|Year : 2022 | Volume
| Issue : 3 | Page : 316-321
Correlation of gender and anthropometric measurement with pulmonary function tests among undergraduate medical students
Iffat Jahan1, Momtaz Begum2, Sharmin Akter Sumi3, Nusrat Jahan4, Md Zakirul Islam5, Mainul Haque6
1 Department of Physiology, Eastern Medical College, Cumilla, Bangladesh
2 Department of Physiology, Chittagong Medical College, Chattogram, Bangladesh
3 Department of Anatomy, BSMMU, Dhaka, Bangladesh
4 Department of Internal Medicine, United Hospital, Dhaka, Bangladesh
5 Department of Pharmacology and Therapeutics, Eastern Medical College, Cumilla, Bangladesh
6 Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia (National Defence University of Malaysia), Kuala Lumpur, Malaysia
|Date of Submission||23-Jun-2022|
|Date of Acceptance||02-Aug-2022|
|Date of Web Publication||15-Sep-2022|
Prof. Mainul Haque
Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia (National Defence University of Malaysia), Kem Sungai, Besi, 57000 Kuala Lumpur
Source of Support: None, Conflict of Interest: None
Introduction: This study aimed to evaluate the effect of gender and anthropometric measurement on pulmonary functions (forced vital capacity [FVC], forced expiratory volume in 1st s [FEV1] and peak expiratory flow rate [PEFR]) of undergraduate medical students to emphasise the need for further research on the aetiology and the prevention of respiratory diseases. Materials and Methods: This cross-sectional study was conducted in the Department of Physiology, Chittagong Medical College (CMC), Chattogram, Bangladesh, from July 2017 to June 2018. A total of 100 participants, aged between 18 and 20 years, studying in the 1st year in CMC, were included by a random sampling method. The participants filled out a questionnaire with general information about previous diseases, medication and family history. Fifty male participants were enrolled in the study group according to inclusion and exclusion criteria. Age and body mass index matched another 50 female participants were included. Respiratory parameters such as FVC, FEV1 and PEFR were measured by a digital spirometer (Chestgraph HI-101, Japan). Readings were taken in normal upright sitting posture. The statistical tests utilised were unpaired Student's t-test and the correlation coefficient conducted using SPSS for windows version 23. Results: Female participants showed significantly lower FVC, FEV1 and PEFR than males. This study observed a significant positive correlation between height and weight and FVC, FEV1 and PEFR. Conclusion: The results of this study help assess pulmonary functions among medical students as pulmonary function tests are one of the indicators of the health status of the individuals.
Keywords: Chittagong Medical College, forced expiratory volume in 1st s, forced vital capacity, healthy young adults, peak expiratory flow rate, pulmonary function test
|How to cite this article:|
Jahan I, Begum M, Sumi SA, Jahan N, Islam MZ, Haque M. Correlation of gender and anthropometric measurement with pulmonary function tests among undergraduate medical students. Adv Hum Biol 2022;12:316-21
|How to cite this URL:|
Jahan I, Begum M, Sumi SA, Jahan N, Islam MZ, Haque M. Correlation of gender and anthropometric measurement with pulmonary function tests among undergraduate medical students. Adv Hum Biol [serial online] 2022 [cited 2022 Oct 7];12:316-21. Available from: https://www.aihbonline.com/text.asp?2022/12/3/316/356100
| Introduction|| |
Pulmonary function tests (PFTs) are used for physiologic study and clinical tools for assessing respiratory status. Hence, they are part of routine respiratory, occupational and sports medicine health examinations. Typical lung function values and ranges are conventionally calculated according to variables such as sex, age, height and weight, which contribute independently to predictions of lung function. Many different lung function parameters can be studied by spirometry. Spirometric lung function parameters are used as a diagnostic tool to monitor therapeutic effectiveness or disease course. The most commonly studied parameters include: (i) vital capacity (VC), the maximum volume of air that can be expelled from the lungs after maximum inspiration and (ii) forced VC (FVC), the volume of air that can forcibly be blown out after full inspiration, (iii) forced expiratory volume in 1st s (FEV1), the maximum volume of air that can be forcibly blow out in the 1st s during the FVC manoeuvre (iv) peak expiratory flow rate (PEFR) is defined as 'The largest expiratory flow rate achieved with a maximally forced effort from a position of maximal inspiration, expressed in liters per minute'. The European Respiratory Society has defined PEFR as the maximal flow achieved during the expiration and delivered with maximal force, starting from the level of maximal lung inflation, following the maximal inspiration expressed in liters per minute.,
