Abstract

The incidence of occupational disease such as diseases of the cardiopulmonary system, arising from exposure to cement is increasing throughout the world. Hence this study is aimed at evaluating the effect of exposure to cement particles on selected cardiovascular and respiratory parameters of cement depot workers in Delta State, Nigeria. This is a cross sectional study that adopted observational and recording method. Four hundred (400) participants were used to carry out this research. Two hundred exposed workers that have been working in the cement depot for 0-> 10 years and two hundred people as unexposed group as control who are matched with socio economic class with workers from the cement depot (exposed group). The research was carried out on workers in sawmill factories across Delta State that have been exposed to sawdust for different period of time. Parameters reviewed were, blood pressure (mmHg), pulse rate, oxygen saturation rate (percentage), peak expiratory flow rate (meter) and inspiratory reserve volume (meter). The parameters collected were compared statistically using SPSS software for the analysis. The result showed that for workers with >5 years of exposure, there was a significant increase in systolic blood pressure (140.29 ± 8.42), diastolic blood pressure (97.45 ± 4.03), expiration rate (357.21 ± 369.05) and inspiration rate (1392.3 ± 421.23), and a significant decrease in pulse rate (53.69 ± 2.213) and SPO₂ (89.08 ± 3.012) of cement workers when compared to the control group (cement workers) (p<0.05). For worker with 0 – 5 years of exposure, There was a significant increase in systolic blood pressure (144.2 ± 10.8), diastolic blood pressure (82.25 ± 6.14), expiration rate (243.60 ± 30.60) and inspiration rate (235.0  ± 63.9), and a significant decrease in pulse rate (77.7 ± 7.44) and SPO₂ (92.5 ± 8.2) of  cement workers when compared to the control group (cement workers) (p<0.05). The findings of these study shows that exposure to cement dust has deleterious effect on cardiopulmonary parameters.

Introduction

Environmental and occupational pollution has always been a major cause of morbidity and mortality. The incidence of occupational disease is constantly increasing throughout the world, especially in developing countries due to the lack of proper quality control documentation and the practical approach towards this mammoth problem. This is also the case with diabetic mellitus a metabolic disorder that has continue to attract public concern in developing countries as a result of increased incidents following urbanization and social life changes.^1-5 Cement industry is one of the largest manufacturing industries and its workers are exposed to dust at various manufacturing and production processes.⁶ It consists of 60-67% calcium oxide (lime), 17-25% silicon oxide, 3-5% aluminium oxide, with some amount of iron oxide, chromium, lead, potassium, sodium, sulphur, mercury, antimony, cadmium, zinc, manganese and magnesium oxide. The aerodynamic diameter of cement dust particles is within the respirable extent, consequently occupational exposure to cement dust can cause numerous health hazards including the onset of acute or chronic respiratory diseases and respiratory function deficits.⁷ Air pollution from cement manufacturing is becoming an environmental problem worldwide.⁸

Exposure to cement dust may occur at most stages of the manufacturing process, and higher dust concentrations have been reported in the crusher and packing sections than in other sections.⁹

Cement production is invariably a dusty operation resulting in the exposure of factory workers to cement dust. Several clinical and epidemiological studies have shown an increased incidence of impairment of respiratory and a prevalence of respiratory symptoms among cement production workers. This study will be useful to cement depot workers, which will enlighten them on the dangers of exposure to cement dust on a daily basis. It will also be useful to other researchers in need of useful information for further research.

The study investigated the effect of exposure to cement particles/dust on some cardiovascular and respiratory parameters of cement depot workers in Delta State, South-South, Nigeria by specifically determining the effect of cement particles on blood pressure, the peak expiratory flow rate, the peak inspiratory flow rate, the oxygen saturation rate (SPO₂), the pulse rate and the inspiratory reserve volume of cement depot workers.

