FTO and Hypertension: Taking FTO–BMI and FTO–hypertension associations from the Hardy et al. and the Timpson et al. studies (Table 2), multiplying the age 53 years estimate (12.78 mmHg per SD of BMI) by the SNP–exposure association at age 20 years (0.1412) divided by the SNP–exposure association at age 53 years (0.0493) gives us the liability effect of BMI on SBP at age 20 years of 4.46 4.46 = 12.78 × 0.04930.1412.