Predictive characteristics for disease recurrence and overall survival in non-metastatic clinical T1 renal cell carcinoma - results from the National Swedish Kidney Cancer Register.

OBJECTIVE: Patients with clinical T1 renal cell carcinoma (cT1RCC) have risks for recurrence and reduced overall survival despite being in the best prognostic group. This study aimed to evaluate the association of different treatments on disease recurrence and overall survival using clinical and pathological characteristics in a nation-wide cT1RCC cohort. MATERIALS AND METHODS: A total of 4,965 patients, registered in the National Swedish Kidney Cancer Register (NSKCR) between 2005 and 2014, with ≥ 5-years follow-up were identified: 3,040 males and 1,925 females, mean age 65 years. Times to recurrence and overall survival were analyzed with Kaplan-Meier curves, log-rank test, and Cox regression models. RESULTS: Age, TNM-stage, tumor size, RCC-type, and performed treatment were all associated with disease recurrence. Patients selected for ablative treatments had increased risk for recurrent disease: hazard ratio (HR) = 3.79 [95% confidence interval (CI) = 2.69-5.32]. In multivariate analyses, age, gender, tumor size, RCC-type, N-stage, recurrence and performed treatment were all independently associated with overall survival. Patients with chRCC had a 41% better overall survival (HR = 0.59, 95% CI = 0.44-0.78; p < 0.001) than ccRCC. Patients treated with partial nephrectomy (PN) had an 18% better overall survival (HR = 0.83, 95% CI = 0.71-0.95, p < 0.001) than patients treated with radical nephrectomy. CONCLUSIONS: Age, gender, T-stage, tumor size, RCC type and treatment modality are all associated with risk of recurrence. Furthermore, age, male gender, tumor size, N-stage and recurrence are associated with reduced overall survival. Patients with chRCC, compared with ccRCC and pRCC patients, and PN compared with RN treated patients, had an advantageous overall survival, indicating a possible survival advantage of nephron sparing treatment.

Surgical waiting times and all-cause mortality in patients with non-metastatic renal cell carcinoma.

OBJECTIVE: To examine the association between surgical waiting times (SWTs) and all-cause mortality (ACM) in non-metastatic patients with RCC, in relation to tumour stage. PATIENTS AND METHODS: This nation-wide population-based cohort study included 9,918 M0 RCC patients registered in the National Swedish Kidney Cancer Register, between 2009 and 2021, followed-up for ACM until 9 December 2021, and having measured SWTs. The associations between primarily SWTs from date of radiological diagnosis to date of surgery (WRS) and secondarily SWTs from date of radiological diagnosis to date of treatment decision (WRT) and date of treatment decision to date of surgery (WTS), in relation to ACM, were analysed using Cox regression analysis, adjusted for clinical and demographic characteristics, stratified and unstratified according to T-stage. RESULTS: During a mean follow-up time of 5 years (49,873 person-years), 23% (n = 2291) of the patients died. The adjusted hazard ratio (AHR) for WRS (months) for all patients was 1.03 (95% confidence interval [CI] = 1.02-1.04; p < 0.001). When subdividing WRS on T-stage, the AHRs were 1.03 (95% CI = 1.01-1.04; p < 0.001) and 1.05 (95% CI = 1.02-1.08; p = 0.003) for stages T1 and T3, respectively, while non-significant for T2 (p = 0.079) and T4 (p = 0.807). Similar results were obtained for WRT and WTS. CONCLUSIONS: Prolonged SWTs significantly increased the risk of early overall death among patients with RCC. The increased risk of early death from any cause show the importance of shortening SWTs in clinical work of patients with this malignant disease.

Clinical T1a Renal Cell Carcinoma, Not Always a Harmless Disease-A National Register Study.

