Fluid Intake and Dietary Factors and the Risk of Incident Kidney Stones in UK Biobank: A Population-based Prospective Cohort Study

Diet and Risk of Incident Lung Cancer: A Large Prospective Cohort Study in UK Biobank

BACKGROUND

Epidemiological evidence remains conflicting regarding diet and risk of lung cancer.

OBJECTIVES

We sought to systematically investigate whether dietary factors are associated with the risk of incident lung cancer in the UK Biobank.

METHODS

A total of 416,588 participants (54% women) from the UK Biobank were included in the present study. Based on baseline data from FFQs, 3 main dietary patterns were identified by using principal component analysis. Cox proportional hazards models were used to investigate the association of individual food groups and dietary patterns with lung cancer risk.

RESULTS

During a median follow-up of 7.13 y, 1782 incident lung cancer cases were documented. The association analysis showed high intake of red meat and processed meat was associated with an increased risk of lung cancer (HRper 50 g/d: 1.36; 95% CI: 1.13, 1.65 for red meat; HRper 25 g/d: 1.30; 95% CI: 1.10, 1.53 for processed meat). However, the consumption of fruits (HRper 100 g/d: 0.90; 95% CI: 0.84, 0.95), vegetables (HRper 100 g/d: 0.89; 95% CI: 0.81, 0.99), breakfast cereals (HRper 50 g/d: 0.81; 95% CI: 0.74, 0.89), and dietary fiber (HRper 5 g/d: 0.76; 95% CI: 0.69, 0.84) was inversely associated with the risk of lung cancer. For the dietary pattern analysis [quartile (Q) comparison], high adherence to the Prudent pattern (HRQ4 compared with Q1: 0.84; 95% CI: 0.73, 0.96) was associated with a lower risk of lung cancer, whereas the Western pattern (HRQ4 compared with Q1: 1.27; 95% CI: 1.11, 1.46) was associated with a higher risk of lung cancer.

CONCLUSIONS

Our study indicated that a diet characterized by high intake of fruits, vegetables, breakfast cereals, and dietary fiber, as well as low intake of red meat and processed meat, was associated with a lower risk of lung cancer.

Role of Citrus Fruit Juices in Prevention of Kidney Stone Disease (KSD): A Narrative Review

To explore the relationship between citrus fruit juices (oranges, grapefruits, and lemonades) and kidney stone disease (KSD).

METHODS

A systematic review was performed using the Medline, EMBASE, and Scopus databases, in concordance with the PRISMA checklist for all English, French, and Spanish language studies regarding the consumption of citrus fruit juices and the relationship to urinary stone disease. The main outcome of interest was the association of citrus fruit juices with KSD.

RESULTS

Thirteen articles met the criteria for inclusion in the final review. Three large epidemiological studies found that grapefruit juice was a risk factor for stone formation, while orange juice did not increase the risk for KSD. Ten small prospective clinical studies found that orange, grapefruit, and lemon juices all increased urinary citrate levels. Only orange and grapefruit juices had an alkalinizing effect and while lemon juice has a protective effect by raising urinary citrate levels, it lacked a significant alkalinizing effect on urine pH. Orange juice and grapefruit juices significantly increased urinary oxalate levels, while orange juice also had a high carbohydrate content.

CONCLUSION

While orange juice seems to play a protective role against stone formation, grapefruit was found to raise the risk of KSD in epidemiological studies but had a protective role in smaller clinical studies. Lemon juice had a smaller protective role than orange juice. Larger amounts of, as well as more accurate, data is needed before recommendations can be made and a high carbohydrate content in these juices needs to be taken into consideration.

Obesity-related indices and its association with kidney stone disease: a cross-sectional and longitudinal cohort study

Obesity increases the risk of several diseases, including kidney stone disease (KSD). The study aimed to explore the relationship between KSD and various obesity-related indices. A total of 121,605 participants in the Taiwan Biobank from December 2008 to February 2020 were analyzed. The association between self-reported history of KSD and eight obesity-related indices, including body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR), abdominal volume index (AVI), body roundness index (BRI), conicity index, and triglyceride glucose index was examined in cross-sectional analysis; additionally, the risk of developing kidney stones was analyzed in a longitudinal cohort of 25,268 participants without KSD at baseline, which was a subset of the main cohort. Of all participants, 77,904 (64.1%) were female. Overall, 10.7% of males and 4.0% of females had KSD. Multivariate-adjusted logistic regression showed that all obesity-related indices were significantly associated with KSD. During a mean follow-up of 47 months, kidney stones occurred in 642 (2.5%) participants, and after adjusting for confounders, the risk of developing kidney stones was higher in participants with higher BMI, WC, WHtR, WHR, AVI and BRI. BMI, WC, WHtR, WHR, AVI, and BRI were found to be associated with a higher prevalence of kidney stones as well as development of incident kidney stones, which could be used as predictive factors for development of KSD in clinical practice.

