advanced and fatal disease. No adiposity measures were associated with total or high-grade disease.

CONCLUSIONS

Specific fat depots as well as BMI and waist circumference were associated with the risk of aggressive prostate cancer, which may help to elucidate underlying mechanisms and target intervention strategies.

Sex differences in relationship between body composition and digit length ratio (2D:4D) in students of military courses

It is believed that the second to fourth finger length ratio is an indirect indicator of fetal testosterone levels. It is pointed out that there is a relationship between the 2nd to 4th finger length ratio and the body structure in women and men. Studies on the relationship between body composition and 2D:4D finger length among military students have not been carried out so far. The work aims to determine the dependence of body composition and the quotient of the 2nd and 4th fingers length of military students. The research material has been gathered as a result of examinations of women and men studying military subjects. The study involved 55 women and 65 men. The tests included anthropometric measurements (body height, body weight, length of the second and the fourth fingers) and body composition measurements. As a result of the tests, no dimorphic differentiations in the digit length ratio (2D:4D) was indicated. The BMI, muscle mass, lean body mass and water in the body demonstrated higher values in men than in women. However, the fat content in men was low. It was found that the relationship exists between muscle mass, lean mass and total water content in the body and the 2D:4D finger length ratio in the left hand in women. A higher level of fetal testosterone, characterized by lower values of the 2nd to 4th finger length ratio, may be associated with a higher content of muscle mass, lean body mass and water in the body of adult women leading a similar lifestyle.

Abdominal obesity and prostate cancer risk: epidemiological evidence from the EPICAP study

Obesity is associated with an increased risk of several cancers, but inconsistent results have been observed between body mass index (BMI) and prostate cancer (PCa) risk. However, some associations have been reported with other indicators such as waist circumference (WC) and waist-hip ratio (WHR). We investigated the role of anthropometric indicators in PCa risk based on data from the Epidemiological study of Prostate Cancer (EPICAP).

EPICAP is a population-based case-control study that included 819 incident PCa in 2012–2013 and 879 controls frequency matched by age. Anthropometric indicators (weight, height, WC, and hip circumference) have been measured at interview. Logistic regression models were used to assess odds ratios (ORs) for the associations between anthropometric indicators (BMI, WC and WHR) and PCa risk.

We observed a slight, but not significant increased risk of PCa for men with a WC > 94 cm (OR 1.20, 95% CI 0.92–1.56) and for men with a WHR ≥ 0.95 (OR 1.30, 95% CI 1.00–1.70 between 0.95 and 1.00, OR 1.25, 95% CI 0.96–1.61 above 1.00). Associations were more pronounced after adjustment and stratification for BMI and in men with aggressive PCa.

Our results suggest that abdominal obesity may be associated with an increased risk of PCa, especially aggressive PCa.

Association of Z-Score of the Log-Transformed A Body Shape Index with Cardiovascular Disease in People Who Are Obese but Metabolically Healthy: The Korea National Health and Nutrition Examination Survey 2007-2010

Background

We aimed at evaluating the effect of the z-score of the log-transformed A Body Shape Index (LBSIZ) on cardiovascular disease (CVD) outcomes according to obesity phenotype.

Methods

Data were collected from the Korea National Health and Nutrition Examination Survey conducted from 2007 to 2010. Obesity was defined as a body mass index above 25 kg/m² and metabolic abnormality was defined as the presence of two or more metabolic risk factors of the Adult Treatment Panel III definition. The participants were classified by obesity and metabolic healthy status: metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO). Each group was further classified into three groups based on the tertile of LBSIZ. A multivariate logistic regression analysis with adjustment for age, sex, smoking status, income, education level, physical activities, alcohol, and energy intake was conducted to evaluate the odds ratio (OR) for CVD events.

Results

In the multivariate logistic regression model, MHO participants who are within the third tertile of LBSIZ had a significantly higher OR for CVD events, whereas those who are within the first and second tertile of LBSIZ were not at high risk of developing CVDs compared to MHNO participants who are within the first tertile of LBSIZ. In addition, a similar increase in the OR was observed in MUNO or MUO participants.

Conclusion

LBSIZ had the lowest risk for CVDs in the first tertile of LBSIZ and a linear relationship with all its tertiles in MHO, MUNO, and MUO participants.

Effectiveness of Z-score of log-transformed A Body Shape Index (LBSIZ) in predicting cardiovascular disease in Korea: the Korean Genome and Epidemiology Study

Body mass index (BMI) and waist circumference (WC) have limitations in stratifying cardio-metabolic risks. Another obesity measure, A Body Shape Index (ABSI), has been introduced but its applicability remains limited. To address this, the z-score of the log-transformed ABSI (LBSIZ) was recently developed. This study aimed to examine the ability of LBSIZ, compared to that of WC and BMI, to predict cardiovascular disease (CVD) risk. The study included 8,485 participants aged 40-69 years (mean age = 52.1) who were followed for 10 years and recruited from the Korean Genome and Epidemiology Study, a population-based cohort study. The area under the curve was 0.635 (95% confidence interval [CI]: 0.614-0.657) for LBSIZ, 0.604 (95%CI: 0.580-0.627) for WC, and 0.538 (95%CI: 0.514-0.562) for BMI. The AUC of the Framingham risk score (FRS) was 0.680 (95%CI: 0.659-0.701) in comparison. When we added LBSIZ to the model, the integrated AUC significantly improved from 0.680 to 0.692 (95%CI: 0.672-0.713; p value, 0.033), whereas there were no changes with BMI (AUC, 0.678; 95%CI: 0.656-0.699) or WC (AUC, 0.679; 95%CI: 0.658-0.701). In the multivariate Cox regression analysis, LBSIZ but not BMI or WC showed a significant hazard ratio of CVD event compared to 1st decile of each parameter. In the restricted cubic spline regression, BMI and WC showed an overall J-shaped relationship with CVD events whereas LBSIZ showed a linear relationship. LBSIZ is strongly associated with CVD risk and should predict CVD risk better than BMI and WC in the general population.

Prospective investigation of risk factors for prostate cancer in the UK Biobank cohort study

BACKGROUND

Prostate cancer is the most common cancer in British men but its aetiology is not well understood. We aimed to identify risk factors for prostate cancer in British males.

