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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 16  |  Issue : 1  |  Page : 32-37

Air quality index and cardiovascular risk factors among automobile technicians in Southwest Nigeria


1 Department of Medicine, Cardiology Unit, Ladoke Akintola University of Technology and Ladoke Akintola University of Technology Teaching Hospital, Ogbomoso, Kwara State, Nigeria
2 Department of Chemical Engineering, University of Ilorin, Ilorin, Kwara State, Nigeria
3 Department of Economics, College of Management and Social Sciences, Osun State University, Okuku, Osun State, Nigeria
4 Department of Medicine, Pulmonology Unit, Ladoke Akintola University of Technology Teaching Hospital, Ogbomoso, Kwara State, Nigeria
5 Department of Chemical Pathology, Ladoke Akintola University of Technology and Ladoke Akintola University of Technology Teaching Hospital, Ogbomoso, Kwara State, Nigeria

Date of Submission16-Jul-2018
Date of Decision24-Apr-2019
Date of Acceptance12-Jun-2019
Date of Web Publication22-Oct-2019

Correspondence Address:
Dr. Adeseye A Akintunde
Department of Medicine, Cardiology Unit, Ladoke Akintola University of Technology and Ladoke Akintola University of Technology Teaching Hospital, P. O Box 3238, Osogbo, Osun State
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njc.njc_16_18

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  Abstract 


Background: Prolonged inhalational injury among automechanics may predispose them to increased oxidative process and cardiovascular diseases. This study was aimed at describing air quality index and pattern of cardiovascular risk factors among automechanics in Ogbomoso, Nigeria.
Materials and Methods: One hundred and three automechanics were randomly recruited from Ogbomoso, Nigeria. Demographic and clinical parameters were collected. Cardiovascular risk factors were assessed. Air quality sampling was done using the gt-321 particle counter. Statistical analysis was done using SPSS 18.0.
Results: The mean age of the study participants was 38.54 ± 11.94 years. The prevalence of cardiovascular risk factors among the study participants was hypertension (25.2%), low high-density lipoprotein-cholesterol (45.6%), elevated low-density lipoprotein-cholesterol (29.1%), and hypercholesterolemia (26.2%). The air quality index for particulate matter (PM)2.5were often three to five times higher than average 24 h mean in urban centers and more than 10 times the total annual mean. Similarly, average PM10,7,4and total suspended particle(TSP) were also significantly higher in automechanic workshops compared to the average urban measure of air quality index reported in 2014.
Conclusion: Air quality indices around autotechnicians workshop are very poor. Cardiovascular risk factors such as hypertension and dyslipidemia still occur frequently among automechanic despite their high physical activity. Proper automobile and emission control and implementation of workplace protection are advised to minimize the impact of air pollution on automechanics in Nigeria.

Keywords: Air pollution, autotechnicians, cardiovascular risk factors, Nigeria


How to cite this article:
Akintunde AA, Adeniran J, Akintunde TS, Oloyede TO, Salawu AA, Opadijo OG. Air quality index and cardiovascular risk factors among automobile technicians in Southwest Nigeria. Nig J Cardiol 2019;16:32-7

How to cite this URL:
Akintunde AA, Adeniran J, Akintunde TS, Oloyede TO, Salawu AA, Opadijo OG. Air quality index and cardiovascular risk factors among automobile technicians in Southwest Nigeria. Nig J Cardiol [serial online] 2019 [cited 2019 Dec 13];16:32-7. Available from: http://www.nigjcardiol.org/text.asp?2019/16/1/32/269647




  Introduction Top


Nigeria is replete with a large number of aging and aged vehicles.[1] The streets are filled with vehicles including heavy duties vehicles with massive exhaust emissions on the streets. Regulatory bodies involved with emission control of vehicles appear to be ineffective in the maintenance of law and order in this respect. The burden of environmental pollution by car exhausts in urban areas of Nigeria with heavy traffic has been suggested to be enormous.[2],[3] Automobile repairs expose autotechnicians and the general populace to many environmentalrisks with the potential high risk of cardiovascular and pulmonary conditions due to the use of premium motor spirit, diesel, paints and other gaseous materials.[4] These could have significant effect on the health of the technicians, as these volatile organic compounds including benzene, nitrobenzene, and heavy metals including lead and chromium accumulate over time with a significant long-term effect on the individual health.[5],[6] Automobile technicians and others working on repair of vehicles are also exposed to significant amount of dust, dust particles, and air pollutants with potential for significant occupational risks.[6],[7] Nigeria has >7 million registered vehicles with road transport system accounting for over 75% of mobility needs in the country.[8] Majority of these vehicles are at various stages of increased emissions.

