In a prospective cohort of 181 individuals followed up since childhood – when aged 9, 12 and 15 years – patients with a family history of premature coronary heart disease (n=18) had higher left ventricular mass index in adulthood – at mean age of 31 years – compared with those without (mean±standard error 39.1±1.9 versus 34.6±0.7 g/m2.7, p=0.04). The correlation between adult left ventricular mass index and child triglycerides (r=0.66, p=0.04 versus r=−0.03, p=0.75; pdiff=0.02) and diastolic blood pressure (r=0.65, p=0.02 versus r=0.16, p=0.07; pdiff=0.05) was stronger among those with a family history of coronary heart disease than in those without. Although preliminary, these data suggest that the higher left ventricular mass index among adults with a family history might be explained by their increased susceptibility to child cardio-metabolic risk factors.