Meo et al.¹⁰ investigated the effect of duration of exposure to cement dust on respiratory function of non-smoking cement mill workers. They reported that there was significant reduction in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Peak Expiratory Flow (PEF) and Maximal Voluntary Ventilation in cement mill workers who had been working in the cement industry for more than 10 years compared to their matched un-exposed group.

Materials

Digital sphygmomanometer, Manual sphygmomanometer, Pulse oximeter, Peak flow meter and Incentive spirometer the cuff was properly sized to at least eighty percent of the circumference upper arm, the cuff was rounded on the upper arm of each participant with the cuff’s edge one inch above the antecubital fossa, the digital sphygmomanometer was put on and it began to take readings of the blood pressure and pulse rate of the participant. After the readings were taken, it was displayed on the screen of the sphygmomanometer and the values for systolic pressure, diastolic pressure and pulse rate were recorded.

Oxygen Saturation Rate Measurement: The oxygen saturation rate was measured by placing the participant’s index finger in the pulse oximeter, then waiting for at least one minute for the reading to show and stabilize, the value was recorded after the result was stable.

Peak Expiratory Flow Rate Measurement: The participants were asked to stand of straight, the red marker of the peak flow meter was at the bottom of the meter. Each participant took a deep breath by filling their lings, the mouth piece of the meter was placed in the mouth of each participant. They also closed their lips on the peak flow meter’s mouthpiece, air was blown out as hard and fast as possible in a single blow, the number by the red marker on the meter was written down. The red marker was put back at the bottom of the meter, and the measurement was repeated three times and the highest of the three readings was recorded.

Inspiratory Reserve Volume Measurement:The participants were asked to put the mouthpiece of the incentive spirometer in their mouth and close their lips tightly around it, inhale slowly and deeply through the mouthpiece to raise the indicator, when they could not inhale again, the value at where they stopped was

Methodology

Study population/ area

Study Population: The study comprised of 100% of the cement depot workers in Delta State, Nigeria. The cement depot workers have been exposed to cement dust for a period of time (0-5 years and >5 years and above). They were matched with people who stay in the same vicinity but do not work in the cement depot (control group).

Study area; The study participants were selected from different cement depot in Delta state which include; Dangote cement depot Police station road Abraka, Dangote cement depot close to Eku junction Eku, Dangote cement depot at Otokutu off DSC Express way, Dangote cement depot before orhuworun bridge Udu and Dangote cement depot along PTI road by Uti junction in Warri.

Study Design: The blood pressure, pulse rate, oxygen saturation rate, peak expiratory flow rate and inspiratory reserve volume of each participant were measured and recorded. An interview was also carried out to determine how long each participant has worked in the cement depot.

Sample Size and Sampling Technique

Three hundred participants were used to carry out this research. Two hundred exposed workers that have been working in the cement depot for 0-> 10 years and one hundred people as unexposed group as control who are matched with socio economic class with workers from the cement depot (exposed group).

The research population was selected using simple random sampling technique.

Methods of Data Collection

Digital Blood Pressure and Pulse rate Measurement: Blood pressure and pulse rate were measured by placing the cuff of the digital sphygmomanometer on the forearm of each participant, the circumference of

Recorded.

Selection Criteria

Inclusion Criteria: The sample consists of apparently healthy looking workers from the study area mentioned earlier from age 18 and above in Delta state.

Exclusion Criteria: asthmatic patients, workers younger than 18, workers not in Delta state and workers with previous medical history of cardiopulmonary diseases and other comorbidity were excluded from the research.

Data Analysis

Data collected were expressed statistically using SPSS software.

Ethical Clearance

Ethical approval was obtained from the ethical committee of the faculty of Basic Medical Sciences, Delta State University, Abraka.

Results

According to the length of exposure to the cement business (0–5 and 5–10 years), the results are reported. Age, height, and weight were the matching variables in statistical comparisons for both groups, and as a result, the statistical validity of this information is not examined.

