Left ventricular mass, abdominal circumference and age: the Fels longitudinal study.

PURPOSE: To determine the relationship of abdominal circumference with increased left ventricular mass (LVM) from young adulthood into old age.
METHODS: Cross-sectional echocardiographic images were taken from 182 men and 220 women in the Fels Longitudinal Study 20 to 75 years of age to determine left ventricular mass. Left ventricular mass was divided by stature raised to the power of 2.7 (LVM/ht2.7) in order to minimize the impact of heart size variation from body size without overcompensating for the adverse effect of obesity. Abdominal circumference was measured and BMI calculated from stature and weight and categories of overweight, obesity and abdominal obesity were determined using published cut points. Regression models were used to describe the relationships of age, abdominal circumference, BMI and self-reported physical activity to LVM/ht2.7.
RESULTS: Age, abdominal circumference and BMI were each positively and significantly related to an increased LVM/ht2.7 in men and women (p < 0.05). In the men, multivariate models indicated that abdominal circumference and BMI were both significantly related to an increased LVM/ht2.7, but the inclusion of BMI in these models for the women reduced the association of abdominal circumference and physical activity below significant levels. In the men, there was also a quadratic association of abdominal circumference with LVM/ht2.7 that was significant along with BMI and physical activity. Sex-specific logistic regressions with BMI and abdominal circumference obesity categories did not change or improve the initial findings in men or women.
CONCLUSIONS: In women, increases in abdominal fatness as reflected in abdominal circumference at any age are linearly related to an increase in LVM/ht2.7, but the relationship of overall fatness as reflected in BMI with LVM/ht2.7 is stronger. In men, both abdominal fatness and overall fatness at any age are linearly related to an increase LVM/ht2.7. However, the significant curvilinear association of abdominal circumference and a linear association of BMI and physical activity with LVM/ht2.7 indicate the possible positive covariate relationship of overall muscle mass with LVM/ht2.7. This reflects the physiological changes with age and demonstrate, in part, the complexity of the interpretations of the inter associations of body composition, the cardiovascular system and the aging process, but the impact among the elderly and the known inadequacy of BMI at these ages remains an area for continued clinical study.