Chronic exposure to air and chemical pollutants has been shown to be related to cardiovascular disease, especially in developed countries.[9],[10] In Nigeria, automobile service technicians are often found in clusters along major roads in many designated repair shops and they repair and maintain light and heavy vehicles. They are therefore exposed to physical and chemical hazards such as inhalation of gasoline fumes during mechanical repairs and inhalation of exhaust gases and particulate matter (PM) from running engines.[11] The chemical composition of the diverse types of aerosols PM found in the automobile repair shops depends on the materials being used.[11],[12] Factors which determine the effect of the PM on human health include the size distribution, the number and the concentration, or chemical composition of the materials.[12] The size of a particle is particularly important as smaller particles enter into the respiratory system and are deleterious to health.[12],[13]

Even though there have been limited studies on automobile mechanics/technicians in Nigeria with conflicting conclusions on their increased susceptibility to cardiovascular diseases compared to normal controls,[14] there is need to document the status of air quality indices around automechanics workshop as a possible predisposition to increased inflammatory conditions including cardiovascular and pulmonary conditions. This study, therefore, describes the state of air pollution among automechanics and the presence of cardiovascular risk factors among them.


  Materials and Methods Top


This is a descriptive study. The study location is Ogbomoso, Southwest of Nigeria. One hundred and three automobile technicians mainly automechanics were recruited consecutively from their workshops into the study. They were recruited randomly from the two local Government areas in Ogbomoso, Oyo State, Nigeria. Informed consent was obtained from every participant in the study. Inclusion criteria included age >15 years and ability to give informed consent to participate in the study. Exclusion criteria include the history of mental illness which could preclude his judgment ability, previous history of lung or heart disease, and inability to give consent to participate in the study. An average of five to eight participants was randomly selected by balloting recruited from each of the workshops from 18 randomly selected automechanic workshops from the two local government area of Ogbomoso (nine from each local government area). The workshops were randomly selected across Ogbomoso North and South Local Government, Oyo State, Nigeria. Each of these participating workshops had between 10 and 22 automechanics clustered together in each workshop. Only relatively big workshops were used for this study.

Participants were included if they fulfilled the inclusion criteria. Demographic and clinical parameters were obtained with the aid of a data collection form. Among the information obtained included age, gender, marital status, duration since starting the present job, and tribe. The previous history of hypertension, use of regular medications, and previous diagnosis of diabetes mellitus were also obtained. Blood pressure was obtained according to standardized guidelines with the patient having rested for at least 5 min. Three readings were obtained and the average of the second and third readings taken as the mean systolic and diastolic blood pressures.

Five milliliters of venous blood was obtained for laboratory investigations from each participant. This includes the lipid profile and the fasting/random blood sugar as appropriate. Weight was done in light clothing to the nearest 0.1 kg with the aid of a digital weighing scale, while height was done with a mobile stadiometer in centimeters to the nearest 1 cm. The body mass index (BMI) was obtained. Obesity was defined as BMI ≥30 kg/m2. Waist circumference was obtained at the midpoint between the lowermost rib and the anterior superior iliac spine. The hip circumference was done at the level of the greater trochanter. Waist circumference >94 cm was used to define visceral obesity as all of them were males.

Air quality sampling was done using the GT-321 particle counter, an equipment from the Met One Instruments Inc., Oregon, the United State of America, a handheld, battery-operated measuring particle ranges of total suspended particles. Sampling was done in selected automechanic workshops and five values obtained at different times and places around the automechanic workshop: At the height of repair such as time when engine is being worked upon and during nonbusy period. Values of PM (PM1, PM2.5, PM7, PM10) and total suspended particulate (TSP) were done and an average of five readings were obtained from the workshops. Each of the readings was separated by at least 10 min and was measured at around the exit or entry of the workshops with at least 10-m distance from a vehicle being repaired. Total suspended particulate (TSP) refers to the totality of small solid matter released, documented, and/or otherwise observed in the atmosphere. Total suspended particulates are considered to be a primary contributor to air pollution, smog formation, and environmental contamination. Dyslipidemia was defined according to standardized criteria in the third report of the Adult Treatment Panel, National Cholesterol Education Program.[15]

Statistical analysis was done using the Statistical Package for the Social Sciences 18.0 (IBM, Chicago, Ill, USA). Quantitative data were summarized as means ± standard deviation. Qualitative data were summarized as frequencies and percentages. Students' t-test and Chi-square were used appropriately to test for differences between the groups. P < 0.05 was considered as statistically significant.


