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ORIGINAL ARTICLE
Year : 2015  |  Volume : 4  |  Issue : 1  |  Page : 8-12

Prehypertension among Medical Students and its Association with Cardiovascular Risk Factors


1 Associate Professor of Cardiology, Andhra Medical College/King George Hospital, Visakhapatnam, India
2 Postgraduate in Orthopedics, Konaseema Institute of Medical Sciences, Amalapuram, Andhra Pradesh, India

Date of Web Publication16-Mar-2015

Correspondence Address:
Dr. Ravi Venkatachelam Chitrapu
Associate Professor of Cardiology, Andhra Medical College, King George Hospital, Visakhapatnam
India
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Source of Support: The study was done as part of the Summer Term Scholarship awarded to Zeeshan Muzahid Thakkallapalli but there was no financial grant to conduct the study., Conflict of Interest: None


DOI: 10.4103/2277-8632.153296

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  Abstract 

Aims and Objectives: To assess the prevalence of prehypertension among medical students and its association with cardiovascular risk factors.
Materials and Methods: Blood pressure and anthropometric data were measured in 275 medical students. An oral glucose tolerance test and lipid profile results were compared in 30 prehypertensives and 30 normotensives.
Results: The overall prevalence of prehypertension in the study sample was 37.45% (103/275) while, 3.63% (10/275) were hypertensive. Prevalence was similar in boys and girls and was associated with a greater mean weight, body mass index and waist circumference, when compared to normotensives. Glucose tolerance and lipid profile levels were similar in both groups.
Conclusion: Prehypertension is prevalent in more than a third of medical students and is associated with body weight, calling for adoption of healthy lifestyle measures to control weight and thus prevent hypertension.
(ClinicalTrials.gov Identifier: NCT01776294)

Keywords: BMI, cardiovascular risk factors, medical students, prehypertension, weight


How to cite this article:
Chitrapu RV, Thakkallapalli ZM. Prehypertension among Medical Students and its Association with Cardiovascular Risk Factors. J NTR Univ Health Sci 2015;4:8-12

How to cite this URL:
Chitrapu RV, Thakkallapalli ZM. Prehypertension among Medical Students and its Association with Cardiovascular Risk Factors. J NTR Univ Health Sci [serial online] 2015 [cited 2019 Dec 12];4:8-12. Available from: http://www.jdrntruhs.org/text.asp?2015/4/1/8/153296


  Introduction Top


The Joint National Commission 7 (JNC 7) on Prevention, Detection, Evaluation and Treatment of High Blood Pressure, released in May 2003, caused a flutter, when it introduced a new term /stage in the spectrum of hypertension, by introducing the concept of "prehypertension" which referred to those persons with a systolic blood pressure of 120-139 or diastolic BP of 80-89. [1] The aim of the JNC-7 was to increase awareness of near-abnormal levels of BP [2] so that such "prehypertensives" would initiate lifestyle changes to delay development of frank hypertension. A meta-analysis of a million adults had shown that in the age group of 40-69, each increase of 20 mm Hg of SBP or about 10 mm Hg of DBP was associated with a two-fold increase in the stroke death rate, and two-fold increase in death rate due to ischemic heart and other vascular diseases. [3] Subsequent studies have shown that prehypertension does increase the risk of cardiovascular morbidity, independently of other risk factors. [2],[4] A recent meta-analysis of 18 prospective cohort studies has shown that prehypertension increases the risk of cardiovascular disease by a relative risk (RR) of 1.55, the risk of coronary heart disease by an RR of 1.5 and that of stroke by an RR of 1.71; an enhanced risk (RR of 1.46) was noticed even in the lower range of prehypertension. [4] Several research papers, meta-analyses, review articles, etc. have been published on the prevalence of prehypertension in several groups, its association with other cardiovascular risk factors and cardiovascular disease and treatment benefits. [5],[6],[7],[8],[9],[10]

Studies from India have given varied prevalence of prephypertension, ranging from 20% to 80%. [11],[12],[13],[14],[15],[16],[17],[18] A study of tribal adults (>20 years) in 9 states in mid and south India showed that 42.4% of men and 39% of women had prehypertension (the corresponding figures for normal BP and hypertension were 32.4%, 25.2% and 38%, 23%, respectively). [11] A study of 1746 adults in Lucknow showed 32.3% to have prehypertension; [12] 300 staff of a medical college in Puducherry showed a prevalence of 22%; [13] a study of 504 individuals in rural Bareilly of Uttar Pradesh showed a prevalence of 27.2%. [14] A high prevalence of 80% was noted when 767 military adults were examined. [15] A study of 500 medical students in a college in Karnataka showed a high prevalence (55%) of prehypertension. [16] School children (n = 1085) in Shimla too had a prehypertension (BP between 90% and 95%) prevalence of 12.3% [17] while in 5 schools of Anand district of Gujarat (n = 1087), it was 10.8%. [18]

The present study was undertaken to assess the prevalence of prehypertension among medical students of a government medical college in a city in Andhra Pradesh and its association with other cardiovascular risk factors. The students hailed from urban and rural backgrounds.


