The Impact of Diabetes on the Risk of Prostate Cancer Development according to Body Mass Index: A 10-year Nationwide Cohort Study

Causal effects of BMI, waist circumference, and body fat percentage on the risk of bladder cancer: A Mendelian randomization study

The causal role of body mass index (BMI) in bladder cancer (BC) by Mendelian randomization (MR) has not yet been reported. We evaluated the causal associations between the measures of obesity (BMI, waist circumference, and body fat percentage) and BC. We conducted a 2-sample MR analysis to assess the genetic effect of measures of obesity on BC. The BMI dataset (GWAS ID: ukb-b-2303) comprised 454,884 Europeans, and we identified 9,851,867 single nucleotide polymorphisms (SNPs). The waist circumference data (GWAS ID: ukb-b-9405) included 462,166 Europeans and 9,851,867 SNPs. The body fat percentage dataset (GWAS ID: ukb-a-264) contained data from 331,117 Europeans and 10,894,596 SNPs. For the outcome data, the GWAS ID was finn-b-C3_BLADDER, consisting of 1115 cases and 217,677 controls, with 16,380,466 SNPs. The inverse-variance weighted (IVW) model was used as the primary MR analysis. Cochran Q-statistic was used to identify heterogeneity between the SNPs. The MR-Egger and MR-PRESSO methods were employed to assess directional pleiotropy and outlier SNPs. We detected a decisive causal link between BMI and BC by the IVW analysis (odds ratio [OR] = 1.41, 95% confidence interval [CI]: 1.08-1.85, P = .011). The IVW analyses revealed a significant correlation between BC and waist circumference (OR = 1.55, 95% CI: 1.08-2.12, P = .016). However, the IVW method (OR = 1.49, 95% CI: 0.99-2.00, P = .05) did not report any statistical significance between body fat percentage and BC. We did not observe heterogeneity and directional pleiotropy in the 3 pairs of MR studies. The 2-sample MR analysis revealed a conceivable causal association between obesity (BMI, waist circumference) and BC.

Big Data Research in the Field of Endocrine Diseases Using the Korean National Health Information Database

The Korean National Health Information Database (NHID) contains big data combining information obtained from the National Health Insurance Service and health examinations. Data are provided in the form of a cohort, and the NHID can be used to conduct longitudinal studies and research on rare diseases. Moreover, data on the cause and date of death are provided by Statistics Korea. Research and publications based on the NHID have increased explosively in the field of endocrine disorders. However, because the data were not collected for research purposes, studies using the NHID have limitations, particularly the need for the operational definition of diseases. In this review, we describe the characteristics of the Korean NHID, operational definitions of endocrine diseases used for research, and an overview of recent studies in endocrinology using the Korean NHID.

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.

Body mass index and cancer risk in patients with type 2 diabetes: a dose-response meta-analysis of cohort studies

Although obesity has been associated with an increased cancer risk in the general population, the association in patients with type 2 diabetes (T2D) remains controversial. We conducted a dose-response meta-analysis of cohort studies of body mass index (BMI) and the risk of total and site-specific cancers in patients with T2D. A systematic literature search was conducted in PubMed, Scopus, and Medline until September 2020 for cohort studies on the association between BMI and cancer risk in patients with T2D. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random effects models. Ten prospective and three retrospective cohort studies (3,345,031 participants and 37,412 cases) were included in the meta-analysis. Each 5-unit increase in BMI (kg/m2) was associated with a 6% higher risk of total cancer (RR: 1.06, 95% CI 1.01, 1.10; I2 = 55.4%, n = 6), and with a 12% increased risk in the analysis of breast cancer (RR: 1.12, 95% CI 1.05, 1.20; I2 = 0%, n = 3). The pooled RRs showed no association with prostate cancer (RR: 1.02, 95% CI 0.92, 1.13; I2 = 64.6%, n = 4), pancreatic cancer (RR: 0.97, 95% CI 0.84, 1.11; I2 = 71%, n = 3), and colorectal cancer (RR: 1.05, 95% CI 0.98, 1.13; I2 = 65.9%, n = 2). There was no indication of nonlinearity for total cancer (Pnon-linearity = 0.99), however, there was evidence of a nonlinear association between BMI and breast cancer (Pnon-linearity = 0.004) with steeper increases in risk from a BMI around 35 and above respectively. Higher BMI was associated with a higher risk of total, and breast cancer but not with risk of other cancers, in patients with T2D, however, further studies are needed before firm conclusions can be drawn.