  Results Top


[Table 1] shows the average of five serialized values of the PM of varying sizes taken selected automechanic workshop sites. The mean PM sizes for the five serialized measurements are shown in [Table 1]. The average of all the measurements was also determined. The mean PM1 and PM2.5 were significantly higher compared to mean annual and daily averages recorded from urban centers and higher than the expected cutoff for estimating risks due to the air quality index. There appear to be relatively small differences in the air quality index at various sites even though they were separated by at least 10–20 min between every measurement. This was in a bit to estimate the average cumulative exposure in the environment.
Table 1: Serialized measurements of particulate matters for automechanic workshops and average values

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The mean age of the study participants was 38.54 (11.94 years), median was 39 years. The age range was from 15 to 79 years. They are skewed toward the younger age groups. The mean BMI and waist circumference were within normal limits (23.1 [4.1] kg/m2 and 83.1 [11.5] cm, respectively). Serum glucose was 5.1 (1.4) mmol/L. Mean systolic and diastolic blood pressures were 128.7 (17.8) versus 81.2 (11.4) mmHg, respectively. The mean Atherogenic Index of Plasma obtained by dividing the total cholesterol with high-density lipoprotein (HDL)-cholesterol, an index of risk for atherogenesis was 4.22 (1.11). Even though the mean values for total cholesterol, triglycerides, HDL cholesterol, and low-density lipoprotein (LDL) cholesterol were within normal limits, a sizeable proportion of study participants had major conventional cardiovascular risk factors. The prevalence of some cardiovascular risk factors include: hypertension (25.2%), visceral obesity (13.6%), high LDL cholesterol (29.1%), generalized obesity (5.8%), low HDL cholesterol (45.6%), hypertriglyceridemia (16.5%), and hypercholesterolemia (26.2%) as shown in [Table 2]. None of the study participants had impaired glucose tolerance or prediabetes. Other cardiovascular risk factors among the study participants include alcohol intake (53.4%) and cigarette smoking in 10.7%. Positive family history of hypertension and diabetes mellitus was documented in 12.6% and 7.8%, respectively. About 4.9% of the study participants even reported a positive family history of sudden death among first-degree relatives or siblings. This is shown in [Table 3]. The mean daily and annual average of PM size from the World Health Organization (WHO) air quality guideline useful in estimating risk due to air pollution is highlighted in [Table 4].
Table 2: Clinical and demographic characteristics of the study participants

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Table 3: Prevalence of conventional cardiovascular risk factors among the study participants

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Table 4: Air quality guideline for estimating risk[17]

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  Discussion Top


More than 90% of the world's population lives in places where air quality index exceeds the required air quality guidelines, as it regards fine PM according to WHO air quality model report. The acceptable guideline worldwide is an annual mean of PM2.5 of 10 μg/m3 and 24 h mean of 25 μg/m3.[16],[17] Examples of PM (PM2.5) includes nitrites, carbon and nitrates. Some of them penetrate into the lungs and the cardiovascular system causing ill health.[16],[17] Reducing the number of deaths and illnesses from air pollution by 2030 is one of the aims of the sustainable development initiative. To achieve this, systematic approach has been approved to reduce air pollution and improve air quality index worldwide.[18],[19] The mean annual concentration of suspended PM which were <2.5 um from the 2014 WHO report is as shown in [Table 5]. It varies between different African countries with the highest recording from Egypt and the lowest from Ghana and Benin Republic. This is a mean reflection of the total amount of air pollution which is due to fine particles and for which cardiovascular and pulmonary function could be affected. It is a reflection of the total amount of air pollution in African countries and an evidence of poor air quality index in most African countries.
Table 5: The mean annual concentration of the suspended particles of <2.5 um in different African countries from a World Health Organization 2014 Report[16]

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This study revealed that roadside automechanics are exposed to a significant level of air pollution as occupational hazard. The air quality index around automechanic workshops where dysfunctional vehicles are repaired without any form of occupational safety mechanism is very poor and can predispose them to a high level of cardiovascular and respiratory morbidity and mortality over the years. The average PM2.5 size in most mechanic workshops was in the average of 10–12 times the annual mean value shown to be useful to estimate risk and also more than 4–5 times of total 24 h mean exposure in the environment. This therefore puts the automechanic at a very increased risk of consequences of long-term exposure to air pollutants, including PM and total suspended particle. PM2.5 is more associated with cardiovascular and lung health.[20] The air quality index in urban Nigeria was reported by the WHO study group to be average of 38 μg/m3.[16] This therefore means that workers and occupants around automechanic workshop are exposed to at least three times the amount of air pollution compared to what an urban dweller is naturally exposed to. This also further put them at increased risk. Average urban quantity of PM2.5 is significantly higher in most African countries with the highest recorded in Egypt and lowest recorded from Ghana and Benin Republic.

