Evaluation of dietary, medical and lifestyle risk factors for incident kidney cancer in postmenopausal women

Effect of smoking, hypertension and lifestyle factors on kidney cancer - perspectives for prevention and screening programmes

Renal cell carcinoma (RCC) incidence has doubled over the past few decades. However, death rates have remained stable as the number of incidental renal mass diagnoses peaked. RCC has been recognized as a European health care issue, but to date, no screening programmes have been introduced. Well-known modifiable risk factors for RCC are smoking, obesity and hypertension. A direct association between cigarette consumption and increased RCC incidence and RCC-related death has been reported, but the underlying mechanistic pathways for this association are still unclear. Obesity is associated with an increased risk of RCC, but interestingly, improved survival outcomes have been reported in obese patients, a phenomenon known as the obesity paradox. Data on the association between other modifiable risk factors such as diet, dyslipidaemia and physical activity with RCC incidence are conflicting, and potential mechanisms underlying these associations remain to be elucidated.

Non-occupational physical activity and risk of cardiovascular disease, cancer and mortality outcomes: a dose-response meta-analysis of large prospective studies

OBJECTIVE

To estimate the dose-response associations between non-occupational physical activity and several chronic disease and mortality outcomes in the general adult population.

DESIGN

Systematic review and cohort-level dose-response meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science and reference lists of published studies.

ELIGIBILITY CRITERIA

Prospective cohort studies with (1) general population samples >10 000 adults, (2) ≥3 physical activity categories, and (3) risk measures and CIs for all-cause mortality or incident total cardiovascular disease, coronary heart disease, stroke, heart failure, total cancer and site-specific cancers (head and neck, myeloid leukaemia, myeloma, gastric cardia, lung, liver, endometrium, colon, breast, bladder, rectum, oesophagus, prostate, kidney).

RESULTS

196 articles were included, covering 94 cohorts with >30 million participants. The evidence base was largest for all-cause mortality (50 separate results; 163 415 543 person-years, 811 616 events), and incidence of cardiovascular disease (37 results; 28 884 209 person-years, 74 757 events) and cancer (31 results; 35 500 867 person-years, 185 870 events). In general, higher activity levels were associated with lower risk of all outcomes. Differences in risk were greater between 0 and 8.75 marginal metabolic equivalent of task-hours per week (mMET-hours/week) (equivalent to the recommended 150 min/week of moderate-to-vigorous aerobic physical activity), with smaller marginal differences in risk above this level to 17.5 mMET-hours/week, beyond which additional differences were small and uncertain. Associations were stronger for all-cause (relative risk (RR) at 8.75 mMET-hours/week: 0.69, 95% CI 0.65 to 0.73) and cardiovascular disease (RR at 8.75 mMET-hours/week: 0.71, 95% CI 0.66 to 0.77) mortality than for cancer mortality (RR at 8.75 mMET-hours/week: 0.85, 95% CI 0.81 to 0.89). If all insufficiently active individuals had achieved 8.75 mMET-hours/week, 15.7% (95% CI 13.1 to 18.2) of all premature deaths would have been averted.

CONCLUSIONS

Inverse non-linear dose-response associations suggest substantial protection against a range of chronic disease outcomes from small increases in non-occupational physical activity in inactive adults. PROSPERO registration number CRD42018095481.

Food groups and urologic cancers risk: a systematic review and meta-analysis of prospective studies

Background

To assess the association between 12 food groups intake and the risk of urologic cancers.

Methods

We scanned PubMed and Web of Science databases up to April 1st, 2023, and 73 publications met the inclusion criteria in the meta-analysis. We used a random effects model to estimate the summary risk ratios (RRs) and 95% confidence intervals (95% CI).

Results

In the linear dose-response meta-analysis, an inverse association was found between each additional daily 100 g of fruits [RR: 0.89, 95%CI = (0.83, 0.97)], 100 g of vegetables [RR: 0.92, 95%CI = (0.85, 0.99)], 12 g of alcohol [RR: 0.91, 95%CI = (0.88, 0.94)] and 1 cup of coffee [RR: 0.95, 95%CI = (0.83, 0.97)] intake and the risk of renal cell carcinoma. Conversely, each additional daily 100 g of red meat intake was positively associated with renal cell carcinoma [RR: 1.41, 95%CI = (1.03, 2.10)]. Inverse associations were observed between each additional daily 50 g of egg [RR: 0.73, 95%CI = (0.62, 0.87)] and each additional daily 1 cup of tea consumption and bladder cancer risk [RR: 0.97, 95%CI = (0.94, 0.99)]. There were no significant associations for nonlinear dose-response relationships between 12 food groups and urological cancers.

Conclusion

Our meta-analysis strengthens the evidence that appropriate intake of specific food groups, such as fruits, vegetables, alcohol, tea, and coffee, is associated with the risk of renal cell carcinoma or bladder cancer. More studies are required to fill the knowledge gap on the links between various food groups and urologic cancers because the evidence was less credible in this meta-analysis.

Systematic Review Registration

This study was registered on PROSPERO (CRD42022340336).

Can Diet Prevent Urological Cancers? An Update on Carotenoids as Chemopreventive Agents

Urological cancers, namely prostate, bladder, kidney, testicular, and penile cancers, are common conditions that constitute almost one-quarter of all malignant diseases in men. Urological cancers tend to affect older individuals, and their development is influenced by modifiable metabolic, behavioral, and environmental risk factors. Phytochemicals may have cancer-fighting properties and protect against cancer development, slow its spread, and reduce the risk of cancer deaths in humans. This paper aims to review the current literature in regard to the effects of carotenoids in reducing urological cancer risk.

LncRNA GAS5 rs145204276 Polymorphism Reduces Renal Cell Carcinoma Susceptibility in Southern Chinese Population

Objective

Methods

Results

Conclusions

Trace elements under the spotlight: A powerful nutritional tool in cancer

Cancer is the second leading cause of death worldwide. Research on the relationships between trace elements (TE) and the development of cancer or its prevention is a field that is gaining increasing relevance. This review provides an evaluation of the effects of TE (As, Al, B, Cd, Cr, Cu, F, I, Pb, Li, Mn, Hg, Mo, Ni, Se, Si, Sn, V and Zn) intake and supplementation in cancer risk and prevention, as well as their interactions with oncology treatments. Advancements in the knowledge of TE, their dietary interactions and their main food sources can provide patients with choices that will help them to improve their quality of life and therapy outcomes. This approach could open new opportunities for treatments based on the integration of conventional therapies (chemotherapy, radiotherapy, and immunotherapy) and dietary interventions that provide advanced personalized treatments.

Components of one-carbon metabolism and renal cell carcinoma: a systematic review and meta-analysis

PURPOSE

Little is known about the aetiology of renal cell carcinoma (RCC). Components of one-carbon (1C) metabolism, which are required for nucleotide synthesis and methylation reactions, may be related to risk of RCC but existing evidence is inconclusive. We conducted a systematic review and independent exposure-specific meta-analyses of dietary intake and circulating biomarkers of 1C metabolites and RCC risk.

METHODS

Medline and Embase databases were searched for observational studies investigating RCC or kidney cancer incidence or mortality in relation to components of 1C metabolism and 12 eligible articles were included in the meta-analyses. We used Bayesian meta-analyses to estimate summary relative risks (RRs) and 95% credible intervals (CrIs) comparing the highest versus lowest categories as well as the between-study heterogeneity.

RESULTS

We did not find convincing evidence of an association between any exposure (riboflavin, vitamin B6, folate, vitamin B12, methionine, homocysteine, choline, or betaine) and RCC risk. However, vitamin B6 biomarker status did have a protective (RR = 0.62) but imprecise (95% CrI 0.39-1.14) effect estimate and folate intake had a notable association as well (RR = 0.85, 95% CrI 0.71-1.01).

