Association between sarcopenic obesity and kidney stones: evidence from a prospective cohort study on the UK Biobank.

BACKGROUNDS: Kidney stone disease (KSD) is closely linked to metabolic disturbances, and sarcopenic obesity (SO) has been proven as a risk factor in multiple diseases. This study is to probe the prospective association and potential mediators between SO and KSD.

METHODS

We conducted a prospective cohort analysis of 157,505 participants from the UK Biobank. The primary exposure was SO, defined by body mass index, handgrip strength, and muscle mass. Participants were classified as control group, obesity alone, sarcopenia alone, and SO group. The primary outcomes were the incidence and onset time of KSD. The potential mediators were multiple insulin resistance-related indexes and inflammatory markers. The models adjusted for social characteristics, personal lifestyle habits, dietary factors, blood biochemistry, and baseline disease history. We applied Cox regression models, cumulative incidence curves, sensitivity analysis, hierarchical and interaction analysis, and mediation analysis to probe these associations.

RESULTS

Among the 157,505 participants, 7,501 (4.76%) had sarcopenia alone, 1,407 (0.89%) had SO, and 1,592 participants (1.01%) developed KSD. In cumulative incidence curves, compared with the control group, a higher incidence of KSD was observed in the SO group. In fully adjusted models, the incident KSD risk was elevated by 48% (95%CI:1.32–1.67), 33% (95% CI: 1.05–1.68), and 83% (95% CI: 1.26–2.67) in the obesity alone group, sarcopenia alone group, and SO group, respectively. Four sensitivity analyses yielded consistent results. In different genders and ages, the increased risk of KSD associated with SO shows some differences: in females, males, participants aged < 60 and ≥ 60 years old, the KSD risk in participants with SO increased by 108% (95%CI:1.18–3.68), 69% (95%CI:1.02–2.80), 103%(95%CI:1.23–3.33), and 61% (95%CI:0.90–2.88), respectively. Triglyceride-glucose (TyG), triglyceride/high-density lipoprotein cholesterol (TG/HDL-C), neutrophil, white blood cell (WBC), C-reactive protein (CRP), monocyte, and CRP-to-Albumin ratio (CAR) partially mediate the association between SO and KSD, with proportions mediated (PM) of 11.2%, 7.2%, 4.5%, 2.7%, 8.7%, 1.2%, and 8.9%, respectively (all P < 0.01).

CONCLUSIONS

Sarcopenia and SO are significantly associated with an elevated incident KSD risk. Insulin resistance and inflammation play a significant partial mediating effect between SO and KSD. Participants with SO should pay attention to the prevention of kidney stones.