Assessment of VO2#sub3 Max among Female Workers of Cotton Textile Industry at Visnagar, North Gujarat Region: A Cross-sectional Study
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Staff Quarters, E Block, G-2, Sankalchand Patel University, Visnagar-384315, Gujarat, India.
Introduction: Occupational lung illness is a significant problem among textile factory workers. Occupational cotton dust exposure has been linked to lung involvement in many epidemiological studies of cotton industry workers. The maximum oxygen intake is one of the measures used to estimate functional capacity (VO2 max) of cardiopulmonary efficiency. The integration of the ventilatory, cardiovascular and neuromuscular system is necessary for attainment of VO2 max.
Aim: To assess the VO2 max among women employees in cotton textile industry and to study the correlation between VO2 max and anthropometric parameters like Body Mass Index (BMI), Body Surface Area (BSA), fat percent (fat %) and Lean Body Mass (LBM).
Materials and Methods: This cross-sectional study was conducted from January 2021 to June 2021 at Nootan Medical College and Research Centre/Nootan General Hospital, Visnagar, Dt. Mehsana, North Gujarat, India, which included study and control group which comprised 50 female workers of cotton industry and 50 age matched females, respectively (n=50 each) who had never worked in the cotton industry or been exposed to cotton dust. The labourers of cotton industry were chosen from the Mehsana district’s numerous cotton factories. Physical examinations (resting heart rate, resting systolic and diastolic blood pressure) and a standardised proforma were used to gather data. VO2 max and anthropometric measurements such as BMI, BSA, fat % and LBM were measured by standard procedure. The statistical analysis was done by using Student’s t-test and Pearson correlation test. The correlation between BMI, BSA, fat percent and LBM with maximal oxygen consumption (VO2 max) was assessed by using Karl-Pearson’s correlation with level of significance was considered statistically significant if p<0.05.
Results: The mean value of VO2 max in study and control group was 35.62±0.34 mL/kg/min and 36.80±0.58 mL/kg/min, respectively. It was decreased significantly (p<0.001) in study group. The r-values of BMI, BSA, LBM and body fat % were 0.262, 0.132, 0.236, 0.224, respectively. In the present study correlation between BMI, BSA, LBM, body fat % with VO2 max was reported as weak positive correlation which was not statistically significant.
Conclusion: VO2 max was significantly decreased in cotton industry workers compared to non exposed control subjects. More studies on the effects of cotton dust on VO2 max should be conducted in future in both genders.
Body mass index, Body surface area, Cotton industry workers, Functional capacity, Lean body mass, Maximum oxygen intake
Cardiorespiratory fitness, also known as cardiovascular fitness or maximal aerobic power, refers to the entire capacity of the circulatory and respiratory systems, as well as the ability to perform extended hard activity (1). Deterioration of the cardiorespiratory system increases morbidity and is a significant and independent predictor of all-cause mortality (2). The maximum oxygen intake is one of the measures used to estimate cardiopulmonary functional capacity (VO2 max) (3). The maximum capacity for oxygen absorption, transportation, and consumption is represented by VO2 max (O2). The integration of the ventilatory, cardiovascular and neuromuscular system is necessary for attainment of VO2 max. People with a low VO2 max have a higher risk of developing chronic diseases, all-cause mortality, and cardiovascular diseases like coronary artery disease, whereas people with a high VO2 max have a lower risk of developing chronic diseases, all-cause mortality, and cardiovascular diseases like coronary artery disease (4). Studies show the establishment of Queens’s College Step Test (QCT) to predict VO2 max indirectly (5). The QCT is accepted and recommended method for evaluation of cardiorespiratory activity when laboratory testing methods are unavailable.