Effect of cement particles on blood pressure, expiration rate, inspiration rate and SPO ₂ of control and workers with greater than 5 years of exposure

Values are expressed in Mean ± Standard, n=200. Values not sharing the same superscript in the same row differ significantly (p<0.05). Values sharing the same superscript in the same row are statistically significant (p<0.05)

Table 1 shows comparison between the cardiopulmonary parameters of the experimental groups (>5 years of exposure of cement workers) and the control groups, the non-cement workers. There was a significant increase in systolic blood pressure, diastolic blood pressure, expiration rate and inspiration rate, and a significant decrease in pulse rate and SPO₂ of cement workers when compared to the control group (cement workers) (p<0.05).

From Figure 1 above, it was observed that there was a significant difference between the control group and experimental group across all parameters studied. There was a significant increase in expiration rate and inspiration rate when compared with the control group.

Figure 1. Comparison between the cardiopulmonary parameters of control group and experimental group group (> 5 years).

Effect of cement particles on blood pressure, expiration rate, inspiration rate and SPO ₂ of control and workers with less than 5 years of exposure

Table 2 shows comparison between the cardiopulmonary parameters of the experimental groups (0-5 years of exposure of cement workers) and the control groups, the non-cement workers. There was a significant increase in systolic blood pressure, diastolic blood pressure, expiration rate and inspiration rate, and a significant decrease in pulse rate and SPO₂ of cement workers when compared to the control group (cement workers) (p<0.05).

Values are expressed in Mean ± Standard, n=200. Values not sharing the same superscript in the same row differ significantly (p<0.05). Values sharing the same superscript in the same row are statistically significant (p<0.05)

Figure 2.

Comparison between the cardiopulmonary parameters of control group and experimental group (0–5 years). From Figure 2 above, it was observed that there was a significant difference between the control group and experimental group across all parameters studied. There was a significant increase in expiration rate and decrease in inspiration rate when compared with the control group.

Effect of cement particles on Anthropometric, FVC, FEF_25–75%, FEV_1, FEV₁/FVC and MVV of control and workers with less than five(0-5) years of exposure

Table 3 highlights the FVC, FEF25-75%, FEV1, FEV1/FVC, and MVV differences between cement workers and their matched control group. FVC and MVV levels were much lower among cementdepot workers who had been exposed for less than five years. There was no significant difference in the means of any other FEF25-75%, FEV1, or FEV1/FVC values between the groups.

Table 3: Showing the Mean ± SD of the Anthropometric, FVC, FEF _{25–75% ,} FEV _{1 ,} FEV ₁ /FVC and MVV value for cement workers with duration of exposure less than five years compared with their matched controls.

Values are expressed in Mean ± Standard, n=200. Values are presented as Mean ± SEM; N S = non-significant.

Effect of cement particles on Anthropometric , FVC, FEF _25–75%, FEV _1, FEV ₁ /FVC and MVV of control and workers with greater than five (5-10) years of exposure

Cement depot workers exposed for more than 5 years had significantly lower FVC, FEV1, and MVV compared to their matched controls (Table 4). However, there was no significant difference in FEV1/FVC, PEF, or FEF25-75% between these workers and controls. There were no significant changes in age, height, or weight between the control and experimental groups.

Values are expressed in Mean ± Standard, n=200. Values are presented as Mean ± SEM; NS = non-significant.

Discussion

Chronic exposure to cement dust has been reported to lead to greater prevalence of various clinical conditions which includes both respiratory and cardiovascular systems involvement.⁷ These conditions are consistently associated with the degree of exposure. Regular use of appropriate personal protective equipment, if available at the work site could protect the cement factory workers from adverse health effects. The main route of entry of cement dust particles in the body is the respiratory tract or the gastrointestinal tract or both by inhalation or swallowing. This has been identified as a skin irritant, which causes itching, skin allergy, boils, and burn.

The result of this present study shows the effect of exposure of cement particle on the male workers. From the results obtained, it shows a significant (p<0.05) increase and decrease (Table 1) in systolic blood pressure, diastolic, purse rate, peak expiratory rate, inspiratory rate and SpO₂ among cement workers when compared to the control.