Background: T1a renal cell carcinoma (RCC) is typically considered a curable disease, irrespective of the choice of local treatment modality. Objective: To identify factors associated with the risk of local and distant recurrence, and overall survival (OS) in patients with primary nonmetastatic clinical T1a RCC. Design setting and participants: A population-based nationwide register study of all 1935 patients with cT1a RCC, diagnosed during 2005-2012, identified through The National Swedish Kidney Cancer Register, was conducted. Outcome measurements and statistical analysis: Outcome variables were recurrence (local or distant) and OS. Possible explanatory variables included tumor size, RCC type, T stage, surgical technique, age, and gender. Associations with disease recurrence and OS were evaluated by multivariable regression and Cox multivariate analyses, respectively. Results and limitations: Among 1935 patients, 938 were treated with radical nephrectomy, 738 with partial nephrectomy, and 169 with ablative treatments, while 90 patients had no surgery. Seventy-eight (4%) patients were upstaged to pT3. Local or metastatic recurrences occurred in 145 (7.5%) patients, significantly more often after ablation (17.8%). The risk of recurrence was associated with tumor size, upstaging, and ablation. Larger tumor size, disease recurrence, and older age adversely affected OS, whereas partial nephrectomy and chromophobe RCC (chRCC) were associated with improved survival. Limitations include register design and a lack of comorbidity or performance status data. Conclusions: Upstaging and recurrence occurred, respectively, in 4.0% and 7.5% of patients with nonmetastatic RCCs ≤4 cm. Tumor size upstaging and ablation were associated with the risk for recurrence, while tumor size and recurrence were associated with decreased OS. Patients with chRCC and partial nephrectomy had prolonged OS in a real-world setting. Patient summary: We studied factors that may influence the risk of disease recurrence and overall survival, in a large nationwide patient cohort having nonmetastatic renal cell carcinoma ≤4 cm. Tumor size, tumor type, and treatment were associated with the risk of recurrence and overall death. Partial nephrectomy prolonged overall survival.

Increased risk for renal cell carcinoma in end stage renal disease - a population-based case-control study.

PURPOSE: End-stage renal disease (ESRD) is a known risk factor for the development of renal cell carcinoma (RCC). This case-control study was performed to assess the risk in a nationwide cohort and evaluate tumor characteristics and survival in the ESRD-RCC population. METHODS: In this study, 9,299 patients with RCC identified in the National Swedish Kidney Cancer Register from 2005 until 2014 and 93,895 matched controls were linked to the Swedish Renal Registry and the National Patient Register. ESRD was defined as chronic kidney disease stage 5, kidney transplantation or kidney dialysis 0-40 years before the diagnosis of RCC. RESULTS: A total of 117 patients with ESRD and subsequent RCC were identified and compared with 9,087 patients with RCC. There was a 4.5-times increased risk for RCC among ESRD patients (95% CI = 3.6-5.6; p < 0.001) compared to matched controls. Longer time with ESRD increased the risk of RCC (ESRD > 9 years, OR = 10.2, 95% CI = 7.0-14.8). The ESRD-RCC patients were younger (p = 0.002), had smaller tumors (p < 0.001) and had lower tumor stage (p = 0.045). The incidence of papillary and chromophobe RCC was higher and clear cell RCC lower among the ESRD patients (p < 0.001). The 5-year overall survival was 50% in ESRD-RCC patients and 63% in RCC-only patients (p < 0.05). CONCLUSION: More than 9 years with ESRD increased the risk of developing RCC 10-times compared to individuals without ESRD and the tumors showed a different histopathological pattern. Despite a less advanced tumor stage at diagnosis, the overall survival in ESRD-RCC patients was lower compared to patients with RCC-only.

Validation of data quality in the National Swedish Kidney Cancer Register.

