Coffee consumption and risk of renal cell carcinoma in the NIH-AARP Diet and Health Study

Coffee consumption and risk of kidney function decline in a Dutch population-based cohort

BACKGROUND AND AIMS

Whether coffee consumption is associated with changes in estimated glomerular filtration rate (eGFR) is unknown. We investigated the relationship between coffee consumption and annual eGFR change in a large Dutch population-based study.

METHODS AND RESULTS

This study was performed in 78,346 participants without chronic kidney disease (CKD) in the population-based Lifelines Cohort Study. Coffee consumption was assessed at baseline using food frequency questionnaires. Outcomes were annual eGFR change and a composite kidney outcome (defined as eGFR <60 mL/min per 1.73 m2 or >20 % eGFR decline). Multivariable linear and logistic regression analyses were used to evaluate the associations of coffee consumption (categories and cups/day) with kidney outcomes. Overall, 90 % of the participants drank coffee daily and 36 % drank >2-4 cups/day. Unadjusted mean ± SD annual eGFR change ranged from -2.86 ± 2.96 (for non-coffee drinkers) to -2.35 ± 2.62 (for participants consuming >6 cups/day) mL/min per 1.73 m2. During 3.6 ± 0.9 years follow-up, 11.1 % of participants reached the composite kidney outcome. As compared to non-coffee drinkers, higher coffee consumption was associated with less annual eGFR decline in multivariable models (β [95 % CIs] ranged from 0.15 [0.07, 0.22] for >0-2 cups/day to 0.29 [0.20, 0.38] for >6 cups/day, P-trend <0.001). Consumption of one more cup of coffee per day was associated with a 3 % lower risk of the composite kidney outcome (OR [95%CI], 0.97 [0.96, 0.99]). The inverse association was more pronounced in a subgroup of individuals with diabetes.

CONCLUSION

Coffee consumption was inversely associated with annual eGFR change and CKD risk in a large Dutch population-based cohort.

Kidney Cancer Integrative Oncology: Possible Options for Care

PURPOSE OF REVIEW

This study aims to review how complementary and integrative medicine (CIM), defined as therapies utilizing nutrition, physical activity, herbs, supplements, mind-body therapies, homeopathy, and other non-traditional therapies, can address the prevention, treatment, side effects, and recurrence of kidney cancer. This review discusses advances and discoveries in research, gaps in research, current debates on the subject, and directions for future research. We queried Ovid MEDLINE and PubMed databases using the search terms kidney cancer, integrative medicine, integrative oncology, nutrition, supplements, treatment, prevention, and therapy. Searches were limited to integrative medicine and integrative oncology. We reviewed CIM therapies related to prevention, treatment, side effect mitigation, and recurrence of kidney cancers.

RECENT FINDINGS

Search results yielded 211 studies, of which 87 were relevant to this review. Studies related to CIM and kidney cancer were clustered into themes, including nutrition, physical activity, supplements, mind-body therapies, and alternative therapies. This review provides a foundation for utilizing the principles of integrative medicine in the prevention of and care for patients with kidney cancer and the need for further focused research on the effectiveness of CIM in kidney cancers.

Health Benefits of Coffee Consumption for Cancer and Other Diseases and Mechanisms of Action

Coffee is one of the most widely consumed beverages worldwide, and epidemiology studies associate higher coffee consumption with decreased rates of mortality and decreased rates of neurological and metabolic diseases, including Parkinson's disease and type 2 diabetes. In addition, there is also evidence that higher coffee consumption is associated with lower rates of colon and rectal cancer, as well as breast, endometrial, and other cancers, although for some of these cancers, the results are conflicting. These studies reflect the chemopreventive effects of coffee; there is also evidence that coffee consumption may be therapeutic for some forms of breast and colon cancer, and this needs to be further investigated. The mechanisms associated with the chemopreventive or chemotherapeutic effects of over 1000 individual compounds in roasted coffee are complex and may vary with different diseases. Some of these mechanisms may be related to nuclear factor erythroid 2 (Nrf2)-regulated pathways that target oxidative stress or pathways that induce reactive oxygen species to kill diseased cells (primarily therapeutic). There is evidence for the involvement of receptors which include the aryl hydrocarbon receptor (AhR) and orphan nuclear receptor 4A1 (NR4A1), as well as contributions from epigenetic pathways and the gut microbiome. Further elucidation of the mechanisms will facilitate the potential future clinical applications of coffee extracts for treating cancer and other inflammatory diseases.