The direct measurement of VO2 max with Cardiopulmonary Exercise Testing (CPET) is extensively considered as a gold standard method for assessment of fitness level of individual (1). Nevertheless, this method is expensive, requires trained staff. Tragically, not all countries meet these requirements to conduct VO2 max with CPET. The assessment is impractical in non laboratory and field-tests condition and also, high level of trained staff and proper supervision is required. It is not suitable for those individuals also for whom vigorous exercise is not recommended. These indirect techniques are much simple and less costly and easier to apply in situations like indoor or outdoor, epidemiological studies. Hence, indirect VO2 max prediction needs to be implemented especially in studies of large population. Body composition factors like BSA, BMI, body fat % and LBM have strong link with cardiorespiratory fitness (2). Researchers have reported conflicting statements in terms of such anthropological parameters in relation to VO2 max (3),(4).
Occupational lung illness is a significant problem among textile factory workers. When operating in various departments of the cotton mill, such as opening, picking, combing, weaving, slashing, and spinning, cotton mill workers are exposed to raw cotton dust. In India, the prevalence rate remains high. Various epidemiologic studies of cotton industry workers have found indications of lung involvement as a result of occupational cotton dust exposure (6),(7) The chronic exposure of cotton dust in cotton industries particularly on female workers has not been clarified (6). The present study was undertaken to assess the VO2 max among women employees in cotton textile industry. The secondary objective of the study was to study the correlation between VO2 max and anthropometric parameters (BMI, BSA, LBM and fat %).
The present study was a cross-sectional study conducted from January 2021 to June 2021 at Nootan Medical College and Research Centre/Nootan General hospital, Visnagar, district Mehsana, North Gujarat, India. Study was approved by Institutional Ethics Committee (IEC) (Approval No: IEC/NMCRC/APPROVAL/22/2021), and all subjects gave their informed consent after the study methods and goal were explained in local language (Gujarati). The experiments followed the amended Helsinki Declaration of 1975 that was revised in 2013.
Convenient non random sampling method was followed for selection of participants. The present study included a study group (group A) and a control group (group B) comprising 50 female workers of cotton industry between the ages of 18 and 40, as well as 50 age-matched females. The labourers were chosen from the Mehsana district’s numerous cotton factories.
Inclusion criteria: Female workers of cotton industries with not less than three years of exposure and healthy females who had never worked in the cotton industry or been exposed to cotton dust were included in study and control groups, respectively. All of the employees volunteered to take part in the present study.
Exclusion criteria: Subjects on medication for cardiorespiratory illness, subjects with a history of diabetes mellitus, psychiatric disease, or a history of smoking were excluded from the study.
Clinical histories of subjects were obtained in detail, including relevant family history, prior history, drug history, and personal history. All volunteers (subjects) were given a standardised proforma in local language (Gujarati) to collect information about their demographic parameters such as (duration of employment) occupational history, which included past and present respiratory diseases (cough, phlegm, chest tightness and dyspnoea) and lassitude (physical or mental tiredness). Anthropometric measurements such as height, weight, BMI, BSA, LBM, and fat L % were recorded. The subjects were instructed to wear light clothing and to stand erect with their arms relaxed at their side, with both feet close together. By using a portable standard weighing machine, weight in kilograms was recorded to the nearest 0.5 kg. Height was measured on a vertical scale with the heel, buttocks and occiput against the wall and the head in the Frankfurt plane to the nearest 0.5 cm. A stadiometer (Prestige and IS Indo Surgical) was used to measure height to the nearest 0.1 cm. Without shoes, the participant stood on the stadiometer with their scapula, buttocks, and heels in contact with the vertical bar, their head held straight, their inferior orbital border in the same horizontal plane as their external auditory meatus (Frankfurt’s plane), and their scapula, buttocks, and heels in contact with one another. BMI was calculated by the formula weight (kg) divided by height squared (metre). The body fat % was calculated by using a formula that converts BMI into an estimate of body fat %: Body fat %=(1.39×BMI)+(0.16×Age)-(10.34×Gender)-9 with gender equal to 1 for men and 0 for the woman (8). BSA was calculated using the formulas created by Mosteller RD (9). Formulas by Monsteller [Height (cm)×Weight (kg)/3600)Â½] and Body [Weight (kg) 0.4838×Height (cm) 0.3×0.017827]. LBM was calculated using Boer formula for males: e LBM=0.407W+0.267H-19.2, for females: e LBM=0.252W+0.473H-48.3 (In this formula, W is the body weight in kilogram and H is the body height in centimetre) (10). The systolic and diastolic artery pressures (SAP and DAP) were measured in supine position using an aneroid sphygmomanometer (DAP). Reading (SAP and DAP) was taken one time only during resting condition. The QCT method was used to investigate VO2 max indirectly (5). A tool with a height of 16.25 inches was used for the step test. Subjects were required to step for 3 minutes at a rate of 22 steps per minute, which was determined using a metronome. The carotid pulse rate was measured from the fifth to the twentieth second of the recovery time after the exercise was completed. The 15-second pulse rate was translated to beats per minute, and the VO2 max was calculated using the equation below. The evaluations were carried out at a room temperature ranging from 27 to 29° Celsius. The following equation was used to predict VO2 max (5). For females: VO2 max=65.81-[0.1847×pulse rate beats/min] [mL/kg/min] (5).
