Open Access Original Article

Inter Arm Blood Pressure Difference

How Strongly the Body Mass Index (BMI) is Associated with Inter Arm Blood Pressure Difference
Muhammad Absar Alam, Anam Rehman*, Javaria Manzoor*, Zafar Ali Zafar, Shireen Jawed*, Benash Altaf*
Independent Medical College, Faisalabad Pakistan, *Aziz Fatimah Medical and Dental College, Faisalabad, Pakistan

ABSTRACT
Objectives: To explore the association between the body mass index (BMI) and inter arm difference (IAD) blood pressure and
to understand how these factors influence blood pressure.
Study Design: Cross-sectional study.
Place and Duration of Study: Aziz Fatimah Medical and Dental College Faisalabad Pakistan, from Nov to Dec 2020.
Methodology: Total 100 healthy medical students aged 19-21 years were included in the study. Height in meters and weight in
kilograms were documented by stadiometer (ZT-100). BMI was assessed by Quetelet's index (BMI=weight in Kg/height in
m2). Blood pressure was recorded simultaneously in both arms by the auscultatory method. Inter arm difference in blood
pressure was estimated by calculating differences in diastolic and systolic pressures between the right and left arm.
Results: Mean age of the participants was 19.83 ± 1.23 years. Significant difference was noted in systolic and diastolic inter-
arm blood pressure among obese and non-obese groups (p-values <0.001). BMI was positively associated with diastolic and
systolic inter-arm blood pressure (p-values <0.001).
Conclusion: Body mass index is positively associated with inter arm difference in blood pressure, and both positively impact
the blood pressure.
Keywords: Body mass index (BMI), Diastolic blood pressure, Inter arm difference (IAD), Systolic blood pressure.
How to Cite This Article: Alam MA, Rehman A, Manzoor J, Zafar AZ, Jawed S, Altaf B. How Strongly the Body Mass Index (BMI) Is Associated with
Inter Arm Blood Pressure Difference. Pak Armed Forces Med J 2022; 72(2): 380-383. DOI: https://doi.org/10.51253/pafmj.v72i2.5916

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc/4.0/), which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

INTRODUCTION by the National Institute for Care and Health Excel-

Due to unhealthy lifestyle, less physical activity lence (NICE) emphasize blood pressure recording in
and increasing consumption of alcoholic beverages, both arms due to natural inter-arm difference in blood
obesity is becoming a significant health issue among pressure but how much difference is significant is a
young adults.1,2 According to the World Health Orga- matter of concern.8,9 The blood pressure should be
nization (WHO) survey, 39% of adults aged 18 and measured in both arms at the first visit because diffe-
above were found overweight, and 13% were obese. rences exist, and measurement in only one arm may
Asians are more prone to obesity-related comorbidities lead to the under-diagnosis of hypertension.
such as diabetes and hypertension at lower body mass Inter arm difference (IAD) in blood pressure has
index (BMI) than their age and sex-matched Europeans caught much attention after finding its association with
due to greater body fat percentages in them.3,4 various peripheral vascular diseases and increasing
Various previous studies conducted in the Indo- cardiovascular morbidity. Recent studies show that
Pak sub-continent have documented the prevalence of ≥15 mmHg systolic IAD in blood pressure is an indica-
45-55% of pre-hypertension among the young popula- tor of underlying chronic conditions like pre-hyperten-
tion of 18 years and above.5 Its prevalence is increasing sion and hypertension in young adults.10 Established
day by day at an alarming rate in Pakistan due to inc- data is available regarding the association between
reasing trends of obesity, increased salt, saturated fat, obesity and hypertension; however, there is a paucity
and low fruits and vegetables consumption.6,7 Being of data concerning the association between BMI and
the silent killer due to the absence of symptoms, its IAD blood pressure, which are possible hypertension
prevalence is even increasing worldwide at a break- associated risk factors. This study focused on the asso-
neck pace, and it is estimated that this rate will hike up ciation between BMI and IAD blood pressure, possibly
to the level of 29%, especially the young adults. Subs- associated risk factors for hypertension. We also aimed
tantial evidence is available showing the positive asso- to seek how these factors influenced blood pressure.
ciation of obesity with hypertension. New guidelines METHODOLOGY
This was a cross-sectional study, conducted at
Correspondence: Dr Javaria Manzoor, Department of Physiology, Aziz
Fatimah Medical and Dental College, Faisalabad, Pakistan Aziz Fatimah Medical and Dental College, Faisalabad,
Received: 22 Dec 2022; revision received: 01 May 2021; accepted: 04 May 2021 from November to December 2020. Open Epi sample
mzahid689@gmail.com