This study showed that there was a significant increase in systolic and diastolic blood pressure of cement factory workers in comparison to the control group. There is a possibility that once particulate matter are deposited in the lungs, pollutants may trigger an inflammatory response and induce oxidative stress through the generation of reactive oxygen species (ROS), the ultrafine particles can penetrate through the alveoli and cause injury to the cardiovascular system The ROS and pro-inflammatory cytokines released in the bloodstream to affect automatic cardiac control (heart rate, heart rate variability and cardiac contractility). The potential toxicity of cement dust particles may involve ROS formation, oxidative damage and inflammation and cause harm to the cardiovascular system.¹¹ This is in agreement with the work of Gong et al.¹², who observed that there is an increase in the systolic blood pressure in healthy subjects on exposure to PM 2.5. This is also related to the result obtained by Urch et al.¹³, who observed a significant increase of about 6mmHg in subjects exposed to particulate matter.

In the present study, there were also observed significant increase in the expiration and inspiration rate of cement workers when compared with non-workers. This suggests that chronic cement dust exposure impairs lung function. It agrees with the findings of Alakija et al.¹⁴ who first reported “Cement factory lung disease” in Nigeria and those of others elsewhere.^{10, 15}

The findings of this study also showed that there were observed significant decrease in pulse rate and SPO₂ of cement factory workers in comparison with non-workers. Low blood oxygen saturation, or hypoxaemia, is an indicator of severe illness including pneumonia and sepsis, and has been identified as a predictor for morbidity and mortality in individuals with respiratory illness.^{15, 16} This result is similar to the reports by Merenu et al.¹⁷ who studied the effect of cement dust exposure on lung function among residents of Kalambaina Community in Sokoto State, Nigeria.

The results of the present study suggest that chronic exposure to cement dust has deleterious effect on the lungs. However the exact mechanism (s) by which it does this is unknown. For instance it is yet to be determined whether these effects are due directly to cement dust or mediated by a metabolic product of cement dust. It will be interesting to further investigate this.

In the present study, the workers were suffering from varied health problems, which was relatively more than the general population. It suggests the cement factory workers were exposed to the dust in the environment, with minimum or no protective equipment. The observed significant difference in the cardiopulmonary parameters of cement workers and non-workers, also, our result further suggests that chronic exposure to cement dust impairs lung function and this corroborate earlier report by Ovuakporaye et al.¹⁸that prolong exposure to gas impact on lung function. This finding is also in consonant with Ovuakporaye et al.^19-21 that prolong exposure to pollutants (gas flare) impact on cardiopulmonary parameters^22,23.

Our research discovered a duration response effect and discovered that long-term exposure to cement dust dramatically reduced lung function. Meo et al. ^[24] also found that the mean values for FVC, FEV1, and MVV were considerably lower in cement depot workers, implying a link between exposure duration and lung function measures. Cement mill workers showed considerably poorer FVC, FEV1, and PEF than unexposed patients, according to Al-Neaimi et al. ^[25]. Nordby et al. ^[26] found that when exposed to the greatest level of cement dust, FEV1 decreased with an exposure-response connection. FVC and FEV1 were considerably lower among cement production workers but not among controls, according to Zelke et al. ^[27]. According to Olerue ^[28] the lung function metrics FVC and FEV1 decreased with length of employment in the cement sector, but this was not statistically significant. Our findings reveal that the duration of occupational exposure to cement dust causes a significant decline in FVC and FEV1. Olerue's ^[28] selection criteria were minimal, which could explain the non-significant change in lung function measures.

It is our recommendation that to safeguard the health of workers and the host community, cement factory management should embark on safety training in work environment and conduct health education on hazards of exposure to cement dust, safety precautions and practices. There should be acquisition of effective protective gadgets and ensure compliance with their usage. Also, there is need for regular and periodic monitoring of cement dust level in and around the factory environment, and containment of dust emission by the use of dust filters.

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