MP03-04 IMPACT OF INSULIN RESISTANCE AND PHYSICAL ACTIVITY ON KIDNEY STONE FORMATION IN THE JAPANESE POPULATION

Abstract

INTRODUCTION AND OBJECTIVE: Development of kidney stones has been linked to metabolic syndrome, which is characterized by insulin resistance (IR). In this prospective study, we followed the baseline cohort for 5 years. This study aimed to examine the impact of IR and physical activity on incident kidney stones. METHODS: A prospective cohort study was performed involving 4,007 (2,084 men and 1,923 women) participants aged 35–79 years who voluntarily underwent medical examinations between April 2007 and August 2011 and were found free of kidney stones. Follow-up data were obtained at 5 years after baseline examination. Participants with diabetes mellitus or fasting glucose level ≥140 mg/dL at baseline were excluded. Based on homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin levels, the participants were divided into three groups: 1) “Control” group: HOMA-IR <2.5 and insulin <15.0 µU/mL; 2) “Moderate IR” group: HOMA-IR ≥2.5 and insulin <15.0 µU/mL; and 3) “Severe IR” group: HOMA-IR ≥2.5 and insulin ≥15.0 µU/mL. None of the participants had low HOMA-IR and high insulin level. Demographic variables and physical activities including walk and sedentary times were compared among the three groups. Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for incident kidney stones at 5 years after baseline. RESULTS: A total of 97 men (4.7%) and 45 women (2.3%) developed kidney stones at 5 years after baseline. At baseline, 1,878 men and 1,812 women were classified into the Control group, 158 men and 91 women into the Moderate IR group, and 48 men and 20 women into the Severe IR group. Body mass index, abdominal circumference, blood pressure, and triglycerides were significantly higher and high-density lipoprotein cholesterol was significantly lower, in the order corresponding to the Control, Moderate IR, and Severe IR groups. After adjustment for multiple variables, the Severe IR group was associated with kidney stone formation (OR, 2.91; 95% CI, 1.02–8.25) in men. Meanwhile, there was no difference between IR and kidney stone formation in women. Sedentary lifestyle was associated with IR. CONCLUSIONS: In Japanese men, severe insulin resistance was associated with kidney stone formation under normoglycemic conditions. Avoiding sedentary lifestyles could prevent kidney stone formation through improving insulin resistance. Source of Funding: none