High Bodyweight Variability Increases Depression Risk in Patients With Type 2 Diabetes Mellitus: A Nationwide Cohort Study in Korea

Objectives: Although obesity is associated with increased risk for depression in patients with type 2 diabetes mellitus (DM), the relationship between body weight variability (BWV) and depression remains poorly studied. This study was to investigate the incidence of depression in patients with type 2 DM according to their BWV. Methods: Intraindividual variation in body weight were measured in the nationwide, population-based retrospective cohort of 540,293 patients with type 2 DM from the Korean national health insurance system between 2009 and 2010. The diagnoses of new-onset depression occurring until the end of 2017 were ascertained. Risk of new-onset depression was examined using multivariate-adjusted Cox proportional hazards regression analysis by BWV quartile. Results: 93,149 (17.2%) patients developed new-onset depression for the follow up. BWV was significantly associated with an increased risk of depression after adjusting for confounding factors. The highest BWV quartile group had a hazard ratio (HR) of 1.17 (95% CI 1.15-1.19) compared to the lowest BWV quartile group as a reference. Obese patients in the highest BWV quartile group showed 12% increased risk of depression (HR 1.12, 95% CI 1.09-1.15) while non-obese patients in the highest BWV quartile group showed 20% increased risk of depression (HR: 1.20, 95% CI: 1.17-1.23) compared to their respective lowest BWV quartile groups. Conclusion: A higher BWV was significantly associated with an increased risk of depression in patients with type 2 DM. Thus, BWV may serve as an indicator for early detection of depression in type 2 DM patients.

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.

Increased incidence of bladder cancer with metabolically unhealthy status: analysis from the National Health Checkup database in Korea

We assessed the association between metabolic health status and the incidence of bladder cancer using nationally representative data from the National Health Insurance System and National Health Checkups (NHC) databases in South Korea. Data for 11,781,768 men who participated in the NHC between 2009 and 2012 were analysed. The normal-weight and physically obese categories were defined as body mass indexes (BMI) < 25 and ≥25 kg/m², respectively. Metabolically obese was defined as the presence of ≥3 components of metabolic syndrome. The participants were stratified into metabolically healthy, normal-weight (MHNW); metabolically obese, normal-weight (MONW); metabolically healthy, obese (MHO); metabolically obese, obese (MOO). Multivariate-adjusted Cox regression analysis was conducted to examine the association between metabolic health status and the incidence of bladder cancer. The study participants included 17,777 men newly registered with bladder cancer. Analysis according to metabolic health status classification revealed a higher multivariable-adjusted hazard ratio in the MOO, MONW group than in the MHO group (1.307 [95% CI: 1.258–1.358], 1.183 [95% CI: 1.137–1.231] and 1.066 [95% CI: 1.017–1.119], respectively; hazard ratios given relative to MHNW group) We found an association between metabolic health status and the incidence of bladder cancer, with an increasing risk according to the number of metabolic health status components.

Dietary lipids and environmental xenobiotics as risk factors for prostate cancer: The role of cytochrome P450

Prostate cancer is one of the most common malignant neoplasms in men. Because of the increase in the number of cases as well as development of cancers resistant to conventional therapy, identification of the new molecular targets for the treatment and prevention is of great importance. For this purpose, many studies are aimed on revealing of molecular mechanisms of prostate cancer development. In this process, dietary lipids and environmental xenobiotics are largely involved and are considered as risk factors. A wide range of endogenous (cholesterol, polyunsaturated fatty acids, etc.) and exogenous (pollutants, drugs) compounds are metabolized in the human organism by cytochrome P450. From other hand, these compounds may alter cytochrome P450 expression levels, especially in prostate, which, in turn, affects cell metabolism. Cytochrome P450 is a member of signaling pathways, regulating cell cycle, apoptosis, invasion and adhesion. Hence, cytochrome P450 most probably plays the important role in initiation and progression of prostate cancer. Based on that, cytochrome P450 enzymes are considered as potential targets for the targeted therapy and prevention, and might serve as specific markers of malignant growth.

