Dietary Factors and the Risk of Incident Kidney Stones in Younger Women: Nurses' Health Study II
ABSTRACT In older women and men, greater intakes of dietary calcium, potassium, and total fluid reduce the risk of kidney stone formation, while supplemental calcium, sodium, animal protein, and sucrose may increase the risk. Recently, phytate has been suggested to play a role in stone formation. To our knowledge, no prospective information on the role of dietary factors and risk of kidney stone formation is available in younger women.
We prospectively examined, during an 8-year period, the association between dietary factors and the risk of incident symptomatic kidney stones among 96 245 female participants in the Nurses' Health Study II; the participants were aged 27 to 44 years and had no history of kidney stones. Self-administered food frequency questionnaires were used to assess diet in 1991 and 1995. The main outcome measure was an incident symptomatic kidney stone. Cox proportional hazards regression models were used to adjust simultaneously for various risk factors.
We documented 1223 incident symptomatic kidney stones during 685 973 person-years of follow-up. After adjusting for relevant risk factors, a higher dietary calcium intake was associated with a reduced risk of kidney stones (P =.007 for trend). The multivariate relative risk among women in the highest quintile of intake of dietary calcium compared with women in the lowest quintile was 0.73 (95% confidence interval, 0.59-0.90). Supplemental calcium intake was not associated with risk of stone formation. Phytate intake was associated with a reduced risk of stone formation. Compared with women in the lowest quintile of phytate intake, the relative risk for those in the highest quintile was 0.63 (95% confidence interval, 0.51-0.78). Other dietary factors showed the following relative risks (95% confidence intervals) among women in the highest quintile of intake compared with those in the lowest quintile: animal protein, 0.84 (0.68-1.04); fluid, 0.68 (0.56-0.83); and sucrose, 1.31 (1.07-1.60). The intakes of sodium, potassium, and magnesium were not independently associated with risk after adjusting for other dietary factors.
A higher intake of dietary calcium decreases the risk of kidney stone formation in younger women, but supplemental calcium is not associated with risk. This study also suggests that some dietary risk factors may differ by age and sex. Finally, dietary phytate may be a new, important, and safe addition to our options for stone prevention.
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- "Similar results were obtained in further epidemiological studies carried out with the same methodology in following years, both in men and women. Hydration as to maintain urinary volume > 2.5 litres per day actually resulted in an average 30% relative risk reduction for kidney stone onset, compared with subjects with a poor hydration status (Curhan et al., 2004; Taylor et al., 2004). "
ABSTRACT: Adequate hydration, as to maintain urinary volume over 2 litres/day, has long been considered as the cornerstone medical prescription for preventing nephrolithiasis. However, scientific evidence about what kind of water stone formers should drink and about the effects of other beverages on urinary stone risk factors is sometimes unclear. Moreover, the recommendation that water therapy prevents kidney stone recurrence relies on only one randomized controlled trial, even if more epidemiologic and basic science studies seem to support this assumption. Therefore, in this review we analyze current evidence that support water therapy in nephrolithiasis and we highlight the possible effects of different types of water and other beverages on lithogenic risk, giving some practical recommendations for what stone formers should be advised to prevent recurrence.Critical reviews in food science and nutrition 05/2015; DOI:10.1080/10408398.2014.964355 · 5.18 Impact Factor
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- "Despite the challenges to linking water intake to health, the available evidence suggests that insufficient water intake is linked to some long-term health issues. Specifically, recent studies linking water intake and disease suggest a relationship between water, hydration, and recurrent kidney stone disease (urolithiasis)   , chronic kidney disease   , blood glucose regulation , and cardiovascular events . Collectively , these observations provide preliminary evidence that daily water intake above the minimum which is physiologically necessary to maintain total body water may confer additional benefits above simply maintaining total body water. "
ABSTRACT: While associations exist between water, hydration, and disease risk, research quantifying the dose-response effect of water on health is limited. Thus, the water intake necessary to maintain optimal hydration from a physiological and health standpoint remains unclear. The aim of this analysis was to derive a 24 h urine osmolality (UOsm) threshold that would provide an index of "optimal hydration," sufficient to compensate water losses and also be biologically significant relative to the risk of disease. Ninety-five adults (31.5 ± 4.3 years, 23.2 ± 2.7 kg·m(-2)) collected 24 h urine, provided morning blood samples, and completed food and fluid intake diaries over 3 consecutive weekdays. A UOsm threshold was derived using 3 approaches, taking into account European dietary reference values for water; total fluid intake, and urine volumes associated with reduced risk for lithiasis and chronic kidney disease and plasma vasopressin concentration. The aggregate of these approaches suggest that a 24 h urine osmolality ≤500 mOsm·kg(-1) may be a simple indicator of optimal hydration, representing a total daily fluid intake adequate to compensate for daily losses, ensure urinary output sufficient to reduce the risk of urolithiasis and renal function decline, and avoid elevated plasma vasopressin concentrations mediating the increased antidiuretic effort.Disease markers 04/2015; 2015:231063. DOI:10.1155/2015/231063 · 1.56 Impact Factor
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- "It has been described that a diet rich in animal protein could be associated to an increased risk of UC. The mechanism has been correlated to an increased urinary calcium excretion and a decreased excretion of citrate (Taylor et al. 2004; Curhan et al. 2004). Obesity has also been considered an independent risk factor in the onset of UC and both body mass index (BMI) and waist circumference measures resulted to be strongly associated (Taylor et al. 2005). "
ABSTRACT: The incidence of nephrolithiasis is rising worldwide, especially in women and with increasing age. Incidence and prevalence of kidney stones are affected by genetic, nutritional, and environmental factors. The aim of this study is to investigate the link between various meteorological factors (independent variables) and the daily number of visits to the Emergency Department (ED of the S. Croce and Carle Hospital of Cuneo for renal colic (RC) and urinary stones (UC) as the dependent variable over the years 2007–2010. The Poisson generalized regression models (PGAMs) have been used in different progressive ways. The results of PGAMs (stage 1) adjusted for seasonal and calendar factors confirmed a significant correlation (p < 0.03) with the thermal parameter. Evaluation of the dose–response effect [PGAMs combined with distributed lags nonlinear models (DLNMs)—stage 2], expressed in terms of relative risk (RR) and cumulative relative risk (RRC), indicated a relative significant effect up to 15 lag days of lag (RR > 1), with a first peak after 5 days (lag ranges 0–1, 0–3, and 0–5) and a second weak peak observed along the 5–15 lag range days. The estimated RR for females was significant, mainly in the second and fourth age group considered (19–44 and >65 years): RR for total ED visits 1.27, confidence interval (CI) 1.11–1.46 (lag 0–5 days); RR 1.42, CI 1.01–2.01 (lag 0–10 days); and RR 1.35, CI 1.09–1.68 (lag 0–15 days). The research also indicated a moderate involvement of the thermal factor in the onset of RC caused by UC, exclusively in the female sex. Further studies will be necessary to confirm these results.International Journal of Biometeorology 06/2014; 59(3). DOI:10.1007/s00484-014-0861-1 · 3.25 Impact Factor