CONCLUSION

There was a lack of precision due largely to the low number of studies. Further investigation is warranted, especially for folate and vitamin B6, which had consistent suggestive evidence of a protective effect for both dietary intake and biomarker status. A unique strength of this review is the use of Bayesian meta-analyses which allowed for robust estimation of between-study heterogeneity.

The Role of Metabolic Factors in Renal Cancers

An increasing number of evidence indicates that metabolic factors may play an important role in the development and progression of certain types of cancers, including renal cell carcinoma (RCC). This tumour is the most common kidney cancer which accounts for approximately 3-5% of malignant tumours in adults. Numerous studies indicated that concomitant diseases, including diabetes mellitus (DM) and hypertension, as well as obesity, insulin resistance, and lipid disorders, may also influence the prognosis and cancer-specific overall survival. However, the results of studies concerning the impact of metabolic factors on RCC are controversial. It appears that obesity increases the risk of RCC development; however, it may be a favourable factor in terms of prognosis. Obesity is closely related to insulin resistance and the development of diabetes mellitus type 2 (DM2T) since the adipocytes in visceral tissue secrete substances responsible for insulin resistance, e.g., free fatty acids. Interactions between insulin and insulin-like growth factor (IGF) system appear to be of key importance in the development and progression of RCC; however, the exact role of insulin and IGFs in RCC pathophysiology remains elusive. Studies indicated that diabetes increased the risk of RCC, but it might not alter cancer-related survival. The risk associated with a lipid profile is most mysterious, as numerous studies provided conflicting results. Even though large studies unravelling pathomechanisms involved in cancer growth are required to finally establish the impact of metabolic factors on the development, progression, and prognosis of renal cancers, it seems that the monitoring of health conditions, such as diabetes, low body mass index (BMI), and lipid disorders is of high importance in clear-cell RCC.

Diabetes and kidney cancer risk among post-menopausal women: The Iowa women's health study

BACKGROUND

Many studies have reported a positive association between diabetes and kidney cancer. However, it is unclear whether diabetes is a risk factor for kidney cancer independent of other risk factors, such as obesity and hypertension. We comprehensively examined the association of diabetes and its duration with incident kidney cancer in the prospective cohort Iowa Women's Health Study (1986-2011).

METHODS

Diabetes status was self-reported at baseline (1986) and on five follow-up questionnaires. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of baseline and time-dependent diabetes with the risk of incident kidney cancer.

RESULTS

During the 25 years of follow-up, 245 cases of kidney cancer occurred among 36,975 post-menopausal women. In an age-adjusted model, there was a significant association between time-dependent diabetes and the risk of kidney cancer [HR (95% CI) = 1.76 (1.26, 1.45)]; the association was attenuated after multivariable adjustment for age, body mass index (BMI), waist-to-hip ratio (WHR), hypertension, physical activity, diuretic use, pack-years of smoking, alcohol intake, and total caloric intake [HR = 1.35 (0.94, 1.94)]. However, among non-obese women or women with a waist circumference less than 34.6 in., diabetes was significantly associated with kidney cancer risk: for time-dependent diabetes, HRs (95% CIs) were 1.82 (1.10, 3.00) among those with BMI < 30 kg/m² and 2.18 (1.08, 4.38) among those with a waist circumference <34.6 in..

CONCLUSIONS

Our results suggest that diabetes is associated with kidney cancer risk among non-obese post-menopausal women.

The Relationship Between Hormone Replacement Therapy and Risk of Kidney Cancer in Women: A Meta-Analysis

Results from the epidemiologic studies on the relationship between hormone replacement therapy (HRT) and the risk of kidney cancer in women were not completely consistent. This meta-analysis aimed to evaluate the relationship between HRT and risk of kidney cancer in women. We performed a meta-analysis of observational studies to assess this association. The PubMed and Embase databases were searched from their inception to January 29, 2020, to identify relevant studies that fit the pre-stated inclusion criteria; reference lists from the retrieved articles were also been reviewed. Relative risks (RRs) with corresponding 95% CIs were extracted and combined using random effects models. Furthermore, dose-response, sensitivity analyses, publication bias, and subgroup analysis by study design, regional location, and exposure assessment method were conducted. Thirteen articles involving 6 cohort studies and 8 case-control studies were included in our meta-analysis. Overall, 4194 women were diagnosed with kidney cancer among 648 107 participants. The pooled RR for kidney cancer was 1.08 (95% CI: 0.96-1.22) in those who were administered HRT compared to those who had not. Subgroup analysis indicated the overall result was not influenced by study type, regional location, or adjusted variables. Dose-response analysis showed a nonlinear relationship between HRT and kidney cancer (P = .0021) and the risk of kidney cancer decreased by 15% to 28% with 12 to 18 years of HRT use. No evidence of publication bias was found (P for Egger =.111). Our meta-analysis showed that HRT use is inversely associated with kidney cancer risk in a dose-dependent fashion.

Cancer-Specific Loss of Urocortin 3 in Human Renal Cancer

INTRODUCTION

The corticotropin-releasing hormone (CRH) system, its receptors corticotropin-releasing hormone receptor 1 (CRHR1) and 2 (CRHR2), and its corresponding binding protein corticotropin-releasing hormone-binding protein (CRHBP) as well as the urocortin proteins-structural homologues to CRH, which are included in this peptide family-have become interesting oncological targets recently. Carcinogenesis of various human tumors has been reported with an altered presence of members of this system. The aim of the present study was to examine the role of urocortin 3 (UCN3) in renal cell carcinoma (RCC).

METHODS

Therefore, tumoral tissues of 106 patients with RCC and available corresponding normal tissues were analyzed using qPCR for quantitative mRNA expression analysis. Tissue localization and protein signals of UCN3 in normal and tumoral renal specimens were evaluated using western blot and immunohistochemistry. In addition, correlation studies of UCN3 mRNA expression with clinicopathological parameters of patients with RCC and different histological subtypes were evaluated.

RESULTS

UCN3 mRNA was significantly downregulated in nearly all tumoral tissues (p = 7.92 × 10^-13). The same effect was observed at protein level using immunohistochemistry. Level of UCN3 mRNA expression was not directly correlated with clinicopathological parameters.

CONCLUSION

We report for the first time the significant downregulation of UCN3 in RCC. These results demonstrate a possible involvement of the CRH system and its significance in carcinogenesis of RCC.

Obesity, abdominal obesity and subsequent risk of kidney cancer: a cohort study of 23.3 million East Asians

Background

Limited evidence exists regarding associations between obesity and kidney cancer among Asians. We examined the associations between obesity measures and risk of kidney cancer.

Methods

We included 23,313,046 adults who underwent health examinations provided by the Korean National Health Insurance Service 2009–2012 and performed multivariable Cox proportional hazards regression analyses.

Results

During 5.4 years of follow-up, 18,036 cases of kidney cancer were recorded, and cumulative incidence was 0.12%. General and abdominal obesity were associated with 1.32-fold increased risk of kidney cancer compared with groups without either obesity status. Underweight individuals showed decreased adjusted hazard ratio (HR) for kidney cancer (0.76, 95% confidence interval: 0.68–0.85) compared to those with normal body mass index (BMI), while the HRs increased among individuals with BMI 23–24.9 kg/m² (1.23, 1.18–1.28), 25–29.9 kg/m² (1.41, 1.36–1.46) and ≥30 kg/m² (1.77, 1.65–1.90) (P for trend < 0.001). HRs of kidney cancer increased with increasing waist circumference (WC) (P for trend < 0.001). Compared to non-obese condition, the coexistence of general and abdominal obesity increased the HR (1.45, 1.40–1.50).

Conclusions

This study demonstrated positive associations of BMI and WC with kidney cancer risk. General and abdominal obesity may be risk factors of kidney cancer.