It is well known that lung function capacity is influenced by the sex of the subject as well as other factors, including age, height and ethnicity., Gender differences in airway behaviour and the clinical manifestations of airway disease occur throughout the human life span and are related to biological and socio-cultural factors. According to Aggarwal et al., the alveoli's number and size increase during postnatal lung development. Respiratory parameters such as FVC, FEV1 and PEFR are significantly lower in female participants than male participants. The female lung is smaller than the male lung and has fewer bronchioles. The number of alveoli per unit of the surface area is the same in both boys and girls. Women tend to have 20%–25% lower lung capacity than men, which is attributed to the smaller lung size of women. The relatively narrow airways in the lungs of females result in lower lung diffusion capacity than males. According to the study performed by Jacobs et al., many of the typical sex differences in respiratory function result from differences in body size. After adolescence, the VC of boys exceeds those of girls of similar height, with most of the differences attributable to differences in proportions of the body frame. The difference might be due to the subject's smaller height, affecting pulmonary function parameters. Because boys have bigger lungs per unit of stature, they have a more significant number of alveoli and a larger alveolar surface area for a given age and stature. The lung function values are higher in males than females because males have larger lungs and muscularity than females.
These results were comparable with the study by Aggarwal et al., in which they found that the mean lung function test was higher in boys than in girls. Budhiraja et al. also reported lower pulmonary function values in female than male participants in similar age groups. This can be attributed to men having bigger lungs for the same height as females. Another contributing factor could be the greater strength of respiratory muscles in males., The sex difference in lung function may be attributed to various factors, including sex hormone, sex hormone receptors or intracellular signalling pathways, in addition to physiological and anatomical differences in the respiratory system of males and females. Alghadir et al. studied PFTs among Saudi adults and found sex-based differences in lung function parameters of Saudi adults, with higher values for males.
Rajput et al. observed that FVC for males was significantly higher than for females. This may be attributed to the greater respiratory muscle strength of males.,,, Males have more alveoli per unit area than their female counterparts, and their alveoli are larger and have greater compliance., All the flow rates were higher in males than females. Larger airways and stronger respiratory muscles of males are responsible for higher flow rates.
According to Jeena et al., increased weight decreases lung volume and capacities by decreasing lung and chest wall compliance. There is also an increase in resistance to outflow of air through the airways in the overweight. The pattern of pulmonary function is found to worsen with the degree of obesity, moving from a restrictive pattern in mild to moderate obesity with both FEV1 and FVC reduced and FEV1/FVC ratio being normal to an obstructive pattern in severe and morbid obesity with a significant decrease in FEV1 as against FVC and FEV1/FVC ratio being decreased.,
Body mass index (BMI) is considered the best variable for anthropometric evaluation in nutritional and general health screening. The height of the subject can affect pulmonary function parameters. Height linearly correlates with lung size. The difference might be due to the smaller stature of the female subjects. For FVC and FEV1, boys had the highest Correlation with height. Ojo et al. observed a significant negative correlation between VC and weight but a significant positive correlation between VC and height in their study. In their research, some investigators found that abdominal obesity is generally associated with reduced FEV1 and FVC in women and specific age groups.
PEFR is positively correlated with an increase in height and weight up to a specific limit and decreases as height and weight increase. Significant correlation has been previously reported for PEFR with height, weight, age, socio-economic conditions, chest circumference and body surface area. The mean values of height, weight and PEFR were higher for males than females. Similar findings were reported by other researchers also.,,,,,,,, In males, PEFR increases significantly with height and weight, which agrees with the reports of other investigators.,,, This was probably because of the greater chest volume in the taller subjects. The growth of the airway passages and the expiratory muscle effort also increases with an increase in height. The male's height is associated with PEFR, and female weight is correlated with PEFR. PEFR was found to be positively correlated with weight and negatively correlated with BMI in another study. There was a decrease in the PEFR with an increase in the BMI. This observation was consistent with the reports of other authors.,, Among different factors affecting PEFR, height and age correlate better with PEFR in both males and females. A positive correlation was seen between age, height, weight and PEFR, and it was concluded that boys had higher values than girls at all heights.
