Metabolic syndrome and risk of esophageal cancer by histological type: Systematic review and meta-analysis of prospective studies.

BACKGROUND

Previous epidemiological studies have provided inconsistent findings regarding the association between metabolic syndrome (MetS) and risk of esophageal cancer.

METHODS

We conducted a comprehensive literature search for prospective studies in MEDLINE and EMBASE databases through April 2024. Random-effects meta-analysis was used to calculate pooled hazard ratios (HR) with 95 % confidence intervals (CI) for the associations between MetS and risk of esophageal cancer by histological type. Between-study heterogeneity was assessed by Cochran's Q test and I statistics.

RESULTS

Among 8097 identified studies, six studies were included. MetS was associated with an increased risk of esophageal adenocarcinoma (pooled HR=1.24; 95 %CI, 1.07-1.42; P=0.392, I=3.8 %, N = 6), but not esophageal squamous cell carcinoma (HR=0.89; 95 % CI, 0.58-1.36; P=0.040, I=68.9 %, N = 3). An increased risk of esophageal adenocarcinoma was indicated for hyperglycemia (HR= 1.14; 95 % CI, 1.01-1.29; P=0.693, I=0.0 %, N = 3) and obesity (HR=1.50; 95 % CI, 1.24-1.82; P=0.191, I=34.5 %, N = 5), rather than the other components of MetS, i.e. hypertension or levels of triglyceride or high-density lipoprotein. Hypertension was associated with seemingly increased risk of esophageal squamous cell carcinoma (HR=1.39; 95 % CI, 0.93-2.09; P=0.030, I=71.4 %, N = 3), while obesity was associated with a decreased risk (HR=0.65; 95 % CI, 0.38-1.12; P=0.009, I=78.7 %, N = 3); no associations were observed for the other components of MetS with esophageal squamous cell carcinoma.

CONCLUSIONS

MetS, particularly hyperglycemia and obesity, may increase the risk of esophageal adenocarcinoma. MetS, by and large, may not influence the risk of esophageal squamous cell carcinoma.