Association between blood pressure and risk of cancer development: a systematic review and meta-analysis of observational studies

With the exception of renal cell carcinoma, studies assessing the association between hypertension and other cancers are inconsistent. We conducted a meta-analysis to assess this evidence. We included observational studies investigating the association between any definition of hypertension or systolic and diastolic blood pressure and risk of any cancer, after searching PubMed until November 2017. We calculated summary relative risks (RR) and 95% confidence intervals (CI) using inverse-variance weighted random effects methods. A total of 148 eligible publications were identified out of 39,891 initially screened citations. Considering only evidence from 85 prospective studies, positive associations were observed between hypertension and kidney, colorectal and breast cancer. Positive associations between hypertension and risk of oesophageal adenocarcinoma and squamous cell carcinoma, liver and endometrial cancer were also observed, but the majority of studies did not perform comprehensive multivariable adjustments. Systolic and diastolic blood pressure were positively associated with risk of kidney cancer but not with other cancers. In addition to the previously well-described association between hypertension and risk of kidney cancer, the current meta-analysis suggested that hypertensive individuals may also be at higher risk of colorectal and breast cancer. However, careful interpretation is required as most meta-analyses included relatively small number of studies, several relative risks had weak or moderate magnitude and maybe affected by residual confounding.

The Association Between Ascorbate and the Hypoxia-Inducible Factors in Human Renal Cell Carcinoma Requires a Functional Von Hippel-Lindau Protein

Hypoxia-inducible transcription factors (HIFs) drive angiogenesis and cancer cell growth, contributing to an aggressive tumor phenotype. HIF-α protein levels and activity are controlled at the post-translational level by HIF hydroxylases. Hydroxylated HIF-α is recognized by the von Hippel Lindau (VHL) tumor suppressor and targeted for degradation. The HIF hydroxylases are members of the iron and 2-oxoglutarate-dependent dioxygenases, which require ascorbate as cofactor for activity. Clear cell renal cell carcinomas (ccRCC) harbor mutations in the VHL gene, whereas papillary RCC (pRCC) have a functional VHL. These natural occurring VHL variants in RCC enable the testing, in clinical samples, of the hypothesis that ascorbate modulates HIF-α levels through its role as a cofactor for the HIF hydroxylases. We measured ascorbate, HIF-1α, and HIF-2α protein and HIF downstream targets BNIP3, CA9, cyclin D1, GLUT1, and VEGF (combined to generate the HIF pathway score) in VHL-defective ccRCC (n = 73) and VHL-proficient pRCC human tumor tissue (n = 41). HIF and ascorbate levels were increased in ccRCC and pRCC tumors compared to matched renal cortex. HIF-1 and total HIF pathway activation scores were decreased with higher ascorbate in pRCC tumors (Spearman r = −0.38, p < 0.05 and r = −0.35, p < 0.05). This was not evident for ccRCC tumors. In mechanistic studies in vitro, ascorbate influenced HIF-1 activity in VHL-proficient, but not VHL-defective ccRCC cells. Our results indicate that ccRCC, which lacks a functional VHL, does not respond to ascorbate-mediated modulation of the HIF response. This contrasts with the demonstrated association between ascorbate content and the HIF pathway observed in pRCC and other tumors with a functional VHL. The results support a role for ascorbate as a modulator of HIF activity and tumor aggression in cancer types with a functional hypoxic response.

The association between BMI and kidney cancer risk: An updated dose-response meta-analysis in accordance with PRISMA guideline

OBJECTIVE

Obesity is considered as one of the risk factors of kidney cancer. However, the results are not consistent in reported original studies, as well as in published meta-analysis. This study aims to clarify the relationship between overweight/obesity and kidney cancer by an updated overall and dose-response meta-analysis.

METHODS

This meta-analysis was conducted in accordance with PRISMA guideline. Relevant studies were searched using PubMed, Embase, and Web of Science databases. The studies were limited to human cohort studies in English and Chinese language. Random-effect models and dose-response meta-analysis were used to synthesize the results. Subgroup analyses were also conducted based on the characteristics of participants.

RESULTS

Twenty-four cohort studies with 8,953,478 participants were included in our meta-analysis. Compared to the normal weight, the pooled RRs of kidney cancer was 1.35 (1.27-1.43) in overweight and 1.76 (1.61-1.91) in obese participants. An increased kidney cancer risk of 1.06 (1.05-1.06) for each 1 kg/m increase in BMI was showed in dose-response meta-analysis. No significant heterogeneity was found across studies with I = 39.4% for overweight, and I = 43.3% for obesity.

CONCLUSION

The overall and dose-response meta-analysis suggested that overweight/obesity increases the risk of kidney cancer both in men and women.

Renal cell carcinoma risk associated with lower intake of micronutrients

Kidney cancer incidence in African Americans (AA) is higher than among European Americans (EA); reasons for this disparity are not fully known. Dietary micronutrients may have a protective effect on renal cell carcinoma (RCC) development by inhibiting oxidative DNA damage and tumor growth. We evaluated whether any micronutrient associations differed by race in the US Kidney Cancer Study. 1142 EA and AA RCC cases and 1154 frequency‐matched controls were enrolled in a population‐based case‐control study between 2002 and 2007. Dietary micronutrient intake was derived from an interviewer‐administered diet history questionnaire. RCC risk associated with micronutrient intake was estimated using adjusted odds ratios from logistic regression comparing lower to highest quartiles of intake and sample weighting. Inverse associations with RCC risk were observed for α‐carotene, β‐carotene, lutein zeaxanthin, lycopene, vitamin A, folate, thiamin, vitamin C, α‐tocopherol, β‐tocopherol, γ‐tocopherol, and selenium. A trend for β‐cryptoxanthin was suggested among EA but not AA or the total sample (P‐interaction = .04). Otherwise, findings did not differ by race, gender, age, or smoking status. The increase in RCC risk associated with lower micronutrient intake is similar within AA and EA populations. A diet rich in sources of micronutrients found in fruits, vegetables, and nuts may help to reduce the overall risk of RCC.

Type 2 Diabetes in Relation to the Risk of Renal Cell Carcinoma Among Men and Women in Two Large Prospective Cohort Studies

OBJECTIVE

We assessed whether type 2 diabetes is associated with renal cell carcinoma (RCC), independent of key potential confounders, in two large prospective cohorts with biennially updated covariate data.

RESEARCH DESIGN AND METHODS

A total of 117,570 women from the Nurses' Health Study (NHS) and 48,866 men from the Health Professionals Follow-Up Study (HPFS) were followed from 1976 and 1986, respectively, through 2014. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs for associations between type 2 diabetes and pathology-confirmed RCC, overall and by stage, grade, and histologic subtype.

RESULTS

During 38 years of follow-up in the NHS, we confirmed 418 RCC case subjects, including 120 fatal cases. Over 28 years in the HPFS, we confirmed 302 RCC case subjects, including 87 fatal cases. Women with type 2 diabetes had a significantly increased risk of RCC compared with women without type 2 diabetes (multivariable HR 1.53; 95% CI 1.14-2.04), with some evidence that the association was stronger for ≤5 (HR 2.15; 95% CI 1.44-3.23) than >5 (HR 1.22; 95% CI 0.84-1.78) years' duration of type 2 diabetes (P_difference 0.03). Among men, type 2 diabetes was not associated with total RCC (HR 0.89; 95% CI 0.56-1.41) or with RCC defined by stage, grade, or subtype. Sample sizes for analyses by stage, grade, and subtype were limited.

CONCLUSIONS

We found that type 2 diabetes was independently associated with a greater risk of RCC in women but not in men.

