Associations of markers in 11 obesity candidate genes with maximal weight loss and weight regain in the SOS bariatric surgery cases.

PURPOSE: To test whether DNA sequence variation in 11 obesity genes is associated with maximum weight loss and weight regain over 6 years of follow-up in bariatric surgery patients of the Swedish obese subjects (SOS) intervention study.

METHODS

A total of 1443 subjects were available for analysis (vertical banded gastroplasty: n = 966, banding: n = 293 and gastric bypass: n = 184). Single-nucleotide polymorphisms (SNPs) from the following 11 genes were included: ADIPOQ, BDNF, FTO, GNB3, LEP, LEPR, MC4R, NR3C1, PPARG, PPARGC1A and TNF. General linear models were used to analyze associations between the SNPs and maximum weight loss and weight regain.

RESULTS

The average maximum weight loss was 33.7 kg (s.d. 13.3; min -95.5 kg, max +2.0 kg), which was reached 2.2 (s.d. 1.6) years after the surgery. Subjects regained approximately 12 kg (range 0.0-51.4 kg) by year 6. After correcting for multiple testing, the FTO SNP rs16945088 remained significantly associated with maximum weight loss (P = 0.0002), as minor allele carriers lost approximately 3 kg less compared with common allele homozygotes. This association was particularly evident in the banding surgery patients (P < 0.0001), whereas no significant association was found in the gastric bypass subjects. No other SNPs were associated with maximum weight loss. Furthermore, no SNPs were significantly associated with weight regain.

CONCLUSION

The FTO SNP rs16945088 was associated with maximum weight loss after banding surgery. We found no evidence that obesity-risk SNPs in FTO or other obesity candidate genes derived from genome-wide association studies are associated with maximum weight loss or weight regain over 6 years of follow-up in bariatric surgery patients. The potential role of other obesity genes remains to be investigated.