Health-related morphological characteristics and physiological fitness in connection with nutritional, socio-economic status, occupational workload of tea garden workers

Background: Reports on the cardiorespiratory fitness and body composition of male workers engaged in processing of tea leaves in factories within the tea-estates of West Bengal, under the influence of physiological workload, are quite scanty. Objectives: This cross-sectional study was conducted to evaluate morphometric characteristics based on physiological status and physical fitness of tea factory laborers who are continuously exposed to tea dust in their work environment for more than two years. Methods: Subjects were divided into control and tea garden workers groups. Height and weight were measured and the body mass index (BMI) was computed. Physiological parameters such as resting heart rate, blood pressure, fitness variables like physical fitness index (PFI), energy expenditure (EE), handgrip strength and anthropometric parameters like mid-upper arm (MUAC), thigh circumference (TC), head circumference (HC) and waist-to-hip ratio (WHR) were measured. Results: Body surface area (BSA), BMI, body fat percentage and fitness variables (PFI, EE) showed significant difference (p<0.05) between the two groups. Anthropometric measures (MUAC, TC, HC, WHR) reflected poor status among laborers. Conclusions: The present study shows that the majority of workers had ectomorph stature, good physical fitness, but had poor nutritional status (BMI and WHR)


Introduction
From time immemorial, tea has been eulogized in so many ways. According to the eighteenth century english poet william cowper, 'it is the cup that cheers, but not inebriates'. 1 The tea of west bengal is well-known for its taste and flavor which is as exotic and mysterious as the hills of darjeeling themselves. Among the teas cultivated in india, the most celebrated one comes from darjeeling himalaya and dooars of north bengal. In consort with tea gardens, plenteous tea factories have been established in these areas. While in tea gardens, the majority of workers are female, the laborers who are extensively exposed to tea dust, in adjacent tea factories, are male. The major classes of male tea factory workers, found in those tea estates, include: operators, fitters, administrative, blenders and others, such as forklift drivers and warehouse employees 2 . Unfortunately, the life situation of these tea laborers is not as good ideal as it should be in our country and especially in west bengal. The tea workers of dooars are among the most exploited laborers in india. The tea laborers, live in villages inside tea estates which are located in the hinterland, and this contributes to backwardness and exploitation by the tea planters. Without the basic amenities of life, the workers live in impoverishment and often die in obscurity. Illiteracy, poverty, addiction of male and females to beer, poor standards of living are the immutable problems in their lives 2,3 .
However, in the tea factories strenuous work is performed by male workers, in traditional ways without knowing the effect of chronic dust exposure on health. As a result of this strenuous work, leisure of the worker decreases and the health is also affected 3 . Besides, dooars is located at about 61 meters above sea level in a cold temperate climate which may also affect the physical and physiological fitness along with the effects of their workload and other exposures in the working environment. There are very few reports about the health status of tea workers in west bengal. In addition, reports about the overall physical fitness pattern with special reference to respiratory and cardiac parameters are scanty. Thus, the present study sought to determine the physical fitness of male tea garden workers and to test the effect of workload on the physical fitness of workers.

Subjects and methods
The present study was carried out in young adults (18-24 years of age). The subjects were divided into two groups: control (n=24) and tea garden workers (n=29). Young adult male tea garden workers (age 20.4±1.92) from cooch behar district, west bengal, were randomly selected to participate in the present study. Control subjects were also randomly selected from college students (age of 21.9±2.25) of kolkata, west bengal. To avoid the specific dynamic action (sda) of food, instruction was given to all the subjects to take their last meal at least two hours before conducting the test. To reduce the seasonal influence on fitness pattern, all the experiments were carried out and measurements were taken in temperature of 20 o -25 o c and relative humidity of about 45-50% in the winter season in india. The experimental protocol was explained to them to allay their apprehension. Consent from each participant was taken for conducting the study and the experiments were carried out following institutional ethical approval. Each measurement was taken three times and the mean was represented as final result to minimize bias.
The body mass index (bmi) was computed using the following formula 4 : bmi = mass (kg) / (height in m) 2 .

