Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
Advanced Dermatology and Cosmetic Surgery - Alexandria, VA.
Cancer Epidemiol Biomarkers Prev. 2023 Oct 2;32(10):1323-1327. doi: 10.1158/1055-9965.EPI-22-0801.
Acidic urine pH is associated with rapid hydrolysis of N-glucuronide conjugates of aromatic amines into metabolites that may undergo metabolism in the bladder lumen to form mutagenic DNA adducts. We previously reported that consistently acidic urine was associated with increased bladder cancer risk in a hospital-based case-control study in Spain. Here, we conducted a separate study in northern New England to replicate these findings.
In a large, population-based case-control study conducted in Maine, New Hampshire, and Vermont, we examined bladder cancer risk in relation to consistent urine pH, measured twice daily by participants over 4 consecutive days using dipsticks. In parallel, we collected spot urine samples and conducted laboratory measurements of urinary acidity using a pH meter. Unconditional logistic regression was used to estimate associations, adjusting for age, gender, race, Hispanic status, and state. Analyses were further stratified by smoking status.
Among 616 urothelial carcinoma cases and 897 controls, urine pH consistently ≤ 6.0 was associated with increased bladder cancer risk (OR = 1.27; 95% confidence interval, 1.02-1.57), with the effect limited to ever-smokers. These findings were supported by analyses of a spot urine, with statistically significant exposure-response relationships for bladder cancer risk overall (Ptrend = 5.1×10-3) and among ever-smokers (Ptrend = 1.2×10-3).
Consistent with a previous study in Spain, our findings suggest that acidic urine pH is associated with increased bladder cancer risk.
Our findings align with experimental results showing that acidic urine pH, which is partly modifiable by lifestyle factors, is linked to hydrolysis of acid-labile conjugates of carcinogenic aromatic amines.
酸性尿液 pH 值与芳香胺的 N-葡萄糖醛酸轭合物迅速水解为代谢物有关，这些代谢物可能在膀胱腔中发生代谢，形成致突变的 DNA 加合物。我们之前的研究报告表明，在西班牙的一项基于医院的病例对照研究中，尿液持续呈酸性与膀胱癌风险增加有关。在这里，我们在新英格兰北部进行了一项独立的研究，以复制这些发现。
在缅因州、新罕布什尔州和佛蒙特州进行的一项大型基于人群的病例对照研究中，我们通过参与者在连续 4 天内每天使用两次尿试纸测量尿液 pH 值，研究了与尿液 pH 值一致性相关的膀胱癌风险。同时，我们收集了点尿样，并使用 pH 计进行了尿液酸度的实验室测量。使用非条件逻辑回归来估计关联，调整年龄、性别、种族、西班牙裔身份和州。分析进一步按吸烟状况进行分层。
在 616 例尿路上皮癌病例和 897 例对照中，尿液 pH 值持续≤6.0 与膀胱癌风险增加相关（OR=1.27；95%置信区间，1.02-1.57），这种效应仅限于曾吸烟者。这些发现得到了点尿分析的支持，总体上膀胱癌风险存在统计学显著的暴露反应关系（Ptrend=5.1×10-3），且在曾吸烟者中（Ptrend=1.2×10-3）也存在这种关系。
与西班牙的先前研究一致，我们的研究结果表明，酸性尿液 pH 值与膀胱癌风险增加有关。
我们的研究结果与实验结果一致，表明酸性尿液 pH 值部分受生活方式因素影响，与致癌芳香胺的酸不稳定轭合物的水解有关。
