Cigarette smoking and incident chronic kidney disease: a systematic review.

BACKGROUND

Several studies have examined the role of cigarette smoking in the development of renal disease in human populations. However, there have been no systematic reviews on the evidence linking smoking with incident renal disease.

METHODS

We performed an evidence-based evaluation of peer-reviewed research published during 1966-2005, from a search of five databases, including Ovid MEDLINE and EMBASE.

RESULTS

Of the 28 studies that were reviewed, 11 were excluded from the final analysis due to poor methodological quality (n = 6), no reported risk estimate for the association between smoking and kidney disease (n = 3), inability to find a Japanese translator (n = 1), and duplicate cohort (n = 1). Seventeen studies were included in the final analysis; seven studies found an overall significant association between smoking and incident chronic kidney disease, and three studies found a significantly increased risk of chronic kidney disease in current smokers that was gender and/or dose related. An increased risk of developing chronic kidney disease among smokers was significantly associated with male gender (relative risk 2.4, 95% confidence interval 1.2-4.5), >20 cigarettes smoked/day (odds ratio 1.51, 95% confidence interval 1.06-2.15, and relative risk 2.3, 95% confidence interval 1.2-4.3), and smoking >40 years (odds ratio 1.45, 95% confidence interval 1.00-2.09). A pooled estimate of the relative risk (meta-analysis) was deemed inappropriate due to the heterogeneity in methodologies utilized by the different studies.

CONCLUSIONS

This comprehensive review reveals overall evidence for current cigarette smoking as a risk factor for incident chronic kidney disease. Further investigation is needed to more carefully examine the strength of the association between cigarette smoking and incident kidney disease.