Butyrylcholinesterase K Variant and Alzheimer’s Disease Risk: A Meta-Analysis

BACKGROUND Although many studies have estimated the association between the butyrylcholinesterase (BCHE) K variant and Alzheimer's disease (AD) risk, the results are still controversial. We thus conducted this meta-analysis. MATERIAL/METHODS We searched NCBI, Medline, Web of Science, and Embase databases to find all eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. RESULTS We found a significant association between BCHE K variant and AD risk (OR=1.20; 95% CI 1.03-1.39; P=0.02). In the stratified analysis by ethnicity, we observed a significant association between BCHE K variant and AD risk in Asians (OR=1.32; 95% CI 1.02-1.72; P=0.04). However, no significant association between BCHE K variant and AD risk in Caucasians was found (OR=1.14; 95% CI 0.95-1.37; P=0.16). When stratified by the age of AD onset, we found that late-onset AD (LOAD) was significantly associated with BCHE K variant (OR=1.44; 95% CI 1.05-1.97; P=0.02). No significant association between BCHE K variant and early-onset AD (EOAD) risk was observed (OR=1.16; 95% CI 0.89-1.51; P=0.27). Compared with non-APOE ε4 and non-BCHE K carriers, no significant association between BCHE K variant and AD risk was found (OR=1.11; 95% CI 0.91-1.35; P=0.30). However, APOE ε4 carriers showed increased AD risk in both non-BCHE K carriers (OR=2.81; 95% CI 1.75-4.51; P=0.0001) and BCHE K carriers (OR=3.31; 95% CI 1.82-6.02; P=0.0001). CONCLUSIONS The results of this meta-analysis indicate that BCHE K variant might be associated with AD risk.