Green tea and coffee consumption and risk of kidney cancer in Japanese adults

The study aimed to evaluate the association between green tea and coffee consumption and the risk of kidney cancer using data from a large prospective cohort study in Japan (the Japan Public Health Center-based Prospective Study: JPHC Study). A total of 102,463 participants aged 40-69 were followed during 1,916,421 person-years (mean follow-up period, 19 years). A total of 286 cases of kidney cancer (199 in men, 87 in women) were identified. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) while adjusting for potential confounders. No statistically significant association between green tea intake and kidney cancer risk was found in the total population. Among women who consumed more than five cups of green tea per day, a statistically significant decreased risk was shown with a HR of 0.45 (95% CI: 0.23-0.89), compared to women who rarely consumed green tea. For coffee consumption, the association of kidney cancer risk was not statistically significant. This large prospective cohort study indicated green tea intake may be inversely associated with kidney cancer risk in Japanese adults, particularly in Japanese women.

Coffee and caffeine consumption and risk of renal cell carcinoma: A Mendelian randomization study

Background

The association between coffee and caffeine consumption and the risk of renal cell carcinoma was inconsistent among observational studies, and whether these observed associations were causal remained unclear. Therefore, we performed two-sample Mendelian randomization (MR) study to assess the causal nature of the association.

Materials and methods

In this study, 12 and two independent single nucleotide polymorphisms (SNPs) related to coffee and caffeine consumption at a genome-wide significance level of p < 5 × 10^–8 were used as instrumental variables (IVs), respectively. Summary-level data for renal cell carcinoma were taken from the FinnGen consortium with up to 174,977 individuals, and the International Agency for Research on Cancer (IARC) with 13,230 individuals. We used inverse-variance weighted (IVW) as the main method, followed by the weighted median method, the MR-Egger regression method, and the MR robust adjusted profile score method. Outlier and pleiotropic variants were assessed by the MR Pleiotropy RESidual Sum and Outlier test and MR-Egger regression. We used meta-analysis methods in fixed-effects to combine the estimates from the two sources.

Results

The genetically predicted coffee consumption was not associated with the risk of renal cell carcinoma in the FinnGen consortium, and the relationship was consistent in the IARC consortium. The pooled odds ratio (OR) per 50% increase of coffee consumption was 0.752 [95% confidence interval (CI), 0.512–1.105; p = 0.147]. In addition, complementary analyses that separated the coffee-related SNPs according to their relationship with blood levels of caffeine metabolites (higher, lower, or unrelated) found no relationship with renal cell carcinoma. The results were consistent after excluding eight SNPs due to potential risk factors at genome-wide significance (p < 5 × 10^–8). Moreover, genetically predicted per 80-mg increase in caffeine consumption was not associated with the risk of renal cell carcinoma (pooled OR = 0.872, 95% CI: 0.676–1.125, p = 0.292).

Conclusion

Our MR study provided no convincing evidence for a causal effect between coffee and caffeine consumption and the risk of renal cell carcinoma. The associations for renal cell carcinoma need to be verified in well-powered studies.

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.

Coffee consumption and risk of renal cancer: a meta-analysis of cohort evidence

PURPOSE

There is increasing evidence that coffee consumption is related to reduced risks for some cancers, but the evidence for renal cancer is inconclusive. Therefore, we conducted a meta-analysis to summarize the cohort evidence of this relationship.

METHODS

A literature search was performed in PubMed and Embase through February 2021. Meta-analyses using a random effects model were conducted for reported relative risk estimates (RRs) relating coffee intake and renal cancer incidence or mortality. We also performed a two-stage random effects exposure-response meta-analysis. Between-study heterogeneity was assessed.

RESULTS

In a meta-analysis of the ten identified cohort studies, we found a summary RR of 0.88 [95% confidence interval (CI) 0.78-0.99] relating the highest vs. the lowest category of coffee intake and renal cancer, with no significant between-study heterogeneity observed (I² = 35%, p = 0.13). This inverse association remained among studies of incident cancers (RR 0.85, 95% CI 0.76-0.96) and studies adjusting for smoking and body mass index (RR 0.87, 95% CI 0.77-0.99).

CONCLUSIONS

Our findings from this meta-analysis of the published cohort evidence are suggestive of an inverse association between coffee consumption and renal cancer risk.