METHODS

We studied 219 335 men from the UK Biobank study who were free from cancer at baseline. Exposure data were collected at recruitment. Prostate cancer risk by the different exposures was estimated using multivariable-adjusted Cox proportional hazards models.

RESULTS

In all, 4575 incident cases of prostate cancer occurred during 5.6 years of follow-up. Prostate cancer risk was positively associated with the following: black ethnicity (hazard ratio black vs white=2.61, 95% confidence interval=2.10-3.24); having ever had a prostate-specific antigen test (1.31, 1.23-1.40); being diagnosed with an enlarged prostate (1.54, 1.38-1.71); and having a family history of prostate cancer (1.94, 1.77-2.13). Conversely, Asian ethnicity (Asian vs white hazard ratio=0.62, 0.47-0.83), excess adiposity (body mass index (⩾35 vs <25 kg m-2=0.75, 0.64-0.88) and body fat (⩾30.1 vs <20.5%=0.81, 0.73-0.89)), cigarette smoking (current vs never smokers=0.85, 0.77-0.95), having diabetes (0.70, 0.62-0.80), and never having had children (0.89, 0.81-0.97) or sexual intercourse (0.53, 0.33-0.84) were related to a lower risk.

CONCLUSIONS

In this new large British prospective study, we identified associations with already-established, putative and possible novel risk factors for being diagnosed with prostate cancer. Future research will examine associations by tumour characteristics.

Body mass index and incidence of nonaggressive and aggressive prostate cancer: a dose-response meta-analysis of cohort studies

The relationship between body mass index (BMI) and incidence of prostate cancer is still inconclusive. We performed a dose-response meta-analysis of eligible cohort studies to evaluate potential association of BMI with prostate cancer risk by subtype of prostate cancer (nonaggressive and aggressive). A comprehensive literature search was performed in PubMed and Web of Science databases through March 22, 2017. Linear and non-linear dose-response meta-analyses were carried out to evaluate the effects of BMI on incidence of prostate cancer. A total of 21 cohort or nested case-control studies (17 for nonaggressive and 21 for aggressive prostate cancer) were included in this meta-analysis. For nonaggressive prostate cancer, the pooled relative risk (RR) per 5 kg/m² increment of BMI with 95% confidence interval (CI) was 0.96 (95% CI 0.92–1.00). Sensitivity analysis indicated that this result was not robust and steady. For aggressive prostate cancer, a significant linear direct relationship with BMI (RR, 1.07; 95% CI 1.03–1.12) for every 5 kg/m2 increase was observed. Statistically significant heterogeneity was detected for nonaggressive prostate cancer (P = 0.020, I² = 46.1%) but not for aggressive prostate cancer (P = 0.174, I² = 22.4%). In conclusion, BMI level may be positively associated with aggressive prostate cancer risk. Further large prospective cohort studies are warranted to confirm the findings from our study.

Is Body Mass Index the Best Adiposity Measure for Prostate Cancer Risk? Results From a Veterans Affairs Biopsy Cohort

OBJECTIVE

To test multiple adiposity measures and prostate cancer (PC) risk in men undergoing prostate biopsy. We hypothesized that body mass index (BMI), body fat, and waist circumference would be highly correlated, and all would be associated with aggressive PC, but not overall risk.

SUBJECTS AND METHODS

A case (483)-control (496) study among men undergoing prostate biopsy from 2007 to 2016 was conducted at the Durham Veterans Affairs Medical Center. Anthropometric and self-reported measurements were taken. Percent body fat was measured. Associations between adiposity measures and PC risk and high-grade PC (Gleason ≥7) were examined using logistic regression.

RESULTS

BMI, percent body fat, and waist circumference were highly correlated (ρ ≥ .79) (P < .001). On multivariable analysis, BMI (P = .011) was associated with overall PC risk, but percent body fat (P = .16) and waist circumference (P = .19) were not. However, all adiposity measurements were associated with high-grade disease (P < .001). We found a strong relationship between self-reported and measured weight (ρ = .97) and height (ρ = .92).

CONCLUSION

BMI, body fat, and waist circumference were all highly correlated and associated with aggressive PC. This study supports the idea that higher adiposity is selectively associated with high-grade PC and reinforces the continued use of self-reported BMI as a measure of obesity in epidemiologic studies of PC.

Association between Adult Height and Risk of Colorectal, Lung, and Prostate Cancer: Results from Meta-analyses of Prospective Studies and Mendelian Randomization Analyses

BACKGROUND

Observational studies examining associations between adult height and risk of colorectal, prostate, and lung cancers have generated mixed results. We conducted meta-analyses using data from prospective cohort studies and further carried out Mendelian randomization analyses, using height-associated genetic variants identified in a genome-wide association study (GWAS), to evaluate the association of adult height with these cancers.

METHODS AND FINDINGS

A systematic review of prospective studies was conducted using the PubMed, Embase, and Web of Science databases. Using meta-analyses, results obtained from 62 studies were summarized for the association of a 10-cm increase in height with cancer risk. Mendelian randomization analyses were conducted using summary statistics obtained for 423 genetic variants identified from a recent GWAS of adult height and from a cancer genetics consortium study of multiple cancers that included 47,800 cases and 81,353 controls. For a 10-cm increase in height, the summary relative risks derived from the meta-analyses of prospective studies were 1.12 (95% CI 1.10, 1.15), 1.07 (95% CI 1.05, 1.10), and 1.06 (95% CI 1.02, 1.11) for colorectal, prostate, and lung cancers, respectively. Mendelian randomization analyses showed increased risks of colorectal (odds ratio [OR] = 1.58, 95% CI 1.14, 2.18) and lung cancer (OR = 1.10, 95% CI 1.00, 1.22) associated with each 10-cm increase in genetically predicted height. No association was observed for prostate cancer (OR = 1.03, 95% CI 0.92, 1.15). Our meta-analysis was limited to published studies. The sample size for the Mendelian randomization analysis of colorectal cancer was relatively small, thus affecting the precision of the point estimate.

CONCLUSIONS

Our study provides evidence for a potential causal association of adult height with the risk of colorectal and lung cancers and suggests that certain genetic factors and biological pathways affecting adult height may also affect the risk of these cancers.