Blood pressure and kidney cancer risk: meta-analysis of prospective studies

BACKGROUND

Globally, kidney cancer is the twelfth most common cancer, accounting for 337 860 cases recorded in 2012. By 2020, this number has been estimated to reach 412 929 or increase by 22%. Over the past few decades, a number of prospective studies have investigated the association between blood pressure (BP) and risk of kidney cancer, using either recorded BP levels or reported hypertension as the principal exposure variable. However, the relation of BP to kidney cancer remains incompletely understood, and the data on sex-specific differences in risk estimates have been inconsistent.

METHOD

PubMed and Web of Science databases were searched for studies assessing the association between BP and kidney cancer through July 2016. The summary relative risk with 95% confidence intervals was calculated using a random-effects model.

RESULT

A total of 18 prospective studies with 8097 kidney cancer cases from 3 628 479 participants were included in our meta-analysis. History of hypertension was associated with 67% increased risk of kidney cancer. Significant heterogeneity and evidence of publication bias were observed. However, the results remain unchanged after introducing the trim and fill method to correct the publication bias. Accordingly, each 10-mmHg increase in SBP and DBP was associated with 10 and 22% increased risk of kidney cancer.

CONCLUSION

Collectively, the present meta-analysis of 18 prospective studies provides further support for a positive association between hypertension and kidney cancer risk.

A posteriori dietary patterns and risk of pancreatic and renal cancers

Purpose

Dietary patterns have been used to explore the association between dietary factors and risk of pancreatic cancer (PC) and renal cancer (RC); however, the association remains unclear. The purpose of this paper is to comprehensively review these associations.

Design/methodology/approach

Pertinent studies published prior to March 2016 were systematically searched and retrieved through PubMed and Scopus databases. Adjusted risk estimates were derived by comparing the highest with the lowest categories of dietary pattern scores and were combined by using the fixed-effects model when no substantial heterogeneity was observed; otherwise, the random-effects model was used.

Findings

A total of nine studies, five for PC (including 2,059 cases and 41,774 participants/controls) and four for RC (with 1,327 cases and 53,007 participants/controls), were included in this meta-analysis. A decreased risk of PC was shown for the highest compared with the lowest categories of the healthy dietary pattern (OR = 0.72, 95 per cent CI = 0.51-0.94, random effects (p-value for heterogeneity = 0.004)), whereas no significant association with Western dietary was observed (OR = 1.16, 95 per cent CI = 0.87-1.44, fixed effects). In the overall analysis, a significant association was found between the healthy dietary pattern and reduced risk of RC (OR = 0.59, 95 per cent CI = 0.48-0.71, fixed effects (p-value for heterogeneity = 0.459)), whereas the Western pattern was positively associated with risk of RC (OR = 1.42, 95 per cent CI = 1.14-1.69, fixed effects). For both cancers, the reduced risk associated with the healthy pattern was restricted to case-control, but not cohort, studies. Furthermore, drinking pattern was significantly related to reduced risk of RC (OR = 0.68, 95 per cent CI = 0.42-0.94).

Originality/value

To the authors’ knowledge, the present study is the first English document to summarize systematically the findings from observational studies in response to this question whether a posteriori dietary patterns are associated with susceptibility to the risk of renal and ovarian cancers.

Alcohol consumption, variability in alcohol dehydrogenase genes and risk of renal cell carcinoma

Alcohol consumption has been associated inversely with renal cell carcinoma (RCC) risk; however, no study has examined effect modification by germline variation in alcohol-metabolizing genes. We investigated whether the association between alcohol intake and RCC risk is modulated by germline variants in alcohol dehydrogenase genes in a large case-control study. Data from 652 RCC cases and 1,366 non-cancer controls were analyzed. Alcohol intake was assessed using a standardized risk factor questionnaire. Three previously genotyped polymorphisms in ADH6 and ADH7 with the TaqMan assay were examined. Odds ratios (ORs) and 95% confidence interval (CI) were calculated using logistic regression, adjusting for covariates. Compared to non-drinkers, ever consumption of alcohol was associated with lower RCC risk (OR = 0.52, 95% CI = 0.42-0.65). Analysis with cubic spline regression curve showed a "J-shaped" relationship between alcohol drinks/day and RCC risk, such that there was no added benefit against RCC for consumption of more than two drinks/day. We observed effect modification by variation in rs1154454 (ADH7) (p_interaction  = 0.007); a per unit increase in alcohol drink/day was associated with 35% lower RCC risk among non-minor allele carriers, a 27% lower risk among those who carry one copy of the minor allele, but no association was observed among those with two copies of the minor allele. These findings indicate that alcohol consumption is associated with lower RCC risk. Consuming more than two drinks a day does not confer additional protection against RCC. The association between alcohol intake and RCC risk appears to be modulated by inter-individual germline variation in alcohol-metabolizing genes.

Associations between polymorphisms in the IL-4 gene and renal cell carcinoma in Chinese Han population

Renal cell carcinoma (RCC) is considered to be a kind of cytokine reactive tumor. The research has been suggested that the host immune system can regulate the clinical course of RCC. Therefore, cytokine gene polymorphisms in RCC patients were analyzed was necessary. Our study is purpose to analyzing the interleukin-4(IL-4) polymorphisms associated with RCC risk from Han Chinese population. IL-4 genetic polymorphisms were genotyped using Massarray technology from a total of 291RCC and 463 controls. Unconditional logistic regression analysis was performed to analyze their relationship with risk of RCC. A significant association was found between the rs2243250 “C” allel and decreased risk of RCC (OR=0.75, 95%CI=0.59-0.96, P=0.02). Stratified analysis based on the age, gender, smoking status, drinking status revealed no significant association with RCC in age>55, female, smoking and nodrinking. However, for age<55 group (rs2243250, rs2243267, rs2243270), male group (rs2243250), nonsmoking group (rs2227284), and drinking group (rs2243250, rs2227284, rs2243267, rs2243270) polymorphisms were found obviously associated with RCC. The haplotype analyses showed that the haplotype have a significant decreased risk of RCC in the rs2243250/rs2227284/rs2243267/rs2243270/rs2243283/rs2243289 (CGGACA) (Total, OR=0.73, 95%CI=0.54-0.98, P=0.034; Male, OR=0.59, 95%CI=0.39-0.90, P=0.014). Therefore, the present study suggests that IL-4 may be a candidate gene for assessing the risk of RCC.

Dietary inflammatory index and risk of renal cancer in the Iowa Women's Health Study

BACKGROUND

The association between inflammatory potential of diet and renal cancer risk has not been investigated.

METHODS

In this study, we explored the association between the dietary inflammatory index (DII) and risk of renal cancer in the Iowa Women's Health Study. From 1986 to 2011, 33,817 women initially recruited at 55-69 years of age were followed for incident renal cancers (n = 263). The DII was computed based on dietary intake assessed using a reproducible and valid 121-item food frequency questionnaire. Cox proportional hazards regression was used to estimate hazard ratios (HR) adjusting for age, body mass index, energy intake, smoking status, education, pack years of smoking, hypertension, and hormone replacement therapy.

RESULTS

Multivariable analyses revealed positive association between higher DII scores and renal cancer risk (HR for DII_continuous: 1.07 per unit increase in DII (corresponding to 10% change in the DII range in the current study); 95% CI 1.00, 1.15; HR for DII_tertile3vs1 = 1.52; 95% CI 1.09, 2.13). Stratified analyses produced slightly stronger associations between DII and renal cancer risk among women with BMI <30 kg/m² (HR_Tertile3vs1 = 1.57; 95% CI = 1.04, 2.36) and ever smokers (HR_tertile3vs1 = 2.35; 95% CI = 1.22, 4.55), although the corresponding interaction p values were not significant.

CONCLUSION

Pro-inflammatory diet, as indicated by higher DII scores, was associated with increased renal cancer risk.

Reduced risk of incident kidney cancer from walking and running

PURPOSE

This study aimed to test whether incident kidney cancer risk is associated with exercise energy expenditure (i.e., metabolic equivalents, 1 MET) when calculated from distance walked or run.