INTRODUCTION: The National Swedish Kidney Cancer Register (NSKCR) was launched in 2005. It is used for health care quality improvement and research. The aim of this study was to validate the register's data quality by assessing the timeliness, completeness, comparability and validity of the register. MATERIAL AND METHODS: To assess timeliness we evaluated the number of days between date of diagnosis and date of reporting the patient to the NSKCR. For completeness, we used data on number of cancer cases reported to the NSKCR compared to cases reported to the Swedish Cancer Register. Comparability was evaluated by reviewing coding routines and comparing data collected in the NSKCR to national and international guidelines. Validity was assessed by reabstraction of data from medical charts from 431 randomly selected patients diagnosed in 2007, 2010, 2013 and 2016. RESULTS: Timeliness has improved since the register started. In 2016, 76.9% and 96.5% of the patients were reported within 6 and 12 months respectively. Completeness was high, with a 99.5% coverage between 2008 and 2017. Registration forms and manuals were updated according to national and European guidelines. Improvements have been made continuously to decrease the risk of reporting mistakes and misunderstandings. Validity was high where a majority of the variables demonstrated an exact agreement >90% and few missing values. CONCLUSION: Overall, the data quality of the NSKCR is high. Completeness, comparability and validity is high. Timeliness can be further improved, which will make it easier to follow changes and improve the care and research of RCC patients.

Survival advantage of upfront cytoreductive nephrectomy in patients with primary metastatic renal cell carcinoma compared with systemic and palliative treatments in a real-world setting.

BACKGROUND: Recently, the CARMENA and SURTIME studies, suggested that upfront cytoreductive nephrectomy (CN) should be abandoned for patients with intermediate and high-risk metastatic renal cell carcinoma (mRCC). However, CN remains an indication in low-risk and when immediate systemic treatment is not required. The aim was to evaluate the long-term overall survival (OS) in patients with primary mRCC, based on the first line treatment. METHODS: There were 1483 patients with primary mRCC in the National Kidney Cancer Registry from 2005 to 2013. Data on primary treatment, TNM stage, RCC type, tumor size, patient age and sex were extracted. Survival time was calculated from time of diagnosis to time of death or until July 2019. Mann-Whitney U and Chi-square tests, the Kaplan-Meyer method and Cox regression analyses were used. RESULTS: Patients primary treated with CN had a significantly longer OS (p < .001) than patients primary treated with systemic therapy or palliation. In a Cox regression multivariate analysis, the hazard ratio for CN compared with no CN was 1.600, 95%Ci (1.492 - 1.691), p < .001. Also occurrence of lymph node metastases, T-stage, patients age and year of diagnosis, remained as independent predictors of OS. CONCLUSION: Patients primary treated with CN survived significantly longer than patients primary treated with systemic therapy or palliation, in all age groups. CN was an important first-line treatment option in mRCC patients.

The renal cell cancer database Sweden (RCCBaSe) - a new register-based resource for renal cell carcinoma research.

Introduction: In 2005, the National Swedish Kidney Cancer Register (NSKCR) was set up to collect data on newly diagnosed patients with renal cell carcinoma (RCC). In 2015, the NSKCR was linked to a number of national healthcare and demographic registers to construct the Renal Cell Cancer Database Sweden (RCCBaSe). The aim was to facilitate research on trends in incidence, effects of treatment and survival, with detailed data on tumour characteristics, treatment, pharmaceutical prescriptions, socioeconomic factors and comorbidity.Material and methods: All patients registered in the NSKCR between 2005 and 2014 were included. For each case, ten controls and first-degree relatives for cases and controls were identified. The RCCBaSe was created linking all cases, controls and first-degree relatives to a number of national registers with information on co-morbidity, socioeconomic factors and pharmaceutical prescriptions.Results: Between 2005 and 2014, a total of 9,416 patients with RCC were reported to the NSKCR. 94,159 controls and a total cohort of 575,007 individuals including cases, controls and first-degree relatives were identified. Linkage to the Swedish cancer register resulted in 106,772 matches. When linked to the National patient register, 432,677 out-patient and 471,359 in-patient matches were generated. When linked to the Swedish renal registry 1,778 matches were generated. Linkage to the Prescribed drug register resulted in 448,084 matches and linkage to the The Longitudinal integration database for health insurance and labour market studies database resulted in 450,017 matches.Conclusion: By linking the NSKCR to several Swedish national databases, a unique database for RCC research has been created.

Cytokine Measurements for Diagnosing and Characterizing Leukemoid Reactions and Immunohistochemical Validation of a Granulocyte Colony-Stimulating Factor and CXCL8-Producing Renal Cell Carcinoma.

