Introduction:
The painters are chronically exposed to lead due to the use of lead based paints. [1]
As the painters are constantly engaged in painting and sand dusting, they will acquire lead by inhalation of surrounding contaminated air and by ingestion of water and food in an unhygienic environment. In adults, about 30-40% of inhaled lead [2] and 10% of ingested lead [3] finds its way into circulation. Toxic effects of lead usually results in cognitive dysfunction, neurobehavioral disorders, neurological damage, hypertension, anaemia, reproductive problems and renal impairment [4]. Lead interferes in the enzymatic activity of heme biosynthesis and also decreases RBC life span, thus resulting in anaemia.[4,5] In India, 82% of paint samples were found to have lead more than the US definition of lead-based paint in existing housing (i.e. >5000ppm).[6]
With this background, to measure the prevalence of anaemia in brush painters as the primary objective and also to assess blood lead levels, hematological indices, health effects and personal hygiene of the brush painters and to find the correlation between them, the present study was undertaken.
Material and Methods:
Settings and Design:
This was a cross sectional study conducted in Mysore city, Karnataka, among occupational residential brush painters during July 2012 and September 2012. Taking prevalence as 25% [7], an absolute precision of 10%, alpha 5%, and non response rate 20%, the sample size was calculated to be 100. The sampling frame couldn’t be made out due to the non availability of the list of painters. Hence snow ball technique was adopted. First few participants were identified by approaching the paint vendor; further participants were approached through their contacts till 100 participants were studied.
Male residential brush painters of more than 15 years of age and with a minimum of 1 year painting experience were included in the study. Spray painters, industrial painters, paint strippers and subjects with history of jaundice, malaria or any chronic infections, hematemesis, hemoptysis, epistaxis, radiation exposure, any recent surgeries undergone, drug intake like HIV medications, chemotherapy, seizure medications, chloramphenicol, antifungals were excluded.
Approval from the Institutional Ethics Committee (IEC) was obtained. Participation was purely voluntary and the written informed consent was taken from all the subjects.
Data collection:
The details of demographic features, occupational history, daily wages, personal hygiene, habits and health complaints were collected during face-to-face interview and nutritional status was assessed during clinical examination. Occupational history included the painting experience (in years); number of working days in the previous month; and number of working hours per day. Questions on personal hygiene included the habit of washing of hands before taking food; frequency of taking bath; frequency of washing clothes which are used while working; usage of personal protective equipments like gloves, masks, respirators or goggles while working. Nutritional status was assessed and classified based on estimation of Body Mass Index (BMI) for Asians. Each subject was asked about the presence or absence of symptoms which are commonly associated with lead poisoning, namely, weakness, dizziness, memory deficit, anxiety, irritability, general body pain, headache and abdominal pain.
Hematological Analysis:
From each subject, venous blood sample was collected into EDTA tubes. All the hematological parameters were measured using Sysmex® Automated Hematology Analyzer. Peripheral blood smear examination was also done. In our study, according to WHO criteria, anemia was defined as hemoglobin concentration less than 13 g/dl.
Blood lead level estimation:
Through systematic random sampling, every 3rd subject was selected to make a sub sample of 30 samples. Based on economical feasibility, only the blood samples of this sub sample were subjected to blood lead level estimation using LEADCARE II Blood Lead Testing System (Magellan Diagnostics, USA) which works on the principle of Anodic Stripping Voltammetry (ASV). [8]
Statistical analysis:
The statistical analysis was conducted using SPSS software Version 13. Descriptive statistics was done by prevalence calculation, mean, standard deviation, range, proportions and correlation coefficient. Inferential statistics was done by using Chi-square test, Fischer test and Pearson’s correlation.
Results
The base line characteristics of the study population are shown in Table 1.
| Table 1: Baseline features of the study population |
|
Mean |
SD |
Maximum-Minimum |
Age |
30.62 |
9.3 |
17-54 |
Daily wages |
319.5 |
47.6 |
200-400 |
| |
% of individuals* |
| Educational Status |
| Illiterate |
15 |
| Primary school |
27 |
| High school |
49 |
| PUC |
9 |
| BMI |
| <18.5 |
26 |
| 18.5-22.9 |
50 |
| 23-24.9 |
13 |
| >25 |
11 |
Smokers |
51 |
Alcohol consumption |
32 |
| * n=100, hence the % is equal to number of subjects |
One third of the study population had a painting experience of under 5 years, 42% had 6-15 years and 23% had >15 years. The pattern of paint exposure among the study population is shown in Table 2. The personal hygiene among the study participants was good except for bathing and use of mask. The pattern of personal hygiene among the study population is shown in Table 3.