Association of body mass index with bladder cancer risk in men depends on abdominal obesity

PURPOSE

The previous epidemiological studies about the associations between obesity and bladder cancer risk have reported inconsistent results. Therefore, we analyzed whether the abdominal obesity effected on the risk of developing bladder cancer according to body mass index (BMI) using nationally representative data from the National Health Insurance System (NHIS).

PATIENTS AND METHODS

Among people who underwent at least one health examination from 2009 to 2012 in Korea, 11,823,876 men without a previous diagnosis of bladder cancer were followed up until December 2015. Multiple Cox regression analysis was conducted to determine the hazard ratio (HR) and 95% confidence interval (CI) for the association between bladder cancer and BMI or waist circumference (WC).

RESULTS

Significant upward trends in the risk of bladder cancer were observed with increasing BMI or WC according to the multivariate-adjusted model. However, the association between BMI and bladder cancer is influenced by the presence of abdominal obesity. In the group with WC < 90 cm, there was no significant change in the HRs for bladder cancer development beyond the reference BMI. In contrast, the HRs for bladder cancer showed statistically significant increase as the BMI increased beyond the reference BMI in the group with WC ≥ 90 cm.

CONCLUSION

This population-based study showed that increasing BMI and increasing WC were risk factors for developing bladder cancer in men, independent of confounding variables. However, there was a discrepancy in the trend of bladder cancer development according to BMI between the groups with abdominal obesity and without abdominal obesity.

Incidence of Prostate Cancer according to Metabolic Health Status: a Nationwide Cohort Study

BACKGROUND

We assessed the association between metabolic health status and incidence of prostate cancer using the National Health Check-ups (NHC) database of Korea.

METHODS

A total of 11,771,252 men who participated in the NHC between 2009 and 2012 and 56,552 men who were newly diagnosed with prostate cancer were analyzed. Normal-weight and obesity were defined as body mass index (BMI) < 25 kg/m² and ≥ 25 kg/m², respectively. Metabolic obesity was defined as the presence ≥ 3 components of the metabolic syndrome. Participants were stratified into 4 groups: metabolically healthy, normal-weight; metabolically obese, normal-weight (MONW); metabolically healthy, obese (MHO); and metabolically obese, obese. Multivariate Cox regression analysis was performed to examine the relationship between metabolic health status and incidence of prostate cancer.

RESULTS

During a mean 5.4 ± 1.1 years of follow-up, 56,552 patients were registered with a diagnosis of prostate cancer. When analyzed according to metabolic health status classification, the multivariable-adjusted hazard ratio (HR) was 1.143 for the MONW group, 1.097 for the MHO group, showing the HR for the MONW group was higher than that for the MHO group. As the number of metabolic syndrome components increased, HR increased significantly. When stratified based on BMI, metabolically obese patients showed significantly higher HR than metabolically healthy patients in all BMI groups.

CONCLUSION

This population-based nationwide study revealed an association between metabolic health status and the incidence of prostate cancer, and the risk increased according to the number of components of the metabolic syndrome.

Type 2 Diabetes in Neuroendocrine Tumors: Are Biguanides and Statins Part of the Solution?

CONTEXT

Biguanides and statins exert beneficial effects on various cancer types. Their precise effects and underlying molecular mechanisms are poorly understood.

MATERIALS AND METHODS

We analyzed the relationship between metabolic syndrome and histological, epidemiological, and prognosis variables in two cohorts of patients with neuroendocrine tumors (NETs): those with lung carcinoids (LCs; n = 81) and those with gastroenteropancreatic NET (GEP-NET; n = 100). Biguanide and statin antitumor effects were investigated by evaluating proliferation, migration, secretion, gene expression, and involved molecular pathways in BON1/QGP1 cell cultures.

RESULTS

Pleura invasion was higher (LCs group; P < 0.05) and tumor diameter tended to be increased (GEP-NET group) in patients with type 2 diabetes (T2DM) than in those without. Somatostatin and ghrelin systems mRNA levels differed in tumor tissue of patients with T2DM taking metformin or not. Biguanides decreased proliferation rate in BON1/QGP1 cells; the effects of statins on proliferation rate depended on the statin and cell types, and time. Specifically, only simvastatin and atorvastatin decreased proliferation in BON1 cells, whereas all statins decreased proliferation rate in QGP1 cells. Metformin and simvastatin decreased migration capacity in BON1 cells; biguanides decreased serotonin secretion in BON1 cells. Phenformin increased apoptosis in BON1/QGP1 cells; simvastatin increased apoptosis in QGP1 cells. These antitumor effects likely involved altered expression of key genes related to cancer aggressiveness.

