group locus on chromosome 9 is known to explain approximately 10% of phenotypic variation for vWF16, through modification of the amount of H antigen expression on the circulating vWF glycoprotein18,19. The estimate of hG2 for weight is 18.6% (s.e. = 2.8%). Because of the high phenotypic correlation between BMI and weight (r = 0.92), results for these two traits are very similar. We therefore report results for BMI in the following sections and for completion give all results for weight in the supplementary online material.