(for male subjects).
Dubois & dubois formula was used to estimate body surface area (bsa) 6 . Resting heart rate was recorded after five minutes of rest; when two successive heart rate scores became equal at carotid pulse 7 . Arterial blood pressure was measured using a sphygmomanometer 8 . Physical fitness index (pfi) was calculated from successive heart rates, measured after performing harvard step test (hst) developed by brouha et al. 9 . Anaerobic power was calculated by performing margaria double step test 10 . Vo 2 max 11 was predicted from the nomogram of astrand. Energy expenditure was determined by a formula using peak heart rate scores recorded during hst 12 : ee (kcal min -2 ) = -1.42 + (0.045 × peak h.r). Hand grip strength was determined by using a hand grip dynamometer to test the maximum voluntary contraction. The best of three trials was accepted with three minutes rest in-between. All the hand grip measurements were taken with the arm straight, i.e. At 0° elbow-angle.
Curvilinear distances were taken around the midpoint of upper arm (muac), thigh (tc), calf muscle (cc), waist (wc), buttock (bc) and head (hc) measuring steel tape 13 . A sliding caliper was used for the measurement of head anthropometry parameters (length and breadth). To measure the percentage of spinal shrinkage, recumbent length was measured on a wooden desk fixed to the wall after a uniform settling down period of 2 minutes fixed arbitrarily. Measurement was taken with the help of anthropometric rod. Spinal shrinkage was measured as the difference between the recumbent length and the standing height. Percentage spinal shrinkage was calculated as :[( recumbent lengthstanding height) × 100] / recumbent length.
Data are expressed as mean ± sd. Comparison of parameters between control and male tea garden workers was done by two tailed unpaired t-test, using microsoft excel-2007 and the result was considered as statistically significant when the two-tailed p-values are equal or less than 0.05 14 .

Results
All the respondents under the present study were employed as casual laborers in the tea estates more than two years. The mean age, height and weight of the respondents were 20.4±1.9 years, 163.5±7.2 cm and 48.3±3.1 kg, respectively. It was revealed that 58.6% of the male tea garden workers were educated up to or above primary school. Most of the adult male workers who participated in this study were non-smokers (75.9%) (table 1).

= 29 (100)
Among the physical and physiological parameters the body weight, bmi, tbf%, bsa, rhr, energy expenditure, handgrip strength (both right and left) were found significantly lower whereas, pfi and vo 2max were found significantly higher (p<0.05) in tea garden workers than in the controls (table 2). Amongst the anthropometric parameters muac, tc, wc, bc, head breadth (table 3) were found significantly lower, but significantly higher head circumference and head length was observed in case of tea factory workers with respect to their corresponding controls. They also showed significantly higher spinal shrinkage than the control subjects (table 3).

Discussion
In contrast to undergraduate college students, tea factory workers were found to have significantly low body weight, BMI, BSA and 7BF (p<0.05) which may be a result of heavy physical workload or their poor socio-economic condition which is reflected in their per capita income. Resting heart rate is a useful parameter of cardiovascular homeostasis 15 which tends to get lower in heavy workers 16 , as reflected in our study. Tea garden workers showed a significantly lower resting heart rate (73.6±6.00) than control subjects (p=0.007). Conversely, vo 2max (3.19 ±0.38) was found to be significantly higher in tea factory laborers, which may have some correlation with the findings of bailey et al. 17 who have found that lower vo 2max levels in men were associated with an increased probability of being overweight or obese. Therefore, it can be presumed that higher body weight of control subjects, in the present study, thus, influenced their oxygen uptake capacity 18 . Systolic and diastolic pressures showed no significant change in respondents (p>0.05). In contrast, their pulse rate recovered quickly, which is an indicator of better fitness and reflected in significantly higher pfi (79.2 ±6.42) and lower energy expenditure (4.50±0.72) than sedentary workers 19-21 . They also showed lower handgrip strength in both right and left hand.
Low waist circumference (WC) and buttock circumference (BC), and thus less waist-to-hip ratio (whr) shows ectomorphic body composition. In addition, mid upper arm circumference (MUAC) and thigh circumference (TC) which are the measures of protein storage in the body are significantly low (p<0.05), which is the indicator of malnutrition. The craniofacial anthropometric measures showed less body growth in tea garden workers. They showed significantly higher head circumference and head length, but lower head breadth (p<0.05), which is an indicator of lower head volume and thus, lower protein composition. Tea garden workers also showed significant spinal shrinkage (1.86%) than control subjects (0.83%), which may be due to working stature. Most of the workers perform their work in standing posture for more than 6 hours a day. There is a gain in stature during relaxed sitting compared to work in a sitting posture. The load on the spine is greatest when work in a standing position is performed. The greater shrinkage of the lumbar spine during work in a standing position compared to a sitting posture is probably due to the effect of bending and torsion while handling the work materials 22 .
There is limited evidence of pulmonary dysfunction of tea factory workers due to the exposure of tea dust 23,24 . As the mean age of the subjects from studied population belongs to young adult category, the effect of tea dust is not too high to modulate the physical fitness parameters. Therefore from the present study it can be concluded that although tea factory workers have good fitness, few have signs of malnutrition. However more detailed studies including a larger sample size, considering socio-economic conditions, nutritional status and age group is essential to draw any definite inference.