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 Inter Arm Blood Pressure Difference

size calculator was used for sample size estimation, Statistical Package for Social Sciences (SPSS)
with power 80%, CI 95%, the ratio of sample size version 21 was used for the data analysis. Continuous
group 2/group1 as 1 the mean values of groups 1 and variables like blood pressure were presented as Means
2 were 2.64 ± 0.36 and 2.86 ± 0.42 respectively.7,8 One ± SD. The normality of data was checked by the Sha-
hundred medical students were recruited by non-pro- piro Wilk test (p-value ≥0.05). The independent t-test
bability convenience sampling technique. Before the was used to compare mean blood pressure among
start of study, ethical approval from the Institutional obese and non-obese. The p-value of ≤0.05 was consi-
Ethical Committee (IEC) was obtained (IEC#73-20). dered statistically significant.
Inclusion Criteria: Medical students of age 19-21 years RESULTS
were included in the study. This study comprised 100 medical students with
Exclusion Criteria: Students with a known history of mean age of 19.83 ± 1.23years (Table-I).
hypertension, diabetes and cardiovascular diseases
were excluded from the study. Table-I: Descriptive statistics of study population (n=100).
Parameters Mean ± Standard deviation
Participants were enrolled after taking informed Age (years) 19.8 ±1.23
consent. They were assured of anonymity.Height in Body Mass Index (Kg /m2) 23.4 ± 4.06
meters and weight in kilograms were documented by Height (cm) 1.69 ± 0.09
a stadiometer (ZT-100). BMI was assessed by Quetelet's Weight (kg) 68.38 ± 15.08
index: BMI=weight in Kg/height in m.2 Subjects were
Of the total population, 46% were obese, having
allowed to relax for five minutes in a comfortable envi-
a BMI of >25 Kg/m2, and 54% of subjects were non-
ronment, and the blood pressure recording was done.
obese. BMI of obese subjects was high as compared to
Blood pressure was recorded simultaneously in both
non-obese subjects. This was a significant difference (p-
arms. Three readings were taken at the one-minute

Table-II: Comparison of Blood Pressure And Body Mass Index BMI Among Obese And Non obese Group (n=100).
Parameters ( mean) Obese Subjects (n=46) Non obese subjects (n=54) p-value
Body Mass Index( kg/m2) 27.07 ± 1.69 20.62 ± 2.87 <0.001*
Systolic Blood Pressure (mmHg) 123.84 ± 13.615 115.74 ± 1.36 <0.001*
Diastolic Blood Pressure (mmHg) 84.89 ± 8.529 79.81 ± 9.19 <0.001*
Pulse Pressure (mmhg) 35.36 ± 9.542 34.31 ± 0.53 0.530
Systolic Inter Arm Difference (mmhg) 12.40 ± 7.73 8.31 ± 5.917 <0.001*
Diastolic Inter Arm Difference (mmhg) 1.58 ± .866 1.19 ± .585 <0.001*