| Table 2: Pattern of occupational history among the study subjects |
|
Mean |
SD |
Minimum - Maximum |
Median |
Painting experience(in years) |
10.8 |
8.4 |
1-35 |
9 |
No. working days in the previous month |
24.5 |
4 |
10-30 |
4 |
Number of working hours/day |
8.3 |
0.8 |
7-12 |
8 |
Number of working hours/month |
204.2 |
45 |
88-360 |
200 |
| Table 3: Pattern of personal hygeine among the painters of this study |
| Personal Hygeine |
% of individuals* |
Washing of hands prior to intake of food during working hours |
61 |
| Frequency of taking bath per week |
|
| 1-2 |
44 |
| 3-4 |
37 |
| >7 |
19 |
| Frequency of washing of working clothes per month |
|
| Never |
2 |
| 1 |
3 |
| 4 |
93 |
| 12 |
2 |
Use of personal protective equipments |
2 |
| * n=100, hence the % is equal to number of subjects |
The prevalence of anaemia (Hb% <13g/dL) is 3% and proportion of subjects with hematocrit value <40% was 11% and that of RBC concentration less than 4.5 million/mm3 was 11%. Blood lead level among the study group (n=30) was 12.9±10.9µg/dL. Except RDW all the other haematological parameters were found to be in the normal range, (Table 4). On peripheral smear examination, 98% of normocytic normochromic blood picture, 1% of macrocytic and normochromic blood picture, and 1% of dimorphic and hypochromic blood picture was found. Eosinophilia was found in 34% of the painters. Basophil stippling was absent in all the subjects.
| Table 4: Blood lead level and haematological parameters among the study subjects |
| Parameters |
Mean±SD |
Minimum-Maximum |
Median |
PbB(µg/dL) |
12.9±10.9 |
4.7-60 |
10.4 |
Hb (g/dL) |
15.5±1.4 |
9.3-18 |
15.6 |
Hct (%) |
45.4±6.4 |
16.9-55.2 |
46.8 |
RBC Concentration (×106/µL) |
5.2±0.7 |
3.3-7.9 |
5.2 |
MCV (fL) |
89.2±9 |
48.3-110.7 |
88.9 |
MCH (pg) |
31.5±8.9 |
21.6-89.8 |
30.1 |
MCHC (%) |
33.5±2.1 |
24.1-41.9 |
33.3 |
RDW (%) |
16.1±7.8 |
12.2-45.2 |
13.8 |
| PbB- Blood lead concentration; Hb- Hemoglobin; Hct- Hematocrit; MCV- Mean cell volume; MCH- Mean corpuscular haemoglobin; MCHC- Mean corpuscular haemoglobin concentration; RDW- Red cell distribution width. |
There was no significant correlation found between the blood lead level and hemoglobin(r=0.025), hematocrit(r= -0.2), RBC concentration(r=0.11), MCV(r= -0.12), MCH(r= 0.28), MCHC(r= -0.01), RDW(r= -0.06).
The prevalence of lead toxicity symptoms among the study population is shown in Figure 1. The correlation between the symptoms and personal hygiene is in the Table 5. Significant correlation was present between the habit of washing of hands before taking food during the working hours and dizziness, memory deficit, anxiety and headache.
 |
| Fig 1: Prevalence of lead toxicity symptoms among the study subjects |
| Table 5: Correlation between Symptoms and Personal hygiene |
Symptoms |
Washing hands before food during the working hours |
Bathing Frequency |
Frequency of washing working clothes |
Yes (n=61) |
Not even once in a day (n=81) |
Daily (n=19) |
< Once in a week (n=5) |
Once in a week (n=95) |
Abdominal pain |
11 (18%) |
21 (25.9%) |
3 (15.8%) |
0 (0%) |
24 (25.3%) |
Dizziness |
23 (37.7%) |
38 (47%) |
7 (36.8%) |
2 (40%) |
43 (45.3%) |
Weakness |
30 (49.2%) |
45 (55.5%) |
8 (42.1%) |
3 (60%) |
50 (52.6%) |
Memory deficit |
16 (26.2%) |
15 (18.5%) |
5 (26.3%) |
2 (40%) |
18 (19%) |
Anxiety |
21 (34.4%) |
37 (45.7%) |
6 (31.6%) |
3 (60%) |
40 (42.1%) |
Irritability |
19 (31.1%) |
31 (38.3%) |
3 (15.8%) |
2 (40%) |
32 (33.7%) |
General body pain |
26 (42.6%) |
41 (50.6%) |
5 (26.3%) |
3 (60%) |
43 (45.3%) |
Headache |
21 (34.4%) |
35 (43.2%) |
8 (42.1%) |
3 (60%) |
40 (42.1%) |
Disturbed sleep |
10 (16.4%) |
17 (21%) |
2 (10.5%) |
2 (40%) |
17 (17.9%) |
Decreased appetite |
9 (14.8%) |
11 (13.5%) |
3 (15.8%) |
1 (20%) |
13 (13.7%) |
| #There was a significant correlation between Dizziness, Memory deficit, Anxiety, Headache and Washing of hands before taking food during the working hours. |
Discussion
In the present study, the prevalence of anaemia in brush painters was found to be low and it is lower than the presumed prevalence of 25%. This observation is in supportive of low prevalence of anaemia (4.3%) found in the study conducted on 1,573 Japanese lead industry workers with similar blood lead levels (12.6 ± 2.0 µg/dL).[9] The possible reason for this low prevalence of anaemia is the low PbB found in the brush painters, which is less than the threshold for lead induced anaemia (50 µg/dL).[4] Thus it is unlikely that the anaemia found in the present study is caused by the occupational exposure to lead. In a study on shipyard painters, the prevalence of anaemia was found to be 10%.[10] But the authors attribute the cause of anaemia to be ethylene glycol ether exposure.