METHODS

Hazard ratios (HR) and 95% confidence intervals (95% CI) from Cox proportional hazard analyses of self-reported physician-diagnosed incident kidney cancer versus MET-hours per week in 91,820 subjects recruited between 1991 and 1993 (7.7 yr follow-up of 42,833 subjects) and between 1998 and 1999 (6.4 yr follow-up of 33,053 subjects) as part of the National Runners' Health Study and between 1998 and 1999 as part of the National Walkers' Health Study (5.7 yr follow-up of 15,934 subjects).

RESULTS

Fifty-two incident cancers were reported. Age- and sex-adjusted risk declined 1.9% per MET-hour per week run or walked (HR = 0.981, 95% CI = 0.964-0.997, P = 0.02). Compared with walking or running below guidelines levels (<7.5 MET·h·wk(-1)), the risk for incident kidney cancer was 61% lower for meeting the guidelines (HR = 0.39, 95% CI = 0.11-1.08, P = 0.07 for 7.5-12.5 MET·h·wk(-1)), 67% lower for exercising one to two times the recommended level (HR = 0.33; 95% CI = 0.15-0.72, P = 0.005 for 12.6-25.1 MET·h·wk(-1)), and 76.3% lower for exercising two times or more the recommended level (HR = 0.24, 95% CI = 0.11-0.52, P = 0.0005 for ≥ 25.2 MET·h·wk(-1)). Incident kidney cancer risk also increased in association with baseline body mass index (P = 0.002), smoking (P = 0.02), and hypertensive (P = 0.007) and diabetes medication use (P = 0.01); however, exercise-associated reductions in kidney cancer risk persisted for 12.6-25.1 MET·h·wk(-1) (HR = 0.35, P = 0.01) and ≥ 25.2 MET·h·wk(-1) (HR = 0.29, P = 0.004) vis-à-vis <7.5 MET·h·wk(-1) when also adjusted for body mass index, hypertension, diabetes, and pack-years smoked.

CONCLUSION

Running and walking may reduce incident kidney cancer risk independent of its other known risk factors.

Epidemiology of Renal Cell Carcinoma

The increasing incidence of RCC in most populations may in part be due to increasing numbers of incidentally detected cancers with new imaging methods. Further, the increase is not only limited to small local tumours but also includes more advanced tumours, which may to some part explain the still high mortality rates. The variation in incidence between populations may have several other explanations. Traditionally the starting point has included thoughts of environmental exposures, which so far have only in part explained the causes of RCC, by means of cigarette smoking and obesity, which may account for approximately 40% of cases in high-risk countries (Table 2). Further, the genetic variations may be of importance as a cause of the difference between populations. Continued research in RCC is needed with the knowledge that nearly 50% of patients die within 5 years after diagnosis. The further search for environmental exposures should take in account the knowledge that RCC consists of different types with specific genetic molecular characteristics. These genetic alterations have in some cases been suggested to be associated with specific exposures. Furthermore, there might exist a modulating effect of genetic polymorphisms among metabolic activation and detoxification enzymes. Hence, a further understanding of the genetic and molecular processes involved in RCC will hopefully give us a better knowledge how to analyse and interpret exposure associations that have importance for both initiation and progression of RCC.

The role of micronutrients in the risk of urinary tract cancer

Prostate, bladder and kidney cancers remain the most common urological malignancies worldwide, and the prevention and treatment of these diseases pose a challenge to clinicians. In recent decades, many studies have been conducted to assess the association between supplementation with selected vitamins and elements and urinary tract tumour initiation and development. Here, we review the relationship between vitamins A, B, D, and E, in addition to calcium, selenium, and zinc, and the risk of developing prostate, kidney and bladder cancer. A relatively consistent body of evidence suggests that large daily doses of calcium (> 2,000 mg/day) increase the risk of prostate cancer. Similarly, supplementation with 400 IU/day of vitamin E carries a significant risk of prostate cancer. However, there have been many conflicting results regarding the effect of these nutrients on kidney and bladder neoplasms. Moreover, the role of other compounds in urinary tract carcinogenesis needs further clarification.

Positive linear dose-response relationships, but no J-shaped relationship, between drinking habits and estimated glomerular filtration rate in middle-aged Japanese men

The relationship between drinking frequency and amount of alcohol consumption (i.e., drinking habits) and the risk of chronic kidney disease (CKD) remains unclear. We aimed to clarify either a linear or J-shaped dose-response relationship between drinking habits and estimated glomerular filtration rate (eGFR) as a biomarker for identifying individuals at high risk of CKD. In a large-scale cross-sectional study, 403 men and 121 women with an eGFR of 30-60 mL/min per 1.73 m(2) were defined as cases, and 1209 men and 363 women with ≥60 mL/min/1.73 m(2) were randomly extracted as controls (one case subject was matched with three control subjects, matched according to age and season of data collection). We calculated multivariate-adjusted CKD risk and the corresponding mean eGFR according to drinking habits. In men, negative and positive linear relationships with drinking habits were found for CKD risk and mean eGFR (p < 0.001 for all linear terms), respectively, but there were no corresponding J-shaped relationships (not significant for all quadratic terms). In regard to the mean eGFR, however, positive linear relationships were only shown in men in the highest eGFR quartile (p < 0.05 and p < 0.01 for drinking frequency and amount of alcohol consumption, respectively). In women, no association was found. Regarding each drinking habit, we found a positive linear dose-response relationship to eGFR in middle-aged men with an eGFR ≥30 mL/min/1.73 m(2).

Obesity and Kidney Cancer

Renal cell cancer (RCC) is the major type of kidney cancer with increasing incidence. Obesity is one of the well-established risk factors for RCC. Meta-analyses including multiple cohort and case-control studies have found a consistent positive association between obesity and RCC. The association appeared to be independent of other RCC risk factors including hypertension and has been often stronger in women, although a positive association has also been observed in men. Obesity has been largely measured as body mass index (BMI). Studies which evaluated other measures of obesity including waist circumference (WC), waist-to-hip ratio (WHR) as well as increase in weight have reported similar positive associations with RCC. Although the mechanisms by which obesity influences renal carcinogenesis have been under-explored, insulin resistance and certain growth factors including insulin-like growth factor (IGF-1), sex steroid hormones, and biochemical markers such as adiponectin may be involved. The positive association with obesity has been observed with the clear cell type of RCC, which is the major histological subtype. On the other hand, the association between obesity and RCC survival appears to be much more complex. An apparent inverse association between obesity at time of diagnosis and RCC survival has been observed in some studies' generating speculation of an "obesity paradox" hypothesis. However, this "paradox" may be due to reverse causation, selection bias, or other forms of bias rather than a true biological association.

Association of Vitamin E Intake with Reduced Risk of Kidney Cancer: A Meta-Analysis of Observational Studies

Background

Several observational studies suggested that vitamin E intake is related to the risk of kidney cancer; however, the results of published studies are inconsistent.

Material/Methods

A meta-analysis was performed to assess the relationship between vitamin E intake and the risk of kidney cancer by searching PubMed and Medline through August 2015. We computed pooled relative risks (RR) and 95%CI of kidney cancer for the highest versus lowest level of vitamin E intake.

Results

A total of 13 observational studies (7 case-control and 6 cohort) were included. The pooled RR (95%CI) of kidney cancer for the highest vs. the lowest level of vitamin E intake was 0.81 (0.69–0.94). In subgroup-analysis, this study found an inverse relationship between vitamin E intake and kidney cancer risk, which was not significantly modified by study design, study population, or sex distribution except in the cohort studies.

Conclusions

Results of the present study suggest an inverse relationship between vitamin E intake and kidney cancer risk. However, additional well designed cohort studies and randomized controlled trials that focus on the relationship between vitamin E intake and kidney cancer risk are needed.