BACKGROUND: Various paraneoplastic syndromes are encountered in renal cell carcinomas. This case report illustrates that a paraneoplastic leukemoid reaction may precede the diagnosis of renal cell carcinoma and be explained by cytokine production from the cancer cells. CASE PRESENTATIONS: A 64-year-old man was referred for hematology workup due to pronounced leukocytosis. While being evaluated for a possible hematologic malignancy as the cause, he was found to have a metastasized renal cell carcinoma, and hyperleukocytosis was classified as a leukemoid reaction. A multiplex panel for measurement of 25 serum cytokines/chemokines showed highly elevated levels of granulocyte colony-stimulating factor (G-CSF) and CXCL8 (C-X-C-motif chemokine ligand 8, previously known as interleukin [IL]-8). By immunohistochemistry it was shown that the renal carcinoma cells expressed both these cytokines. Two additional, consecutive patients with renal cell carcinoma with paraneoplastic leukocytosis also showed elevated serum levels of CXCL8, but not of G-CSF. Nonparametric statistical evaluation showed significantly higher serum concentrations of CXCL8, IL-6, IL-10, monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor, but lower interferon gamma (IFN-γ) and IL-1α, for the 3 renal cell carcinoma cases compared with healthy blood donors. CONCLUSIONS: In suspected paraneoplastic leukocytosis, multiplex serum cytokine analyses may facilitate diagnosis and provide an understanding of the mechanisms for the reaction. In the index patient, combined G-CSF and CXCL8 protein expression by renal carcinoma cells was uniquely documented. A rapidly fatal course was detected in all 3 cases, congruent with the concept that autocrine/paracrine growth signaling in renal carcinoma cells may induce an aggressive tumor phenotype. Immune profiling studies could improve our understanding for possible targets when choosing therapies for patients with metastatic renal cell carcinoma.

Clinical outcome and time trends of surgically treated renal cell carcinoma between 1986 and 2010: results from a single centre in Sweden.

OBJECTIVE: The aims of this study were to create a cohort of retrospectively collected renal cell carcinoma (RCC) specimens to be used a basis for prognostic molecular studies, and to investigate the outcome and time trends in patients surgically treated for RCC in a single-centre cohort. MATERIALS AND METHODS: Patients undergoing surgery for RCC between 1986 and 2010 were included in the study. Medical records were reviewed, and the diagnostic tissue was re-evaluated according to a modern classification. The change in patient and tumour characteristics over time was analysed. RESULTS: The study included 345 patients. Smaller tumours, as indicated by primary tumour diameter, tumour (T) stage and American Joint Committee on Cancer (AJCC) stage, were found more frequently in later years compared to the early 1990s. No changes in the clinical outcome for the patients were seen among the time periods investigated. Increasing T stage, AJCC stage, primary tumour diameter and decreasing haemoglobin levels were associated with cancer-specific mortality in univariate analysis. A high calcium level was significantly associated with increased cancer-specific mortality (hazard ratio = 4.25, 95% confidence interval 1.36-13.28) in multivariate analysis. CONCLUSIONS: This study on patients who underwent surgery for RCC from 1986 to 2010 at a single institution in Sweden indicates that there has been a change in tumour characteristics of patients diagnosed with RCC over time. It was also shown that calcium levels were an independent prognostic factor for cancer-specific mortality in this cohort. This cohort could provide a valuable basis for further molecular studies.

Renal cell carcinoma recurrences and metastases in primary non-metastatic patients: a population-based study.