Oncolytic adenovirus-mediated therapy for prostate cancer

Prostate cancer is a leading cause of cancer-related death and morbidity in men in the Western world. Tumor progression is dependent on functioning androgen receptor signaling, and initial administration of antiandrogens and hormone therapy (androgen-deprivation therapy) prevent growth and spread. Tumors frequently develop escape mechanisms to androgen-deprivation therapy and progress to castration-resistant late-stage metastatic disease that, in turn, inevitably leads to resistance to all current therapeutics, including chemotherapy. In spite of the recent development of more effective inhibitors of androgen–androgen receptor signaling such as enzalutamide and abiraterone, patient survival benefits are still limited. Oncolytic adenoviruses have proven efficacy in prostate cancer cells and cause regression of tumors in preclinical models of numerous drug-resistant cancers. Data from clinical trials demonstrate that adenoviral mutants have limited toxicity to normal tissues and are safe when administered to patients with various solid cancers, including prostate cancer. While efficacy in response to adenovirus administration alone is marginal, findings from early-phase trials targeting local-ized and metastatic prostate cancer suggest improved efficacy in combination with cytotoxic drugs and radiation therapy. Here, we review recent progress in the development of multimodal oncolytic adenoviruses as biological therapeutics to improve on tumor elimination in prostate cancer patients. These optimized mutants target cancer cells by several mechanisms including viral lysis and by expression of cytotoxic transgenes and immune-stimulatory factors that activate the host immune system to destroy both infected and noninfected prostate cancer cells. Additional modifications of the viral capsid proteins may support future systemic delivery of oncolytic adenoviruses.

Association of a New Measure of Obesity with Hypertension and Health-Related Quality of Life

Background

Despite its shortcomings, body mass index (BMI) has traditionally been used to define obesity. Another recently introduced obesity measure, A Body Shape Index (ABSI), has been introduced to focus on abdominal obesity, but its applicability remains limited. We analyzed the statistical properties of the ABSI and propose a modified ABSI, the z-score of the log-transformed ABSI (LBSIZ), to improve its applicability. We also examined the sensitivity of the newly introduced index in diagnosing obesity based on the percentage of body fat and its ability to predict hypertension and impaired health-related quality of life (HRQOL).

Methods and Results

We transformed the ABSI to the LBSIZ in order to create a standard normalized obesity measure. All available data from the Korea National Health and Nutrition Examination Survey (KNHANES) (1998–2012) have shown BMI to be highly correlated with weight (r = 0.85 for women, r = 0.87 for men) and waist circumference (WC) (r = 0.86 for women, r = 0.85 for men), but the LBSIZ was found to be weakly correlated with weight (r = 0.001 for women, r = 0.0001 for men) and moderately correlated with WC (r = 0.51 for women, r = 0.52 for men). BMI showed an inverted U-shaped pattern when plotted against age, but a linear pattern was observed for the LBSIZ, indicating they are different kinds of obesity measures. Logistic regression showed that the odds ratio of obesity for the LBSIZ was 1.86 (95% confidence interval [CI] = 1.73–2.00) for males and 1.32 (95% CI = 1.24–1.40) for females after adjusting for weight, height, age, and year of participation in the KNHANES. While both BMI and the LBSIZ were significantly related to hypertension, the LBSIZ alone was significantly associated with impaired HRQOL.

Conclusions

The LBSIZ is a standard normalized obesity measure independent of weight, height, and BMI. LBSIZ is a new measure of abdominal obesity with the ability to predict hypertension and impaired HRQOL, irrespective of BMI.

Childhood height, adult height, and the risk of prostate cancer

PURPOSE

We previously showed that childhood height is positively associated with prostate cancer risk. It is, however, unknown whether childhood height exerts its effects independently of or through adult height. We investigated whether and to what extent childhood height has a direct effect on the risk of prostate cancer apart from adult height.

METHODS

We included 5,871 men with height measured at ages 7 and 13 years in the Copenhagen School Health Records Register who also had adult (50-65 years) height measured in the Danish Diet, Cancer and Health study. Prostate cancer status was obtained through linkage to the Danish Cancer Registry. Direct and total effects of childhood height on prostate cancer risk were estimated from Cox regressions.

RESULTS

From 1996 to 2012, 429 prostate cancers occurred. Child and adult heights were positively and significantly associated with prostate cancer risk. When adjusted for adult height, height at age 7 years was no longer significantly associated with the risk of prostate cancer. Height at 13 years was significantly and positively associated with prostate cancer risk even when adult height was adjusted for; per height z-score the hazard ratio was 1.15 [95% confidence interval (CI) 1.01-1.32].

CONCLUSIONS

The effect of height at 13 years on the risk of prostate cancer was not entirely mediated through adult height, suggesting that child height and adult height may be associated with prostate cancer through different pathways.

Metabolic abnormalities linked to an increased cardiovascular risk are associated with high-grade prostate cancer: a single biopsy cohort analysis

BACKGROUND

Smoking, hypertension, abdominal obesity and metabolic abnormalities have been considered individual factors involved in prostate cancer (PCa) pathogenesis. All of these factors are used to define the individual cardiovascular risk (CVR). The aim of our study was to evaluate the association between CVR and PCa diagnosis and grade among a consecutive series of men undergoing prostate biopsy.

METHODS

From 2010 onwards, consecutive patients undergoing 12-core prostate biopsy were enrolled. Body mass index was measured before the biopsy. Blood samples were collected and tested for: PSA, fasting glucose, triglycerides and high-density lipoproteins. Blood pressure was also recorded. Metabolic syndrome was defined according to the Adult Treatment Panel III and CVR according to the European Association of Cardiologist Guidelines. We evaluated the association between CVR and PCa biopsy Gleason score using logistic regression analyses.

RESULTS

Five hundred and eighty-four patients were enrolled. Four hundred and six patients (70%) presented a moderate/high CVR. Two hundred and thirty-seven (40.6%) patients had cancer on biopsy; 157 with moderate/high CVR and 80 with low/no CVR (P=0.11). Out of the 237 patients with PCa, 113 had a Gleason score 6 and 124 a Gleason score ⩾7. Out of them, 92/124 (75%) presented a moderate/high CVR (P=0.004). Moderate/high CVR was not associated with an increased risk of PCa (odds ratio (OR): 0.741, confidence interval (CI): 0.474-1.156; P=0.186) but with an increased risk of Gleason score ⩾7 (OR: 2.154, CI: 1.076-4.314; P=0.030).