Alcohol consumption and the risk of renal cancers in the European prospective investigation into cancer and nutrition (EPIC)

Epidemiologic studies have reported that moderate alcohol consumption is inversely associated with the risk of renal cancer. However, there is no information available on the associations in renal cancer subsites. From 1992 through to 2010, 477,325 men and women in the European Prospective Investigation into Cancer and Nutrition cohort were followed for incident renal cancers (n = 931). Baseline and lifetime alcohol consumption was assessed by country-specific, validated dietary questionnaires. Information on past alcohol consumption was collected by lifestyle questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated from Cox proportional hazard models. In multivariate analysis, total alcohol consumption at baseline was inversely associated with renal cancer; the HR and 95% CI for the increasing categories of total alcohol consumption at recruitment versus the light drinkers category were 0.78 (0.62-0.99), 0.82 (0.64-1.04), 0.70 (0.55-0.90), 0.91 (0.63-1.30), respectively, (ptrend  = 0.001). A similar relationship was observed for average lifetime alcohol consumption and for all renal cancer subsites combined or for renal parenchyma subsite. The trend was not observed in hypertensive individuals and not significant in smokers. In conclusion, moderate alcohol consumption was associated with a decreased risk of renal cancer.

CTLA-4 and CD28 genes' polymorphisms and renal cell carcinoma susceptibility in the Polish population--a prospective study

Polymorphisms in co-stimulatory genes are associated with susceptibility to several malignances such as breast cancer, cervical cancer and chronic lymphocytic leukemia, but have been scarcely investigated in renal cell cancer (RCC). A total of 310 RCC patients and 518 controls were genotyped for single-nucleotide polymorphisms (SNPs) in the CTLA-4 and CD28 genes: CTLA-4c.49A>G (rs231775), CTLA-4g.319C>T (rs5742909), CTLA-4g.*6230G>A (CT60; rs3087243), CTLA-4g.*10223G>T (Jo31; rs11571302), CD28c.17+3T>C (rs3116496) and CD28c.-1042G>A (rs3181098). The distribution of the alleles, genotypes and haplotypes in the CTLA-4 and CD28 genes were similar in the RCC patients and in the controls. However, among the patients with a clear cell RCC (CCRCC), the G allele carriers of CT60 and Jo31 SNPs were overrepresented, and the overrepresentation became significant for the carriers of CT60[G] allele in CCRCC patients with necrosis in the primary tumor (P = 0.046). The CTLA-4c.49A>G[A]/CTLA-4g.319C>T[C]/CT60[A]/Jo31[T]/CD28c.17+3T>C[T]/ CD28c.1042G>A[G] haplotype was associated with an approximately threefold increased risk of primary tumor necrosis in CCRCC patients (P corrected = 0.0000007) and with the advanced stage of disease (IV) (P corrected = 0.001). When stratified by gender, CD28c.-1042G>A[GG] genotype was more frequent in the female CCRCC patients compared with healthy women (P = 0.042). Polymorphisms in the CTLA-4 and CD28 genes, in particular considered together as haplotypes, were associated with increased risk of CCRCC, especially with necrosis and with the advanced stage of disease. The CD28c.-1042G>A SNP modulates the risk of CCRCC in women. These findings indicate that the associations of the CTLA-4 and CD28 polymorphisms with the risk of renal cancer are worth further study in a larger group of patients.

Association of hypertension and obesity with renal cell carcinoma risk: a report from the Shanghai Men's and Women's Health Studies

PURPOSE

Consistently reported associations between hypertension and obesity and renal cell carcinoma (RCC) risk have largely come from studies in Western populations. These associations were examined in a case-control study nested in the Shanghai Women's Health Study (SWHS, 1996-2000) and Shanghai Men's Health Study (SMHS, 2001-2006).

METHODS

Overall, 271 incident RCC cases (124 women, 147 men) were identified through 31 December 2011, and 2,693 controls were individually matched by sex, age, and calendar time at cohort enrollment, and menopausal status (for women). Participants completed a structured questionnaire by in-person interview at baseline, and conditional logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Self-reported hypertension was associated with a significant 40 % increased risk of RCC among women and men (95 % CI 1.1, 1.9). Body mass index (BMI), modeled continuously, was associated with an elevated risk of RCC among men, with an OR of 1.5 (95 % CI 1.1, 2.0) per 5 kg/m(2) increase in BMI, but not among women.

CONCLUSIONS

Hypertension is independently associated with risk of RCC among both women and men in Shanghai, while overweight and obesity appear to be associated with risk of RCC in Chinese men only.

Antioxidant micronutrients and the risk of renal cell carcinoma in the Women's Health Initiative cohort

BACKGROUND

Renal cell carcinoma (RCC) is the eighth leading cancer among women in incidence and commonly is diagnosed at a more advanced stage. Oxidative stress has been considered to play an important role in the pathogenesis of RCC. Various dietary micronutrients have antioxidant properties, including carotenoids and vitamins C and E; thus, diets rich in these nutrients have been evaluated in relation to RCC prevention. The objective of this study was to explore the correlation between antioxidant micronutrients and the risk of RCC.

METHODS

In total, 96,196 postmenopausal women who enrolled in the Women's Health Initiative (WHI) between 1993 and 1998 and were followed through July 2013 were included in this analysis. Dietary micronutrient intake was estimated from the baseline WHI food frequency questionnaire, and data on supplement use were collected using an interview-based inventory procedure. RCC cases were ascertained from follow-up surveys and were centrally adjudicated. The risks for RCC associated with intake of α-carotene, β-carotene, β-cryptoxanthin, lutein plus zeaxanthin, lycopene, vitamin C, and vitamin E were analyzed using Cox proportional hazards regression adjusted for confounders.

RESULTS

Two hundred forty women with RCC were identified during follow-up. Lycopene intake was inversely associated with RCC risk (P = .015); compared with the lowest quartile of lycopene intake, the highest quartile of intake was associated with a 39% lower risk of RCC (hazard ratio, 0.61; 95% confidence interval, 0.39-0.97). No other micronutrient was significantly associated with RCC risk.

CONCLUSIONS

The current results suggest that further investigation into the correlation between lycopene intake and the risk of RCC is warranted.

Vitamin E Intake and Risk of Renal Cell Carcinoma: A Meta-Analysis of 7 Case-Control Studies

OBJECTIVE

Vitamin E intake may reduce the risk of renal cell carcinoma, but the results were inconsistent. Hence, we conducted a meta-analysis to assess the association between dietary vitamin E intake and the risk of renal cell carcinoma.

METHODS

We searched PubMed to identify the relevant case-control studies up to June 2014. Reference lists of retrieved articles were also reviewed. Odds ratios and corresponding 95% confidence intervals were used to estimate the association between dietary vitamin E intake and the risk of renal cell carcinoma.

RESULTS

We identified 7 case-control studies regarding dietary vitamin E intake and risk of renal cell carcinoma, involving 5789 cases and 14866 controls. The odds ratio of renal cell carcinoma for the highest compared with the lowest dietary vitamin E intake was 0.75 (95% confidence interval: 0.59-0.91), and heterogeneity was observed across studies. The association between dietary vitamin E intake and the risk of renal cell carcinoma was not significantly differed by gender, but this association were inconsistent in the North American and European populations.

CONCLUSION

Our study provided a evidence that there was a significant inverse association of dietary vitamin E intake with risk of renal cell carcinoma. However, this finding was based on the case-control studies, more well-designed cohort studies are needed.

Physical activity and renal cell carcinoma among black and white Americans: a case-control study

Background

Renal cell carcinoma (RCC) has a higher incidence in blacks than in whites. Physical activity may influence the risk of renal cell cancer, but the evidence is inconsistent. No previous study has investigated this relationship in the black population.