The study participants were averagely young and considering their energy demanding job routine, obesity (both generalized and visceral obesity) was rare among them. The prevalence of obesity quoted in this study is much lower than that reported from other occupations in Nigeria.[21],[22],[23] In most of these studies, at least a third were classified as obesity. It is suggested that obesity and physical inactivity seems to be the driving force in many cardiovascular risk factors clustering, and it is the template upon which many other cardiovascular risk factors seem to readily associate with.[23],[24],[25] Impaired glucose tolerance was not seen any of the study participants. Even, the only individual previously diagnosed diabetic was found to have good glucose control. This is not strange as the nature of work of automechanics is quite energy sapping and burns a lot of energy.

Despite the low prevalence of obesity among these autotechnicians, many conventional cardiovascular risk factors were seen among the study participants. These include hypertension (25.2%), low HDL cholesterol (45.6%), high LDL cholesterol (29.1%), hypercholesterolemia (26.2%), and hypertriglyceridemia (16.5%). It is therefore plausible that among other confounding factors, an additional driving force for the clustered cardiovascular risk factors among these individuals may be due to and closely related to the air pollution. The excessively high risk of air pollution these autotechnicians are exposed to may increase their risk of cardiovascular disease. Even though this may be associated, a well-conducted prospective study could identify a possible link between air pollution and cardiovascular disease among automechanics.

Mortalities related to outdoor air pollution is up to some 3 million deaths/year. Indoor and outdoor air pollutions are similarly dangerous. An estimated 6.5 million deaths (11.6% of all global deaths) were associated with indoor and outdoor air pollution in 2012.[26] Up to 90% of air pollution-related deaths occur in low- and middle-income countries.[16] Ninety-four percent were due to noncommunicable diseases, notably cardiovascular diseases, stroke, chronic obstructive pulmonary disease, and lung cancer.[27] Air pollution also increases the risks for acute respiratory infections. The major sources of air pollution include inefficient modes of transport, household fuel and waste burning, coal-fired power plants, and industrial activities. The activity of the roadside mechanics may therefore constitutes a health risk not only to the automechanics alone but also to the general population. Effective legislation to control and regulate emission control from combustible engines and vehicles are therefore important to achieve part of the sustainable development goals in 2030 and achieve better health for all, especially in developing countries like Nigeria.[16],[27]

PM10 include coarse and fine particles of sizes between 2.5 and 10 μm and those <2.5 μm, respectively. They are known to contribute to the health effects observed in urban environments.[28] PM2.5-10 is a byproduct of many processes, including construction works, dust, and wind. PM2.5 results from product of combustion. Coarse and fine particles are present in varying amount in different environment and population. In areas where wood burning and use of other biomass fuels predominate, PM2.5 will predominate in such area. The consequences of air pollution irrespective of their size are, however, similar in all population.[28],[29] A similar guideline can be used for indoor pollution, especially in the developing world like Nigeria, where a lot of indoor use of biomass fuels occur. The trend of exposure to air pollutants among autotechnicians in Nigeria is therefore enormous and therefore necessary to implement occupational safety mechanisms to first reduce the release of these PM and appropriate masks to reduce contact with these air pollutants.

A global campaign to increase the awareness of air pollution as a major health risk and potential hazard for climate change is being coordinated by the WHO together with the United Nations Environmental Programme called the BreatheLife campaign. The major aim is to improve climate health and improved clean air coalition and also to reduce environmental pollutants. Important steps in the achieving optimal climate health include provision of better housing, energy and transport, and proper waste disposal. It also involves measures to improve the quality of air such as halting burning of waste, promoting green environment, and reducing combustible engine output by walking/cycling. These are known to improve air quality.[30]

A limitation of this study is the inability of the study to determine causality. A long-term follow-up of these individuals with periodic evaluation of their air quality indices will be a good research option to answer that important research question. Furthermore, the sample size was relatively small. However, this appears to be the first set of information describing air pollution among automechanics in Nigeria and cardiovascular risk factors, and it is hoped that it will stimulate further research interest in that area as cardiovascular diseases continues to ravage developing countries and several etiological concepts are being looked at to combat it.


  Conclusion Top


Air quality index around autotechnicians workshops in Nigeria is very poor. The average particle size is in excess of tens in multiple folds of daily and annual averages even in urban cities. Despite the low prevalence of obesity and physical inactivity among these group of high energy demanding workers, conventional cardiovascular risk factors such as hypertension, dyslipidemia, and alcohol intake still occurs appropriate cross-sectional and observational studies linking cardiovascular health to chronic air pollution and air quality is advised. Proper automobile and emission control, both locally and nationally, and implementation of workplace protection are advised to minimize the impact of air pollution on automechanics in Nigeria.

Acknowledgments

The interns and resident doctors of the Department of Medicine, Ladoke Akintola University of Technology Teaching Hospital, Ogbomoso, Nigeria.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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[PUBMED]  [Full text]  
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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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