Gross Olfaction Before and After Laparoscopic Gastric Bypass

Obes Surg. 2017 Nov;27(11):2988-2992. doi: 10.1007/s11695-017-2733-3.


Background: Obesity leads to olfaction alterations, and this can further impact food choices, appetite, and nutritional status. Bariatric procedures induce weight loss and change in taste and smell perception, but more information is needed, especially using objective olfaction tests.

Methods: A prospective study was conducted during 6 months, with candidates to laparoscopic gastric bypass at a single institution. A preoperative nasofibroscopy and gross smell identification test (The Pocket Smell Test ®) were performed in those meeting the inclusion criteria. After 6 months, a new test was performed, and the primary objective was to determine if there was an improvement in the olfaction score. Weight loss and comorbidities improvement were also analyzed.

Results: From the 30 patients with morbid obesity enrolled, 21 met the inclusion criteria and ENT evaluation. At baseline, 42.8% of patients scored 3 points, 53.3% scored 2 points, and 4.7% scored 1 point. After 6 months, there was a -81.1% of change. Seventeen patients scored 3 points (p = 0.002 vs initial) and two scored 2 points (p = 0.006 vs initial). There were no patients with less than 2 points. Weight and comorbidities had a significant improvement as well.

Conclusion: Laparoscopic gastric bypass improves the olfaction scores of the Pocket Smell Test in morbidly obese patients 6 months after their procedure. More complex tests can be used in candidates to bariatric surgery if low scores are detected initially. Other causes of olfaction dysfunctions should be determined if there is no improvement after weight loss.

Keywords: Bariatric surgery; Laparoscopic gastric bypass; Obesity; Olfaction; Olfactory; Smell.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Comorbidity
  • Female
  • Follow-Up Studies
  • Gastric Bypass / methods
  • Gastric Bypass / statistics & numerical data*
  • Humans
  • Laparoscopy / methods
  • Laparoscopy / statistics & numerical data
  • Male
  • Obesity, Morbid / complications
  • Obesity, Morbid / epidemiology*
  • Obesity, Morbid / physiopathology
  • Obesity, Morbid / surgery*
  • Olfaction Disorders / complications
  • Olfaction Disorders / epidemiology*
  • Olfaction Disorders / surgery
  • Postoperative Period
  • Preoperative Period
  • Smell / physiology*
  • Taste / physiology
  • Weight Loss / physiology
  • Young Adult