PURPOSE: To present the occurrence of metastases and local recurrences in primary non-metastatic patients with renal cell carcinoma (RCC) in a contemporary Swedish population-based cohort. METHODS: Between 2005 and 2009, a total of 4527 patients were included in the prospective National Swedish Kidney Cancer Register accounting for nearly all RCC patients in Sweden. Among M0 patients, 472 (13 %) had no follow-up data registered within 5-year follow-up time and were excluded from the analysis. RESULTS: In total, 939 (21 %) had distant metastases at presentation with a decrease from 23 to 18 % during the inclusion period. Of 3107 patients with follow-up data and with M0 disease, 623 (20 %) were diagnosed with a tumor recurrence during 5-year follow-up. Mean time to recurrence was 24 months (SD ± 20 months). Among these, 570 patients (92 %) were at primary diagnosis treated with radical nephrectomy, 23 patients (3.7 %) with partial nephrectomy and 12 patients (1.9 %) with minimally invasive treatments. The most frequent sites of metastases were lung (54 %), lymph nodes (22 %) and bone (20 %). The treatment of recurrence was in 50 % systemic treatments, while metastasectomy was performed in 17 % of the patients, out of which 68 % were with a curative intention. CONCLUSIONS: In this population-based study, 21 % of the patients had metastatic disease at presentation, with a decreasing trend over the study period. During 5-year follow-up, 20 % of the primary non-metastatic patients had recurrent disease. Of the patients with recurrence, half were given systemic oncological treatment and 17 % underwent metastasectomy.

Impact of quality indicators on adherence to National and European guidelines for renal cell carcinoma.

OBJECTIVE: The aim of this population-based study was to evaluate the impact of quality indicators on the adherence to guidelines for renal cell carcinoma (RCC). MATERIAL AND METHODS: Since 2005, virtually all patients with newly diagnosed RCC in Sweden have been registered in the National Swedish Kidney Cancer Register (NSKCR). The register contains information on histopathology, nuclear grade, clinical stage, preoperative work-up, treatment, recurrence and survival. In addition, a number of quality indicators have been measured in the register aiming to increase the quality of care. The quality indicators are: the coverage of the register, histology reports, preoperative chest computed tomography (CT), partial nephrectomy, laparoscopic surgery, centralization to high-volume hospitals and waiting times. RESULTS: A total of 8556 patients with diagnosed RCC were registered from 2005 to 2013 (99% coverage). In 2013, 99% of the histopathology reports were standardized. The number of patients with preoperatively chest CT increased from 59% in 2005 to 89% in 2013. The proportion of patients with RCC T1aN0M0 who underwent partial nephrectomy increased from 22% in 2005 to 56% in 2013. Similarly, laparoscopic radical nephrectomies increased from 6% in 2005 to 24% in 2013. The median tumour size at detection decreased from 60 mm in 2005 to 55 mm in 2013. The proportion of patients who were incidentally detected increased from 43% in 2005 to 55% in 2013. CONCLUSIONS: The data show an improved adherence to the guidelines for RCC as measured by quality indicators and a steady process of earlier detection of patients with RCC.

Cancer Characteristics and Current Treatments of Patients with Renal Cell Carcinoma in Sweden.

METHODOLOGY: Since the start in 2005 virtually all patients with newly diagnosed renal cell carcinoma (RCC) in Sweden are reported to the National Swedish Kidney Cancer Register (NSKCR). The register contains information on histopathology, nuclear grade, clinical stage, preoperative work-up, treatment, recurrence, and survival. RESULTS: A total of 8556 patients with newly diagnosed RCC were registered in the NSKCR from 2005 to 2013 resulting in a coverage of 99% as compared to the Swedish Cancer Registry. The mean tumor size at detection decreased from 70 mm in 2005 to 64 mm in 2010. The proportion of patients who were incidentally detected increased. The proportion of patients with tumor stage T1a who underwent partial nephrectomy increased from 22% in 2005 to 56% in 2012. Similarly, the proportion of laparoscopically performed radical nephrectomies increased from 6% in 2005 to 17% in 2010. During the five years of follow-up 20% of the patients had a recurrence. CONCLUSION: Over the last decade there has been a trend of earlier detection and less advanced tumors at detection in patients with RCC. An increasing proportion of the patients undergo laparoscopic and nephron-sparing procedures.

Epidemiology of renal cell cancer.