  Aims and Objectives Top


To determine the prevalence of prehypertension among medical college students and study the association between prehypertension and cardiovascular risk factors viz. body mass index (BMI), waist circumference (WC), glucose tolerance and lipid profile.


  Materials and Methods Top


A total of 275 medical students of first to final year MBBS in the age group 17-25 were included in the study. There were 148 males and 127 females. History and clinical findings were obtained. Blood pressure was measured by a qualified doctor, with a mercury sphygmomanometer, as per JNC 7 guidelines. [1] Disappearance of Korotkoff sounds (onset of phase 5) was taken as diastolic pressure. Two measurements were obtained and the average was taken as blood pressure. Subjects were classified as:

  • Normotensive (systolic blood pressure (SBP) <120 mmHg and diastolic BP (DBP) <80 or
  • Hypertensive (SBP >140 Or DBP >90) or
  • Prehyperensive (SBP 120-139 Or DBP 80-89)


Weight and height were measured with standard instruments and waist circumference measured at the level of the umbilicus. [19]

Then, 30 normotensives and 30 prehypertensives were selected randomly for estimating lipid profile and glucose tolerance. After an overnight fast, fasting venous blood sample was collected for estimation of plasma glucose and lipids. Then they were given 75 grams of glucose mixed in 300 ml of water and plasma glucose was estimated 2 h later. Glycemic status was classified as

  • Normal fasting glucose if plasma glucose <100 mg% (5.6 mmol/l).
  • Impaired fasting glucose if FG 100-125 (5.6-6.9).
  • Impaired glucose tolerance if 2 h. glucose 140-199 (7.8-11.1).
  • Diabetes if FG > 126 mg% (7 mmol/l) or 2 h glucose >200 (11.1). [20]


Data was expressed as mean and standard deviation. t-test was used to compare means and chi-square test to compare proportions.


  Results Top


Blood pressure

The overall prevalence of prehypertension among the whole group was 37.45% as 103 of 275 students (37.45%) were prehypertensive while 162 (58.9%) were normotensive. 10 students (3.63%) were hypertensive. The prevalence of prehypertension among boys and girls was similar (58/148 (39.18%) vs. 45/127 (35.43%)) (P = NS).



Weight

The mean weight of the prehypertensive group of students was 61.69 ± 11.86 kg and was significantly higher than that of the normotensive group which was 57.03 ± 8.84 kg (P = 0.0007).

Similarly the mean body mass index of the prehypertensive group (22.49 ± 3.67) was significantly higher than of the normotensive group (21.16 ± 2.94) (P = 0.002).

The mean waist circumference too was higher among the prehypertensives (80.16 ± 9.57 cm) than in the normotensives (77.2 ± 7.33 cm) (P = 0.008).



However, when the students in both groups were categorized based on their BMI, the proportion of subjects who were underweight, normal, overweight and obese were similar in the prehypertensives as well as in the normotensives (P = NS), as shown below. About 8.6% (14/162) of normotensives and 11.6% (12/103) of prehypertensives were overweight with a BMI between 25 and 29.9, while 2 and 4 subjects in the two groups, respectively, were obese (BMI ≥ 30). Most of the subjects were in the normal BMI category.



A total of 30 subjects from the normotensive group and 30 from the prehypertensive group were randomly selected and tested for their fasting blood sugar, 2 h post-glucose blood sugar and fasting lipid profile.

Glucose tolerance test

The mean fasting glucose and 2 h blood glucose levels were similar in normotensives and prehypertensives (p = NS) = 77.46 ± 4.41 mg% vs. 77.38 ± 11.87 mg% and 90.46 ± 9.27 mg% vs. 95.46 ± 23.37 mg%. (P = 0.97 and 0.31, respectively).

One student with prehypertension was found to have mild diabetes and was advised lifestyle modification and regular follow-up.

Lipid profile

There was no statistically significant difference in the mean levels of lipids (Total Cholesterol, LDL, HDL, VLDL and Triglyceride) between the prehypertensive and normotensive groups.




  Discussion Top


The present study included 275 medical students with a male preponderance (M:F ratio of 1.16:1).

The overall prevalence of prehypertension in the entire group was 37.45%. The prevalence was similar in boys and girls -39.18% and 35.43%, respectively. Hypertension was found in 3.63% of students of whom nine were male and one was female.

