title: Changes in uric acid levels following bariatric surgery are not associated with SLC2A9 variants in the Swedish Obese Subjects Study.
abstract: OBJECTIVE
  Obesity and SLC2A9 genotype are strong determinants of uric acid levels. However, data on SLC2A9 variants and weight loss induced changes in uric acid levels are missing. We examined whether the changes in uric acid levels two- and ten-years after weight loss induced by bariatric surgery were associated with SLC2A9 single nucleotide polymorphisms (SNPs) in the Swedish Obese Subjects study.
  
  
  METHODS
  SNPs (N = 14) identified by genome-wide association studies and exonic SNPs in the SLC2A9 gene locus were genotyped. Cross-sectional associations were tested before (N = 1806), two (N = 1664) and ten years (N = 1201) after bariatric surgery. Changes in uric acid were compared between baseline and Year 2 (N = 1660) and years 2 and 10 (N = 1172). A multiple testing corrected threshold of P = 0.007 was used for statistical significance.
  
  
  RESULTS
  Overall, 11 of the 14 tested SLC2A9 SNPs were significantly associated with cross-sectional uric acid levels at all three time points, with rs13113918 showing the strongest association at each time point (R(2) = 3.7-5.2%, 3.9×10(-22)≤p≤7.7×10(-11)). One SNP (rs737267) showed a significant association (R(2) = 0.60%, P = 0.002) with change in uric acid levels from baseline to Year 2, as common allele homozygotes (C/C, N = 957) showed a larger decrease in uric acid (-61.4 µmol/L) compared to minor allele carriers (A/X: -51.7 µmol/L, N = 702). No SNPs were associated with changes in uric acid from years 2 to 10.
  
  
  CONCLUSIONS
  SNPs in the SLC2A9 locus contribute significantly to uric acid levels in obese individuals, and the associations persist even after considerable weight loss due to bariatric surgery. However, we found little evidence for an interaction between genotype and weight change on the response of uric acid to bariatric surgery over ten years. Thus, the fluctuations in uric acid levels among the surgery group appear to be driven by the weight losses and gains, independent of SLC2A9 genotypes.
authors.affiliation: Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sarzynski
authors.forename: Peter
authors.initials: P
authors.lastname: Jacobson
authors.forename: Tuomo
authors.initials: T
authors.lastname: Rankinen
authors.forename: Björn
authors.initials: B
authors.lastname: Carlsson
authors.forename: Lars
authors.initials: L
authors.lastname: Sjöström
authors.forename: Claude
authors.initials: C
authors.lastname: Bouchard
authors.forename: Lena M S
authors.initials: LM
authors.lastname: Carlsson
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000379:methods*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D051246:Glucose Transport Proteins, Facilitative / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D013548:Sweden; D013997:Time Factors; D014527:Uric Acid / Q000378:metabolism*
chemical_list: D051246:Glucose Transport Proteins, Facilitative; C411811:SLC2A9 protein, human; D014527:Uric Acid