CONCLUSIONS

In our study, a moderate/high CVR is associated with an increased risk of a high-grade Gleason score when PCa is diagnosed on biopsy. Although these results should be confirmed in multicentre studies, patients with moderate/high CVR should be carefully evaluated for PCa diagnosis.

Body size across the life course and prostate cancer in the Health Professionals Follow-up Study

Current evidence of an association between body size and prostate cancer is conflicting, possibly due to differential effects of body size across the lifespan and the heterogeneity of the disease. We therefore examined childhood and adult body size in relation to total incident prostate cancer and prognostic subtypes in a prospective cohort of 47,491 US men in the Health Professionals Follow-up Study. We assessed adult height, body mass index (BMI) in early and middle-to-late adulthood, adult waist circumference, and body shape at age 10. With follow-up from 1986 to 2010, we estimated the relative risk (RR) of prostate cancer using Cox proportional hazards models. We identified 6,183 incident cases. Tallness was associated with increased risk of advanced-stage tumors, particularly fatal disease (RR = 1.66, 95% CI 1.23-2.23, highest vs. lowest quintile, ptrend < 0.001). High BMI at age 21 was inversely associated with total prostate cancer (RR = 0.89, 95% CI 0.80-0.98, BMI ≥ 26 vs. 20-21.9, ptrend = 0.01) and with fatal and advanced disease. The association for late adult BMI differed by age (pinteraction < 0.001); high BMI was inversely associated with total prostate cancer (RR = 0.64, 95% CI 0.51-0.78, BMI ≥ 30 vs. 21-22.9, ptrend <0.001) and with non-advanced and less aggressive tumors among men ≤ 65 years, whereas no association was seen among men >65 years. Adult waist circumference was weakly inversely associated with less aggressive disease. Childhood obesity was unclearly related to risk. Our study confirms tall men to be at increased risk of fatal and advanced prostate cancer. The influence of adiposity varies by prognostic disease subtype and by age. The relationship between body size and prostate cancer is complex. Body size changes progressively throughout life and consequent effects on prostate cancer risk may be associated with related changes in hormonal and metabolic pathways. This large prospective study examined potential associations between the risk of various prostate cancer subtypes and multiple anthropometric measures at different ages in men. Tallness was confirmed to be associated with an elevated risk of advanced prostate cancer, particularly fatal disease. The extent to which body weight influenced risk varied according to factors such as age and disease subtype.

Diabetes mellitus and the risk of prostate cancer: an update and cumulative meta-analysis

INTRODUCTION

To provide further insight into the association between type 2 diabetes mellitus (T2DM) and the pathophysiology of prostate cancer, we conducted an updated, detailed meta-analysis of 56 published case-control and cohort studies.

METHODS

MEDLINE and EMBASE were used to identify the literature published in April 2012 related to both diabetes mellitus and prostate cancer. A sensitivity analysis was performed, and potential confounding effects were investigated using a stratified meta-analysis. A cumulative meta-analysis was also carried out to evaluate the cumulative effect estimate over time.

RESULTS

A total of 24 case-control and 32 cohort studies with information on a total of ~8,000,000 subjects and ~140,000 individuals with prostatic cancer showed published estimates of the association between diabetes and prostate cancer malignancy. The pooled effect estimate revealed a relative risk (RR) of 0.88 (95% CI, 0.82-0.93). Interestingly, there was an increased trend for Asians (RR = 1.72, n = 7) but not Americans (RR = 0.82, n = 28) and Europeans (RR = 0.86, n = 21) regarding the association between diabetes mellitus and prostate cancer. The sensitivity analysis, excluding any one study, did not significantly change the pooled RR. The range for the pooled RR when one study was omitted was 0.84-0.89.

DISCUSSION

The findings of our meta-analysis provide strong evidence of an inverse association between diabetes and prostate cancer.

CONCLUSIONS

Further research should focus on limitations in the current literature and re-assess the relationship between diabetes and prostate cancer by analyzing the two different diabetes mellitus types separately.

Is the negative relationship between obesity and bone mineral content greater for older women?

Obesity and osteoporosis are two important body composition problems with increasing prevalences in aged populations. Traditionally, obesity has been regarded as being beneficial to bone health. However, the protective effect of obesity on osteoporosis has been questioned. In some recent studies, obesity, as defined by percentage body fat, was regarded as a risk factor for osteoporosis. The purpose of this study was to (1) evaluate the effect of waist circumference, a surrogate measure for abdominal obesity, on bone mineral content (BMC) and (2) examine whether the effect of waist circumference increases with advancing age. The study population is made up of women aged over 45 years who completed the body composition and bone mineral density examinations in the fifth Korea National Health and Nutrition Examination Survey in 2010. Subjects who take estrogen or are under medical treatment for osteoporosis were excluded. Stroke patients are also excluded. Femoral neck, total-hip, and whole-body BMC were measured by dual-energy X-ray absorptiometry. A total of 1,434 subjects were included in the analysis. Waist circumference was negatively associated with BMC in all tested regions after correction for weight, menopausal status, smoking, drinking, and exercise. In addition, the negative association between waist circumference and BMC in the femoral neck and total hip increases with age, after correction for confounding factors, showing an interaction effect between waist circumference and age on BMC. In conclusion, this study shows that the negative relationship between waist circumference and BMC in the femoral neck and total hip is greater for older women.

TCF7L2 type 2 diabetes risk variant, lifestyle factors, and incidence of prostate cancer

BACKGROUND

Variation in transcription factor 7-like 2 (TCF7L2), the strongest genetic risk factor for type 2 diabetes (T2D), may play a role in prostate cancer (PCa) depending on lifestyle factors. The aims of this study were to determine if TCF7L2 rs7903146 is associated with risk of PCa and if the association is modified by lifestyle factors independently of T2D status.

METHODS

We prospectively followed 8,558 men in the Malmö Diet and Cancer Study from baseline 1991-1996 until end of 2009. Cox regression models were used to assess the association between rs7903146 T2D-risk allele (T) and PCa. Effect modification by incident T2D status, fasting glucose levels, dietary, and lifestyle risk factors were tested.