Renal cell cancer (RCC) is increasingly diagnosed at an early stage in many countries, which likely contributes to the recent leveling of RCC mortality in the United States and many European countries. However, over all stages nearly 50% of the patients die within 5 years after diagnosis. Smoking and obesity may account for approximately 40% of all incidental cases in high-risk countries. Besides obesity, rising prevalence of hypertension may play a growing role. Several other occupational and lifestyle factors may also affect the risk of RCC. Genetic variations may be an important factor in the differing incidence among populations.

Obesity and risk for chronic renal failure.

Few large-scale epidemiologic studies have quantified the possible link between obesity and chronic renal failure (CRF). This study analyzed anthropometric data from a nationwide, population-based, case-control study of incident, moderately severe CRF. Eligible as cases were all native Swedes who were aged 18 to 74 yr and had CRF and whose serum creatinine for the first time and permanently exceeded 3.4 mg/dl (men) or 2.8 mg/dl (women) during the study period. A total of 926 case patients and 998 control subjects, randomly drawn from the study base, were enrolled. Face-to-face interviews, supplemented with self-administered questionnaires, provided information about anthropometric measures and other lifestyle factors. Logistic regression models with adjustments for several co-factors estimated the relative risk for CRF in relation to body mass index (BMI). Overweight (BMI>or=25 kg/m2) at age 20 was associated with a significant three-fold excess risk for CRF, relative to BMI<25. Obesity (BMI>or=30) among men and morbid obesity (BMI>or=35) among women anytime during lifetime was linked to three- to four-fold increases in risk. The strongest association was with diabetic nephropathy, but two- to three-fold risk elevations were observed for all major subtypes of CRF. Analyses that were confined to strata without hypertension or diabetes revealed a three-fold increased risk among patients who were overweight at age 20, whereas the two-fold observed risk elevation among those who had a highest lifetime BMI of >35 was statistically nonsignificant. Obesity seems to be an important-and potentially preventable-risk factor for CRF. Although hypertension and type 2 diabetes are important mediators, additional pathways also may exist.

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.

Alcohol consumption and risk of renal cell carcinoma: a prospective study of Swedish women.

Previous literature, although not consistent, suggests that moderate alcohol consumption might be associated with decreased risk of renal cell carcinoma (RCC) in women. Thus, we examined the association between alcohol intake and the incidence of RCC by analyzing data from the Swedish Mammography Cohort, a population-based prospective cohort of 59,237 women, aged 40-76 years, who, at baseline in 1987-1990, were cancer free and had completed a food-frequency questionnaire including questions about alcohol consumption. Through June 30, 2004, 132 incident cases of RCC were diagnosed. We used the Cox proportional hazards model to estimate age and body mass index (BMI) adjusted rate ratios (RRs) and their 95% confidence intervals (CIs). Women who consumed >4.3 grams per day of alcohol (ethanol) had nonsignificantly lower risk of RCC than did women who consumed <2.5 g/d (RR = 0.71, 95% CI 0.42-1.19); among women > or = 55 years of age at entry into the cohort, corresponding risk estimates were RR = 0.33, 95% CI 0.10-1.05, p for trend = 0.04 and among women with BMI >25 kg/m2, RR = 0.30, 95% CI 0.09-0.97, p for trend = 0.04. Consistent with these findings, women who drank 1 or more servings of total alcoholic beverages per week had lower RCC risk than did women who drank less (RR = 0.62, 95% CI 0.41-0.94); the corresponding estimate for women > or = 55 years of age was RR = 0.44, 95% CI 0.22-0.88. Results from our prospective cohort study of middle-aged and elderly women indicate that moderate alcohol consumption may be associated with decreased risk of RCC.

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.

Association between smoking and chronic renal failure in a nationwide population-based case-control study.