Statistical Package for the Social Sciences (SPSS) was used to conduct the statistical analysis (version 17.0). The Student’s t-test was used to examine the results, which are given as mean±standard deviation (SD). A statistically significant p-value of 0.05 was used. The relation between BMI, BSA fat % and LBM with maximal oxygen consumption (VO2 max) was done using ‘Karl-Pearson’s correlation with level of significance was considered statistically significant if p<0.05’.
The mean age was 28.44±6.83 years, 26.68±7.53 years in study group (cotton industry workers) and control groups, respectively. Anthropometric particulars (BMI, BSA, Fat %, and LBM) of cotton textile industry workers and control subjects were studied thoroughly (Table/Fig 1).
(Table/Fig 2) shows mean value of VO2 max, resting heart rate, systolic blood pressure (resting), diastolic blood pressure (resting). The mean value of VO2 max in study group was decreased significantly (p<0.001) when compared with control group (Table/Fig 2). There were no significant result found in other parameters.
Karl Pearson’s correlation test was used to assess correlation between VO2 max and BMI, BSA, LBM, and Body fat % among study group subjects. Correlation values between VO2 max and BMI, BSA, LBM, Body fat % is given in (Table/Fig 3). There was no significant correlation obtained in any of the parameters.
No significant correlation was not obtained between VO2 max and all the parameters as represented in (Table/Fig 4), (Table/Fig 5), (Table/Fig 6), (Table/Fig 7). Correlation between BMI, BSA, LBM, body Fat % with VO2 max was reported as weak positive correlation and was not statistically significant.
The above mentioned anthropometric parameters were not statistically significant when compared with control subjects. The majority of respiratory problems experienced by cotton workers in the previous 12 months were work-related. Cough (20%) and dyspnea (20%) were the symptoms most closely linked to the workplace in cotton spinners in the present study (Table/Fig 8).
The association between exposure to cotton dust and the development of a sickness known as byssinosis. The goal of this study was to see how exposure to cotton dust affects VO2 max in cotton textile workers. “VO2 max also known as maximal oxygen consumption, peak oxygen uptake, maximal oxygen uptake, or maximal aerobic capacity is the maximum capacity of an individual’s body to transmit through circulatory system and use oxygen in motor muscles.” In the textile industry, byssinosis is the most well-known and specific work-related sickness. Fever, malaise, chest tightness, and dyspnoea are the hallmark signs of byssinosis. The maximum quantity of oxygen a person can take in (VO2 max) is reduced in Chronic Obstructive Pulmonary Disease (COPD) patients due to poorer cardiovascular capabilities and weaker peripheral skeletal muscle strength, resulting in a lower VO2 max.
In the present study, VO2 max was significantly reduced in study group participants. Exercise (VO2 max) capacity in COPD was linked to deterioration of both inspiratory (active) and expiratory (passive components) muscles of lungs, according to Loiseau A et al., (11). Since VO2 max is linked with impaired lung function such as restrictive and obstructive type of lung disease present study findings support the theory that COPD patients’ exercise tolerance is limited by weak inspiratory muscles (12),(13). The results of VO2 max among control subjects in present study were consistent with other studies that have examined VO2 max in female subjects in India. It gives a confirmation of VO2 max level among Indian women and used for comparison with study group participants (14).