The proposed mechanism for the link between obesity and deceased PFTs explained by the restrictive effect on the lung and chest wall as the accumulation of excess fat could interfere with the movement of the chest wall and descent of the diaphragm. Increased adiposity has been associated with increased levels of cytokines such as interleukin 6 and tumour necrosis alpha and decreased adiponectin levels, thereby increasing systemic inflammation and negatively affecting lung function.,
In one study, investigators have observed a positive correlation among all the lung function parameters with BMI when the BMI of participants is within the normal range for their age and sex.
| Materials and Methods|| |
This research work was a cross-sectional study. It was conducted in the Department of Physiology, Chittagong Medical College (CMC), Chattogram, Bangladesh, from July 2017 to June 2018.
A total of 100 research participants (RPs) were recruited for this study, 50 males were selected, and the other 50 were female. RPs were the Year-1 medical students of CMC, aged 18–20 years with a BMI of 18.5–22.9 kg/m2, fulfilling the inclusion and exclusion criteria enrolled in the study with informed consent.
Simple random sampling by lottery method was adopted to select all the RP.
The study duration was from July 2017 to June 2018.
The study was conducted in the Department of Physiology, CMC, Chattogram, Bangladesh.
The Year-1 medical students aged 18–20 years with BMI 18.5–22.9 kg/m2 of CMC, Chattogram, fulfilling the inclusion and exclusion criteria, were enrolled in the study with informed consent. Detailed personal information and medical and family history were recorded in a pre-fixed questionnaire from all the RPs who participated voluntarily.
The previous history of cardiovascular, respiratory illness, having any nasal pathology, smokers, RPs receiving respiratory depressant drugs and vertebral deformities were excluded from the study.
Age, height, body weight and BMI of the RPs were recorded in a pre-designed case record form. Height was measured in inches by a height measuring scale. A height scale was drawn on the classroom wall using the wooden scale, measuring tape and pencil. It was later converted to a meter. Height was measured in the bare foot from the top of the vertex to the bottom of the foot, standing straightly against the wall scale plotted earlier and recorded. Weight was measured barefoot and avoiding excess clothing or baggage by an analogue standard weight machine (Tanita, HA-620-China) and measured in kilogram (kg). BMI was calculated by the formula BMI = Weight in kg/height in m2.
Lung function tests were conducted by digital spirometer (Chestgraph, HI-101, Japan). Participants were asked to rest sitting on a stool in an erect posture without support and remain calm and quiet for 5 min. The detailed procedure was explained to the subject. The spirometer switch was on, and the window (dialogue box) was opened. The subject information form was filled up and saved. The mouthpiece of the spirometer was cleaned with alcohol and cotton, and then, the mouthpiece was placed between the lips. The subject was asked to hold the mouthpiece in their hand horizontally. To make a good seal, the subject was asked to put the lips tightly around outside the mouthpiece. The subject was asked to inhale as deeply and rapidly as possible. Then, they were asked to exhale forcefully and for the most prolonged period into the mouthpiece. The measured predicted and percentage values of FVC, FEV1 and PEFR were recorded from the spirometer monitor. Three consecutive readings were taken, and the best value was noted on tracing paper. It was collected and preserved.
Data collection details
Detailed personal information and medical and family history were recorded in a pre-fixed questionnaire from all the RPs who participated voluntarily.
All data were compiled and processed after collection. Results were expressed as mean ± Standard Deviation and range. The independent t-test analysed FVC, FEV1, and PEFR records in SPSS-23 (IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY, USA: IBM Corp.). Pearson's correlation test was used to observe the relationship between lung functions and height, weight and BMI. 95% confidence limit was taken as a minimum level of significance. In interpreting the results, P < 0.05 was accepted as the significance level.
The protocol of this study was approved by the members of the Ethical Review Board of CMC, Chattogram, and received a certificate of ethical clearance from ERB (Reference No: CMC/PG/2018/403. Dated 10 May 2018).
| Results|| |
[Table 1] shows no significant difference in age but in height, weight and BMI between males and females. [Table 2] shows the significant difference in FVC, FEV1 and PEFR in the female group.
|Table 1: Age, height, weight and body mass index distribution of subjects (n=100)|
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|Table 2: Forced vital capacity, forced vital capacity in 1 s and peak expiratory flow rate of subjects (n=100)|
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| Discussion|| |
This cross-sectional study was conducted in the Department of Physiology, CMC, Chattogram, from July 2017 to June 2018 to assess the effects of gender and anthropometric measurement on FVC, FEV1 and PEFR in healthy young adults. The present study provides an understanding of the fundamental relationship of FVC, FEV1 and PEFR with height, weight and BMI in undergraduate medical students.
