Journal of Dr. NTR University of Health Sciences

ORIGINAL ARTICLE
Year
: 2017  |  Volume : 6  |  Issue : 4  |  Page : 236--241

Study of respiratory status in young male automobile painters: A cross sectional study


Vitthal Khode, Ruikar Komal 
 Department of Physiology, SDM College of Medical Sciences, Dharwad, Karnataka, India

Correspondence Address:
Dr. Vitthal Khode
Department of Physiology, SDM College of Medical Sciences, Sattur, Dharwad, Karnataka
India

Abstract

Background: Painters are exposed to solvent fumes and aerosols containing various concentrations of pigments, binders, fillers (talc), and chemically reactive monomers. Specific components in paint, such as isocyanates and dimethyl ethanolamine, are capable of inducing acute and chronic forms of airflow obstruction. Our study aims to establish the hypothesis that even young male painters may be at an increased risk of developing respiratory impairment. We studied the respiratory status of young male painters exposed to paints for more than 5 years and compared their pulmonary functions to a group of age- and sex-matched controls. Aims: To compare various parameters of lung functions in young male automobile spray painters with age- and sex-matched controls. Materials and Methods: This cross sectional study was conducted in the department of physiology and medicine. Fifty-eight young male spray painters who attended the medical outpatient department of our college were selected. Fifty-two age- and sex-matched controls were also selected from subjects who attended the medical outpatient department for routine medical checkup for recruitment in the same automobile company. After history and routine examinations, the patients were subjected to pulmonary function tests. Schiller's spirovit SP-1 was used. The data were analysed using Student's t test. Results: Significantly reduced forced expiratory volume in 1 s (FEV1)/slow vital capacity (SVC) (P < 0.001) and maximal voluntary ventilation (MVV) (P < 0.05) were observed among painters as compared to the controls. There was significant differences in SVC (P < 0.001) and FEV1 (P < 0.05) in grade 1, grade 2, and grade 3 exposed groups. There was no significant correlation between numbers of hours of exposure to SVC (P = 0.420) and FEV1 (P = 0.377) in painters. Conclusions: Potential respiratory health hazard exists in automobile painters and exposure to organic solvents should be prevented in order to improve their health status.



How to cite this article:
Khode V, Komal R. Study of respiratory status in young male automobile painters: A cross sectional study.J NTR Univ Health Sci 2017;6:236-241


How to cite this URL:
Khode V, Komal R. Study of respiratory status in young male automobile painters: A cross sectional study. J NTR Univ Health Sci [serial online] 2017 [cited 2020 May 29 ];6:236-241
Available from: http://www.jdrntruhs.org/text.asp?2017/6/4/236/221530


Full Text



 Introduction



Painters are exposed to solvent fumes and aerosols containing various concentrations of pigments, binders, fillers (talc), and chemically reactive monomers. Specific components in paint, such as isocyanates and dimethyl ethanolamine, are capable of inducing acute and chronic forms of airflow obstruction.[1],[2],[3],[4],[5],[6] Car spray-painters are exposed to isocyanates,[7] which are a group of low molecular weight aromatic and aliphatic compounds containing the highly reactive isocyanate group (–NCO). The most commonly used isocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and biuret modified HDI (HDI-BT).[8] Inhalation and dermal exposure can occur during the manufacture and use of these compounds. Isocyanates are used as cross-linking agents in polyurethane products such as foams, varnishes, and paints. Therefore, workers and individuals in proximity to spray applications of polyurethane paints are very likely to be exposed.[9] In acute toxicity, all workers will develop eye, nose, and throat irritation with coughing and labored breathing. More severe exposure may result in hypersensitivity pneumonitis and pulmonary edema. Chronic inhalation can cause immune disorders as well as nasal and lung lesions. Chronic inhalation exposure to isocyanates in plant workers has been linked to pulmonary effects that are characterized by dyspnea, wheezing, and bronchial constriction.[10],[11] Our study was conducted to establish the proposed hypothesis that even young male painters may be at an increased risk of developing respiratory impairment. We studied the respiratory status of painters who had exposure to paints for more than 5 years and compared their pulmonary functions to a group of age- and sex-matched controls.

