BLOOD PRESSURE AND ANTHROPOMETRY OBESITY INDICES IN FIRST PROFESSIONAL MEDICAL STUDENTS AT A PRIVATE MEDICAL COLLEGE OF PAKISTAN – A CROSS-SECTIONAL STUDY

ABSTRACT


INTRODUCTION
Hypertension is a major public health concern in Pakistan and other countries because of its rising trend and significant association with adverse cardiovascular outcomes and premature morbidities. It is a preventable noncommunicable disease and effective time management of hypertension can reduce the incidence of coronary artery disease, stroke, and metabolic syndrome-related derangements 1 . About one-fourth of the adult population globally is suffering from hypertension and this figure is expected to be 29% in 2029. On the basis of the evaluation of different population-based surveys, the pooled prevalence of hypertension in Pakistan was reported to be 26.43% with a higher urban burden (26.6%) as compared to that of the rural (21.3%). Prevalence in males was 24.99% and in females it was 24.74%. Its preponderance in the adult population was reported to be 23.23% 2 . Another epidemiological survey in Pakistan reported the age-adjusted prevalence of hypertension in Pakistan to be 46%, where 25% is self-reported and 21% is newly diagnosed 3 . The evolution of behavioral and environmental changes as a result of rapid urbanization, modernization, and economic up-gradation have been linked with the global crisis of hypertension.
Changing trends in sociocultural and lifestyle influences have also been reported to be associated with the universal rise in non-communicable diseases such as obesity, hypertension, and metabolic syndrome 4 .
Obesity is an epidemic worldwide now and according to an estimate by World Health Organization (WHO), 57.8% of the population will be identified as obese by 2030. Obesity is defined as excessive and abnormal fat accumulation that is associated with considerable comorbidities such as metabolic syndrome, insulin resistance, adverse coronary artery, and circulatory events. WHO and the National Institute of Health both have considered body mass index (BMI) as a criterion for obesity. It is the first screening step in the evaluation of an adult or pediatric subject for obesity. The data from National Health and Nutrition Examination survey states that obesity (based upon BMI> 30kg/m 2 ) affects 35% of males and 40% of females in the United States. Its burden in Asian adult males and females is about 12.5% respectively 5, 6 .
Two commonly employed methods to determine whether one is a normal healthy weight or not are BMI and waist circumference measurements. BMI is calculated by dividing the weight (taken in kilograms) by the height (taken in meter square). It has certain limitations as it does not distinguish whether the fraction of weight is due to muscle or fat and it also can not discriminate about the fat distribution arrangement. Reliance on BMI alone is inadequate as susceptibility to obesitylinked comorbidities depends upon individual variations in the pattern of fat distribution 7 . Carrying excessive waist fat is significantly associated with a higher health risk as compared to the fat in thighs and buttocks. Therefore, waist circumference measurement is an estimation of alarming visceral fat that is coating the internal organs 8 . In addition to the above-mentioned anthropometric health indices, waist-to-hip ratio and mid-upper arm circumference have also been shown to be associated with central obesity, insulin resistance, and type 2 diabetes mellitus 9 . Mid-upper arm circumference measured midway between the acromion and olecranon of the ulna is a body composition indicator in children and adults. It represents muscle mass and subcutaneous fat. Its value of less than 12.5 cm indicates malnutrition and greater than 13.5 cm is considered normal 10 . Asian Indians are at higher risk of getting obesity-related complications at a lower BMI and waist circumference as compared to white Caucasians. Therefore in this ethnic group, diagnosis of overweight and obese is done in accordance with the guidelines of Asian Indians at BMI cut-offs; ≥23kg/m 2 and 25kg/m 2 ; the cut-offs for central obesity in males and females are waist circumference ≥90 cm and 80 cm respectively 11 .
Obesity a significant public health issue requires immediate attention to prevent obesity-mediated health concerns. Previous studies have reported prevalence of obesity among medical students to be 10-20% and hypertension 4-15%. There is an increased risk of developing these health issues at an early age due to physical inactivity, academic load, faulty lifestyle with an intake of sugary trans-fat-rich food, and use of mobiles or gadgets 12 . Medical education is a full-time stressful training span due to the quantity and quality of the study required, examination strain, and discrepancy between the expectations and outcome. These various psychological and physical modes of stress have resulted in premature onset of obesity and hypertension in medical undergraduates. Determination and management of modifiable risk elements at an early age should be a basic preventive educational strategy.
The present study aimed to determine blood pressure and anthropometric obesity indices (including BMI, waist circumference, waist-to-hip ratio, and mid-upper arm circumference) of 1st Professional MBBS students at a private medical college, in Lahore, Pakistan and also to find an association of BP with anthropometric indices.