This study observed no difference between males and females regarding age, height, weight and BMI. It indicates that the subject selection was similar in both groups [Table 1] and [Figure 1].
|Figure 1: Comparison of mean of demographic and respiratory parameters between genders. BMI: Body mass index, FVC: Forced vital capacity, FEV1: Forced vital capacity in 1st s, PEFR: Peak expiratory flow rate|
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[Table 2] and [Figure 1] show a significant difference in FVC, FEV1 and PEFR among the male and female RPs. Previous studies also supported these findings.,,,,,,
Male had higher FVC, FEV1 and PEFR than age-matched females in our study, and the difference between the male and female respondents was statistically significant. It might be due to sex hormone, sex hormone receptors or intracellular signalling pathways, in addition to physiological and anatomical differences in the respiratory system of males and females. The female lung is smaller than the male lung and has fewer bronchioles. The number of alveoli per unit of the surface area is the same in both boys and girls. After adolescence, the VC of boys exceeds those of girls of similar height, with most of the differences attributable to differences in proportions of the body frame. The difference might be due to the subject's smaller height, affecting pulmonary function parameters. This may be attributed to the greater respiratory muscle strength of males.,,, Larger airways and stronger respiratory muscles in males are responsible for higher flow rates. Several other studies reported no significant gender differences in the pulmonary function profiles in the sample studied.,,,
The correlation coefficients ascertained the connections between the measured parameter; FVC, FEV1 and PEFR with anthropometric measurement in male and female RPs. [Table 3] shows a positive correlation between FVC, FEV1 and PEFR and height, weight and BMI among both genders. However, a significant positive correlation between FEV1 and PEFR and BMI were found only in female. In males, no significant correlation was noticed between BMI and FEV1 and PEFR. Ojo et al. found a significant negative correlation between VC and weight but a significant positive correlation between VC and height. An increase in weight may reduce the VC. An increase in BMI and a tall individual may have enhanced VC. Aggarwal et al. observed a positive correlation among all the lung function parameters with BMI when the BMI of participants is within the normal range for their age and sex. They suggested a significant impairment of lung functions in overweight individuals. These observations agree with several cross-sectional studies that found an association between FVC and FEV1 with BMI., Proposed mechanism for the link between obesity and deceased PFTs explained by the restrictive effect on the lung and chest wall as an accumulation of excess fat could interfere with the movement of the chest wall and descent of the diaphragm. Other investigators found that obesity does not affect the spirometry tests (except PEF) among healthy, non-smoking Saudi adults. Dharamshi et al. observed that PEFR positively correlates with increased height and weight up to a certain limit. The association of PEFR with height and weight in both genders, males and females, increases to a certain level of increasing height and weight and then decreases as the height and weight increase further. Significant correlation has been previously reported for PEFR with height, weight, age, socio-economic conditions, chest circumference and body surface area. This study also showed that in males, PEFR increases significantly with height and weight, which agrees with the reports of other investigators.,,,, This was probably because of the greater chest volume in the taller subjects. The growth of the airway passages and the expiratory muscle effort also increases with an increase in height. Jena concluded that PEFR declines with increased BMI, and there is a negative correlation between BMI and PEFR.,
|Table 3: Relationship of respiratory parameters and gender variation with height, weight, and body mass index (n=50)|
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| Conclusion|| |
The present study showed that males had higher FVC, FEV1 and PEFR than females. Positive correlation between FVC, FEV1 and PEFR and height, weight and BMI among both genders. However, a significant positive correlation between FEV1 and PEFR and BMI were found only in female. In males, no significant correlation was noticed between BMI and FEV1 and PEFR. Although this study gave us an insight into the PFTs situation in a particular medical college, a community-based study with a representative sample to develop a national database reflecting the age, sex, height and weight standardised on FVC, FEV1 and PEFR of a young adult from all socio-economic status is recommended for our country.
Limitations of the study
The comparatively shorter period for conducting this cross-sectional study and smaller sample size based on medical students of specific age groups enrolled first limits the representative criteria of the findings. Socio-demographic factors were not assessed in the study.
The authors would like to acknowledge the support of the Department of Physiology, CMC, Chattogram during sample collection and laboratory instrument uses. The authors also thank the study participants for their active, sincere and voluntary participation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]