 Materials and Methods



After getting approval of the ethical clearance committee of the institution, this cross sectional study was conducted over 6 months (August 2011 to January 2012). The selection of the sample was performed from the outpatient department of medicine of our institution. One hundred and ten individuals participated in the study. The whole population was divided into two groups. Group 1 consisted of randomly selected subjects who had exposure to organic solvents for more than 5 years. All were males working in an automobile company as spray workers and were aged 18-35 years. Group 2 consisted of randomly selected sex- and age-matched controls, and had no exposure to any organic solvents. All were getting recruited for the same automobile company. The sample size was determined by standard error obtained by a pilot study. Each individual was briefed about the study beforehand; its importance and procedural details were given and written consents of the participants were taken before recording the various spirometric parameters. The following subjects were excluded from the study: smokers, individuals with diabetes mellitus, hypertension, cardiovascular, cerebrovascular disorders, neuropathy, and chronic renal disorders, and those taking any bronchodilator.

At the time of the health screening, all participants were asked to complete a questionnaire covering their medical and occupational histories, with special emphasis on the extent of exposure to paint. The painters were asked the number of years they had painted, the number of weeks they had worked with solvent paints during the past year, and the fraction of time they had used spray application methods, both for the entire time they had been painting and during the past year. All frequencies were converted into hours per year and hours per lifetime (which was defined as the number of years multiplied by hours per year). Based on the exposure hours per lifetime, the subjects were categorized into grade 1 exposure group (1,200-4,000-h work as a painter), grade 2 exposure group (4,000-5,000-h work as a painter), and grade 3 exposure group (>5,000-h as a painter). Questions concerning respiratory symptoms, acute irritation to eyes, throat, and nose were asked. The painters were asked if they ever suffered from an itchy, runny, or stuffy nose and if their eyes ever itched or watered and if their throats ever became dry or irritated. If they response was affirmative, they were asked if it happened at least once a week. The painters who indicated that they usually coughed 4 or more days a week during the day or at night (not just on getting up in the morning) or brought up phlegm from their chest throughout the day (not just in the morning) were also asked whether these symptoms changed during weekends or holidays. Following the definition of the American Thoracic Society,[12] chronic bronchitis was defined as cough with phlegm on most days for as much as 3 months during the year for at least 2 years.

Pulmonary function tests

Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/SVC, forced expiratory flow (FEF) 0.2-1.2, 25-75%, 75-85%, peak expiratory flow (PEF), FEF 25%, 50%, 75% and maximal voluntary ventilation (MVV) were measured, using Schiller's SPIROVIT SPIROVIT SP-1 (Switzerland). An attempt was made to obtain at least three acceptable recordings for each participant. Standing height was measured without shoes, in meters. Weight was measured in kilograms. Measurements of SVC, FEV, and FVC were considered reproducible if the difference between the largest two values from the acceptable tracings did not exceed 5% of the largest value or 100 mL, whichever was greater. The largest values for FEV and FVC were used as the observed values but they may have been taken from the different maneuvers. Restrictive lung disorder was diagnosed if SVC or FVC was smaller than 80% of the predicted value. Obstructive disorder was diagnosed if FEV1 was smaller than 70% of the predicted value.

Predicted values for pulmonary function tests

Predicted values for SVC, FEV1, FVC, and FEF 25-75% were derived from the Indian population. These prediction equations include the terms for age, sex, weight, and standing height but they do not include the terms for smoking history because they are based on a nonsmoking population. Since these prediction equations were based on the Indian population, the predicted values were generated for Indians in the study population. Separate equations were used for men under 30 years of age and for men aged 30 years and above.

Statistical analysis

All analyses were performed on a personal computer with the assistance of Statistical Package for the Social Sciences (SPSS) version 16 (2007, USA). Differences in the proportions of symptoms in the cases and controls were tested using chi-square test with one degree of freedom. Differences in the mean values for continuous variables in the cases and controls were tested with the independent t-test. Sub group analysis was done by one way ANOVA in cases with significance at P< 0.05. A Pearson's correlation coefficient was used to examine the association between duration of exposure and FEV1, SVC. All P values were two-tailed except for chi-square tests where the matter does not arise.

 Results



The mean age of painters included in this study was 28.6 ± 5.5 years (range: 18-35 years) compared to 25.7 ± 3.8 years [Table 1] and the mean number of years employed as a painter was 5.93 years (range: 5-13 years). All the painters were both directly exposed and less directly exposed to paints. The prevalence of respiratory symptoms was breathlessness in 10.3%, eye irritation in 17.2%, nose irritation in 20.7%, and throat irritation in 8.6%, all of which were significantly higher among the painters than the controls [Table 2]. The respiratory symptoms occurred usually right after exposure or during the work hours. Some subjects said that they did not experience any of these symptoms when they stopped working. Two subjects said that they left painting for a couple of years and resumed painting when their symptoms had improved; however, they were still complaining of respiratory symptoms during work with painting. A chi-square test for the proportions indicated an increasing prevalence of breathlessness (P< 0.001), transient nose irritation (P< 0.001), eye irritation (P< 0.001), and throat irritation (P ≤ 0.001) in painting that were significant. The prevalence of chronic bronchitis was 6.9% in painters compared to the controls, which was significantly high when chi-square test was done for proportion. (P< 0.001).{Table 1}{Table 2}