RESULTS

During follow-up 855 incident PCa cases were registered. We observed a non-significant tendency for the TCF7L2 variant to associate with higher risk of PCa, which was unaffected by adjustment for incident T2D (HR = 1.24; 95% CI: 0.96, 1.60; P = 0.079) but more pronounced among subjects who developed T2D (HR = 1.91, 95% CI: 0.88, 4.14; P = 0.064). In a sub-sample of hyperglycemic men we observed an increased risk of PCa among T-allele carriers (HR = 2.72, 95% CI: 1.22, 6.04; P = 0.014; P(interaction)  = 0.056). T-allele carriers with higher number of lifestyle risk factors had an increased risk of PCa (P(interaction)  = 0.006).

CONCLUSIONS

We found no independent association between TCF7L2 rs7903146 and PCa risk. However, among hyperglycemic men we observed that the risk allele may increase risk of PCa. The association between rs7903146 and PCa risk may also be modified by lifestyle factors.

Lifetime body size and prostate cancer risk in a population-based case-control study in Sweden

PURPOSE

The role of body size in prostate cancer etiology is unclear and potentially varies by age and disease subtype. We investigated whether body size in childhood and adulthood, including adult weight change, is related to total, low-intermediate-risk, high-risk, and fatal prostate cancer.

METHODS

We used data on 1,499 incident prostate cancer cases and 1,118 population controls in Sweden. Body figure at age 10 was assessed by silhouette drawings. Adult body mass index (BMI) and weight change were based on self-reported height and weight between ages 20 and 70. We estimated odds ratios (ORs) with 95 % confidence intervals (CIs) by unconditional logistic regression.

RESULTS

Height was positively associated with prostate cancer. Overweight/obesity in childhood was associated with a 54 % increased risk of dying from prostate cancer compared to normal weight, whereas a 27 % lower risk was seen in men who were moderately thin (drawing 2) in childhood (P trend = 0.01). Using BMI <22.5 as a reference, we observed inverse associations between BMI 22.5 to <25 at age 20 and all prostate cancer subtypes (ORs in the range 0.72-0.82), and between mean adult BMI 25 to <27.5 and low-intermediate-risk disease (OR 0.75, 95 % CI 0.55-1.02). Moderate adult weight gain increased the risk of disease in men with low BMI at start and in short men.

CONCLUSIONS

Our comprehensive life-course approach revealed no convincing associations between anthropometric measures and prostate cancer risk. However, we found some leads that deserve further investigation, particularly for early-life body size. Our study highlights the importance of the time window of exposure in prostate cancer development.

Pleiotropy between genetic markers of obesity and risk of prostate cancer

BACKGROUND

To address inconsistent findings of obesity and prostate cancer risk, we analyzed the association between prostate cancer and genetic markers of obesity and metabolism.

METHODS

Analyses included 176,520 single-nucleotide polymorphisms (SNP) associated with 23 metabolic traits. We examined the association between SNPs and prostate cancer in 871 cases and 906 controls, including 427 high-grade cases with Gleason ≥ 7. Genetic risk scores (GRS) for body mass index (BMI) and waist-to-hip ratio (WHR) were also created by summing alleles associated with increasing BMI or WHR.

RESULTS

Prostate cancer was associated with five loci, including cyclin M2, with P values less than 1 × 10(-4). In addition, the WHR GRS was associated with high-grade prostate cancer versus controls [OR, 1.05; 95% confidence interval (CI), 1.00-1.11; P = 0.048] and high-grade prostate cancer versus low-grade prostate cancer (OR, 1.07; 95% CI, 1.01-1.13; P = 0.03). None of these findings exceeds the threshold for significance after correction for multiple testing.

CONCLUSIONS

Variants in genes known to be associated with metabolism and obesity may be associated with prostate cancer. We show evidence for pleiotropy between WHR GRS and prostate cancer grade. This finding is consistent with the function of several WHR genes and previously described relationships with cancer traits.

IMPACT

Limitations in standard obesity measures suggest alternative characterizations of obesity may be needed to understand the role of metabolic dysregulation in prostate cancer. The underlying genetics of WHR or other Metabochip SNPs, while not statistically significant beyond multiple testing thresholds within our sample size, support the metabolic hypothesis of prostate carcinogenesis and warrant further investigation in independent samples.

The use of bioelectrical impedance analysis for body composition in epidemiological studies

BACKGROUND/OBJECTIVES

Bioelectrical impedance analysis (BIA) is a relatively simple, inexpensive and non-invasive technique to measure body composition and is therefore suitable in field studies and larger surveys.

SUBJECTS/METHODS

We performed an overview of BIA-derived body fat percentages (BF%) from 55 published studies of healthy populations aged 6-80 years. In addition, the relationship between body mass index (BMI) and body composition is documented in the context of BIA as a good alternative to closely differentiate which composition of the body better relates to the risk of cardiovascular diseases (CVDs)and all-cause mortality.

RESULTS AND CONCLUSIONS

BIA-estimated percentage of BF varies greatly with population and age. BIA-estimated BF% is directly and closely related to various health outcomes such as CVDs, which is in contrast to BMI where both high and low BMIs are associated with increased risk of developing chronic diseases. Studies, among others using BIA, suggest that low BMI may reflect low muscle and high BMI fat mass (FM). BIA-derived lean and FM is directly associated with morbidity and mortality. To the contrary, BMI is rather of limited use for measuring BF% in epidemiological studies.

High dairy fat intake related to less central obesity: a male cohort study with 12 years' follow-up

OBJECTIVE

To study associations between dairy fat intake and development of central obesity.

DESIGN

A prospective population-based cohort study with two surveys 12 years apart.

SETTING

Nine municipalities selected from different parts of Sweden representing the rural areas in the country.

SUBJECTS

1782 men (farmers and non-farmers) aged 40-60 years at baseline participated in a baseline survey (participation rate 76%) and 1589 men participated at the follow-up. 116 men with central obesity at baseline were excluded from the analyses.

MAIN OUTCOME MEASURES

Central obesity at follow-up defined as waist hip ratio ≥ 1.

RESULTS

197 men (15%) developed central obesity during follow-up. A low intake of dairy fat at baseline (no butter and low fat milk and seldom/never whipping cream) was associated with a higher risk of developing central obesity (OR 1.53, 95% CI 1.05-2.24) and a high intake of dairy fat (butter as spread and high fat milk and whipping cream) was associated with a lower risk of central obesity (OR 0.52, 95% CI 0.33-0.83) as compared with medium intake (all other combinations of spread, milk, and cream) after adjustment for intake of fruit and vegetables, smoking, alcohol consumption, physical activity, age, education, and profession. The associations between dairy fat intake and central obesity were consistent across body mass index categories at baseline.

