Diet, obesity and risk for renal cell carcinoma: results from a case control-study in Germany

The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies

BACKGROUND

Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. We aimed to summarize evidence associating dietary factors with RCC incidence and assess the strength and validity of this evidence.

METHODS

We conducted an umbrella review of systematic reviews or meta-analyses (SRoMAs) that assessed the association between diet and RCC incidence. Through April 2021, PubMed, Web of Science, Embase, The Cochrane Library, Scopus, and WCRF were searched. Two independent reviewers selected studies, extracted data, and appraised the quality of SRoMAs. According to credibility assessment criteria, evidence can be divided into five categories: convincing (class I), highly suggestive (class II), suggestive (class III), weak (class IV), and nonsignificant (class V).

RESULTS

Twenty-nine meta-analyses were obtained after screening. After excluding 7 overlapping meta-analyses, 22 meta-analyses including 502 individual studies and 64 summary hazard ratios for RCC incidence were included: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15), and micronutrients (n =19). No meta-analyses had high methodological quality. Five meta-analyses exhibited small study effects; one meta-analysis showed evidence of excess significance bias. No dietary factors showed convincing or highly suggestive evidence of association with RCC in the overall analysis. Two protective factors had suggestive evidence (vegetables (0.74, 95% confidence interval 0.63 to 0.86) and vitamin C (0.77, 0.66 to 0.90)) in overall analysis. One protective factor had convincing evidence (moderate drinking (0.77, 0.70 to 0.84)) in Europe and North America and one protective factor had highly suggestive evidence (cruciferous vegetables (0.78, 0.70 to 0.86)) in North America.

CONCLUSIONS

Although many meta-analyses have assessed associations between dietary factors and RCC, no high-quality evidence exists (classes I and II) in the overall analysis. Increased intake of vegetables and vitamin C is negatively associated with RCC risk. Moderate drinking might be beneficial for Europeans and North Americans, and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution. More researches are needed in the future.

TRIAL REGISTRATION

PROSPERO CRD42021246619.

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.

Consumption of fruits and vegetables and risk of renal cell carcinoma: a meta-analysis of observational studies

Background

There have been inconsistent results about the association between consumption of fruits and vegetables and renal cell carcinoma (RCC) risk. We conducted a meta-analysis of the published observational studies to explore this association.

Results

Nineteen observational studies (4 cohort, 1 pooled and 14 case-control studies), involving 10,215 subjects with RCC were part of this meta-analysis. The SRR for the highest vs. the lowest intake of vegetables was 0.73 (95% CI: 0.63–0.85; P_{heterogeneity} = 0.004, I² = 53.5%), whereas for fruits it was 0.86 (95% CI: 0.75–0.98; P_{heterogeneity} = 0.012, I² = 47.4%). Linear dose-response analysis also showed similar results, e.g., for per 1 serving/day increment of vegetables, the SRR was 0.90 (95% CI: 0.84–0.96) and for fruits it was 0.97 (95% CI: 0.93–1.01). Nonlinear association was only observed for vegetables (P_nonlinearity = 0.001), but not for fruits (P_nonlinearity = 0.221).

Materials and Methods

Eligible studies up to August 31, 2016 were identified and retrieved by searching MEDLINE and EMBASE databases along with manual review of the reference list from the retrieved studies. Quality of included studies was evaluated using Newcastle-Ottawa Quality Assessment Scale (NOS). Random-effects model was used to calculate summary relative risk (SRR) and corresponding 95% confidence interval (CI).

Conclusions

This meta-analysis indicated a protective effect of consumption of vegetables and fruits on RCC risk. Further studies are warranted with prospective designs that use validated questionnaires and control for important confounders.

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.

Vitamin C intake and risk of renal cell carcinoma: a meta-analysis

Studies have showed that vitamin C intake is linked to renal cell carcinoma risk, however, the results were inconsistent. Hence, the present meta-analysis was to examine the association between vitamin C intake and RCC risk. We searched the published studies that reported the relationship between vitamin C intake and RCC risk using PubMed and Embase up to January 2015. Based on a fixed effects model, RR and the corresponding 95% CI were used to assess the pooled risk. 3 prospective cohort studies and 7 case-control studies were included. The overall RR (95% CI) of RCC for the highest vs. the lowest levels of vitamin C intake was 0.78(0.69,0.87). Little evidence of heterogeneity was found. In the subgroup analyses, we found an inverse association between vitamin C intake and RCC risk in the case-control studies but not in the prospective cohort studies. Additionally, this association between vitamin C intake and RCC risk was not differed by population distribution. Our study provides evidence that vitamin C intake is associated with a reduced RCC risk. However, our conclusion was just based on ten including studies, so more high-quality of case-control studies or cohort studies which report this topic are needed.

The association between fish consumption and risk of renal cancer: a meta-analysis of observational studies

Background

Several case-control studies and cohort studies have investigated the association between fish intake and renal cancer risk, however, they yielded conflicting results. To our knowledge, a comprehensive assessment of the association between fish consumption and risk of renal cancer has not been reported. Hence, we conducted a systematic literature search and meta-analysis to quantify the association between fish consumption and renal cancer.

Methods

A systematic search was performed using the PubMed, Embase, and Cochrane Library Central database for case-control and cohort studies that assessed fish intake and risk of renal cancer. Two authors independently assessed eligibility and extracted data. Fixed-effect and random-effect models were used to estimate summary relative risks (RR) and the corresponding 95% confidence intervals (CIs). Subgroup analyses, sensitivity analysis and cumulative meta-analysis were also performed.