MATERIALS AND METHODS
It was a cross sectional survey conducted in the Department of Physiology, Lahore Medical and Dental College (LMDC), Lahore, Pakistan. Duration of the study was three months from May 2022 to August 2022. Study population included all students registered in first year MBBS (150 students) who agreed to participate in the study. Sampling technique was convenience sampling. The inclusion criteria were both male and female subjects with age ranging from 18-30 years, and having normal cardiac and respiratory functions. Whereas, the exclusion criteria were participants with history of liver, respiratory, and cardiovascular diseases.

Data Collection Procedure
A structured questionnaire was used consisting of two sections. The first section of the questionnaire contained; background information of study participants such as gender (male or female), pre-medical qualification (F, Sc., A levels or American Board), and residential status (day scholar or residing in hostel). The second section included anthropometric indices and blood pressure. Blood pressure was taken using a standard mercury sphygmomanometer with the correct cuff size for arm circumference. Subject was made to sit on a chair with straight back and feet touching the ground. He was rested for 5 minutes before taking BP. Two BP readings were taken at an interval of 5 minutes and average of the two was taken 13 . Unit of measurement was milimeter of mercury. Every subject's height was measured in meters while the participant stood still without shoes and weight was measured to the nearest 0.1 kg with electronic weight scale in kilograms with the participant lightly clothed. BMI was calculated as weight divided by square of height (kg/m 2 ) 14 . Waist circumference was measured in centimeters at the midpoint between the bottom of the ribs and the top of the iliac crest with nonstretchable measuring tape at the end of expiration. Subjects were in standing erect posture, arms by the side and feet nearly approximated 15 . Hip circumference was measured in cm at the widest extension of the buttocks. Waist to hip ratio was calculated by dividing these two values with each other. Mid upper arm circumference was measured in cm midway between the acromion of scapula and olecranon process of ulna with a nonstretchable measuring tape and rounded to the nearest 0.1 cm 16 .

Waist circumference (WC):
A WC of >90 cm in males and >80 cm in females is considered for abdominal obesity 20,21,22 .

Waist to hip ratio (W/H):
• Women should have W/H ratio of 0.85 or less than this.
• Men should have W/H ratio of 0.9 or less than this.
• A ratio higher than 1.0 for either sex means a much higher chance of health problems. This is in accordance with WHO guidelines.

Mid upper arm circumference (MUAC):
A measurement of <23cm in men and <22 cm in women will be considered low and a value >30.9 cm in males and > 30 cm in females will be considered high 23 .

Ethical Considerations
College Institutional Review Board (IRB) approval was acquired before commencement of the study. Informed verbal consent was obtained from the study participants, assuring maintenance of confidentiality during data processing and publication of the study results.

Data Analysis
Data were entered, cleaned and analyzed using Statistical Package for Social Sciences (SPSS), version 25. Descriptive statistics was used in terms of number, percentages and mean scores. Chi square test was applied to find the association of BP with gender and anthropometric measurements. Binary logistic regression was used to find the association of BP with anthropometric measurements by controlling the confounder variables.