Many research papers have used heart rate to assess mental workload, physical workload, weariness, rating of perceived exertion and other physiological factors, demonstrating the accuracy of heart rate as a physiological factor and VO2 max is one of the most commonly used parameter in exercise physiology for cardiorespiratory fitness measurement (15),(16),(17),(18). Generally, regular involvement in physical activity beyond certain period can decrease individuals resting heart rate by increasing the contractile strength and the length of time the heart fills with blood. An increase in parasympathetic nervous system activity and possibly a decrease in sympathetic nervous system activity cause a drop in heart rate. In the present study, no significant change was observed in resting heart rate between study and control group. Similarly the present study wasn’t able to find any differences in resting systolic and diastolic blood pressure between study and control group members.
Blood pressure appears to be substantially affected by noise exposure, since noise causes larger changes in blood pressure among textile employees working in “high noise areas compared to those working in low noise areas (19). In the present study, many workers have been working in low noise areas and do not have exposure more than five years in cotton textile industry area. A study from Gupta S et al., and Koskinen HL et al., reported that noise exposure in working atmosphere was positively associated with hypertension and many studies were in support of their statement (20),(21). Kalantary S et al., showed an increase in blood pressure in workers after exposure to noise in industry environment (22). In the present study, there was no such noise related impact in present study workers. In the present study, an association between BMI, BSA, LBM, Fat % with VO2 max was reported weak positive correlation since the r value was less than 0.3. When fat mass was taken into account, Welch BE et al., found that VO2 max was much lower in overweight people, indicating the changes in cardiorespiratory performance in severely overweight people (23). Obesity exacerbates exercise intolerance and inadequate aerobic capacity, excessive body fat places an adverse stress on cardiac function, especially during intensive activity, when excessively hyperactive body muscles fails to absorb appropriate amounts of oxygen due to the deposition of proportionately large amounts of fat mass (23). In the present study, there was no significant change reported on BMI, BSA, LBM and fat % and there is no negative correlation. This suggests the effect of such anthropometric parameters on VO2 max was not statistically significant. Many subjects in present study belonged to younger age group and reported less exposure to cotton dust and other co-morbidities. Since the findings in present study revealed a modest positive association between VO2 max and weak factors such as BMI, BSA, LBM, and body fat %, these anthropometric characteristics must be included when predicting VO2 max in different age groups with various duration of cotton dust exposure in a thorough manner.
The following recommendations are given based on the findings of this research: i. A similar study might be undertaken with male subjects or with populations of varying ages and levels of participation. ii. Additional research can be done utilising additional measurement methods on the above-mentioned physical and physiological factors. iii. A similar study on psychological and sociological aspects could be done. iv. A similar study might be done on a bigger scale with the same or different factors. v. The findings of this study will aid future research in the field of sports physiology.
An important limitation of this study was that male individuals was not included and the study population was limited to those between 18-40 years old and thus may not represent the broader population in slums, but it still gives useful information regarding this age group. The present study doesn’t contain any noise interruption in the working environment. Noise pollution is common in majority of factories. Further studies assessing the noise effect can be conducted in future.
The VO2 max was significantly decreased in cotton industry workers compared to non exposure control subjects. All people with decreased VO2 max who have a decreased quality of life and/or physical capabilities should be offered fitness training as part of their rehabilitation. It is, stated that VO2 max is an essential determinant of an individual’s ability to work for long periods of time and is the best measure of physical fitness. More studies on the effects of cotton dust on VO2 max are needed to be conducted in future in both genders.
Date of Submission: May 20, 2022
Date of Peer Review: Jul 13, 2022
Date of Acceptance: Sep 20, 2022
Date of Publishing: Nov 01, 2022
• Financial or Other Competing Interests: ICMR-New Delhi for approval under Short-Term
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. NA
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