Results

A total of 12 case-control studies and three cohort studies published between 1990 and 2011 were included in the meta-analysis, involving 9,324 renal cancer cases and 608,753 participants. Meta-analysis showed that fish consumption did not significantly affect the risk of renal cancer (RR=0.99, 95% CI [0.92,1.07]). In our subgroup analyses, the results were not substantially affected by study design, region, gender, and confounder adjustments. Furthermore, sensitivity analysis confirmed the stability of results.

Conclusions

The present meta-analysis suggested that there was no significant association between fish consumption and risk of renal cancer. More in-depth studies are warranted to report more detailed results, including stratified results by fish type, preparation method, and gender.

Alcohol intake and renal cell cancer risk: a meta-analysis

BACKGROUND

An inverse association between alcoholic beverage intake and risk of renal cell cancer has been suggested in recent studies.

METHODS

We examined the association between alcoholic beverages and renal cell cancer risk in a meta-analysis. We identified relevant studies by searching the database of PubMed, EMBASE, and MEDLINE published through August 2011. We combined the study-specific relative risks (RRs) using a random-effects model.

RESULTS

A total of 20 case-control studies, 3 cohort studies, and 1 pooled analysis of cohort studies were included in the meta-analysis. We observed that alcoholic beverage intake was associated with a lower risk of renal cell cancer in combined analysis of case-control and cohort studies; for total alcoholic beverage intake, combined RRs (95% confidence intervals) comparing top with bottom categories were 0.76 (0.68-0.85) in case-control studies, and 0.71 (0.63-0.78) in cohort studies (P for difference by study design=0.02). The inverse associations were observed for both men and women and for each specific type alcoholic beverage (beer, wine, and liquor). Also, we found that one drink per day of alcoholic beverage conferred the reduction in renal cell cancer risk, but further drinking above that level did not add benefit.

CONCLUSION

The findings from our meta-analysis support the hypothesis that alcoholic beverage intake is inversely associated with a lower risk of renal cell cancer, with moderate consumption conferring the protection and higher consumption conferring no additional benefits.

Fruit, vegetables, fibre and micronutrients and risk of US renal cell carcinoma

The association between renal cell cancer (RCC) and intake of fruit, vegetables and nutrients was examined in a population-based case-control study of 323 cases and 1827 controls; dietary intake was obtained using a mailed questionnaire. Cancer risks were estimated by OR and 95 % CI, adjusting for age, sex, smoking, obesity, hypertension, proxy status, alcohol consumption and dietary fat intake and energy. Intake of vegetables was associated with a decreased risk of RCC (OR 0·5; 95 % CI 0·3, 0·7; P trend = 0·002), (top compared to the bottom quartile of intake). When intake of individual nutrients was investigated, vegetable fibre intake was associated with decreased risks (OR 0·4; 95 % CI 0·2, 0·6; P < 0·001), but this was not the case with fruit fibre (OR 0·7; 95 % CI 0·4, 1·1) or grain fibre (OR 1·0; 95 % CI 0·6, 1·5). β-Cryptoxanthin and lycopene were also associated with decreased risks, but when both were included in a mutually adjusted backwards stepwise regression model, only β-cryptoxanthin remained significant (OR 0·5; 95 % CI 0·3, 0·8). When other micronutrients and types of fibre were investigated together, only vegetable fibre and β-cryptoxanthin had significant trends (P < 0·01) (OR 0·6; 95 % CI 0·3, 0·9) (OR 0·5; 95 % CI 0·3, 0·9), respectively. These findings were stronger in those aged over 65 years (P interaction = 0·001). Among non-smokers, low intake of cruciferous vegetables and fruit fibre was also associated with increased risk of RCC (P interaction = 0·03); similar inverse associations were found for β-cryptoxanthin, lycopene and vitamin C. When nutrients were mutually adjusted by backwards regression in these subgroups, only β-cryptoxanthin remained associated with lower RCC risk. These findings deserve further investigation in ongoing prospective studies when sample size becomes sufficient.

Investigations on the diagnosis and retroviral aetiology of renal neoplasia in budgerigars (Melopsittacus undulatus)

The high susceptibility of budgerigars (Melopsittacus undulatus) to neoplasia, and specifically renal neoplasia, has often been reported. Further investigations led to a suspicion of a retrovirus as the causative agent for renal neoplasia in budgerigars, but definitive proof has yet to be found. In the present study, 32 budgerigars suspected of having renal neoplasia (based on the clinical presentation) were examined. The objectives were to investigate the use of different diagnostic methods for the ante-mortem diagnosis of this condition and to find more supporting evidence of a retroviral aetiology. The predominant clinical signs observed in budgerigars with renal neoplasia were lameness and absence of deep pain sensation of one leg. Alterations in haematology, plasma chemistry, and urine analyses could not pinpoint the cases of renal neoplasia. Contrast radiography of the intestinal tract proved to be diagnostically more useful compared with plain radiographic studies. Histology confirmed the renal neoplasia as adenocarcinoma. Investigations for virus identification included product-enhanced reverse transcriptase assay and enzyme-linked immunosorbent assay for the detection of avian leucosis virus group-specific antigen. Cell cultures and electron microscopy were performed on a limited number of patients. These investigations could find no presence of an exogenous, replicating retrovirus, neither could viral particles be detected by electron microscopy. Based on the current findings, it can be concluded that there is no evidence of retroviral involvement in the occurrence of renal neoplasia in budgerigars.

