The prevalence of bipolar disorder in China: A meta-analysis

Objective This is a meta-analysis of the prevalence of bipolar disorders (BD) in the general population of China. Methods A systematic literature search was conducted via the following databases: PubMed, EMBASE, PsycINFO, China National Knowledge Infrastructure (CNKI), WanFang and SinoMed. Studies on the prevalence of BD in the general population in China were identified. Statistical analyses were performed using the Comprehensive Meta-Analysis program. Results Altogether 32 studies conducted between 1984 and 2013 with 470,411 participants met the inclusion criteria for the analysis; the median age was 44.6 years and 49.6% of participants were female. The estimated point, 12-month and lifetime prevalence of BD in China were 0.09% (95% Confidence interval [CI]: 0.06–0.12%), 0.17% (95% CI: 0.10–0.29%) and 0.11% (95% CI: 0.07–0.17%), respectively. For BD-I, the estimated point, 12-month and lifetime prevalence rates were 0.06% (95% CI: 0.04–0.10%), 0.08% (95% CI: 0.02–0.30%) and 0.09% (95% CI: 0.05–0.16%), respectively. For BD-II, the estimated point and lifetime prevalence rates were 0.04% (95% CI: 0.02–0.06%) and 0.04% (95% CI: 0.02–0.09%), respectively. The 12-month prevalence of BD before the year 2010 was significantly lower than that after 2010 (0.12% vs. 0.26%, P=0.04). Meta-regression analysis revealed that younger age was significantly associated with higher 12-month prevalence of BD (coefficient=0.096, 95% CI: 0.027, 0.164, P=0.006). Conclusion This first meta-analysis of the pooled prevalence of BD in China found that rates are generally lower than those reported in Western countries. Future studies with more rigorous and refined methodology are needed.