CONCLUSION

A high intake of dairy fat was associated with a lower risk of central obesity and a low dairy fat intake was associated with a higher risk of central obesity.

Why are diabetics at reduced risk for prostate cancer? A review of the epidemiologic evidence

A large body of epidemiologic evidence provides strong support for the notion that type-2 diabetics are at decreased risk for prostate cancer. In this review article, we summarize the epidemiologic literature that explores the role of diabetes mellitus and related biomarkers in prostate cancer risk and detection, in order to create a better understanding of the potential mechanisms that underlie this inverse association. The bulk of the data supporting this association comes from the USA, as evidence for this association is less consistent in many other regions of the world. The relationship between diabetes and prostate cancer is suspected to be causal due to evidence of decreasing prostate cancer risk with increasing diabetes duration and lack of evidence for any confounding of this association. Hypothesized mechanisms for decreased prostate cancer risk among diabetics include (1) decreased levels of hormones and other cancer-related growth factors among diabetics, (2) the impact of diabetes on detection-related factors, such as prostate size, circulating prostate-specific antigen (PSA), and health-care seeking behaviors, (3) protective effects of diabetes medications, and (4) a protective effect of diabetes-induced vascular damage in the prostate. The evidence for screening-related factors is compelling, as diabetics appear to have reduced PSA and lower levels of health-care seeking behavior compared with nondiabetics. Furthermore, the inverse association between diabetes and prostate cancer is much less apparent in populations that do not perform biopsies based on PSA levels and in studies restricted to biopsied individuals. The inverse association appears to be stronger for low-grade disease, as compared with high-grade (Gleason >7), which is consistent with the observation that among patients receiving biopsy or prostate cancer treatment, diabetics are more likely to have high-grade disease as compared to nondiabetics, potentially resulting in worse outcomes for diabetics. Epidemiological research has reveals a great deal regarding the relationship between diabetes and prostate cancer risk, but additional research is needed to further clarify the mechanisms underlying this inverse association.

Effect of metabolic syndrome and its components on prostate cancer risk: meta-analysis

BACKGROUND

Literature data examining the role of metabolic syndrome and its components in prostate cancer risk are limited and contradictory.

AIM

We did a meta-analysis of studies that evaluated the association between metabolic syndrome, its components, and risk of prostate cancer.

SUBJECTS AND METHODS

We conducted an electronic search for articles published through September 2012 without restrictions. Every included study was to report risk estimates with 95% confidence intervals for the association between metabolic syndrome and prostate cancer.

RESULTS

The final number of papers included in the meta-analysis was 14, all published in English, with 4728 prostate cancer cases. Metabolic syndrome was associated with a 12% increase in prostate cancer risk (p=0.231), that was lower in cohort studies (7 studies, RR=1.04, p=0.791) than other studies (RR=1.23, p=0.125). The association was significant in the 8 European studies (RR=1.30, p=0.034), but not in the 4 U.S. or 2 Asiatic studies. The risk estimates of prostate cancer for higher values of body mass index, dysglycemia or dyslipidemia (high triglycerides, low HDL-cholesterol) were not significant; on the contrary, hypertension and waist circumference >102 cm were associated with a significant 15% (p=0.035) and 56% (p=0.007) greater risk of prostate cancer, respectively.

CONCLUSIONS

Metabolic syndrome is weakly and non significantly associated with prostate cancer risk, but associations vary with geography. Among single components of the syndrome, hypertension and higher waist circumference are significantly associated with increased risk of prostate cancer.

Different measures of body weight as predictors of sickness absence

AIMS

Excessive weight is associated with increased sickness absence from work due to obesity-linked health problems. However, it is not known which obesity measure best predicts sickness absence. First, we aimed to compare body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) as predictors of sickness absence spells of various lengths. Second, we aimed to compare BMI based on self-reported and measured weight and height as a predictor of sickness absence to assess the validity of self-reported BMI.

METHODS

The participants were 5750 employees of the City of Helsinki, aged 40-60 years, who were followed up on average for 4.8 years using the employer's register. Sickness absence spells were classified as self-certified short (1-3 days), medically certified medium length (4-14 days), and long (>14 days) absence spells.

RESULTS

All measures of body weight predicted sickness absence. The relative rates of long sickness absence in the highest quintile as compared to the lowest quintile varied in women from 1.62 (95% CI 1.35-1.94) to 1.89 (95% CI 1.62-2.23) and in men from 1.40 (95% CI 0.76-2.59) to 2.33 (95% CI 1.32-4.11). Differences in the predictive power of BMI and WC were small: both were more strongly associated with sickness absence than WHR. Self-reported BMI performed equally well as measured BMI.

CONCLUSIONS

BMI - measured or self-reported - is a valid anthropometric indicator of body weight and predictor of obesity-associated health-risks. Its use is feasible for research purposes as well as for the assessment of weight-related risks to work ability.

Diabetes mellitus and risk of prostate cancer: an updated meta-analysis based on 12 case-control and 25 cohort studies

The association between diabetes and risk of prostate cancer has been investigated widely. However, study results remain inconsistent and contradictory. Using a meta-analytic approach, the present study explore the relationship incorporating more recent studies and provide more powerful evidence without the limitations of any individual study. Relevant studies were identified by searching Pubmed and the Cochrane Central Register of Controlled Trials through May 18, 2012. The strength of the relationship between diabetes mellitus and risk of prostate cancer was assessed using relative risk (RR). Either a fixed effects or random effects model was used to calculate the pooled RRs. Stratification analyses and sensitivity analyses were conducted, and publication bias was assessed by Egger's test and Begg's test. Twelve case-control studies involving 9,767 cases and 19,790 controls, and 25 cohort studies involving 118,825 cases were included. The person-years of follow-up ranged from 29,963 to 6,264,890 among included cohort studies. Diabetes was not significantly associated with incidence of prostate cancer in our analysis of case-control studies only (RR = 0.846, 95 % CI [0.710, 1.009]) or that of cohort studies only (RR = 0.925, 95 % CI [0.811, 1.054]). However, through subgroup analyses, statistically significant associations between diabetes and prostate cancer were found when considering population-based studies only (RR = 0.719, 95 % CI [0.637, 0.812]), cohort studies conducted in the United States (RR = 0.789, 95 % CI [0.727, 0.857]), and studies with follow-up of more than 5 years. Compared to risk of prostate cancer among people without diabetes, diabetic patients using insulin treatment experienced reduced incidence of prostate cancer in both case-control and cohort studies. The results suggest that diabetes mellitus is associated with decreased incidence of prostate cancer, specifically in the population of the United States. In addition, the time since onset of diabetes was positively associated with decreasing incidence of prostate cancer. The present conclusions should be considered carefully, however, and confirmed with further studies.