No association between fruit, vegetables, antioxidant nutrients and risk of renal cell carcinoma

Previous epidemiologic studies that have examined the relationship between renal cell carcinoma (RCC) risk and intakes of plant foods and antioxidant nutrients have yielded inconsistent results. We therefore examined the associations between intakes of fruit, vegetables, carotenoids, flavonoids, vitamin E and vitamin C and RCC risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study cohort. At baseline, 27,062 male Finnish smokers aged 50-69 years completed a 276-item dietary questionnaire that included questions on frequency of consumption and portion size. During up to 19 years of follow-up, 255 men developed RCC. Cox proportional hazards models were utilized to estimate relative risks (RR) and 95% confidence intervals (CI). Despite a large range in intake, no association was observed between fruit, vegetables or antioxidant nutrients and RCC risk. For example, multivariate RRs and 95% CIs for the highest versus the lowest quartile of intake were 0.79 (0.55-1.14), 1.23 (0.85-1.79), 1.09 (0.74-1.60), 0.83 (0.57-1.21), 1.09 (0.73-1.64) and 0.99 (0.67-1.46) for fruit, vegetables, total carotenoids, total flavonoids, total vitamin E and vitamin C, respectively (all p values for trend > 0.05). Our results indicate that diet may not play a large role in the etiology of RCC in male smokers, although further examination of these associations in nonsmokers, women and diverse racial populations is warranted.

Epidemiologic characteristics and risk factors for renal cell cancer

Incidence rates of renal cell cancer, which accounts for 85% of kidney cancers, have been rising in the United States and in most European countries for several decades. Family history is associated with a two- to four-fold increase in risk, but the major forms of inherited predisposition together account for less than 4% of renal cell cancers. Cigarette smoking, obesity, and hypertension are the most consistently established risk factors. Analgesics have not been convincingly linked with renal cell cancer risk. A reduced risk of renal cell cancer among statin users has been hypothesized but has not been adequately studied. A possible protective effect of fruit and vegetable consumption is the only moderately consistently reported dietary finding, and, with the exception of a positive association with parity, evidence for a role of hormonal or reproductive factors in the etiology of renal cell cancer in humans is limited. A recent hypothesis that moderate levels of alcohol consumption may be protective for renal cell cancer is not strongly supported by epidemiologic results, which are inconsistent with respect to the categories of alcohol consumption and the amount of alcohol intake reportedly associated with decreased risk. For occupational factors, the weight of the evidence does not provide consistent support for the hypotheses that renal cell cancer may be caused by asbestos, gasoline, or trichloroethylene exposure. The established determinants of renal cell cancer, cigarette smoking, obesity, and hypertension, account for less than half of these cancers. Novel epidemiologic approaches, including evaluation of gene–environment interactions and epigenetic mechanisms of inherited and acquired increased risk, are needed to explain the increasing incidence of renal cell cancer.

Legume intake and the risk of cancer: a multisite case-control study in Uruguay

BACKGROUND

Previous studies have suggested that a high intake of legumes may decrease the risk of stomach and prostate cancer and some other cancers. However, the evidence is still limited. To further explore the association between legume intake and cancer risk we conducted a case-control study of 11 cancer sites in Uruguay between 1996 and 2004, including 3,539 cancer cases and 2,032 hospital controls.

RESULTS

The highest versus the lowest tertile of legume intake was associated with a significant decrease in the risk of cancers of the oral cavity and pharynx (OR = 0.48, 95% CI: 0.34-0.68), esophagus (OR = 0.54, 95% CI: 0.38-0.77), larynx (OR = 0.55, 95% CI: 0.40-0.77), upper aerodigestive tract (OR = 0.50, 95% CI: 0.40-0.63), stomach (OR = 0.69, 95% CI: 0.49-0.97), colorectum (OR = 0.43, 95% CI: 0.32-0.59), kidney (OR = 0.41, 95% CI: 0.24-0.71), and all sites combined (OR = 0.68, 95% CI: 0.59-0.78). No significant association was observed between legume intake and cancers of the lung (OR = 1.03, 95% CI: 0.83-1.27), breast (OR = 0.89, 95% CI: 0.65-1.20), prostate (OR = 0.87, 95% CI: 0.64-1.18) or bladder (OR = 0.82, 95% CI: 0.57-1.17). Similar results were found for both beans and lentils.

CONCLUSION

Higher intake of legumes was associated with a decreased risk of several cancers including those of the upper aerodigestive tract, stomach, colorectum, and kidney, but not lung, breast, prostate or bladder. Further investigations of these associations in prospective cohort studies are warranted.

Food groups and renal cell carcinoma: results from a case-control study

BACKGROUND

The role of diet in renal cell carcinoma risk has been inconclusive. This study uses an integrative approach to assess the role of food groups and food items in renal cell carcinoma risk.

DESIGN

A case-control study was conducted from 2003-2006.

SUBJECTS/SETTING

Incident cases (n=335) were identified from hospital records and the Florida cancer registry, and population controls (n=337) frequency matched by age (+/-5 years), sex, and race were identified through random-digit dialing. Eating habits were assessed through the use of the 70-item Block food frequency questionnaire.

STATISTICAL ANALYSES

Odds ratios (ORs), 95% confidence intervals (CIs), and tests for trends were calculated using logistic regression, controlled for age, sex, race, income, body mass index, and pack-years of smoking.