Methods

We examined the association between self-reported physical activity at different ages and risk of RCC in a population based case-control study of 1217 cases (361 black, 856 white) and 1235 controls (523 black, 712 white) frequency-matched on age, race, and gender. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression.

Results

Among whites, increased risks of RCC were observed among participants reporting low levels of transportation-related activity in their 20’s (OR _{<1 hr/wk vs >7 hr/wk} (95% CI): 1.42 (1.10, 1.83)) and leisure time activity in their 50’s (OR _{<1 hr/wk vs >7 hr/wk} (95% CI): 1.49 (1.00, 2.20)). We found no association between physical activity and RCC risk among blacks.

Conclusion

Our results suggest that physical activity may be inversely associated with RCC risk in whites, but there was no evidence of such an association in blacks. As this is the first study evaluating the effect of physical activity on RCC risk among blacks, further investigations are needed to clarify the relationship in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-707) contains supplementary material, which is available to authorized users.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Hypertension and obesity and the risk of kidney cancer in 2 large cohorts of US men and women

Kidney cancer incidence is increasing globally. Reasons for this rise are unclear but could relate to obesity and hypertension. We analyzed longitudinal relationships between hypertension and obesity and kidney cancer incidence in 156 774 participants of the Women's Health Initiative clinical trials and observational studies over 10.8 years. In addition, we examined the effect of blood pressure (BP) on kidney cancer deaths for over 25 years among the 353 340 men screened for the Multiple Risk Factor Intervention Trial (MRFIT). In the Women's Health Initiative, systolic BP (SBP) was categorized in 6 groups from <120 to >160 mm Hg, and body mass index was categorized using standard criteria. In age-adjusted analyses, kidney cancer risk increased across SBP categories (P value for trend <0.0001) and body mass index categories (P value for trend <0.0001). In adjusted Cox proportional hazards models, both SBP levels and body mass index were predictors of kidney cancer. In the MRFIT sample, there were 906 deaths after an average of 25 years of follow-up attributed to kidney cancer among the 353 340 participants aged 35 to 57 years at screening. The risk of death from kidney cancer increased in a dose-response fashion with increasing SBP (hazard ratio, 1.87 for SBP>160 versus <120 mm Hg; 95% confidence interval, 1.38-2.53). Risk was increased among cigarette smokers. Further research is needed to determine the pathophysiologic basis of relationships between both higher BP and the risk of kidney cancer, and whether specific drug therapies for hypertension can reduce kidney cancer risk.

Genetic variations in microRNAs and the risk and survival of renal cell cancer

MicroRNAs (miRNAs) are a class of short non-coding, single-stranded RNAs, which perform posttranscriptional regulatory functions as tumor suppressors or oncogenes. Single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) genes are currently being identified for contributing to cancer risk, prognosis and survival. We investigated whether genetic variations of miRNAs were associated with the risk and prognosis of renal cell carcinoma (RCC). We genotyped four common miRNA SNPs (i.e. miR-146a rs2910164, miR-149 rs2292832, miR-196a2 rs11614913 and miR-499 rs3746444) to assess their associations with RCC risk in a two-stage case-control study (355 cases and 362 controls in discovery set, meanwhile 647 cases and 660 controls in validation set), as well as RCC survival in 311 patients. We found that the miR-196a2 SNP rs11614913 was associated with RCC susceptibility in recessive model [CC versus TT/TC, adjusted odds ratio = 0.65, 95% confidence interval (CI) = 0.52-0.83] and with survival of RCC in dominant model (TC/CC versus TT, adjusted hazard ratio = 0.40, 95% CI = 0.18-0.89). Meanwhile, the rs11614913 CC genotype was associated with the significantly decreased expression of miR-196a-5p in 26 renal cancer tissues (P = 0.018). Moreover, luciferase reporter assays revealed the potential effect of rs11614913 SNP on the binding of miR-196a-3p to its targets. These results suggested that the miR-196a2 rs11614913 may contribute to the genetic susceptibility and prognosis for RCC, which may act as a biomarker for RCC occurrence and prognosis.

Body mass index and risk of renal cell cancer: a dose-response meta-analysis of published cohort studies

Obesity is accepted as one of the major risk factors for renal cell cancer (RCC). However, conflicting results persist for the pooled risks based on the results from case-control and cohort studies combined, and the exact shape of the dose-response relationship has not been clearly defined yet. To help elucidate the role of obesity, PubMed and Embase databases were searched for published cohort studies on associations between body mass index (BMI) and risk of RCC. Random-effects models and dose-response meta-analyses were used to pool study results. Subgroup analyses were conducted by the available characteristics of studies and participants. Cohort studies (21) with 15,144 cases and 9,080,052 participants were identified. Compared to normal weight, the pooled relative risks and the corresponding 95% confidence intervals of RCC were 1.28(1.24-1.33) for preobesity and 1.77(1.68-1.87) for obesity, respectively. A nonlinear dose-response relationship was also found for RCC risk with BMI (p = 0.000), and the risk increased by 4% for each 1 kg/m(2) increment in BMI. There was no significant between-study heterogeneity among studies (I(2) = 35.6% for preobesity and I(2) = 44.2% for obesity, respectively). Subgroup analysis showed a basically consistent result with the overall analysis. These results suggest that increased BMI are associated with increased risk of RCC both for men and women.

Obesity and hypertension interact to increase risk of renal cell carcinoma in Iowa, USA

SUMMARY

Renal cell carcinoma (RCC) rates in the US have risen, along with those of obesity and hypertension. We investigated the interactive relationship with obesity and hypertension (HT) through a population-based case-control study of RCC in Iowa consisting of 406 cases and 2434 controls. Data on height and weight at various ages and history of HT were collected and interaction tested by log-likelihood ratio tests. After adjustment, both obesity and HT were independently and interactively associated with increased RCC risk. Hypertensive subjects, obese (BMI ≥ 30) at age 40 were 4.2 (CI: 2.38-6.53) times more likely to develop RCC as normotensive individuals of normal weight (BMI < 25). A similar interactive pattern was observed for obesity at age 60 (p = 0.02). Interaction with obesity was more evident in women (pinteraction = 0.04 age 40, pinteraction = 0.01 age 60). Our findings suggest that maintaining body weight and/or controlling HT are strategies for preventing RCC.:

Parity and kidney cancer risk: evidence from epidemiologic studies

BACKGROUND

Observational studies have reported conflicting results between parity and kidney cancer risk. To our knowledge, a comprehensive and quantitative assessment of the association between parity and kidney cancer has not been reported. Thus, we conducted a systematic review and dose-response meta-analysis of published epidemiologic studies to summarize the evidence of this association.

METHODS

Relevant published studies of parity and kidney cancer were identified using MEDLINE (PubMed) database through end of June 2013. Two authors independently assessed eligibility and extracted data. Six prospective and eight case-control studies reported relative risk (RR) estimates and 95% confidence intervals (CI) of kidney cancer associated with parity or parity number. Fixed- or random-effects models were used to estimate summary relative risk.

RESULTS

The summary relative risk of kidney cancer for the parity versus nulliparous was 1.23 (95% CI, 1.10-1.36; Q = 12.41; P = 0.413; I(2) = 3.3%). In addition, significant association was also found for the highest versus lowest parity number, with summary RR = 1.36 (95% CI, 1.19-1.56; Q = 8.24; P = 0.766; I(2) = 0%). In the dose-response analysis, the summary per one live birth relative risk was 1.08 (95% CI: 1.05-1.10; Q = 9.34; P = 0.500; I(2) = 0%), also indicating the positive effect of parity on kidney cancer risk. No evidence of publication bias and significant heterogeneity between subgroups was detected by meta-regression analyses.

CONCLUSIONS

In summary, findings from this meta-analysis suggest that ever parity and higher parity number is significantly associated with increased risk of kidney cancer.