CONCLUSION

A clear inhibitory effect of biguanides and statins was seen on NET-cell aggressiveness. Our results invite additional exploration of the potential therapeutic role of these drugs in treatment of patients with NETs.

Exposure to air pollution during preconceptional and prenatal periods and risk of hypertensive disorders of pregnancy: a retrospective cohort study in Seoul, Korea

Background

Previous studies suggested associations between prenatal exposure to air pollution and hypertensive disorders of pregnancy. We explored the associations between ambient concentrations of five major air pollutants during preconceptional and prenatal periods and three hypertensive disorders of pregnancy in Seoul, Korea, using a population-representative cohort.

Methods

We obtained heath and demographic data of pregnant women residing in Seoul for 2002–2013 from the Korean National Health Insurance Service–National Sample Cohort. For mother’s individual exposures to air pollution, we computed concentrations of particulate matter ≤10 μm in diameter (PM₁₀), nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂), and ozone (O₃) during 1, 3, 6, and 12 months to birth using regulatory monitoring data in Seoul. The associations between air pollution and hypertensive disorders were explored by using logistic regression models after adjusting for individual confounders.

Results

Among 18,835 pregnant women in Seoul, 0.6, 0.5, and 0.4% of women developed gestational hypertension, preeclampsia, and preeclampsia requiring magnesium sulfate (Mg-preeclampsia), respectively. Although most odds ratios (ORs) were not statistically significant, we found increasing risk gradients with disease severity depending on the pollutant. There was the association between PM₁₀ during 6 months to birth and gestational hypertension (OR for an interquartile range increase = 1.68 [95% confidence interval = 1.09–2.58]). NO₂ and ozone during 12 and 1 month, respectively, before birth were associated with Mg-preeclampsia (1.43 [1.01–2.03], 1.53 [1.03–2.27]).

Conclusions

We observed positive associations of exposure to some air pollutants before and during pregnancy with hypertensive disorders of pregnancy among the Korean general population. Future studies with refined exposure metrics should confirm our findings.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1982-z) contains supplementary material, which is available to authorized users.

Body mass index and cancer risk among Chinese patients with type 2 diabetes mellitus

Background

Obesity and diabetes are two risk factors for cancer. To evaluate the association of body mass index (BMI) with cancer risk in diabetic patients may improve current understanding of potential mechanisms.

Methods

A retrospective cohort study was conducted in 51,004 newly diagnosed T2DM patients derived from an electronic health record (EHR) database of Minhang district in Shanghai, China. Incident cancer cases and all-cause deaths occurred before September 30, 2015 were identified by linking with the Shanghai Cancer Registry and the Shanghai Vital Statistics. To examine the potential non-linear and linear relationships of BMI and cancer risk, Cox proportional hazard models with and without restricted cubic spline functions were used, respectively.

Results

A non-linear association was observed between BMI and overall cancer incidence in men younger than 60 years old (p for non-linearity = 0.009). Compared with those having BMI of 25.0 kg/m², the cancer risk increased in those with either lower or higher BMI. In women older than 60 years old, linear dose-response relationships were observed between BMI and the risk of both overall cancer and breast cancer. As each unit increase in BMI, the overall cancer risks elevated by 3% (95%CI: 1–5%) and the breast cancer risks increased by 7% (95%CI: 1–13%). No significant association was observed between BMI and other common cancer sites.

Conclusions

Our results show that the effect of BMI on cancer risk in Chinese patients with T2DM may vary by gender, age and cancer subtypes, suggesting different underlying biological mechanisms.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4675-0) contains supplementary material, which is available to authorized users.