Coffee and Caffeine Consumption and Risk of Kidney Stones: A Mendelian Randomization Study

RATIONALE & OBJECTIVE

Coffee and caffeine consumption have been associated with a lower risk of kidney stones in observational studies. We conducted a Mendelian randomization study to assess the causal nature of these associations.

STUDY DESIGN

Mendelian randomization analysis.

SETTING & PARTICIPANTS

Independent genetic variants associated with coffee and caffeine consumption at the genome-wide significance level were selected from previously published meta-analyses as instrumental variables. Summary-level data for kidney stones were obtained from the UK Biobank study (6,536 cases and 388,508 noncases) and the FinnGen consortium (3,856 cases and 172,757 noncases).

EXPOSURE

Genetically predicted coffee and caffeine consumption.

OUTCOME

Clinically diagnosed kidney stones.

ANALYTICAL APPROACH

Mendelian randomization methods were used to calculate causal estimates. Estimates from the 2 sources were combined using the fixed-effects meta-analysis methods.

RESULTS

Genetically predicted coffee and caffeine consumption was associated with a lower risk of kidney stones in the UK Biobank study, and the associations were directionally similar in the FinnGen consortium. The combined odds ratio of kidney stones was 0.60 (95% CI, 0.46-0.79; P < 0.001) per a genetically predicted 50% increase in coffee consumption and 0.81 (95% CI, 0.69-0.94; P = 0.005) per a genetically predicted 80-mg increase in caffeine consumption.

LIMITATIONS

Genetic influence on kidney stone risk via pathways not involving coffee or caffeine.

CONCLUSIONS

Using genetic data, this study provides evidence that higher coffee and caffeine consumption may cause a reduction in kidney stones.

Nutrition and Kidney Stone Disease

The prevalence of kidney stone disease is increasing worldwide. The recurrence rate of urinary stones is estimated to be up to 50%. Nephrolithiasis is associated with increased risk of chronic and end stage kidney disease. Diet composition is considered to play a crucial role in urinary stone formation. There is strong evidence that an inadequate fluid intake is the major dietary risk factor for urolithiasis. While the benefit of high fluid intake has been confirmed, the effect of different beverages, such as tap water, mineral water, fruit juices, soft drinks, tea and coffee, are debated. Other nutritional factors, including dietary protein, carbohydrates, oxalate, calcium and sodium chloride can also modulate the urinary risk profile and contribute to the risk of kidney stone formation. The assessment of nutritional risk factors is an essential component in the specific dietary therapy of kidney stone patients. An appropriate dietary intervention can contribute to the effective prevention of recurrent stones and reduce the burden of invasive surgical procedures for the treatment of urinary stone disease. This narrative review has intended to provide a comprehensive and updated overview on the role of nutrition and diet in kidney stone disease.

Consumption of Tea, Alcohol, and Fruits and Risk of Kidney Stones: A Prospective Cohort Study in 0.5 Million Chinese Adults

A few prospective studies have suggested that tea, alcohol, and fruit consumption may reduce the risk of kidney stones. However, little is known whether such associations and their combined effect persist in Chinese adults, for whom the popular tea and alcohol drinks are different from those investigated in the aforementioned studies. The present study included 502,621 participants from the China Kadoorie Biobank (CKB). Information about tea, alcohol, and fruit consumption was self-reported at baseline. The first documented cases of kidney stones during follow-up were collected through linkage with the national health insurance system. Cox regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI). During a median of 11.1 years of follow-up, we collected 12,407 cases of kidney stones. After multivariable adjustment, tea, alcohol, and fruit consumption were found to be negatively associated with kidney stone risk, but the linear trend was only found in tea and fruit consumption. Compared with non-tea consumers, the HR (95% CI) for participants who drank ≥7 cups of tea per day was 0.73 (0.65-0.83). Compared with non-alcohol consumers, the HR (95% CI) was 0.79 (0.72-0.87) for participants who drank pure alcohol of 30.0-59.9 g per day but had no further decrease with a higher intake of alcohol. Compared with less-than-weekly consumers, the HR (95% CI) for daily fruit consumers was 0.81 (0.75-0.87). Even for those who did not drink alcohol excessively, increasing tea and fruit consumption could also independently reduce the stone risk. Among Chinese adults, tea, alcohol, and fruit consumption was associated with a lower risk of kidney stones.

