Allometric body shape indices, type 2 diabetes and kidney function: A two-sample Mendelian randomization study

Diabetes Obes Metab. 2023 Jul;25(7):1803-1812. doi: 10.1111/dom.15037. Epub 2023 Mar 15.

Abstract

Aim: To examine the association between body mass index (BMI)-independent allometric body shape indices and kidney function.

Materials and methods: We performed a two-sample Mendelian randomization (MR) analysis, using summary statistics from UK Biobank, CKDGen and DIAGRAM. BMI-independent allometric body shape indices were: A Body Shape Index (ABSI), Waist-Hip Index (WHI) and Hip Index (HI). Kidney function outcomes were: urinary albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate and blood urea nitrogen. Furthermore, we investigated type 2 diabetes (T2D) as a potential mediator on the pathway to albuminuria. The main analysis was inverse variance-weighted random-effects MR in participants of European ancestry. We also performed several sensitivity MR analyses.

Results: A 1-standard deviation (SD) increase in genetically predicted ABSI and WHI levels was associated with higher UACR (β = 0.039 [95% confidence interval: 0.016, 0.063] log [UACR], P = 0.001 for ABSI, and β = 0.028 [0.012, 0.044] log [UACR], P = 6 x 10-4 for WHI) in women, but not in men. Meanwhile, a 1-SD increase in genetically predicted HI was associated with lower UACR in women (β = -0.021 [-0.041, 0.000] log [UACR], P = 0.05) and in men (β = -0.026 [-0.058, 0.005] log [UACR], P = 0.10). Corresponding estimates in individuals with diabetes were substantially augmented. Risk of T2D increased for genetically high ABSI and WHI in women (P < 6 x 10-19 ) only, but decreased for genetically high HI in both sexes (P < 9 x 10-3 ). No other associations were observed.

Conclusions: Genetically high HI was associated with decreased risk of albuminuria, mediated through decreased T2D risk in both sexes. Opposite associations applied to genetically high ABSI and WHI in women only.

Keywords: Mendelian randomization analysis; albuminuria; blood urea nitrogen; chronic; diabetes mellitus; glomerular filtration rate; kidney function tests; obesity; renal insufficiency; type 2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albuminuria / complications
  • Albuminuria / genetics
  • Diabetes Mellitus, Type 2* / complications
  • Diabetes Mellitus, Type 2* / epidemiology
  • Diabetes Mellitus, Type 2* / genetics
  • Female
  • Genome-Wide Association Study
  • Glomerular Filtration Rate
  • Humans
  • Kidney
  • Male
  • Mendelian Randomization Analysis
  • Somatotypes