After stratification by age (≥ 65 years or < 65 years), sex, race, education, marital status, PIR, walking or cycling for transportation (min/week), work activity (min/week), recreational activity (min/week), stage of CKD, and urinary albumin/creatinine ratio, subgroup analyses showed that an inverse relationship still existed between SB and depression in all stratifications (Fig. 2). The gene discussed is ALB; the disease is major depressive disorder.