title: Body mass index and annual estimated GFR decline in Chinese adults with normal renal function.
abstract: OBJECTIVE
  The objective of this study was to examine the association between body mass index (BMI) and the annual estimated glomerular filtration rate (eGFR) decline in a rural lean Chinese cohort.
  
  
  METHODS
  A total of 2696 subjects with an eGFR ⩾ 60 ml/min per 1.73 m(2) were followed up for 7 years. Our primary outcome was annual eGFR decline, calculated as (eGFR at baseline-eGFR at revisit)/years of follow-up.
  
  
  RESULTS
  During the 7-year follow-up, the mean (s.d.) of annual eGFR decline was 1.7 (1.9) ml/min per 1.73 m(2) per year. Compared with subjects with normal weight (BMI 19-22.9 kg/m(2)), overweight subjects (BMI 23-26.9 kg/m(2)) had a more rapid annual eGFR decline (β, 0.33; 95% confidence interval (0.18-0.47) ml/min per 1.73 m(2) per year), whereas no significant difference was found when comparing the underweight (<19 kg/m(2)) and the obese (⩾ 27 kg/m(2)) groups with the normal-weight group. Moreover, in the 19- to 26.9-kg/m(2) range, BMI was positively linearly associated with annual eGFR decline (β2, 0.09 (0.05 to 0.12) ml/min per 1.73 m(2) per year, P<0.001), whereas in the <19 (β1, -0.21(-0.45-0.02), P = 0.073; β2 versus β1: P = 0.009) and ⩾ 27 kg/m(2) (β3, -0.24 (-0.48-0.00), P=0.053; β3 versus β2: P=0.010) range a negative but statistically insignificant trend of association was detected.
  
  
  CONCLUSIONS
  Our results suggested a nonlinear S-shaped association between BMI and annual eGFR decline among Chinese adults with normal renal function.
authors.affiliation: Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: 1] Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China [2] Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
authors.forename: X
authors.initials: X
authors.lastname: Qin
authors.affiliation: Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: D
authors.initials: D
authors.lastname: Xie
authors.affiliation: Institute of Biomedicine, Anhui Medical University, Hefei, China.
authors.forename: G
authors.initials: G
authors.lastname: Tang
authors.affiliation: Institute of Biomedicine, Anhui Medical University, Hefei, China.
authors.forename: H
authors.initials: H
authors.lastname: Xing
authors.affiliation: Institute of Biomedicine, Anhui Medical University, Hefei, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.affiliation: 1] Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China [2] Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.affiliation: 1] Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China [2] Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
authors.forename: F
authors.initials: F
authors.lastname: Hou
authors.affiliation: 1] Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China [2] Guangdong Institute of Nephrology, Southern Medical University, Guangzhou, China.
authors.forename: X
authors.initials: X
authors.lastname: Xu
mesh_terms: D000328:Adult; D044466:Asian People; D015992:Body Mass Index; D002681:China; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000503:physiopathology; D012424:Rural Population; D013997:Time Factors