The association of smoking with ultrasound-measured kidney dimensions
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Purpose: Ultrasound is considered a preferred first-line imaging technique for the assessment of kidney function. The potential relationship between tobacco smoke exposure and ultrasound-measured renal characteristics has yet to be explored. We hypothesized that exposure to tobacco smoke would be associated with reduced kidney dimensions. Materials and methods: This was a cross-sectional study that included all individuals over age 18 at a single site in Mojokerto, Indonesia. A questionnaire was used to assess prior history and environmental exposure, and blinded evaluators performed ultrasound assessments. Six kidney parameters (length, width, and parenchymal thickness of each kidney) were considered as dependent variables, and statistical relationships were assessed using multivariate analysis. Echogenicity was evaluated using a 5-point grading scale described previously. Results; Of the 445 participants assessed, a total of 138 male and 269 female subjects were included in the final analysis. There was a statistically significant association between kidney measures and the following independent variables: pack years smoking (p < 0.001), height (p < 0.001), weight (p < 0.001), and beginning to smoke at the age of 25 or younger (p < 0.001). There was not a statistically significant association between kidney measures and hypertension (p > 0.05) or diabetes (p > 0.05). Echogenicity was similar among all smoking groups. Conclusion: Kidney dimensions were decreased in individuals with increased smoking history. This association is notable, particularly given that statistically significant associations were not observed between renal dimensions and hypertension or diabetes. The null findings using echogenicity are consistent with previous studies.