The prevalence of prehypertension in the present study is higher than the 21.7% prevalence reported from a study in a medical college in Puducherry [13] but is lower when compared to several other studies in medical students. A study of 100 medical students in Davangere showed a prevalence of prehypertension in 64% [21] while two studies of 100 boys + girls and 150 girls in a medical college in Wardha showed a prevalence of prehypertension in 52% and 58% respectively. [22],[23] A third study from a medical college in Dehradun among 400 students also revealed an overall prevalence of prehypertension of 58.75%. [24]

A study of 500 medical students in a Mangalore college showed a point prevalence of 55.4%. [16] A possible reason for the lower prevalence of prehypertension in our group could be the lower prevalence of overweight among our students. The Mangalore group had a higher prevalence of overweight of 31.8% (159/500) compared to the present study which showed a prevalence of 12.1% of overweight + obesity in the entire group. A positive correlation has been shown between prehypertension and BMI in these studies among boys [16] among girls [23] and in both genders in the third study. [21] Our study also revealed a higher mean BMI among prehypertensives compared to normotensives, though the proportions of overweight and obese subjects in the two groups were not statistically significant. The lower BMI in our study group could be one reason for the lower prevalence of prehypertension in them. Our college has a large playground with facilities for cricket, basketball, tennis, etc. and a gymnasium, all of which are well utilized by the students and the college hosts 2 or 3 sports events each year. This could explain a lower BMI rate and lower prehypertension prevalence in our group of students. One limitation of our study is that BP was recorded only on a single day - a repeat measurement after a week would have probably given a lower prevalence.

There was a significant association between excess weight and prehypertension in our study, similar to findings in other studies. [16],[21],[22],[23] A study from Israel concluded that BMI was the strongest predictor of prehypertension among males and females. [25] A study among medical students in coastal Karnataka has found a significant correlation between prehypertension and BMI in boys [16] while a study in Jamaica found a relation to overweight/obesity and waist circumference among younger prehypertensives. [26] A population study from China also concluded that BMI was a major determinant of prehypertension even after controlling for gender, lipid profile, uric acid, insulin resistance, smoking and drinking. [27] In the present study, the mean weight, body mass index and waist circumference, were all significantly higher among the prehypertensive group compared to the normotensive subjects. The mean weight was 61.7 kg in the former which was more than 4 kg heavier than the latter with a mean of 57 kg. Similarly the mean waist circumferences in the two groups were about 80.2 cm and 77.2 cm respectively, while the mean BMI was a point higher that is 22.5 and 21.2, respectively. However, the proportion of students in different categories of BMI (underweight, normal, overweight, obese) was similar among normotensives and prehypertensives.

Studies have found an association of dyslipidemia, overweight and glucose intolerance with prehypertension. [12],[25],[27],[28],[29] A population study in China in 1154 subjects found that total cholesterol and triglycerides were significantly higher in prehypertensives compared to normotensives but LDL and HDL were similar; [27] BMI and waist circumference were of course higher among the prehypertensives. The Puducherry study too reported similar relation to the lipid profile. [13]

Studies have also reported an association between prehypertension and glucose intolerance with the Lucknow study of 1746 adults (>30 yrs) showing, from multiple logistic regression analysis that impaired glucose tolerance, along with age, BMI and obesity were independent risk factors for hypertension and prehypertension. [12] A study in 83 prehypertensives found a higher response to oral glucose tolerance test suggesting insulin resistance, but the fasting glucose levels were similar to normotensives. [30]

However, in the present study, the mean fasting and 2-hour blood glucose levels were similar in both the groups. Similarly there was no significant difference in lipid profile between the samples of prehypertensives and normotensives tested. One reason could be the small sample size as financial constraints made us randomly select only 30 prehypertensives and 30 normotensive controls for testing their lipid profile. A study from Iran among 892 adults (>30 years) however found, from multivariate logistic regression analysis, that overweight /obesity was the strongest predictor for prehypertension with an odds ratio of over 2.5 followed by male gender (OR = 1.89), while diabetes, cholesterol, triglyceride, HDL and LDL were not significantly associated. [31] The authors, like others, recommend healthy lifestyle methods including exercise for maintaining a normal weight and preventing obesity and overweight as most studies have found that BMI /weight is a very strong predictor of prehyperension. [16],[31],[24]


  Conclusion Top


In conclusion, our study among healthy medical students found a prevalence of prehypertension of 37.45% and this was associated with a higher mean weight, BMI and weight circumference, calling for adoption of healthy lifestyle measures from the student period itself.


  Acknowledgement Top


Indian Council for Medical Research (ICMR) which granted the summer term scholarship to Zeeshan to conduct this project.

 
  References Top

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  In this article
Abstract
Aims and Objectives
Materials and Me...
Results
Discussion
Conclusion
Acknowledgement
Introduction
References

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