Frequent left ventricular hypertrophy independent of blood pressure in 1851 pre-western Inuit

BACKGROUND: Elevated blood pressure is a risk factor for cardiovascular disease and may be detected by left ventricular hypertrophy (LVH) in electrocardiogram (ECG). Pre-western Inuit had frequent signs of LVH in ECG predominantly in the 3rd decade while a low occurrence of ischemic heart disease.

METHODS: We evaluated the association between blood pressures and ECG signs of LVH, cardiac auscultation, and symptoms related to heart disease in the recently recovered data from the survey of 1851 Inuit conducted in 1962-1964 in East Greenland.

RESULTS: The participation rate was 97%. Among the 812 Inuit aged 18 years or above blood pressure was unaltered until the age of 39 years (systolic, p=76; diastolic, p=0.36) and increased subsequently (both, p<0.001). Systolic blood pressure >140 mmHg was more frequent when aged >40 years (p<0.001) and diastolic blood pressure >90 mmHg was more common in men (p<0.001) and in men and women aged >40 years (p<0.001). ECG signs of LVH were more frequent in men (p<0.01) but the occurrence decreased from the age of 40 years (p<0.01), and were not influenced by systolic (p=0.97), diastolic (p=0.87) or pulse pressure (p=0.69).

CONCLUSIONS: Blood pressure rose only after the age of 40 years in pre-western Inuit. Left ventricular hypertrophy peaked among 30-year olds and was independent of elevated blood pressure. It may be speculated that the common left ventricular hypertrophy was due to marked physical activity that contributed to the low occurrence of ischemic heart disease among pre-western Inuit.