IMPACT

The present results suggest a positive association between parity and kidney cancer risk.

Racial difference in histologic subtype of renal cell carcinoma

In the United States, renal cell carcinoma (RCC) has rapidly increased in incidence for over two decades. The most common histologic subtypes of RCC, clear cell, papillary, and chromophobe have distinct genetic and clinical characteristics; however, epidemiologic features of these subtypes have not been well characterized, particularly regarding any associations between race, disease subtypes, and recent incidence trends. Using data from the Surveillance, Epidemiology, and End Results (SEER) Program, we examined differences in the age-adjusted incidence rates and trends of RCC subtypes, including analysis focusing on racial differences. Incidence rates increased over time (2001-2009) for all three subtypes. However, the proportion of white cases with clear cell histology was higher than among blacks (50% vs. 31%, respectively), whereas black cases were more likely than white cases to have papillary RCC (23% vs. 9%, respectively). Moreover, papillary RCC incidence increased more rapidly for blacks than whites (P < 0.01) over this period. We also observed that increased incidence of papillary histology among blacks is not limited to the smallest size strata. We observed racial differences in proportionate incidence of RCC subtypes, which appear to be increasing over time; this novel finding motivates further etiologic, clinical, molecular, and genetic studies.

Diabetes mellitus and incidence and mortality of kidney cancer: a meta-analysis

BACKGROUND

Diabetes is associated with increased risk of a spectrum of cancers, but there are few meta-analyses on the association between diabetes and kidney cancer. We performed a meta-analysis of case-control studies and cohort studies to address the incidence and mortality of kidney cancer in diabetes.

METHODS

Studies were identified by searching PubMed database and manual assessment of the cited references in the retrieved articles. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were estimated using a random-effect model. Study quality was assessed using the Newcastle-Ottawa scale.

RESULTS

A total of 24 studies were included. We found that diabetes was significantly associated with increased risk of kidney cancer (RR=1.40, 95% CI=1.16 to 1.69), and the results were consistent between case-control and cohort studies. A slightly stronger positive relation was observed in women (RR=1.47, 95% CI=1.18 to 1.83) than in men (RR=1.28, 95% CI=1.10 to 1.48). Additional analyses indicated that the increased risk of kidney cancer was independent of alcohol consumption, body mass index (BMI)/obesity and smoking. However, there was no association between diabetes and mortality of kidney cancer (RR=1.12, 95% CI=0.99 to 1.20), without heterogeneity (P=0.419, I(2)=1.8%).

CONCLUSIONS

Diabetes mellitus may increase the risk of kidney cancer in both women and men.

Association of dyslipidemia with renal cell carcinoma: a 1∶2 matched case-control study

Abnormal serum lipid profiles are associated with the risk of some cancers, but the direction and magnitude of the association with renal cell carcinoma is unclear. We explore the relationship between serum lipids and renal cell carcinoma via a matched case-control study. A 1∶2-matched case-control study design was applied, where one renal cell carcinoma patient was matched to two non-renal-cell-carcinoma residents with respect to age (±0 year) and gender. Cases (n = 248) were inpatients with a primary diagnosis of renal cell carcinoma, confirmed by pathology after operations. Controls were sampled from a community survey database matched on age and gender with cases, 2 controls for each case. Stratified Cox proportional hazard regression analysis was used to obtain hazard ratios and corresponding 95% confidence intervals of lipids level and dyslipidemia for the risk of renal cell carcinoma. Elevated serum cholesterol (p<0.001), LDL cholesterol (p<0.001), and HDL cholesterol (p = 0.003) are associated with decreased hazard of renal cell carcinoma, adjusting for obesity, smoke, hypertension and diabetes. However, risk caused by hTG showed no statistical significance (p = 0.263). This study indicates that abnormal lipid profile influences the risk of renal cell carcinoma.

Metabolic factors associated with risk of renal cell carcinoma

Previous studies have shown that obesity and hypertension are associated with increased risk of renal cell carcinoma (RCC), but less is known about the association to other metabolic factors. In the Metabolic Syndrome and Cancer project (Me-Can) data on body mass index (BMI, kg/m2), blood pressure, and circulating levels of glucose, cholesterol, and triglycerides were collected from 560,388 men and women in cohorts from Norway, Austria, and Sweden. By use of Cox proportional hazard models, hazard ratios (HR) were calculated for separate and composite metabolic exposures. During a median follow-up of 10 years, 592 men and 263 women were diagnosed with RCC. Among men, we found an increased risk of RCC for BMI, highest vs. lowest quintile, (HR = 1.51, 95% CI 1.13–2.03), systolic blood pressure, (HR = 3.40, 95% CI 1.91–6.06), diastolic blood pressure, (HR = 3.33, 95% CI 1.85–5.99), glucose, (HR = 3.75, 95% CI 1.46–9.68), triglycerides, (HR = 1.79, 95% CI 1.00–3.21) and a composite score of these metabolic factors, (HR = 2.68, 95% CI 1.75–4.11). Among women we found an increased risk of RCC for BMI, highest vs. lowest quintile, (HR = 2.21, 95% CI 1.32–3.70) and the composite score, (HR = 2.29, 95% CI 1.12–4.68). High levels of the composite score were also associated with risk of death from RCC among both men and women. No multiplicative statistical or biological interactions between metabolic factors on risk of RCC were found. High levels of BMI, blood pressure, glucose and triglycerides among men and high BMI among women were associated with increased risk of RCC.

The association between physical activity and renal cancer: systematic review and meta-analysis

Background:

Physical activity may decrease renal cancer risk by reducing obesity, blood pressure, insulin resistance, and lipid peroxidation. Despite plausible biologic mechanisms linking increased physical activity to decreased risk for renal cancer, few epidemiologic studies have been able to report a clear inverse association between physical activity and renal cancer, and no meta-analysis is available on the topic.

Methods:

We searched the literature using PubMed and Web of Knowledge to identify published non-ecologic epidemiologic studies quantifying the relationship between physical activity and renal cancer risk in individuals without a cancer history. Following the PRISMA guidelines, we conducted a systematic review and meta-analysis, including information from 19 studies based on a total of 2 327 322 subjects and 10 756 cases. The methodologic quality of the studies was examined using a comprehensive scoring system.

Results:

Comparing high vs low levels of physical activity, we observed an inverse association between physical activity and renal cancer risk (summary relative risk (RR) from random-effects meta-analysis=0.88; 95% confidence interval (CI)=0.79–0.97). Summarising risk estimates from high-quality studies strengthened the inverse association between physical activity and renal cancer risk (RR=0.78; 95% CI=0.66–0.92). Effect modification by adiposity, hypertension, type 2 diabetes, smoking, gender, or geographic region was not observed.

Conclusion:

Our comprehensive meta-analysis provides strong support for an inverse relation of physical activity to renal cancer risk. Future high-quality studies are required to discern which specific types, intensities, frequencies, and durations of physical activity are needed for renal cancer risk reduction.

The epidemiology and risk factors for renal cancer

BACKGROUND

Renal cancer is a frequently occurring malignancy with over 270,000 new cases diagnosed and it being responsible for 110,000 deaths annually on a global basis. Incidence rates have gradually increased whilst mortality rates are starting to plateau.

OBJECTIVE

To review epidemiology and risk factors for renal cancer.

METHODS

The current data is based on a thorough review of available original and review articles on epidemiology and risk factors for renal cancer with a systemic literature search utilising Medline.

RESULTS

The prevalence of associated risk factors such as genetic susceptibility, smoking, hypertension and obesity are changing and could account for the changes in incidence whilst the role of diet and occupational exposure to carcinogens requires further investigation.

CONCLUSION

Despite the evidence of various associated risk factors, further work is required from well designed studies to gain a greater understanding of the etiology of renal cancer.