17β-estradiol and ureteral contractility: A role for the G protein-coupled estrogen receptor

The aim of this study was to investigate the unknown effects of 17β-estradiol (E2) on ureteral contractility and the receptor and mechanisms involved. By utilising isolated porcine distal ureteral strips, we observed that E2 (30-300 μM) and a G protein-coupled estrogen receptor specific agonist G-1 (30 μM) both increased the frequency of phasic contractions of the ureter (P<0.05). E2 also decreased the maximum amplitude of these contractions (P<0.05). The G protein-coupled estrogen receptor specific antagonist G-36 (10 μM) reversed E2 enhancement effects on frequency, but did not alter its effects on maximum amplitude of contractile responses. Additionally, it was observed that the effects of E2 were unaltered by removing the urothelium, inhibiting nitric oxide and prostaglandin production or preventing neuronal conduction. In the presence of a potassium channel blocker, 4-aminopyridine (10 μM), the effects of E2 on frequency were prevented. This finding suggests that G protein-coupled estrogen receptor mediates the increase in frequency of ureteral phasic contractions induced by E2 via activation of potassium channels, while E2 alters the amplitude of these contractions through an unknown mechanism.

Tea and coffee consumption and the risk of urinary stones-a systematic review of the epidemiological data

OBJECTIVE

To explore the relationship between the consumption of coffee and tea with urolithiasis. We evaluated large epidemiological and small clinical studies to draw conclusions regarding their lithogenic risk.

METHODS

A systematic review was performed using the Medline and Scopus databases, in concordance with the PRISMA statement. English, French, and Spanish language studies regarding the consumption of caffeinated and decaffeinated coffee and tea, and the relationship to urinary stone disease were reviewed. Case reports and letters, unpublished studies, posters, and comments were excluded.

RESULTS

As per the inclusion criteria, 13 studies were included in the final review. Most studies, including four large prospective studies and one meta-analysis, reported a reduced risk of stone formation for coffee and tea. Caffeine has a diuretic effect and increases the urinary excretion of calcium, but if these losses are compensated for, moderate caffeine intakes may have little or no deleterious effects. Green and Herbal teas infused for short time had low oxalate content compared to black tea.

CONCLUSION

There is no evidence that moderate consumption of coffee raises the risk for stone formation in healthy individuals, provided the recommended daily fluid intake is maintained. The currently available literature supports in general a protective role for tea against the stone formation, mainly for green tea. However, heterogeneity of published data and lack of standardization needs to be addressed before final and clear conclusions can be given to patients and to the public in general.

Prevalence and Trends in Kidney Stone Among Adults in the USA: Analyses of National Health and Nutrition Examination Survey 2007-2018 Data

BACKGROUND

The contemporary prevalence and trends of kidney stones are not clear.

OBJECTIVE

To evaluate the gender-specific prevalence and trends in kidney stones among the US population.

DESIGN, SETTING, AND PARTICIPANTS

Data on self-reported history of kidney stones from 34 749 participants aged ≥20 yr from the National Health and Nutrition Examination Survey (NHANES) were analyzed.

INTERVENTION

Six 2-yr study cycles (2007-2008 to 2017-2018) of nationally representative series of surveys evaluated the health status of the US population.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Weighted prevalence estimates of kidney stones and 95% confidence intervals (CIs) were calculated in each study cycle. Multivariable-adjusted logistic regression models were used to investigate the temporal trends.

RESULTS AND LIMITATIONS

In the 2017-2018 cycle, the prevalence of kidney stones was 10.9% (CI: 9.3-12.7) in men as compared with 9.5% (CI: 8-11.2) in women. The prevalence of kidney stones increased steadily from 6.5% in the 2007-2008 cycle to 9.4% in the 2017-2018 cycle (p_trend = 0.001) among women but not among men (p_trend = 0.1). These trends remained after adjusting for sociodemographic correlates in both genders. Sensitivity analyses further adjusting for dietary information held the same results in trends (men: p_trend = 0.15; women: p_trend = 0.001). Non-Hispanic white ethnicity, obesity, gout, history of two or more pregnancies, menopause, and using female hormones were associated with a higher prevalence of kidney stones. The main limitation is the cross-sectional design of the study.

CONCLUSIONS

Although kidney stones are more common in men than in women in the USA, the gender gap in kidney stone prevalence appears to be closing in the past decade. Kidney stones are consistently higher among non-Hispanic white and obese, and women who have had multiple pregnancies or have used female hormone therapy.