RESULTS

Decreased renal cell carcinoma risk was observed among the total sample and for men for vegetable consumption (all subjects: OR 0.56, 95% CI 0.35, 0.88; men: OR 0.49, 95% CI 0.25, 0.96) but not for fruit consumption. Tomato consumption decreased renal cell carcinoma risk for the total population and for men (all subjects: OR 0.50, 95% CI 0.31, 0.81; men: OR 0.47, 95% CI 0.24, 0.95). Increased risk of renal cell carcinoma was observed among all subjects and among women with increased consumption of red meat (all subjects: OR 4.43, 95% CI 2.02, 9.75; women: OR 3.04, 95% CI 1.60, 5.79). White bread consumption increased renal cell carcinoma risk among women only (OR 3.05, 95% CI 1.50, 6.20), as did total dairy consumption (OR 2.36, 95% CI 1.21, 4.60).

CONCLUSIONS

The protective role of vegetables and the increased risk of renal cell carcinoma with meat consumption are supported. The protective role of fruits is not. Novel findings include the increased risk of renal cell carcinoma with white bread and white potato consumption and the decreased risk of renal cell carcinoma with tomato consumption.

Dietary fat and risk of renal cell carcinoma in the USA: a case-control study

An increased risk of renal cell carcinoma (RCC) has been linked with obesity. However, there is limited information about the contribution of dietary fat and fat-related food groups to RCC risk. A population-based case-control study of 406 cases and 2434 controls aged 40-85 years was conducted in Iowa (1986-89). For 323 cases and 1820 controls from the present study, information on dietary intake from foods high in fat nutrients and other lifestyle factors was obtained using a mailed questionnaire. Cancer risks were estimated by OR and 95 % CI, adjusting for age, sex, smoking, obesity, hypertension, physical activity, alcohol and vegetable intake and tea and coffee consumption. In all nutrient analyses, energy density estimates were used. Dietary nutrient intake of animal fat, saturated fat, oleic acid and cholesterol was associated with an elevated risk of RCC (OR = 1.9, 95 % CI 1.3, 2.9, P trend < 0.001; OR = 2.6, 95 % CI 1.6, 4.0, P trend < 0.001; OR = 1.9, 95 % CI 1.2, 2.9, P trend = 0.01; OR = 1.9, 95 % CI 1.3, 2.8, P trend = 0.006, respectively, for the top quartile compared with the bottom quartile of intake). Increased risks were also associated with high-fat spreads, red and cured meats and dairy products (OR = 2.0, 95 % CI 1.4, 3.0, P trend = 0.001; OR = 1.7, 95 % CI 1.0, 2.2, P trend = 0.01; OR = 1.8, 95 % CI 1.2, 2.7, P trend = 0.02; OR = 1.6, 95 % CI 1.1, 2.3, P trend = 0.02, respectively). In both the food groups and nutrients, there was a significant dose-response with increased intake. Our data also indicated that the association of RCC with high-fat spreads may be stronger among individuals with hypertension. These findings deserve further investigation in prospective studies.

Obesity and cancer

The prevalence of obesity, defined as a BMI of > or =30.0 kg/m2, has increased substantially over previous decades to about 20% in industrialized countries, and a further increase is expected in the future. Epidemiological studies have shown that obesity is a risk factor for: post-menopausal breast cancer; cancers of the endometrium, colon and kidney; malignant adenomas of the oesophagus. Obese subjects have an approximately 1.5-3.5-fold increased risk of developing these cancers compared with normal-weight subjects, and it has been estimated that between 15 and 45% of these cancers can be attributed to overweight (BMI 25.0-29.9 kg/m2) and obesity in Europe. More recent studies suggest that obesity may also increase the risk of other types of cancer, including pancreatic, hepatic and gallbladder cancer. The underlying mechanisms for the increased cancer risk as a result of obesity are unclear and may vary by cancer site and also depend on the distribution of body fat. Thus, abdominal obesity as defined by waist circumference or waist:hip ratio has been shown to be more strongly related to certain cancer types than obesity as defined by BMI. Possible mechanisms that relate obesity to cancer risk include insulin resistance and resultant chronic hyperinsulinaemia, increased production of insulin-like growth factors or increased bioavailability of steroid hormones. Recent research also suggests that adipose tissue-derived hormones and cytokines (adipokines), such as leptin, adiponectin and inflammatory markers, may reflect mechanisms linked to tumourigenesis.

Carotenoid and vitamin intake, von Hippel-Lindau gene mutations and sporadic renal cell carcinoma

OBJECTIVE

We investigated whether dietary carotenoid and vitamin intake and supplemental vitamin use were inversely associated with RCC risk and with Von Hippel-Lindau (VHL)-gene mutations in clear-cell renal cell carcinoma (RCC).

METHODS

The Netherlands Cohort Study on diet and cancer (NLCS) includes 120,852 persons, who completed a self-administered food-frequency questionnaire in 1986. After 11.3 years of follow-up, 284 cases and a random sample of 4,095 persons (subcohort) with complete data were included in multivariable analyses using a case-cohort approach. VHL gene mutational analysis was complete for 225 cases. Rate ratios and corresponding 95% confidence intervals were estimated using Cox proportional hazard models, while adjusting for age, sex, smoking, body mass index, and a history of hypertension.

RESULTS

We observed no association for dietary carotenoid and vitamin intake and RCC risk, and a somewhat increased risk with supplemental vitamin E, AD, and multivitamin use. Results were suggestive of higher RRs for alpha-carotene, beta-cryptoxanthin, folate, and supplemental vitamin C and multivitamin intake for wildtype VHL tumors compared to VHL-mutated tumors.

CONCLUSIONS

There was no association of carotenoid, vitamin or supplemental vitamin intake and RCC risk. These associations should be investigated by others to confirm the current observations.

