Altered cardiovascular autonomic function in young normotensive offspring of hypertensive parents - Is obesity an additional risk factor?

Abstract

A study was undertaken to analyze the nature and magnitude of autonomic dysregulation that starts early in the offspring of a hypertensive parent and also whether obesity in them add an additional risk for future hypertension. Forty normotensive subjects aged 18-25 years with at least one hypertensive parent constitute the study group. The study group was divided into obese and non-obese depending on their body mass index (non-obese with BMI 18.50-24.99 kg/m2; obese with BMI≥30 kg/m2). Twenty age-matched normotensive, without parental history subjects constitute the control group. Anthropometric parameters, heart rate, systolic and diastolic pressures were recorded. Heart rate variability indices like total power, LF, HF, LF/HF, SDNN, RMSSD, and PNN50% were studied. One-way ANOVA was used for simultaneous multiple group comparison followed by post hoc Tukey's test for groupwise comparison. The Pearson correlation coefficient was used to assess the relationship between BMI and other variables. Subjects who were obese with parental history of hypertension showed significantly higher heart rate, diastolic blood pressure, LF, LF/HF ratio and reduced total power, HF, SDNN, RMSSD, and PNN50% compared to the other groups with normal BMI. HF and all the time domain indices showed negative correlation and LF a positive correlation with BMI. In the obese offspring of hypertensive parents, HRV markers, which represent a vagal dominance were reduced substantially, and indices of sympathetic activity were increased. So obesity in a normotensive offspring of a hypertensive parent is an additional risk factor for the future development of hypertension as it further dysregulates the autonomic control of the heart.