The PbB found in the brush painters of the present study is less than that found in the studies conducted on spray painters of India.[5,11,12] It is known that the ambient lead concentration in the air is higher in the spray painting environment than the brush painting environment.[13] Probably, due to this difference in air concentration, the brush painters may absorb less lead and thus leading to lower lead concentration. But in a study on spray painters of Thailand,[14] they were found to have a PbB which is slightly less than the present study.
The PbB indicates only the recent exposure (30-35 days) to lead.[15] As the PbB in the present study is indicative of regular exposure to lead, the PbB found could be slightly less than the actual, because of the varying lead exposure in the present study group, which is reflected by their wide range of working hours per month (88 - 360 hours/month). In the present study, one subject (n=30, PbB 60 µg/dL) was found to have PbB higher than the biological exposure index for lead(PbB 30 µg/dL).[16] This is possibly indicative that, depending on the exposure, the painters may have acute lead toxicity overlapping on pre-existing chronic lead exposure.
The hematological parameters in the present study are similar to the observations conducted on spray painters,[11] pigment manufacturers[9] and tile workers[17] with either similar or higher(3 times) PbB. But in a study conducted on battery workers[18] with PbB 5 times higher than the present study, the hemoglobin and hematocrit were found to be decreased. It is indicative that the hematological indices will not change substantially till the PbB is higher than the threshold. The high prevalence of eosinophilia in the present study could be due to the allergic reaction produced by the inhalation of the volatile organic compounds present in paint.[19,20] As in the present study, there was no significant correlation found between PbB and hematological parameters in many other studies with higher PbB.[11,17] This could be due to the threshold effect of PbB. In a study on Japanese lead workers with similar PbB(12.6±2 µg/dL) was found to have significant positive correlation with the haematological indices.[9] But in the present study this correlation was not found, possibly due to the small sample size of the present study and racial difference between the two studies.
Studies on battery workers[18] and tile factory workers[17] with PbB 4 and 3 times higher than the present study respectively, have reported lower prevalence of lead toxicity symptoms than the present study. This higher prevalence in the present study could be due to two reasons. Firstly, volatile organic compounds (VOCs) in paints can also cause neuro-psychological symptoms.[21] Thus there will be overlapping effects of lead toxicity and VOCs among the painters, which was not possible to be distinguished in the present study. Secondly, the PbB indicates only the recent exposure and doesn’t indicate the body lead burden.[15] So the painters may be suffering from long term health effects of lead even at low levels of exposure. Hence further studies on brush painters using X-ray fluoroscopy (XRF) or EDTA mobilisation test are required to assess the body lead burden.[15]
The significant association of certain hygiene practices with the symptoms in the present study is suggestive that the maintenance of good hygiene could substantially decrease the lead exposure in painters. Thus it is suggestive for the need of behaviour change communication for the brush painters in order to decrease their occupational exposure to paint.
Limitations
Sub sampling has been done for blood lead level estimation. Complete dietary history has not been taken, which could be a potential confounder for anemia.
In conclusion, the prevalence of anaemia in painters was found to be 3% and the PbB in painters (12.9 ± 10.9 µg/dL) is found to be less than 30 µg/dL (Biological exposure index), which is the threshold for occupational exposure. All the haematological parameters were found to be in the normal range. And there was no relationship found between PbB and the haematological parameters, possibly due to low PbB in the painters. As the threshold for alteration of haematological parameters is >50 µg/dL and the PbB in painters is found to be less than the threshold, the haematological examination is not useful in screening of lead toxicity in painters and lead induced anaemia is not a health risk in painters. The high prevalence of lead toxicity symptoms indicates that the painters are suffering from long term health effects of lead even at low levels of exposure. And also, the symptoms were found to be less in the painters who were more hygienic. Hence, in painters, proper awareness about the health effects of lead must be created and they must be educated about the benefits of maintenance of good hygiene. This easily achievable goal among the painters could decrease the lead exposure to a great extent.
