Univariate MR analysis results showed that: genetically predicted OSA was associated with decreased estimated glomerular filtration ratecystatin c (eGFRcystatin c) level (OR = 0.997, 95% CI: 0.995–0.999, P < .05), increased blood urea nitrogen (BUN) levels (OR = 1.023, 95% CI: 1.008–1.038, P < .05), increased serum creatinine levels (OR = 1.010, 95% CI: 1.002–1.018, P < .05), increased serum cystatin C levels (OR = 1.015, 95% CI: 1.005–1.026, P < .05). This evidence concerns the gene CST3 and obstructive sleep apnea syndrome.