APOE and diabetes mellitus: In the sensitivity analysis, only heterozygous-APOE ε4 carriers had a 4% higher MCF (95% CI 1–7%, p = 0.016) which persisted after adjusting for sex and SEP (95% CI 1–7%, p = 0.013), and BMI (95% CI 1–7%, p = 0.018), but was attenuated to 3% after adjusting for CVD (95% CI 0–6%, p = 0.043, diabetes (95 CI % 0–7%, p = 0.060), or hypertension (95% CI 0–6%, p = 0.028, Table 5, Supplementary Table S4) in the meta-analysis.