Prevalence of renal cell carcinoma: a nation-wide survey in Japan, 2002

OBJECTIVE

To investigate the incidence of renal cell carcinoma, classified by sex, age group and region in Japan, following a 5-year interval after a previous survey performed in 1997.

METHODS

The survey was conducted between the beginning of January 2002 and the end of December 2002. A total of 1288 institutions in all 47 prefectures throughout Japan were requested to register cases.

RESULTS

There were 7405 persons with renal cell carcinoma, consisting of 5063 males and 2342 females. Crude incidence rates were 8.2 and 3.6 per 100 000 population for men and women, respectively. Incidence rates in the Hokkaido region were highest followed by the Shikoku region.

CONCLUSIONS

Despite incidence of renal cell carcinoma increasing to 7405 from the 6358 persons in 1997, statistical data reported by the Ministry of Health, Labor and Welfare indicate that rising age-adjusted death rate for this tumor reached a ceiling in the past decade. Early detection may have contributed to this current trend; however, further epidemiological research is required to fully elucidate this.

Alcoholic beverages and risk of renal cell cancer

Using a mailed questionnaire, we investigated the risk of renal cell cancer in relation to different types of alcoholic beverages, and to total ethanol in a large population-based case–control study among Swedish adults, including 855 cases and 1204 controls. Compared to non-drinkers, a total ethanol intake of >620 g month⁻¹ was significantly related to a decreased risk of renal cell cancer (odds ratio (OR) 0.6, 95% confidence interval (CI) 0.4–0.9; P-value for trend=0.03). The risk decreased 30–40% with drinking more than two glasses per week of red wine (OR 0.6, 95% CI 0.4–0.9), white wine (OR 0.7, 95% CI 0.4–1.0), or strong beer (OR 0.6, 95% CI 0.4–1.0); there was a clear linear trend of decreasing risk with increasing consumption of these beverages (P-values for trends <0.05).

Micronutrients and the risk of renal cell cancer: a case-control study from Italy

The role of various micronutrients on the risk of renal cell cancer (RCC) was examined in a multicentric case-control study from Italy, in which information on dietary habits were collected using a validated food-frequency questionnaire. Cases were 767 patients (494 men and 273 women) with incident, histologically confirmed RCC; controls were 1,534 subjects (988 men and 546 women) admitted to the same hospitals as cases for a wide spectrum of acute, nonneoplastic conditions. After allowing for energy and other major covariates, a significant inverse association was found for vitamin E (odds ratio, OR, for the highest quintile of intake versus the lowest one 0.56, 95% confidence interval, CI 0.41-0.75), and vitamin C (OR = 0.72, 95% CI = 0.54-0.96), although the trend in risk for vitamin C was of borderline significance. No significant trend of decreasing risk was found for other micronutrients analyzed, although for most of them the risk estimates were below unity for intakes above the lowest. The ORs for the upper quintile of intake when compared with the lowest one were 0.80 (95% confidence interval, CI = 0.59-1.08) for retinol, 0.82 (95% CI = 0.61-1.10) for alpha-carotene, 0.90 (95% CI = 0.68-1.20) for beta-carotene, 0.94 (95% CI = 0.73-1.21) for beta-criptoxanthin, 0.85 (95% CI = 0.63-1.14) for lutein/zeaxanthin, 0.76 (95% CI = 0.57-1.01) for vitamin D, 0.75 (95% CI = 0.55-1.01) for thiamine, 0.88 (95% CI = 0.66-1.19) for riboflavin, 0.85 for vitamin B6 (95% CI = 0.64-1.13), 0.85 (95% CI = 0.64-1.12) for folate and 0.80 (95% CI = 0.60-1.07) for niacin. No meaningful associations emerged for lycopene (OR = 1.11). The present findings support a possible beneficial effect of vitamin E and C on RCC.

Consumption of different types of meat and the risk of renal cancer: meta-analysis of case-control studies

BACKGROUND

Kidney cancers account for almost 2% of all cancers worldwide, with 150,000 new cases and 78,000 deaths from the disease occurring annually. An increase in the incidence of kidney neoplasm in western countries was noticed in the past few years. Between 1988 and 1992, the incidence of renal cancer per 100,000 person-year among males in USA, Norway, and France was 34.1, 9.00, and 16.10, respectively. Among females in the same countries, it was 5.70, 5.00, and 7.30, respectively. Although several individual case-control studies examined the association of meat intake and renal cancer risk, the results were inconsistent because of the insufficient statistical power of the individual studies. Therefore, the following meta-analysis was designed to help in clarifying the association.

METHODS

Electronic search of MEDLINE, OVID, and PUBMED databases which have articles published between (1966 and 2006) was conducted to select studies for this meta-analysis.

STATISTICAL ANALYSIS

Fixed and random-effects meta-analytical techniques were used to estimate the overall association between meat consumption and kidney cancer.

RESULTS

Thirteen case-control studies were found. This meta-analysis supported a positive relationship between meat consumption and risk of renal cancer. Summary results indicated that there was from 20% to 22% higher risk of renal cancer among those in the highest relative to the lowest category of poultry and processed meat consumption. Consumption of all meat and red meat was associated with 27% and 30% higher risk, respectively. The increased risks were statistically significant.

CONCLUSIONS

Increased consumption of all meat, red meat, poultry, and processed meat is associated with an increase risk of kidney cancer. Reduction of meat consumption is an important approach to decreasing the incidence of kidney cancer in the general population.