For determining whether smoking is associated with an increased risk for chronic renal failure (CRF) overall and by type of renal disease, smoking data were analyzed from a nationwide population-based case-control study. Eligible as cases were native 18- to 74-yr-old Swedes whose serum creatinine for the first time and permanently exceeded 3.4 mg/dl (men) or 2.8 mg/dl (women). A total of 926 cases (78% of all eligible) and 998 control subjects (75% of 1330 randomly selected subjects from the source population), frequency matched to the cases by gender and age within 10 yr, were included. A face-to-face interview and a self-administered questionnaire provided information about smoking habits and other lifestyle factors. Logistic regression models estimated odds ratios (OR) as measures of relative risk for disease-specific types of CRF among smokers compared with never-smokers. Despite a modest and nonsignificant overall association, the risk increased with high daily doses (OR among smokers of >20 cigarettes/d, 1.51; 95% confidence interval [CI], 1.06 to 2.15), long duration (OR among smokers for >40 yr, 1.45; 95% CI, 1.00 to 2.09), and a high cumulative dose (OR among smokers with >30 pack-years, 1.52; 95% CI, 1.08 to 2.14). Smoking increased risk most strongly for CRF classified as nephrosclerosis (OR among smokers with >20 pack-years, 2.2; 95% CI, 1.3 to 3.8), but significant positive associations were also noted with glomerulonephritis. This study thus suggests that heavy cigarette smoking increases the risk of CRF for both men and women, at least CRF classified as nephrosclerosis and glomerulonephritis.

Dietary acrylamide and risk of renal cell cancer.

The detection of acrylamide, classified as a probable human carcinogen, in commonly consumed foods created public health alarm. Thus far, only 2 epidemiologic studies have examined the effect of dietary acrylamide on cancer risk. Presently, we reanalyzed data from a large population-based Swedish case-control study of renal cell cancer. Food frequency data were linked with national food databases on acrylamide content, and daily acrylamide intake was estimated for participants. The risk of renal cell cancer was evaluated for intake of food items with elevated acrylamide levels and for total daily acrylamide dose. Adjusting for potential confounders, there was no evidence that food items with elevated acrylamide, including coffee (OR(highest vs. lowest quartile) = 0.7; 95% CI = 0.4-1.1), crisp breads (OR(highest vs. lowest quartile) = 1.0; 95% CI = 0.6-1.6) and fried potatoes (OR(highest vs. lowest quartile) = 1.1; 95% CI = 0.7-1.7), were associated with a higher risk of renal cell cancer risk. Furthermore, there was no association between estimated daily acrylamide intake through diet and cancer risk (OR(highest vs. lowest quartile) = 1.1; 95% CI = 0.7-1.8; p for trend = 0.8). The results of this study are in line with the 2 previous studies examining dietary acrylamide and suggest there is no association between dietary acrylamide and risk of renal cell cancer.

Absence of association between organic solvent exposure and risk of chronic renal failure: a nationwide population-based case-control study.

Exposure to organic solvents has been suggested to cause or exacerbate renal disease, but methodologic concerns regarding previous studies preclude firm conclusions. We examined the role of organic solvents in a population-based case-control study of early-stage chronic renal failure (CRF). All native Swedish residents aged 18 to 74 yr, living in Sweden between May 1996 and May 1998, formed the source population. Incident cases of CRF in a pre-uremic stage (n = 926) and control subjects (n = 998), randomly selected from the study base, underwent personal interviews that included a detailed occupational history. Expert rating by a certified occupational hygienist was used to assess organic solvent exposure intensity and duration. Relative risks were estimated by odds ratios (OR) in logistic regression models, with adjustment for potentially important covariates. The overall risk for CRF among subjects ever exposed to organic solvents was virtually identical to that among never-exposed (OR, 1.01; 95% confidence interval [CI], 0.81 to 1.25). No dose-response relationships were observed for lifetime cumulative solvent exposure, average dose, or exposure frequency or duration. The absence of association pertained to all subgroups of CRF: glomerulonephritis (OR, 0.96; 95% CI, 0.68 to 1.34), diabetic nephropathy (OR, 1.02; 95% CI, 0.74 to 1.41), renal vascular disease (OR, 1.16; 95% CI, 0.76 to 1.75), and other renal CRF (OR, 0.92; 95% CI, 0.66 to 1.27). The results from a nationwide, population-based study do not support the hypothesis of an adverse effect of organic solvents on CRF development, in general. Detrimental effects from subclasses of solvents or on specific renal diseases cannot be ruled out.