Association between circulating CTRP12 levels and type 2 diabetes: A meta-analysis

BACKGROUND C1q/TNF-related protein 12 (CTRP12) is an important adipokine that plays a critical role in the regulation of energy metabolism and is considered to have potential protective effects in the development of type 2 diabetes mellitus (T2DM). AIM To conduct a comprehensive systematic review and meta-analysis of published papers evaluating the association between CTRP12 levels and the risk of T2DM. METHODS A literature search of PubMed, Web of Science, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, VIP Chinese Science Journals Database, Wanfang, and SinoMed was conducted to identify studies published up to November 2025. Thirteen cohort studies met the inclusion criteria after stepwise screening. Given the substantial heterogeneity among studies, pooled estimates were derived using a random-effects model. Subgroup analyses were undertaken to explore potential sources of variability. Publication bias was assessed using Egger’s and Begg’s tests, along with funnel plot inspection. RESULTS The 13 studies included in the analysis involved 2193 participants including patients with T2DM and healthy controls. Meta-analysis demonstrated that circulating CTRP12 levels were significantly lower in patients with T2DM than those in healthy controls (Z = 6.96, P < 0.00001). Sensitivity analysis showed stable results, indicating robust pooled effects. Subgroup analysis suggested that heterogeneity primarily originated from participants’ body mass index and the homeostasis model assessment of insulin resistance. Quality assessment showed that most included studies achieved relatively high Newcastle-Ottawa Scale scores, suggesting that the overall methodological quality was generally satisfactory. CONCLUSION The meta-analysis demonstrated that circulating CTRP12 levels were significantly reduced in individuals with T2DM. This finding suggests that CTRP12 may exert protective effects in disorders of glucose and lipid metabolism.