Fruit and vegetables in cancer prevention

Our aim was to review the epidemiological literature on possible cancer-preventive effects of the consumption of fruits and vegetables in humans, to quantify the effect of high versus low consumption of fruits and vegetables, and to give an overall assessment of the existing evidence. We based our work on an expert meeting conducted by the International Agency for Research on Cancer in 2003. A qualitative reading and evaluation of relevant articles on the cancer-preventive effect of the consumption of fruits and vegetables was made followed by the calculation of the mean relative risk and range for cohort and case-control studies separately. The possible population-preventable fraction for modifying diet in relation to fruit and vegetable consumption was calculated as well as an overall statement about the degree of evidence for the cancer-preventive effect of fruit and vegetable consumption for each cancer site. There is limited evidence for a cancer-preventive effect of the consumption of fruits and vegetables for cancer of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary (vegetables only), bladder (fruit only), and kidney. There is inadequate evidence for a cancer-preventive effect of the consumption of fruits and vegetables for all other sites. Applying this range of risk difference to the range of prevalence of low intake, the preventable fraction for low fruit and vegetable intake would fall into the range of 5-12%. It is important to recognize that this is only a crude range of estimates and that the proportion of cancers that might be preventable by increasing fruit and vegetable intake may vary beyond this range for specific cancer sites and across different regions of the world.

Emerging global epidemic of obesity: the renal perspective

Obesity, as a core component of the metabolic syndrome, is among the top ten global health risks classified by the World Health Organization (WHO) as being strongly associated with the development and progression of chronic renal disease--a widely prevalent but often silent condition. Obesity carries elevated risks of cardiovascular morbidity and mortality besides having an array of metabolic complications. Maladaptive glomerular hemodynamics with increased intraglomerular pressure in association with vasoactive, fibrogenic substances released from adipocytes, in addition to cytokines and hormones, are the key factors in the causation of renal injury and the progression of nephron loss among obese subjects.

Fruits and vegetables and renal cell carcinoma: Findings from the European prospective investigation into cancer and nutrition (EPIC)

We examined the association between fruits and vegetables and risk of renal cell carcinoma (RCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake data and complete follow-up information on cancer incidence were available for 375,851 participants recruited in EPIC centers of 8 countries. During an average follow-up of 6.2 years, 306 incident cases of RCC were identified. The associations of consumption of total vegetables, total fruits, combined total fruits and vegetables and specific subtypes of vegetables with RCC risk were analyzed using Cox proportional hazards, stratified by centre and adjusted for potential confounders. No significant associations between fruit and vegetable consumption and RCC risk were observed despite a wide range of intake. The estimated relative risks (95% confidence intervals [CI]) in men and women combined were 0.97 (0.85-1.11) per 40 g increase in vegetable intake, 1.03 (0.97-1.08) per 40 g increase in fruit intake and 1.02 (0.93-1.11) per 80 g increase in fruit and vegetable intake combined. Among the vegetable subtypes, an inverse association was observed for root vegetables (RR per 8 g increase: 0.88; 95% CI: 0.78-0.99). These results suggest that total consumption of fruits and vegetables is not related to risk of RCC, although we cannot exclude the possibility that very low consumption is related to higher risk. The relationship of specific fruit and vegetable subgroups with RCC risk warrant further investigation.

Food groups and renal cell carcinoma: A case–control study from Italy

Although nutrition and diet have been related to renal cell carcinoma (RCC), the role of specific foods or nutrients on this cancer is still controversial. We evaluated the relation between a wide range of foods and the risk of RCC in an Italian case-control study including 767 patients (494 men and 273 women) younger than 79 years with incident, histologically confirmed RCC, and 1,534 controls (988 men and 546 women) admitted to the same hospitals as cases for a wide spectrum of acute, non-neoplastic conditions, not related to long term diet modifications. A validated and reproducible food frequency questionnaire, including 78 foods and beverages, plus a separate section on alcohol drinking, was used to assess patients' dietary habits 2 years before diagnosis or hospital admission. Multivariate odds ratios (OR) were obtained after allowance for energy intake and other major confounding factors. A significant direct trend in risk was found for bread (OR = 1.94 for the highest versus the lowest intake quintile), and a modest excess of risk was observed for pasta and rice (OR = 1.29), and milk and yoghurt (OR = 1.27). Poultry (OR = 0.74), processed meat (OR = 0.64) and vegetables (OR = 0.65) were inversely associated with RCC risk. No relation was found for coffee and tea, soups, eggs, red meat, fish, cheese, pulses, potatoes, fruits, desserts and sugars. The results of this study provide further indications on dietary correlates of RCC, and in particular indicate that a diet rich in refined cereals and poor in vegetables may have an unfavorable role on RCC.

Vegetable and fruit consumption and risk of renal cell carcinoma: results from the Netherlands cohort study

Vegetable and fruit consumption is generally inversely associated with various cancer types, including renal cell carcinoma (RCC). The Netherlands cohort study on diet and cancer (NLCS) consists of 120,852 men and women, aged 55-69 years, who filled out a self-administered questionnaire that includes 150-item food-frequency questions and additional questions on lifestyle factors, at baseline in 1986. A case-cohort approach was used. After 9.3 years of follow-up, 275 microscopically confirmed incident cases were identified. Subjects with incomplete or inconsistent dietary data were excluded, leaving 260 RCC cases for analyses on fruit consumption and 249 RCC cases for analyses on vegetable consumption. Incidence rate ratios (RR) and corresponding 95% confidence intervals (CI) were estimated using Cox proportional hazard models. RRs for exposure variables are expressed per increment of 25 g/day and are adjusted for age, sex, smoking, body mass index and history of hypertension at baseline. The RRs for vegetable consumption were further adjusted for fruit consumption and vice versa. Total vegetable and fruit consumption (RR: 1.00; 95% CI 0.97-1.02), vegetable (RR: 1.00, 95% CI 0.96-1.06) and fruit consumption (RR: 1.00; 95% CI 0.97-1.03) were not associated with RCC risk. Also, no association existed for botanical subgroups of vegetables and fruit. For 30 individual vegetables and fruits, we observed one that significantly increased RR (mandarin consumption, RR: 1.76; 95% CI 1.28-2.42), which must be regarded cautiously because of multiple testing. These results suggest the absence of an association between vegetable and/or fruit consumption and RCC risk.