interval by sphygmomanometer of the appropriate value <0.001) (Table-II). Statistically significant differ-
sized cuff. As per the American Heart Association ences in mean systolic and diastolic blood pressure
(AHA) recommendation, the subject was made to sit were noted among obese and non-obese subjects. A
with the arm supporting at the heart level.11 It was significant difference was noted concerning both
assured that zero apparatus error was checked prior to groups' systolic and diastolic inter-arm differences (p-
taking the blood pressure readings. Systolic and dia- value <0.001). All these blood pressure parameters
stolic blood pressure was recorded with the appea- were comparatively higher in obese than non-obese.
rance and disappearances of clear Korotkoff sounds, Both groups' mean pulse pressure was not significantly
respectively. To avoid parallax error, the mercury level different (p-value=0.53). Our results indicated the
of the sphygmomanometer was noted. The inter-arm significant positive association of BMI with diastolic
difference in blood pressure was estimated by taking and systolic blood pressure.
systolic and diastolic differences between the right and DISCUSSION
left arms.
The present study was aimed to highlight the
For comparison purposes, the study subjects relation between IAD blood pressure and BMI and
were divided into two groups, i.e. obese and non-obese how these associated hypertension risk factors affect
groups, based on BMI. According to WHO guidelines blood pressure. Hypertension has become a significant
for Asians, subjects with BMI ≥25 kg/m2 were consi- health-related problem. It is documented that preva-
dered obese, and ≤25 kg/m2 were considered non- lence of hypertension is 35% in Pakistani popula-tion.
obese.12 Early stages of hypertension are asymptomatic. Most

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 Inter Arm Blood Pressure Difference

of the young population remains undiagnosed until or the acquired disease that produces compression on
the disease becomes advanced and symptomatic.12,13 It the main vessels, thrombus embolus and atheroma.19
is necessary to identify hypertension associated risk As extensive data is not available concerning the asso-
factors for early recognition of high-risk populations. ciation of IAD and BMI, more research is needed on an
The variation in blood pressure among both arms is extensive scale to open new horizons in the medical
not infrequent while doing the routine clinical assess- field as it can be taken as a non-invasive marker to
ment in a general health care centre. However, the provide a clue for the underlying disease.
point of concern is exactly how much alteration in LIMITATION OF STUDY
blood pressure is existent.14 In this study, only one parameter of obesity was focu-
Our study comprised 100 subjects, among them sed. Although BMI is a gold standard parameter of obesity as
46% were obese, and 54% were non-obese. Similar it determines the overall adiposity, it cannot measure the fat
results were also found in a study done by Khan et al, distribution in the body. The waist-hip ratio and the waist-
hip circumferences are the best indicators of central obesity.
who found 37% of the participants obese.12
As most of the normal weight subjects at risk are frequently
We have found a significant difference in both misdiagnosed, the parameters for central obesity should be
diastolic and systolic blood pressure in our study focused. Moreover, this study had the drawback of having a
groups. We found markedly raised blood pressure in small sample size.
obese subjects. Current results agreed with the results CONCLUSION
of the study from Faisalabad by Jawed et al, which also Body mass index is positively associated with inter arm
reported a positive impact of BMI on blood pressure.13 difference in blood pressure, and both positively impact the
These findings were also supported by a study conduc- blood pressure.
ted in Karachi that showed a similar relation in chil- Conflict of Interest: None.
dren.14 Indian study conducted at Amritsar also repor- Authors’ Contribution
ted similar findings.15
MAA: Study design, data analysis and manuscript write up.
Significant IAD difference was observed in Reviewed and approved the manuscript, AR: Data acquisi-
systolic and diastolic blood pressure of obese and non- tion, manuscript writing, reviewed and approved the manu-
obese subjects. IAD was significantly higher in obese script, JM: Study design, data collection interpretation of
subjects whose BMI was more than 25 kg/m2. The cur- results, revising manuscript critically, ZAZ: Data analysis
rent findings were in accordance with Muñoz-Torres et and interpretation and write up of results, reviewed and
approved the manuscript, SJ: Study design, datacollection,
al, study from the United States that also reported
andrevised manuscript critically for important intellectual
similar results.16 content, BA: Data collection, drafting and formatting of final
Current results showed a significant positive manuscript, revised and approve the final manuscript.
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