ASSESSMENT OF AMBIENT AIR PARTICULATE MATTER CONCENTRATION, CARDIOVASCULAR AND RESPIRATORY FUNCTIONS IN CEMENT WORKERS, AUTOMOBILE SPRAY PAINTERS AND WOODWORKERS

S.C. Ibeneme^1,2, R.N. Ativie¹, G.C. Ibeneme³, H. Myezwa², A.D. Ezuma⁴, A. Nnamani⁵, S. Ezeofor⁵, J.M. Nwankwo⁶, T.U. Ettu⁷, I.J. Okoye⁵, G. Fortwengel⁸

Background: An upsurge in cardiovascular and respiratory dysfunction in Enugu Metropolis, Southeast Nigeria, involved mainly cement workers, automobile spray painters, and woodworkers, suggesting an association with workplace ambient air pollution, which may be of health importance, and was investigated.

Purpose: To assess ambient air particulate matter (PM) concentration and its relationship with cardiovascular and respiratory diseases observed in Enugu residents.

Methods: Eighty consenting participants (working in New layout -residential district in Enugu), comprising 20 cement workers (39.50±14.95years), 20 automobile painters (40.75±9.85years), 20 woodworkers (52.20±9.77years), and 20 control group/university staff (42.30±9.06years), were randomly selected in a non-matched case-control study. Ambient PM concentration, Fibrinogen (Fc), C-reactive protein (CRP), and cardiopulmonary parameters were measured/analyzed using ANCOVA; while posthoc analysis involved Bonferroni test, at p<0.05.

Results: The mean diastolic (F=19.073, p=0.001), and systolic (F=2.903,p=0.040) blood pressure(mmHg) differed significantly across the groups, but was below the normal range (140/80mmHg) in cement workers (121.40/68.00mmHg)/automobile spray painters (121.10/63.30mmHg) unlike the woodworkers (146.50/96.20mmHg) and control (123.50/94.85mmHg). The majority of the cement workers(55%) and spray painters (50%) had a stuffy nose, while woodworkers (65%) and control (60%) had red, itchy and watery eyes. The dry season particulate matter(PM) in ambient air exceeded the WHO standards in New layout [PM₁₀=541.17±258.72µg.m-3; PM2.5=72.92±25.81µg.m-3] and the university campus [PM₁₀=244±74.79µg.m-3; PM_2.5=30.33±16.10µg.m-3], but the former was twice higher. The PM differed significantly (p<0.05) across the sites. Forced expiratory volume at the first second (FEV₁)(F=6.128,p=0.001), Peak expiratory flow rate (PEF)(F=5.523, p=0.002), and QTc (F=4.521, p=0.006), differed significantly across the groups. FEV₁/FVC% were as follows: Control=70.66%; Cement workers=55.33%; Paint workers=72.22%; woodworkers=61.79%. CRP(normal range≤3.0mg/L) was high in cement workers (3.32±0.93mg/L) and control (3.06±0.82mg/L). Fc values was above the normal range (1.5-3.0mg/dL) in cement workers (3.06±0.82mg/dL). QTc interval was significantly (F=4.521, p=0.006) prolonged across the groups, especially in woodworkers (431.50±5.75) but the effect size was highest (moderate) in spray painters (d=0.55). There is a significant negative relationship between FEV₁ and duration of occupation in cement workers (r=-0.46, r²=0.2116, p=0.041, one-tailed). A positive relationship exists between QRS duration and the duration of occupation in cement workers (r=0.45,r²=0.20,p=0.048,one-tailed); and control (r=0.481,r²=0.23.14,p=0.032, one-tailed); and between P-R interval and CRP (r=0.580,r²=0.34,p=0.007), and Fc (r=0.26,r²=0.34, p=0.022), in spray painters, respectively.

Conclusion(s): There is evidence of ambient air pollution at the study sites, especially in the dry season. The endpoint of the health outcomes included significant dangers of hypotension, due to a reduction in the diastolic blood pressure in cement workers and spray painters, and hypertension among woodworkers. There are significant risks of seasonal obstructive pulmonary disease, among cement workers and spray painters; and restrictive lung diseases in woodworkers. The trend in Fc is similar to CRP suggesting a role for the inflammation-sensitive proteins in the determination of cardiovascular risk but is of greater concern in cement workers and controls. The woodworkers' ECG hints of underlying cardiac abnormalities, which may be aggravated by the duration of occupational exposure to pollutants, especially, the significantly prolonged ventricular repolarization which might contribute to the mechanism of arrhythmogenic conditions.

Implications: There is an environmental pollution concern in Enugu metropolis which affects workers, both occupationally exposed and unexposed to industrial pollutants and requires urgent public health action.

Funding, acknowledgements: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Keywords: Ambient air particulate matter concentration, cement workers; spray painters; woodworkers, cardiovascular and cardiorespiratory function

Topic: Occupational health & ergonomics

Did this work require ethics approval? Yes

Institution: University of Nigeria

Committee: Health Research Ethics Committee on Certificate Number

Ethics number: NHREC/05/01/2008B