RESULTS
The present study included 120 participants. Out of total, 55 (46%) were males and 65 (54%) females. Mean ± standard deviation (SD) age of the participants was 19.05±0.82 years. Characteristics of the study population are presented in Table.1. Mean systolic and diastolic BP of the participants was 116.05±13.21 and 74.85±9.81 respectively. However, 67 (56%) participants were having their BP ≥ 120/80 mm of mercury and were identified as pre-hypertensive or hypertensive respectively and 53 (44%) were having normal BP. Out of 67 (56%) participants with deranged BP; 31 (26%) were hypertensive {10(8%) with stage 1 and 21 (17.5%) with stage 2 hypertension} and the rest 36 (30%) were having elevated BP (as presented in Figure-1). This grading of BP is in accordance with American Heart Association guidelines 17,18 . Three blood pressure measurements on multiple days for a clinical diagnosis of hypertension were undertaken. On application of chi-square test (nonadjusted model) there was significant association of hypertension with anthropometry indices such as BMI, waist circumference and mid upper arm circumference there was no significant association with waist to hip ratio (Table 3). Logistic regression analysis (adjusted model) was applied (Table 4) where hypertension was taken as dependent variable and all other independent covariates such as anthropometry indices (BMI, waist circumference, waist to hip ratio, mid upper arm circumference), gender, age and residential status were controlled; association of hypertension remained significant with gender (p=0.001) and waist circumference (p=0.000). (Normal BP is defined as: Systolic <120 and diastolic <80 mm of mercury. Elevated BP is: systolic BP of 120-129 and diastolic <80 mm of mercury. Hypertension: systolic BP of >130 or a diastolic BP of ≥80 mm of mercury).

DISCUSSION
The present study aimed to determine BP and anthropometry obesity indices of 1st year MBBS students. The mean systolic and diastolic BP of the subjects was found to be 116±13.21 and 74.85±9.81 respectively. These values were within the normal range and in accordance with the BP guidelines set by the American Heart Association 17 . However 26% of the study subjects were having their BP >130/80 ( Figure 1) and were identified as hypertensive and 30% were prehypertensive 18 . This observation was in concordance with that of a previous study conducted on students of a medical school from Karnataka, India 24 . Another study from Qasim University, Saudi Arabia, reported 21% prevalence of hypertension among 130 medical students 25 . A study from Lincoln Memorial University reported 26% prevalence of hypertension in preclinical medical students 26 . A crosssectional study on 1st and 2nd year American medical students reported prevalence of pre-hypertension of 16% and hypertension 29% respectively 27 . There was no history of smoking by any of the participants in the current study. However, hypertension was significantly associated with male gender. Out of 55 male subjects 22 were hypertensive, whereas 9 out of 65 females were hypertensive. There was 4 times increased risk of hypertension in males as compared to the females. This finding was in accordance with the previous studies on University students of Jordon and Saudi Arabia within the age group of 18-26 year as mentioned above.
Anthropometry obesity indices of the medical students were also measured and on the basis of BMI; 55.8% subjects were within the normal range, 16.7% were overweight and 27.5% were obese (figures: 2-4). This grouping was based upon ethnic specific guidelines for South East Asians; as previous studies have revealed that Asian ethnic class is at risk of diabetes mellitus and adverse coronary events at a lower body fat status. Asian Indians also have higher accumulation of hepatic and perivisceral fat at a BMI of non-obese level (23-25 Kg/m 2 ) considered for other races.
Central adiposity indicators such as waist circumference or waist to hip ratio cut-off is also lower in Asian Indian ethnic group. Following these guidelines in this study 29% male and 27% female participants were having central adiposity, which is directly linked with insulin resistance, poor glucose disposal and future morbidities. Present results are in concordance with the previous epidemiological studies on Pakistanis, South Asians and Asian Indians 28 .
In the current study, when chisquare test was applied there was significant association of hypertension with the obesity indices such as BMI, waist circumference and mid upper arm circumference. No considerable association was found with waist to hip ratio (tables 3,4). However, after controlling the confounder variables with the binary logistic statistics, significant association remained with gender and waist circumference. These results were in accordance with the previous study on Americans reporting significant association of hypertension with waist circumference 29 . Various studies have highlighted waist circumference as a prime determinant of cardiovascular and all-cause mortality beyond body mass index. Waist circumference is robustly related to absolute peri-visceral and abdominal fat mass compared to BMI. It is a considerable clinical marker in identifying the high risk adiposity phenotype 29 . In this study we were unable to find significant association of BP with BMI in adjusted model after controlling all the anthropometry indices however previous studies conducted on medical students in Pakistan reported significant association of BP with BMI 30,31 . According to the present study, abdominal fat deposition depicted by waist circumference is found to be a high-risk phenotype associated with hypertension after controlling other confounder variables.

CONCLUSION
This study highlights an important health concern issue. Repeated surveys and regular monitoring can give information about the emerging trends in blood pressure. Students need to modify life style strategies for preventing obesity and hypertension.