Genetic variants of glucose-dependent insulinotropic polypeptide (GIP) signalling as proxy for body weight reduction and cardiovascular risk

BACKGROUND AND AIMS: Anti-obesity therapies co-targeting the glucose-dependent insulinotropic polypeptide (GIP) receptor achieve greater weight loss compared with glucagon-like peptide-1 receptor agonists. However, the implications for cardiovascular risk reduction and the mechanisms involved remain unclear. This study aimed to (i) investigate whether genetically proxied body weight reduction via the GIP receptor pathway lowers cardiovascular disease risk and (ii) compare the effect to polygenic weight reduction, excluding GIP-related genes, to assess if the observed benefits are attributable to weight loss per se or involve additional GIP-related effects. METHODS: Genetic scores were constructed using four variants in GIP-related genes associated with lower body mass index (BMI) and 31 variants linked to lower BMI in general. Observational and one-sample Mendelian randomization (MR) analyses were performed in 408 056 individuals from the UK Biobank and two-sample MR analyses using summary statistics from 419 821 individuals in FinnGen. RESULTS: In one-sample MR analyses, 1 kg/m² lower BMI via the GIP/GIPR score was associated with 29% lower risk of major adverse cardiovascular events (MACE) (P = .0002) and 43% lower risk of heart failure (P = 5 × 10⁻⁵). Corresponding lower risks with the polygenic BMI score were 3% (P = .002) and 13% (P < 1 × 10-300). Two-sample MR analyses showed similar results. Of the reduced risk via the GIP/GIPR score, BMI and glycated haemoglobin (HbA1c) mediated 13% and 22% of the lower risk of MACE and 16% and 17% of the lower risk of heart failure (all P ≤ 7 × 10-5). CONCLUSIONS: Genetic proxies for body weight reduction via GIP receptor targeting reduces the risk of MACE and heart failure, mediated partly through lower BMI and partly through lower HbA1c.