Association between biomarkers of obesity and risk of high-grade prostatic intraepithelial neoplasia and prostate cancer--evidence of effect modification by prostate size

Prostate enlargement is common with aging and obesity. We investigated the association between obesity and prostate cancer controlling for differential detection related to prostate enlargement. In an analysis of 500 men, we found body mass index, waist-hip ratio, and blood leptin levels were significantly associated with high-grade PC, but only among men without prostate enlargement. Leptin was also significantly associated with high-grade prostatic intraepithelial neoplasia (HGPIN) in the absence of prostate enlargement. Our results suggest obesity advances prostate carcinogenesis, and that detection biases at prostate biopsy may explain past inconsistencies in the association between obesity and PC.

Type 2 diabetes and risk of prostate cancer: a meta-analysis of observational studies

BACKGROUND

Emerging evidence suggests that diabetes may increase the risk of cancers. However, available evidence on prostate cancer is conflicting. We therefore examined the association between Type 2 diabetes and risk of prostate cancer by conducting a detailed meta-analysis of all studies published regarding this subject.

METHODS

PubMed database and bibliographies of retrieved articles were searched for epidemiological studies (published between 1970 and 2011), investigating the relationship between Type 2 diabetes and prostate cancer. Pooled risk ratio (RR) was calculated using random-effects model. Subgroup, sensitivity analysis and cumulative meta-analysis were also done.

RESULTS

Forty-five studies (29 cohort and 16 case-control studies) involving 8.1 million participants and 132 331 prostate cancer cases detected a significant inverse association between Type 2 diabetes and risk of prostate cancer (RR 0.86, 95% confidence interval (CI) 0.80-0.92). For cohort studies alone, the RR was 0.87 (95% CI 0.80-0.94), and for case-control studies alone, the RR was 0.85 (95% CI 0.74-0.96). Sensitivity analysis done by excluding one outlier further strengthened our negative association (RR 0.83, 95% CI 0.78-0.87). No evidence of publication bias was observed.

CONCLUSIONS

This meta-analysis provides strongest evidence supporting that Type 2 diabetes is significantly inversely associated with risk of developing prostate cancer.

Measures of birth size in relation to risk of prostate cancer: the Malmö Diet and Cancer Study, Sweden

There is some evidence that perinatal factors, specifically birth weight (BW), may be related to the onset of prostate cancer (PRCA). This case–control study, nested within the Malmö Diet and Cancer Cohort Study, used archived birth record data from 308 incident PRCA cases diagnosed between 1991 and 2005, and 637 age-matched controls among 4781 men born (1923–1945) in Malmö and Lund, Sweden. We applied conditional logistic regression to examine the birth size–PRCA association, including tumour subtypes, adjusting for perinatal and adult factors. Compared with controls, cases had a non-significantly higher mean BW and were more likely to have high (>4000 g) BW (21% v. 18%), but did not differ in other birth size measures, nor in mean adult body mass index . We observed a non-linear association between BW and PRCA risk. Compared with BWs between 3000 and 3500 g (reference), the fully adjusted odds ratios (OR, 95% CI) were 0.55 (0.33–0.91) for <3000 g, 0.86 (0.61–1.22) for 3500–4000 g and 0.98 (0.64–1.50) for >4000 g. Among men with aggressive tumours, the reduction in risk for those with BWs <3000 g (OR 0.26, 95% CI 0.09–0.72) was stronger than the rate of risk for PRCA overall. Crude risk estimates were minimally attenuated when adjusted for gestational age, maternal age, birth order and adult factors. Birth length, head circumference and placental weight were not associated with prostate cancer. Our results indicate a protective effect of lower BW on risk of total and aggressive prostate cancer, rather than any direct effect of larger birth size.

Obesity, body composition, and prostate cancer

Background

Established risk factors for prostate cancer have not translated to effective prevention or adjuvant care strategies. Several epidemiologic studies suggest greater body adiposity may be a modifiable risk factor for high-grade (Gleason 7, Gleason 8-10) prostate cancer and prostate cancer mortality. However, BMI only approximates body adiposity, and may be confounded by centralized fat deposition or lean body mass in older men. Our objective was to use bioelectric impedance analysis (BIA) to measure body composition and determine the association between prostate cancer and total body fat mass (FM) fat-free mass (FFM), and percent body fat (%BF), and which body composition measure mediated the association between BMI or waist circumference (WC) with prostate cancer.

Methods

The study used a multi-centered recruitment protocol targeting men scheduled for prostate biopsy. Men without prostate cancer at biopsy served as controls (n = 1057). Prostate cancer cases were classified as having Gleason 6 (n = 402), Gleason 7 (n = 272), or Gleason 8-10 (n = 135) cancer. BIA and body size measures were ascertained by trained staff prior to diagnosis, and clinical and comorbidity status were determined by chart review. Analyses utilized multivariable linear and logistic regression.

Results

Body size and composition measures were not significantly associated with low-grade (Gleason 6) prostate cancer. In contrast, BMI, WC, FM, and FFM were associated with an increased risk of Gleason 7 and Gleason 8-10 prostate cancer. Furthermore, BMI and WC were no longer associated with Gleason 8-10 (OR_BMI = 1.039 (1.000, 1.081), OR_WC = 1.016 (0.999, 1.033), continuous scales) with control for total body FFM (OR_BMI = 0.998 (0.946, 1.052), OR_WC = 0.995 (0.974, 1.017)). Furthermore, increasing FFM remained significantly associated with Gleason 7 (OR_FFM = 1.030 (1.008, 1.052)) and Gleason 8-10 (OR_FFM = 1.044 (1.014, 1.074)) after controlling for FM.

Conclusions

Our results suggest that associations between BMI and WC with high-grade prostate cancer are mediated through the measurement of total body FFM. It is unlikely that FFM causes prostate cancer, but instead provides a marker of testosterone or IGF1 activities involved with retaining lean mass as men age.

