Smoking is associated with renal impairment and proteinuria in the normal population: the AusDiab kidney study. Australian Diabetes, Obesity and Lifestyle Study.
BACKGROUND
Smoking has been associated with the prevalence, development, and progression of kidney disease. The effect of smoking on kidney function in the healthy population is unclear. We examined the relationship between smoking and indicators of kidney damage in a healthy population without impaired fasting glucose levels, impaired glucose tolerance, diabetes mellitus, or hypertension.


METHODS
This is a randomly selected, population-based, cross-sectional study of 11,247 Australian adults. Smoking status was determined by questionnaire. Subjects were tested for indicators of kidney damage: renal impairment by Cockcroft-Gault-estimated glomerular filtration rate less than 60 mL/min/1.73 m2 and proteinuria by urine protein-creatinine ratio of 0.20 mg/mg or greater.


RESULTS
After adjusting for potential confounding factors, smoking was significantly associated with renal impairment in men with an odds ratio of 3.59, but not in women. Smoking was significantly associated with proteinuria in subjects with high-normal systolic blood pressure, with odds ratios ranging from 3.64 at 131.5 mm Hg to 5.76 at 139.5 mm Hg, and in subjects with high-normal 2-hour glucose levels, with odds ratios ranging from 1.76 at 7.0 mmol/L to 10.84 at 7.7 mmol/L. Lifetime exposure, but not current level of smoking, correlated with lower estimated glomerular filtration rate and greater urine protein-creatinine ratio.


CONCLUSIONS
Smoking is associated with renal impairment and proteinuria in a population without hypertension or abnormal glucose metabolism. A dose-response relationship was found between cumulative amount of smoking and indicators of kidney damage. In conjunction with other studies and plausible biological mechanisms, this study suggests that smoking may cause kidney damage, even in a healthy population.
D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007674:Kidney Diseases / Q000453:epidemiology*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011507:Proteinuria / Q000453:epidemiology*; D011897:Random Allocation; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D013599:Systole
D003404:Creatinine