Pulmonary function test (PFT) values were measured in painters and controls by the same. The values were compared in each case with the predicted values, and results are reported in percent of predicted. Out of 58 painters, five were diagnosed having restrictive lung disorder compared to none from the control group. Though none of the painters had obstructive lung disorder, FEV1/SVC, FEF 25-75%, FEF 75-85%, and MVV were significantly lower in the painters than in the controls [Table 3]. Subgroup analysis in the painters showed significantly lower SVC, FEV1, FEF 25-75%, and FEF 75-85% among grade 1, grade 2, and grade 3 exposure groups [Table 4].{Table 3}{Table 4}

However, there was an insignificant negative correlation between the number of hours of exposure to FEV1 and SVC with r = −0.119, −0.108 and P = 0.377, 0.420 respectively.

 Discussion



In the current study, we identified the impact of spray painting on their respiratory health, and found significantly higher work exposure-induced respiratory symptoms in spray painters than in the control population. Our findings indicate impaired PFT values in spray painters, compared to the control population.

Several epidemiologic studies have reported an association between occupational exposure to inorganic and organic dusts and chemical agents and increased risk of COPD among those employed in industries.[13],[14],[15],[16],[17] The aforementioned results can be explained in the light of the findings of Wisnewski et al. They revealed that high exposure to polyisocyanates can induce extrinsic allergic alveolitis and reactive airways dysfunction syndrome (RADS) while sensitization-induced asthma can be provoked with very low exposure. Likewise, Glindmeyer et al. demonstrated a statistically significant reduction in pulmonary functions in 240 painters spraying polyurethane enamels at four aircraft maintenance plants.[18] Furthermore, they found that exposure-related adverse effects on lung functions were reduced by frequent use of respiratory protective equipment.

Decreased lung function parameters and a high prevalence of asthma symptoms have been reported in the spray painting industry.[19] A study conducted by Tornling et al. has incorporated exposure assessment and demonstrated a relation between peak exposure and reduced lung function in car painters who smoke.[20] Another study that assessed the complex exposure patterns of isocyanates revealed that positive associations with exposure were found for asthma-like and chronic obstructive pulmonary disease (COPD)-like symptoms, work-related chest tightness, and work-related conjunctivitis.[9] Most of the studies have shown smoking and advancing age as confounding factors in assessing the respiratory status in occupational lung diseases. By excluding smokers and the elderly in our study, we have tried to minimize these confounding factors. We found five painters having restrictive lung disorder compared to none in the control group. But when FEV or SVC of the painters was compared to the controls, there was no significant change. Though we did not find any obstructive lung disorder in the painters or controls, there was a significant difference in FEV1/SVC in the painters compared to the controls. Regarding subgroup analysis in painters of different grades of exposure, there was a significant difference in SVC and FEV1. We found a decrease in FEF 25-75% and FEF 75-85% in painters compared to the controls and subgroups in painters, which indicates the involvement of smaller airways. There was an insignificant correlation between the hours of exposure to FEV1 and SVC in painters.

Two different measures were used to assess obstructive disease in this study, spirometric measures of pulmonary function, and questionnaires. Spirometry is viewed by many as the more objective measure but in this instance, it suffers from reliance on potentially noncomparable populations to generate expected values and dependence on cutoff values to define disease. Self-reports of the symptoms may be more subjective but the symptoms of chronic bronchitis may be a more specific measure of the functional abnormality of interest.

The limitations of the present study are the small study size, self-reported health data, no review of medical records of the participants to confirm their respiratory conditions, and lack of environmental air data confirming exposures, all of which require further study. The shortcomings of these cross sectional studies are compounded by the crude measures of exposures. Industrial hygiene measurements are preferable but may not be very informative since the composition of paint materials and working conditions change from one worksite to another. In terms of health risks, more may be learned from an examination of toxicity studies of specific paint components than could ever be shown from the epidemiological studies of spray painters. Perhaps the most valuable contribution of epidemiological studies is the measure of risks related to the failure to apply knowledge about toxicity to reduce health hazards. The results of this study suggest that greater attention should be paid to the identification of respiratory toxins present in paints and to the reduction of exposures to these toxins.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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