PATIENT SUMMARY

The prevalence of kidney stones remains higher in adult US men than in women, but the trend has been increasing only in women, closing the gender gap in kidney stone prevalence.

The association of dietary inflammatory index with urinary risk factors of kidney stones formation in men with nephrolithiasis

Objective

Inflammation plays a leading role in the pathogenesis of nephrolithiasis. The association of the dietary inflammatory index (DII) with urinary lithogenic factors is unclear. This study aimed to evaluate the relation of DII to urinary risk factors of kidney stones formation.

Results

Of 264 participants, 61.4% (n = 162), 72% (n = 190), 74.6% (n = 197), 68.6% (n = 181), and 80.3% (n = 212) had hyperoxaluria, hypercreatininuria, hypercalciuria, hyperuricosuria, hypocitraturia, respectively. There was a significant increasing trajectory in urinary calcium, uric acid, and creatinine as well as a decreasing trend in urinary citrate across tertiles of DII score (all P = ≤0.001). After multivariate adjustment for energy intake, age, physical activity and body mass index, high DII scores were associated with elevated odds of having hypercreatininuria (OR = 2.80, 95%CI: 1.10–7.12, P_trend = 0.04), hypercalciuria (OR = 7.44, 95%CI: 2.62–21.14, P_trend ≤ 0.001), hyperuricosuria (OR = 2.22, 95%CI: 1.001–4.95, P_trend = 0.05), and hypocitraturia (OR = 5.84, 95%CI: 2.14–15.91, P_trend ≤ 0.001). No association was identified between DII and hyperoxaluria.

Dietary and lifestyle factors for primary prevention of nephrolithiasis: a systematic review and meta-analysis

BACKGROUND

Dietary and lifestyle factors may play an important role in the increasing prevalence of nephrolithiasis. We aimed to review and quantify the associations between lifestyle factors and incident nephrolithiasis and suggest lifestyle changes for the primary prevention of nephrolithiasis.

METHODS

PubMed, EMBASE, and Cochrane Library were searched up to May 2019, for observational studies and randomized controlled trials (RCTs) that assessed modifiable lifestyle factors and risk of nephrolithiasis in adults. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were computed using a random effects model. The I² statistic was employed to evaluate heterogeneity. Subgroup analysis, sensitivity analysis and meta-regression were also conducted whenever possible.

RESULTS

Fifty relevant articles with 1,322,133 participants and 21,030 cases in total were identified. Prominent risk factors for incident stones were body mass index (1.39,1.27-1.52), dietary sodium (1.38, 1.21-1.56), fructose, meat, animal protein, and soda. In contrast, protective factors included fluid intake (0.55, 0.51-0.60), a Dietary Approaches to Stop Hypertension (DASH) style diet (0.69, 0.64-0.75), alcohol (0.69, 0.56-0.85), water, coffee, tea, vegetables, fruits, dietary fiber, dietary calcium (0.83, 0.76-0.90), and potassium. Vitamin D (1.22, 1.01-1.49) and calcium (1.16, 1.00-1.35) supplementation alone increased the risk of stones in meta-analyses of observational studies, but not in RCTs, where the cosupplementation conferred significant risk.

CONCLUSIONS

Several modifiable factors, notably fluid intake, dietary patterns, and obesity, were significantly associated with nephrolithiasis. Long-term RCTs are required to investigate the cost-effectiveness of dietary patterns for stone prevention. The independent and combined effects of vitamin D and calcium supplementation on nephrolithiasis need further elucidation.

Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian-Vegan Diets

Nephrolithiasis is a common medical condition influenced by multiple environmental factors, including diet. Since nutritional habits play a relevant role in the genesis and recurrence of kidney stones disease, dietary manipulation has become a fundamental tool for the medical management of nephrolithiasis. Dietary advice aims to reduce the majority of lithogenic risk factors, reducing the supersaturation of urine, mainly for calcium oxalate, calcium phosphate, and uric acid. For this purpose, current guidelines recommend increasing fluid intake, maintaining a balanced calcium intake, reducing dietary intake of sodium and animal proteins, and increasing intake of fruits and fibers. In this review, we analyzed the effects of each dietary factor on nephrolithiasis incidence and recurrence rate. Available scientific evidence agrees on the harmful effects of high meat/animal protein intake and low calcium diets, whereas high content of fruits and vegetables associated with a balanced intake of low-fat dairy products carries the lowest risk for incident kidney stones. Furthermore, a balanced vegetarian diet with dairy products seems to be the most protective diet for kidney stone patients. Since no study prospectively examined the effects of vegan diets on nephrolithiasis risk factors, more scientific work should be made to define the best diet for different kidney stone phenotypes.