Body mass index and incidence of localized and advanced prostate cancer--a dose-response meta-analysis of prospective studies

BACKGROUND

The relationship between obesity and risk of prostate cancer (PCa) is unclear; however, etiologic heterogeneity by subtype of PCa (localized, advanced) related to obesity was suggested. Therefore, we conducted a dose-response meta-analysis of prospective studies to assess the association between body mass index (BMI) and risk of localized and advanced PCa.

MATERIALS AND METHODS

Relevant prospective studies were identified by a search of Medline and Embase databases to 03 October 2011. Twelve studies on localized PCa (1,033,009 men, 19,130 cases) and 13 on advanced PCa (1,080,790 men, 7067 cases) were identified. We carried out a dose-response meta-analysis using random-effects model.

RESULTS

For localized PCa, we observed an inverse linear relationship with BMI [Ptrend<0.001, relative risk (RR): 0.94 (95% confidence interval, 95% CI, 0.91-0.97) for every 5 kg/m2 increase]; there was no evidence of heterogeneity (Pheterogeneity=0.27). For advanced PCa, we observed a linear direct relationship with BMI (Ptrend=0.001, RR: 1.09 (95% CI 1.02-1.16) for every 5 kg/m2 increase); there was weak evidence of heterogeneity (Pheterogeneity=0.08). Omitting one study that contributed substantially to the heterogeneity yielded a pooled RR of 1.07 (95% CI 1.01-1.13) for every 5 kg/m2 increase (Pheterogeneity=0.26).

CONCLUSIONS

The quantitative summary of the accumulated evidence indicates that obesity may have a dual effect on PCa-a decreased risk for localized PCa and an increased risk for advanced PCa.

Global Igfbp1 deletion does not affect prostate cancer development in a c-Myc transgenic mouse model

Circulating insulin-like growth factor binding protein 1 (IGFBP1) levels vary in response to nutritional status, and pre-clinical studies suggest that elevated IGFBP1 may be protective against the development and progression of prostate cancer. We hypothesized that global deletion of Igfbp1 would accelerate the development of prostate cancer in a c-Myc transgenic mouse model. To test our hypothesis, c-Myc transgenic mice (Myc/BP-1 wild-type (WT)) were crossed and interbred with the Igfbp1 knockout mice (Myc/BP-1 KO). The animals were placed on a high-protein diet at weaning, weighed every 2 weeks, and euthanized at 16 weeks of age. Prostate histopathology was assessed and proliferation status was determined by Ki-67 and proliferating cell nuclear antigen analyses. IGF-related serum biomarkers and body composition were measured. No significant difference in the incidence of prostate cancer was observed between the Myc/BP-1 KO and the Myc/BP-1 WT mice (65 and 80% respectively, P=0.48). Proliferation was significantly decreased by 71% in prostate tissue of Myc/BP-1 KO mice compared with Myc/BP-1 WT mice. Myc/BP-1 KO mice exhibited a significant 6.7% increase in body weight relative to the Myc/BP-1 WT mice that was attributed to an increase in fat mass. Fasting insulin levels were higher in the Myc/BP-1 KO mice without any difference between the groups in fasting glucose concentrations. Thus, contrary to our hypothesis, global deletion of Igfbp1 in a c-Myc transgenic mouse model did not accelerate the development of prostate cancer. Global Igfbp1 deletion did result in a significant increase in body weight and body fat mass. Further studies are required to understand the underlying mechanisms for these metabolic effects.

Metabolic syndrome is associated with high grade Gleason score when prostate cancer is diagnosed on biopsy

BACKGROUND

To evaluate the association between metabolic syndrome (MS) and prostate cancer diagnosis and grade in patients undergoing prostate biopsy.

METHODS

From 2009 onwards, a consecutive series of patients undergoing 12-core prostate biopsy for PSA value ≥4 ng/ml and/or positive digital rectal examination (DRE) were prospectively enrolled. Body mass index (BMI), waist circumferences, and blood pressure were measured before the biopsy. Blood samples were tested for: PSA, fasting glucose, triglycerides, and cholesterol HDL. MS presence was defined according to Adult Treatment Panel III criteria.

RESULTS

One hundred ninety five patients were enrolled with a median age and PSA of 69 years and 5.6 ng/ml respectively. Median BMI was 27.6 kg/m(2) with 64 patients (33%) being classified as obese (BMI ≥ 30 kg/m(2) ). Eighty-six patients (44%) had MS. Eighty-three patients (43%) had cancer on biopsy; 37 (45%) with MS and 46 (55%) without (P = 0.48). PSA was independently associated with higher risk of cancer (OR 1.12/1 U PSA, P = 0.01). Out of 83 patients with prostate cancer, 42 (51%) had Gleason score 6 (12 (28.5%) presented a MS) and 41 (49%) a Gleason score ≥7 (25 (61%) presented a MS). The presence of MS was not associated with an increased risk prostate cancer (OR: 0.97, P = 0.94) but with an increased risk of Gleason ≥7 (OR: 3.82; P = 0.013).

CONCLUSIONS

In our single center study, MS is associated with an increased risk of high grade Gleason score when prostate cancer is diagnosed on biopsy. However, these results should be confirmed in a larger multicenter study. .

Adult stature, body proportions and age at menarche in the United States National Health and Nutrition Survey (NHANES) III

BACKGROUND

Previous studies have found that age at menarche is associated with stature, primarily via leg length. However, the effects appear to vary by population and/or time period. Improving socioeconomic conditions might amplify the association.

AIM

To test whether the association between early menarche and reduced stature in industrialized countries is mediated by leg length. To further test whether these effects are modified by years of education, as a proxy for socioeconomic conditions.

SUBJECTS AND METHODS

The study used data on from 3174 21-40 year-old women who participated in the third National Health and Nutrition Survey of the US (NHANES III). The anthropometric measurements employed were stature, sitting height and upper leg length. Leg length, lower leg length and ratio of sitting height to leg length were calculated.

RESULTS

Earlier menarche was associated with shorter stature, by ~ 3.9 mm per year of advancement, all of which was attributable to shorter leg length. Almost two-thirds of the effect was in the lower (distal) leg. Years of education did not significantly modify effects of pubertal timing on stature or body proportions.

CONCLUSION

Socioeconomic conditions might not explain variable associations between linear body proportions and pubertal timing.