Body size and risk of renal cell carcinoma in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Previous studies suggest that obesity is related to increased risk of renal cell carcinoma (RCC); however, only a few studies report on measures of central vs. peripheral adiposity. We examined the association between anthropometric measures, including waist and hip circumference and RCC risk among 348,550 men and women free of cancer at baseline from 8 countries of the European Prospective Investigation into Cancer and Nutrition (EPIC). During 6.0 years of follow-up we identified 287 incident cases of RCC. Relative risks were calculated using Cox regression, stratified by age and study center and adjusted for smoking status, education, alcohol consumption, physical activity, menopausal status, and hormone replacement therapy use. Among women, an increased risk of RCC was conferred by body weight (relative risk [RR] in highest vs. lowest quintile = 2.13; 95% confidence interval [CI] = 1.16-3.90; p-trend = 0.003), body mass index (BMI) (RR = 2.25; 95% CI = 1.14-4.44; p-trend = 0.009), and waist (RR = 1.67; 95% CI = 0.94-2.98; p-trend = 0.003) and hip circumference (RR = 2.30; 95% CI = 1.22-4.34; p-trend = 0.01); however, waist and hip circumference were no longer significant after controlling for body weight. Among men, hip circumference (RR = 0.44; 95% CI = 0.20-0.98; p-trend = 0.03) was related significantly to decreased RCC risk only after accounting for body weight. Height was not related significantly to RCC risk. Our findings suggest that obesity is related to increased risk of RCC irrespective of fat distribution among women, whereas low hip circumference is related to increased RCC risk among men. Our data give further credence to public health efforts aiming to reduce the prevalence of obesity to prevent RCC, in addition to other chronic diseases.

Major dietary patterns and risk of renal cell carcinoma in a prospective cohort of Swedish women

Links between specific foods and the risk of renal cell carcinoma (RCC) are not well established. Dietary patterns may be a better predictor of RCC risk. Our aim was to identify and examine major dietary patterns and their relation to the risk of RCC in a large prospective cohort study of Swedish women. Complete dietary information was available from a FFQ from 46,572 women aged 40-76 y at baseline. We conducted factor analysis to identify dietary patterns. Cox proportional hazard models were used to estimate rate ratios (RRs) and 95% CIs. During a mean of 14.3 y of follow-up, we identified 93 cases of RCC. We observed 3 major dietary patterns in the cohort: Healthy (vegetables, tomato, fish, fruits, poultry, whole grains), Western (sweets, processed meat, refined grains, margarine/butter, high-fat dairy products, fried potato, soft drinks, meat) and Drinker (wine, hard liquor, beer, snacks) pattern. Higher Healthy pattern scores were not significantly associated with decreased risk of RCC (highest vs. lowest tertile RR = 0.81; 95% CI 0.45-1.48 and RR = 0.54; 95% CI 0.27-1.10 among women < or = 65 y). There was a suggestion of an inverse association between the Drinker pattern and RCC risk (RR comparing the 2nd and 3rd with the first tertile, 0.56; 95% CI, 0.34-0.95; and 0.72; 95% CI, 0.42-1.22, respectively, P = 0.08 by Wald test); the association was clearer among women < or = 65 y (P = 0.02 by Wald test). Our data suggest an inverse association between Drinker pattern and the risk of RCC.

Relation of height, body mass, energy intake, and physical activity to risk of renal cell carcinoma: results from the Netherlands Cohort Study

Data from the Netherlands Cohort Study on Diet and Cancer were used to investigate the association between anthropometry, energy intake, and physical activity and risk of renal cell carcinoma (RCC). The Netherlands Cohort Study on Diet and Cancer consists of 120,852 men and women aged 55-69 years who completed a self-administered questionnaire at baseline (1986). A case-cohort approach was used. After 9.3 years of follow-up, 275 microscopically confirmed incident cases were available for analysis. Incidence rate ratios for RCC were estimated using Cox proportional hazards models. Height was associated with RCC risk only in women (per 5-cm increment, rate ratio (RR) = 1.23, 95% confidence interval (CI): 1.03, 1.46). Body mass index (weight (kg)/height (m)(2)) was associated with increased risk of RCC (per 1-kg/m(2 )increment, RR = 1.07, 95% CI: 1.02, 1.12) for men and women, as was gain in body mass index from age 20 years to baseline (per 1-kg/m(2 )increment, RR = 1.06, 95% CI: 1.01, 1.10). Energy intake was not related to RCC risk, while a possible protective effect was observed for physical activity in men. These results suggest that body mass index and gain in body mass index since age 20 are associated with increased risk of RCC.