Difference in prostate cancer incidence around sixty years: effects of age and metabolic diseases

We examined the risk of prostate cancer in the Korean population stratified on the basis of age group and risk based on metabolic diseases, using National Health Insurance System (NHIS) data. Of the 51,827,813 people from the NHIS data in 2015, 10,879,591 men without prostate cancer who underwent a health examination were analyzed. The risk of prostate cancer was analyzed with stratification by age. Multivariate-adjusted Cox regression analysis was conducted to examine the association between prostate cancer and metabolic diseases by age groups. The risk of prostate cancer increased continuously with age and 59 years may be a point of inflection. The hazard ratio (HR) of prostate cancer development rose sharply as that age point passed. The population with metabolic diseases was more likely to develop prostate cancer than the population without any of these components. In addition, the incidence rate ratio (IRR) decreased from the youngest age group to the age group comprising 55-59 year olds. Beyond this age group, there was a plateau. The relative risk for prostate cancer associated with metabolic diseases also showed divergent associations with age. The risk of prostate cancer increased continuously with age and the peak Youden index was at 59 years. The relative risk for prostate cancer according to metabolic diseases also showed divergent associations beyond 59 years of age. Therefore, setting the age threshold at 59 years would improve the present clinical risk stratification for prostate cancer in Korea.

Obesity and prostate cancer

PURPOSE OF REVIEW

To investigate the association between obesity and prostate cancer (PCa).

RECENT FINDINGS

Obesity has been proposed to be involved in the pathogenesis of PCa through different biological mechanisms that include deregulation of the insulin axis, sex hormone secretion, adipokines signaling, and oxidative stress. Hypertrophic peritumoral adipocytes may also facilitate the local spread of PCa through the chemo-attraction of tumor cells. Clinical studies demonstrate that obesity might have clinical implications also in disease detection and management. Obese men have been shown to be less likely to be diagnosed with early-stage disease. Moreover, they are at increased risk of experiencing upgrading and upstaging when managed with active surveillance. However, the association between obesity and the risk of PCa recurrence and mortality after radical treatment is still debated.

SUMMARY

Obesity may facilitate the development and progression of PCa trough different biologic mechanisms that may pose obese men at higher risk of advanced and high-grade disease. However, the association between obesity and long-term oncologic outcome after radical treatments appears unclear.

Estimating the impact of body mass index on bladder cancer risk: Stratification by smoking status

We estimated the impact of obesity on bladder cancer with stratification by smoking status using nationally representative data on the Korean population from the National Health Insurance System (NHIS). Of the 45,850,458 people who underwent at last one health examination from 2009 to 2012, 23,378,895 without bladder cancer were followed from the January 2009 to the December 2015. First, the HR for bladder cancer was lowest in people with a BMI < 18.5 (HR = 0.92) and highest for those with BMI ≥ 30 (HR = 1.17) in multiple Cox regression analyses. The positive association between bladder cancer and BMI showed an increasing trend beyond the reference BMI. Second, an analysis of HR for bladder cancer stratified by obesity across smoking status strata showed a significant trend of increasing HR for bladder cancer across obesity and smoking status in multivariate-adjusted models. Conclusively, this population-based study showed that increasing BMI was a risk factor for bladder cancer independent of confounding variables. When stratified by smoking status, there was still a positive association between bladder cancer and BMI (P for trend < 0.01).

Obesity Is Inversely Related to Hydrogen-Producing Small Intestinal Bacterial Overgrowth in Non-Constipation Irritable Bowel Syndrome

There have been inconsistent findings on the association of obesity and non-constipation irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) with hydrogen (H₂) gas forming-microflora causes non-constipation IBS. But, the effect of H₂ producing SIBO on obesity in non-constipation IBS patients has not been studied yet. The aim of this study was to investigate the association between obesity and SIBO in non-constipation IBS patients. We reviewed the charts of patients who showed IBS symptoms along with the documented results of their lactulose hydrogen breath test (LHBT) for SIBO. Multivariate models were used to assess the association between obesity and SIBO. Four-hundred fifty-eight patients were retrospectively included in the study. Of the 485 IBS patients, 158 (30.7%) subjects had positive results for LHBT. Subjects without SIBO showed significantly higher levels of body mass index (24.8 vs. 23.3; P < 0.001) and waist circumference (86.5 vs. 82.7; P < 0.001) as compared to subjects with SIBO. In multivariate analysis, the odds ratios of SIBO were 0.396 (P = 0.018) for obesity and 0.482 (P = 0.021) for abdominal obesity. This is the first human study to demonstrate that obesity is inversely related to SIBO with H₂ gas production in non-constipation IBS patients.