Presentation Authors: Ryosuke Ando*, Sadao Suzuki, Takeshi Nishiyama, Hiroko Nakagawa, Akihiro Hosono, Miki Watanabe, Nagoya, Japan, Tamaki Yamada, Okazaki, Japan, Kazumi Taguchi, Shuzo Hamamoto, Atsushi Okada, Keiichi Tozawa, Kenjiro Kohri, Takahiro Yasui, Nagoya, Japan
Introduction: Kidney stone development has been linked to metabolic syndrome (MetS), which is characterized by insulin resistance. In a previous cross-sectional analysis, we reported that the homeostasis model assessment of insulin resistance (HOMA-IR) and serum insulin levels are associated with a history of kidney stones. In this prospective study, we followed the baseline cohort for 5 years. The aim of this study was to examine the impact of insulin resistance on incident kidney stones.
Methods: A prospective cohort study was performed in 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 free of kidney stones. Follow-up data were obtained at 5 years after baseline examination. Insulin resistance was defined by high HOMA-IR (â‰¥2.5) or hyperinsulinemia (â‰¥15.0Î¼U/mL). Participants with diabetes mellitus or fasting glucose â‰¥140 mg/dL at baseline were excluded. Demographic variables were compared between subjects with or without insulin resistance at baseline. Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for incident kidney stone at 5 years after baseline. All procedures were approved by the Nagoya City University Institutional Review Board.
Results: A total of 97 men (4.7%) and 45 women (2.3%) developed kidney stones at 5 years after baseline. At baseline, 48men (2.3%) and 20 women (1.0%) were diagnosed with hyperinsulinemia and 206 men (9.9%) and 111 women (5.8%) had high HOMA-IR values. Body mass index, abdominal circumference, blood pressure, and triglycerides were significantly higher, and high-density lipoprotein cholesterol was significantly lower, in subjects of both sexes with insulin resistance. After adjustment for multiple variables, hyperinsulinemia was associated with kidney stone formation (OR, 3.06; 95% CI, 1.09-8.55) in men. On the other hand, there was no difference between insulin resistance and kidney stone formation in women.
Conclusions: In Japanese men, hyperinsulinemia was associated with kidney stone formation. The mechanism by which sex differences in insulin resistance affect kidney stone development is uncertain; however, there could be an interaction between insulin resistance and sex on kidney stone formation.