Acknowledgement
Authors are thankful to Dr Venkatesh Thuppil, Principal advisor, Quality Council of India, and National Referral Centre for Lead Poisoning in India and professor, Department of Bio-Chemistry and Bio-Physics, St John’s Medical College for providing equipment for the blood lead level estimation. We also thank ICMR-STS 2012 and Karnataka State Pollution Control Board for providing research grants.
References
- Gordon JN, Taylor A, Bennett PN. Lead poisoning: case studies. Br J Clin Pharmacol 2002;53:451–458.
- Phillip AT, Gerson B. Lead poisoning – Part I. Incidence, etiology, and toxicokinetics. Clin Lab Med 1994;14:423-444.
- Markowitz M. Lead poisoning. Pediatr Rev. 2000;21:327-335.
- Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological profile for lead. Atlanta, GA: U.S. Department of Health and Human Services (Public Health Service) 2007:1-253.
- Mohammad IK, Mahdi AA, Raviraja A, Najmul I, Iqbal A, Thuppil V. Oxidative stress in painters exposed to low lead levels. Arh Hig Rada Toksikol 2008; 59:161-169.
- Clark CS, Rampal KG, Thuppil V, Chen CK, Clark R, Roda S. The Lead Content of Currently Available New Residential Paint in Several Asian Countries. Environmental Research 2006;102(1):9 -12.
- Cullen MR, Robins JM, Eskenazi B. Adult inorganic lead intoxication: presentation of 31 new cases and a review of recent advances in the literature. Medicine 1983;62:221–227.
- LEADCARE ® II. North Billerica(MA): Megellan diagnostics. [Cited 2013 June 5]. Available from: http://www.leadcare2.com/
- Makino S, Shimizu Y, Takata T. A study on the relationship between blood lead levels and anemia indicators in workers exposed to low levels of lead. Ind Health 1997;35:537–541.
- Welch LS, Cullen MR. Effect of exposure to ethylene glycol ethers on shipyard painters: III. Hematologic effects. Am J Ind Med 1988;14(5):527–536.
- Patil JA, Bhagwat RV, Patil AJ, Dongre NN, Ambekar GJ, Das KK. Biochemical aspects of lead exposure and toxicity in spray painters of Western Maharashtra (India). J Environ Health Res 2007; 6:101-110.
- Rao GM, Shetty BV, Sudha K. Effect of lead on oxidant: antioxidant balance in painters. Clin Chim Acta 2006;367:209-210.
- Code of practice: Spray Painting. WorkSafe Western Australia Commission. Amended June 2009 - [Cited 2013 June 5]. Available from: http://www.commerce.wa.gov.au/worksafe/PDF/Codes of_Practice/Code_spray_painting.pdf
- Vitayavirasuk B, Junhom S, Tantisaeranee P. Exposure to Lead, Cadmium and Chromium among Spray Painters in Automobile Body Repair Shops. J Occup Health 2005;47: 518-522.
- Lyn Patrick, ND. Lead toxicity, A review of the literature. Part I: Exposure, Evaluation, and Treatment. Altern Med Rev 2006;11(1):2-22.
- ACGIH. Documentation of the Biological Exposure Indicies, 7th Edition, 2001 and NIOSH Alert “Preventing Lead Poisoning in Construction Workers”, 91-116a, 1992.
- Mood MB, Shademanfar S, Mogadham JR, Afshari R et al. Occupational Lead Poisoning in Workers of Traditional Tile Factories in Mashhad, Northeast of Iran. Int J of Occup and Environ Health 2010;3:29-38.
- Memon F, Vasandani AGM, Seehar GM, Bhanger MI. Effect of low blood lead levels on anaemic indicators and creatinine rate of workers occupationally exposed to lead. Pak J Physiol 2009;5(2):31-33.
- Koren HS, Graham DE, Devlin RB. Exposure of humans to volatile organic mixture. III. Inflammatory response. Arch Environ Health 1992;47:39-44.
- Pazdrak K, Gorski P, Krakowiak A, Ruta U. Changes in nasal lavage fluid due to formaldehyde inhalation. Int Arch Occup Environ Health 1993;64:515-519.
- Chen R, Dick F, Seaton A. Health effects of solvent exposure among dockyard painters: mortality and neuropsychological symptoms. Occup Environ Med 1999;56(6):383–387.
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