Cancer Cluster Investigations

A rural community expressed concern about a perceived excess of kidney and pancreatic cancer coupled with contamination of drinking water with atrazine, benzene, ethylene dibromide, and nitrate. Incidence and mortality for these two cancers were compared to what might be expected. A literature review was conducted for risk factors for kidney and pancreatic cancer as well as for the effects of the above 4 chemicals on these 2 cancers. Interviews with cases or surrogates ascertained chemical and risk factor exposures for these 2 cancers. Chemical exposures found in the public drinking water supply were evaluated as to their carcinogenicity. Hospital cases were compared to cases in the cancer registry. No statistically significant increases in kidney and pancreatic cancer incidence or mortality were found. The major risk factor found in the literature for these 2 cancers was smoking. Most of the cases were smokers and the chemicals found in the drinking water were not found to pose a risk for these 2 cancers. This approach provided considerable information, suggested prevention options and additional research, and is recommended for responding to cancer cluster concerns originating in the community (reactive approach). A proactive approach to cancer cluster surveillance and research was also used and is recommended for state or large local health departments.

The impact of obesity in urology

The incidence and progression of urologic diseases, as well as several urologic cancers.depend on many interrelated factors, such as obesity, diet, genetics, environment, age, and the immune system. Obesity is a risk factor for stress urinary incontinence, ED, infertility, and renal calculi. Numerous publications have demonstrated that a high dietary intake of fat increases prostate cancer risk, although the mechanisms are not clear. Although some reports may demonstrate an association between obesity and prostate cancer, it may be hard to establish because, in general, men with obesity have a high-fat diet. Obesity, recurrent urinary tract infections, increased intake of protein and fried foods, and female sex seem to increase the risk of renal cancer. Environmental toxins seem to be the major factors affecting the incidence of bladder cancers. Thus, dietary modification and other public health measures directed at reducing weight may reduce the incidence of urologic illnesses. More studies are necessary to determine the therapeutic effects of weight loss and dietary modification on the incidence and progression of urologic tumors.

Fruits, vegetables and risk of renal cell carcinoma: A prospective study of Swedish women

Findings of epidemiologic studies on the relationship between fruit and vegetable consumption and renal cell carcinoma (RCC) risk have been inconclusive. To study the association between fruits and vegetables and risk of RCC in a population-based prospective cohort study of Swedish women, we collected dietary information from 61,000 women age 40-76 years by a food-frequency questionnaire. During 13.4 years of follow-up 122 women developed RCC. Cox proportional hazards models were used to estimate relative risks (RR) with 95% confidence interval (CI). Women consuming 5 or more servings of fruit and vegetables daily had a relative risk of 0.59 (95% CI = 0.26-1.34) in comparison to them consuming less than once daily. When fruits and vegetables were examined separately, those who consumed more than 75 servings per month of fruits or vegetables had multivariate relative risk of 0.59 (95% CI = 0.27-1.25) and 0.60 (95% CI = 0.31-1.17) respectively, compared to those consuming 11 or less servings per month. Within the group of fruits, the strongest inverse association was observed for banana (p = 0.07 by Wald test). The risk of RCC increased monotonically with increasing intake frequencies of fruit juice (p-value for trend = 0.10). Within the group of vegetables, the strongest inverse association was observed for root vegetables (p = 0.03 by Wald test). The risk of RCC decreased with increasing consumption frequencies of white cabbage (p for trend = 0.07). Frequent consumption of salad vegetables (once or more per day) decreased the risk by 40% (RR = 0.60; 95% CI = 0.30-1.22), in comparison to no consumption. Our results suggested that high consumption of fruits and vegetables might be associated with reduced risk of RCC.

Obesity and renal cell cancer--a quantitative review

Obesity has been associated with an increased risk of renal cell cancer among women, while the evidence for men is considered weaker. We conducted a quantitative summary analysis to evaluate the existing evidence that obesity increases the risk of renal cell cancer both among men and women. We identified all studies examining body weight in relation to kidney cancer, available in MEDLINE from 1966 to 1998. The quantitative summary analysis was limited to studies assessing obesity as body mass index (BMI, kg m(-2)), or equivalent. The risk estimates and the confidence intervals were extracted from the individual studies, and a mixed effect weighted regression model was used. We identified 22 unique studies on each sex, and the quantitative analysis included 14 studies on men and women, respectively. The summary relative risk estimate was 1.07 (95% CI 1.05-1.09) per unit of increase in BMI (corresponding to 3 kg body weight increase for a subject of average height). We found no evidence of effect modification by sex. Our quantitative summary shows that increased BMI is equally strongly associated with an increased risk of renal cell cancer among men and women.

The prevalence of renal cell carcinoma: a nation-wide survey in Japan in 1997

BACKGROUND

The present study was conducted to investigate the incidence of renal cell carcinoma by sex, age group and different regions in Japan.

METHODS

The survey was conducted from the beginning of January 1997 to the end of December 1997. A total of 1306 Institutions in all 47 prefectures throughout Japan were requested to register cases.

RESULTS

There were 6358 persons with renal cell carcinoma, consisting of 4372 men and 1986 women. The age-specific incidence rates showed a peak in the age group of 65-70 years in both men and women. The crude incidence rates per 100 000 population for men and women were 7.1 and 3.1, respectively, and age-standardized incidence rates per 100 000 population for men and women were 4.9 and 1.8, respectively. The incidence rates in the Hokkaido region were significantly higher than in other regions (P < 0.05), among which there was no significant difference in incidence rates.

CONCLUSIONS

The present study showed that the incidence rates of renal cell carcinoma in Japan were approximately the same as among Japanese in Los Angeles. The rates were, however, lower than North American and European countries, but higher than China, Central or South American countries and African countries. The reasons for the high incidence of renal cancer in the Hokkaido region are not entirely clear. Further epidemiologic research is required.