Bidirectional association between NAFLD and gallstone disease: a systematic review and meta-analysis of observational studies

Background Growing evidence indicates an association between NAFLD and gallstone disease (GD), while some does not support this. The aim of this meta-analysis was to evaluate the bidirectional association between NAFLD and GD.Research design and methods Five electronic databases were searched from inception to May 2022. The association was analyzed based on the odds ratio (OR) and 95% confidence interval (CI) with Reviewer Manager 5.3.Results Ten studies involving 284,512 participants met the criteria for GD predicting the onset of NAFLD. GD patients had a higher incidence of NAFLD (OR:1.48, CI:1.32–1.65, p < 0.00001), especially the incidence of moderate-to-severe NAFLD (OR:1.63; CI:1.40–1.79), with females at a higher risk (OR: 1.84; CI: 1.48–2.29). The inverse association was explored in eight studies involving 326,922 participants. The GD incidence in NAFLD patients was higher (OR:1.71, CI:1.63–1.79, p < 0.00001) and may increase due to female sex (OR: 4.18; CI: 1.21–14.37) and high BMI (OR: 1.80; CI: 1.36–2.56), compared with the non-NAFLD group. Besides, this bidirectional association was also confirmed in the Chinese population.Conclusions The findings supported positive concurrent and bidirectional relationships between NAFLD and GD. Therefore, clinicians may alert the possibility of NAFLD in patients with GD and vice versa.