Association of nephrolithiasis with the intake of carbonated drinks.
Objective: To determine the association between the consumption of carbonated drinks and development of kidney stones. Study Design: Matched Case-control study. Setting: Liaquat National Hospital Karachi, Pakistan. Period: June 2017 to December 2017. Material & Methods: We recruited patients of nephrolithiasis admitted in Nephrology ward at Liaquat National Hospital as cases and controls from General Surgery ward. The sample size calculated was 186, with 93 cases and 93 controls, matched for age. Descriptive statistics of socio-demographic variables were computed. Multivariate logistic regression analysis was applied to determine the association between predictor and outcome variables. Results: A total of 186 patients participated in the study. Mean ages of the cases and controls were 34.92 (SD: 16.81) years and 31.76 (SD: 14.49) years, respectively. Around 66% of the cases and 75% of the controls had formal education. Approximately 16% of the cases and 10% of the controls were consuming soft drinks daily. Of them 77% were taking for more than 5 years. In multivariate analysis, we were unable to find significant associations between intake of carbonated drinks and kidney stones. However, the adjusted matched odds ratio (adj. mOR) for calcium intake was 6.36 (CI: 1.81- 22.33) and for caffeine intake was 7.9 (CI: 2.12 – 30.04). Those who had a past history of kidney diseases were at higher risk of developing kidney stones (mOR14.5; CI: 3.20- 65.76). Conclusion: The Study did not show any significant association of kidney stones with the intake of carbonated drinks. However, further longitudinal studies are required in order to confirm or refute any association between intake of carbonated drinks and nephrolithiasis.