Hyposalivation is prevalent in bariatric patients but improves after surgery

Background: Obesity and type 2 diabetes can be associated with poor oral health. This can be because of hyposalivation leading to chronic oral inflammation (OI) and periodontal disease.

Objective: To assess the prevalence of hyposalivation and OI in individuals undergoing Roux-en-Y gastric bypass (RYGB) and determine the relationship with metabolic and anthropometric parameters before and after RYGB.

Setting: University hospital in Canada.

Methods: This was a cross-sectional and prospective cohort study of 59 patients undergoing RYGB from September 2015 to December 2019. Anthropometric, biochemical, and oral measurements were taken before surgery and 1 and 6 months post RYGB. Oral parameters included salivary flow rate and neutrophil count as marker of OI.

Results: Fifty-nine patients were enrolled with 29 completing this study. At baseline, the median age was 47 years and body mass index was 46.5 kg/m², 52 (88.1%) were female and 14 individuals (23.7%) had type 2 diabetes; 54.2% (n = 32) of patients had hyposalivation and 13.6% (n = 8) had high neutrophil count. Patients with hyposalivation had significantly higher fasting glucose (5.7 mmol/L) compared with those without hyposalivation (5.2 mmol/L) but no difference was found between high versus low neutrophil count. At 6 months post RYGB, all variables except oral neutrophil count significantly improved. Hyposalivation persisted in 7 (24%) individuals.

Conclusions: In our bariatric patients, more than half the patients had hyposalivation before RYGB and this was associated with higher fasting glucose. Hyposalivation improved post RYGB in parallel with improvements in metabolic parameters but there was no change in OI. Increased salivation may reduce the risk of periodontal disease.

Keywords: Bariatric surgery; Hyposalivation; Obesity; Oral health; Type 2 diabetes.