Association of chronic constipation and chronic diarrhea with renal stones: a cross-sectional study of the National Health and Nutrition Examination Survey 2007-2010.

Background: Renal stone is a highly prevalent life-long disease with a high recurrence rate. Chronic bowel diseases, including chronic gastrointestinal symptoms (chronic constipation or chronic diarrhea), are common gastrointestinal problems. We aimed to evaluate the associations of chronic constipation and chronic diarrhea with renal stones.

Methods: This large-scale, cross-sectional study was performed within participants (≥20 years old) from the National Health and Nutrition Examination Survey from 2007 to 2010. Logistic regression and sensitivity analyses were conducted to clarify the association between chronic bowel diseases and renal stones.

Results: A total of 8,067 participants aged ≥20 years were included. The prevalence of renal stones is 9.14%. Chronic diarrhea was positively related to the risk of renal stones [odds ratio (OR) =1.681, 95% confidence interval (CI): 1.212 to 2.330, P=0.004] after adjusting for all covariates. In participants with body mass index (BMI) over 30 kg/m², chronic constipation was correlated with kidney stones in fully adjusted model 2 (OR =2.142, 95% CI: 1.389 to 3.303, P=0.004).

Conclusions: Our findings provide evidence that chronic diarrhea is associated with an increased risk of renal stones. Chronic constipation is positively related to the risk of renal stones in participants with BMI over 30 kg/m². Health care should focus more on bowel health status for the prevention of related diseases. More prospective cohort studies are needed.