Family History, BMI and Sympathetic Hyperactivity in Healthy Offsprings of Hypertensive Parents

Objective: Hypertension is associated with large and growing health and economic burden of Cardiovascular and renal diseases. Hypertension doubles the risk of cardiovascular disease, including coronary heart disease(CHD), congestive heart failure, ischemic and hemorrhagic stroke , renal failure and peripheral arterial disease. Recent study suggests prevalence of Hypertension is increasing as a consequence of increasing obesity. Both environmental and Genetic factors contribute to the increased prevalence of Hypertension. Obesity and weight gain are strong, independent risk factors for hypertension. Aim of this study was to assess relation between Family history, BMI and autonomic function tests in healthy offsprings of hypertensive parents. Method: The present study was conducted in 35 normotensive healthy offsprings of Hypertensive parents (Study Group) and 35 normotensive healthy offsprings of Nonhypertensive parents (Control Group), in the age groupof 18-21 years, randomnly selected from 1 st and 2 nd MBBS Students of Shri.BM patil Medical College. Bijapur. Results: There is also significant increase in sympathetic function tests and insignificant increase in the readings of parasympathetic function tests and significant increase in resting Respiratory rate and Resting Systolic Blood Pressure in study group compared to control group. Conclusion: This cross sectional study showed increase in prevalence of cardiac autonomic dysfunction more of sympathetic overactivity in normotensive healthy offsprings of Hypertensive parents, compared to normotensive healthy offsprings of Nonhypertensive parents.


INTRODUCTION
Hypertension is associated with a large and growing health and economic burden of Cardiovascular and renal diseases 1,2 .Hypertension doubles the risk of cardiovascular disease, including coronary heart disease(CHD), congestive heart failure, ischemic and hemorrhagic stroke , renal failure and peripheral arterial disease.
Recent study suggests that prevalence of Hypertension is increasing as a consequence of increasing obesity.Both environmental and Genetic factors contribute to the increased prevalence of Hypertension.Obesity and weight gain are strong, independent risk factors for hypertension.It has been estimated that 60% of hypertensives are >20% overweight 3 .About 30% of patients with primary hypertension have genetic predisposition 4 .The ANS maintains Cardiovascular homeostasis via pressure , volume and chemoreceptor signals 3 .In both normal weight and obese individuals, hypertension often is associated with increase in sympathetic outflow 3 .Aim of this study was to assess the relation between Family history, BMI and autonomic function tests in healthy offsprings of hypertensive parents.

MATERIALS AND METHOD
The present study was conducted in 35 normotensive healthy offsprings of Hypertensive parents (Study Group) and 35 normotensive healthy offsprings of Nonhypertensive parents (Control Group), in the age groupof 18-21 years, randomnly selected from 1 st and 2 nd MBBS Students of Shri.BM patil Medical College.Bijapur.

Subject on any medication
History of Chronic disease.

Smokers
Subject with a history of tobacco and alcohol intake.

Inclusion Criteria:
Only healthy subjects of Indian origin were included in the study.The subjects without the signs of Cardiovascular, Endocrinological, Neurological, Hematological and inflammatory diseases were selected for the study.Systolic BP (SBP) in the range of 90-139mm Hg, Diastolic BP(DBP) between 60-89 mmHg was considered for the study 2 .Informed Consent was taken from all the subjects in the study.
All the tests were done in morning hours to maintain uniformity among subjects.Subjects were informed about the procedure.

STATISTICAL ANALYSIS:
The ECG recordings for these tests were performed on Computerized 4 channel Physiopac(Medicaid). Blood pressure (BP) was measured with the help of mercury sphygmomanometer (Diamond).

RESULTS
Results were tabulated and analysed using 't'test.*p value <0.05 was considered Significant

DISCUSSION.
The present study was carried out in 70 healthy normotensive subjects (Offsprings of Hypertensive parents n=35, Offsprings of Nonhypertensive Parents n=35).In our study, we recored physical and physiological parameters in both control and study groups.Autonomic functions were assessed by Heart Rate response to Valsalva Maneuver, Heart rate response to deep breathing, Immediate heart rate response to standing (30:15 ratio): Blood pressure response to standing, Blood pressure response to sustained handgrip exercise.
Present study showed significant increase in Weight and height in study group Compared to control group.Our study is in accordance with studies done by Josiane M. Motta et al 7 Nafiu et al 8 Present study also showed significant increase in resting Respiratory rate and Resting Systolic Blood Pressure in Study group compared to control group.Our study is in accordance with studies done by Schneider GM et al, Lopes HF et al 9,10 There is also significant increase in sympathetic function tests and insignificant increase in the readings of parasympathetic function tests in study group compared to control group.Our study is in accordance with studies done by Rathi P et al 11 , Matthews CF et al 12.

CONCLUSION
This cross sectional study showed increase in prevalence of cardiac autonomic dysfunction more of sympathetic overactivity in normotensive healthy offsprings of Hypertensive parents, compared to normotensive healthy offsprings of Nonhypertensive parents.These tests can be used as routine tests for earlier detection of hypertension in persons who have genetic predisposition.Health promoting lifestyle modifications like regular physical activity, healthy diet are recommended for individuals with prehypertension.Prevention and treatment of obesity are also important factors for reducing blood pressure and cardiovascular disease risk.

Ethical Clearance:
The ethical clearance for the study was obtained from ethical committee.

Source of Funding: Self
Statistical analysis was done by Students t test using SPSS software version 20.p Value >0.05 is taken as not significant.p Value <0.05 is taken as significant.p Value <0.01 is taken as highly significant.p Value <0.001 is taken as very highly significant.