The main characteristics of included studies regarding the association between the <i>GNB3</i> C825T polymorphism and hypertension.

HT, hypertension; SOC, source of control; PB, population-based, controls were blood donors, healthy controls matched for age, gender and domicile and participants in an health service programme from the same geographical region without clinically detectable hypertension; HB, hospital-based, controls were patients admitted to hospital without hypertension matched for age, gender and domicile; HWE, Hardy–Weinberg equilibrium; and MAF, minor allele frequency; Three publications [26]–[28] contained more than one independent population, therefore, we considered them as different studies. Two studies [57], [80] were limited to the relationship in males. The samples [54], [75] were from individuals of African descent.