Cement dust exposures has been reported to result in significant occupational health problems and long term complications and symptoms.
In this present study we monitored some haematological parameters; Packed Cell Volume (PCV), Haemoglobin (HB), Erythrocyte Sedimentation Rate (ESR), White Cell Count (WBC) and Platelet (PLC) count of 100 workers (mean age 37.42 ± 10.14 years) who were occupationally exposed to cement dust (mean years of exposure 9.9 ±5.6 years).
Fifty age and gender matched non -exposed individuals were monitored as controls. The PCV was significantly lower among exposed subjects compared to non-exposed (31.1 ± 3.3 versus 40.7 ± 3.8), p=0.001. Platelet, WBC and ESR were significantly higher among exposed subjects (262 ± 57.2, 15.5 ± 11.9 and 13.2 ±1.7) compared to non-exposed controls (204 ±36.7, 12.9 ± 10.2 and 10.4 ± 1.3) respectively.
We observed an age dependent higher PCV and ESR among non-exposed controls as well as a lower age-related lower WBC and platelet count. We observed a significant positive correlation between age of exposure and WBC (r= 0.48). Our finding does indicates that occupational exposure to cement dust may have a negative impact on the haemopoietic function.
There is need for cement producing companies to provide appropriate personalprotective equipment for their staff as ensure that staff are compliant in the use of these equipment. There is also the need to periodically monitor the health and well being of staff exposed to cement dust.
Vol 1,issue 7 Effect of occupational exposure of cement dust on some haematological parameters of workers in a cement company in Sokoto, Nigeria
1. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-704)
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2. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-704)
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Effect of occupational exposure of cement dust on some haematological parameters of
workers in a cement company in Sokoto, Nigeria
Erhabor O, Kebbe BI 1
, Isaac IZ 1
, Yakubu A 1
, Marafa Y 1
, Okwesili AN 1
, Buhari HA 1
, Wase A 1
,
Onuigwe FU 1
Aghedo F 2
, Ikhuenbor D 2
, Mainasara A 3
, Dallatu MK 3
, Uko EK 4
, Udomah FP 5
, ,
Iwueke IP 6
, Adias TC 7
, Igbineweka OO 8
1. Department of Haematology and Transfusion Medicine Faculty of Medical Laboratory Science UsmanuDanfodio University Sokoto, Nigeria
2. Department of Haematology and Transfusion Medicine UsmanuDanfodio University Teaching Hospital Sokoto, Nigeria
3. Department of Chemical Pathology Faculty of Medical Laboratory Science, UsmanuDanfodio University Sokoto, Nigeria
4. Department of Haematology University of Calabar
5. Department of Medical Laboratory Sciences, University of Calabar Teaching Hospital, Calabar, Nigeria
6. Pathology Department, Federal Neuro Psychiatric Hospital Kware, Sokoto, Nigeria
7. College of Health Technology Bayelsa State, Nigeria
8. One Brigade Medical Centre Sokoto, Nigeria .
All Correspondence to:
DrErhaborOsaro-Associate Professor of Haematology and Transfusion Medicine,Faculty of Medical Laboratory
Science-UsmanuDanfodiyo University,Sokoto, Nigeria
Abstract:
Cement dust exposures has been reported to result in significant occupational health problems and long term
complications and symptoms. In this present study we monitored some haematological parameters; Packed Cell Volume
(PCV), Haemoglobin (HB), Erythrocyte Sedimentation Rate (ESR), White Cell Count (WBC) and Platelet (PLC) count of
100 workers (mean age 37.42 ± 10.14 years) who were occupationally exposed to cement dust (mean years of exposure
9.9 ±5.6 years). Fifty age and gender matched non -exposed individuals were monitored as controls. The PCV was
significantly lower among exposed subjects compared to non-exposed (31.1 ± 3.3 versus 40.7 ± 3.8), p=0.001. Platelet,
WBC and ESR were significantly higher among exposed subjects (262 ± 57.2, 15.5 ± 11.9 and 13.2 ±1.7) compared to
non-exposed controls (204 ±36.7, 12.9 ± 10.2 and 10.4 ± 1.3) respectively. We observed an age dependent higher PCV
and ESR among non-exposed controls as well as a lower age-related lower WBC and platelet count. We observed a
significant positive correlation between age of exposure and WBC (r= 0.48). Our finding does indicates that occupational
exposure to cement dust may have a negative impact on the haemopoietic function.There is need for cement producing
companies to provide appropriate personalprotective equipment for their staff as ensure that staff are compliant in the use
of these equipment. There is also the need to periodically monitor the health and well being of staff exposed to cement
dust.
Key Words:Occupational exposure, cement dust, haematological parameters, worker
Introduction
World demand for cement and concrete additives is
projected to increase 8.3 percent annually to $15.8
billion in 2015, a significant improvement over the
performance of the 2005-2010 period. In developing
markets, growth has been boosted by sustained levels of
construction activity with associated increased cement
consumption. Exposure to cement dust has long been
associated with the prevalence of diseases including lung
and laryngeal cancer, gastrointestinal tumours and
dermatitis 1, 2
. Industrial production is often associated
with the generation of waste, some of which have a
significant negative health hazard. Cement industry is
often associated with cement dust exposure. Cement is
adhesive mineral dust containing mixture of calcium
oxide, silicon oxide, aluminum tri oxide, ferric oxide,
magnesium oxide and also clay, shale, sand and other
impurities. High concentration and prolonged inhalation
of cement dust can potentially provoke clinical
symptoms and inflammatory response that may result in
functional, structural as well as other abnormalities 3
.
Haematological parameters are a sensitive and important
diagnostic indices in the monitoring to changes resulting
from exposures to toxins. Most studies have previously
attempted to evaluate the effects of cement dust exposure
on the respiratory system. However, there is paucity of
data on the effects of cement dust on the haemopoietic
systems in humans. Exposure to Cement dusts is even a
larger problem in developing countries as personal
protection equipment is often limited and health and
safety as well as occupational issues and safety and
occupational health regulations are often compromised 4
.
Therefore, the aim of this case control study is to
investigate the potential toxic effects of occupational
exposure of cement dust and to minimize the health risks
among workers in cement factories by providing them
with evidenced- based information about the hazards of
cement dust.
Materials and methods
Study design
This case-control study was designed to determine the
effect of occupational exposure to cement dust on some
haematological parameters. We monitored the PCV, HB,
ESR, WBC and PLC count of 100 workers (mean age
37.42 ± 10.14 years) who were occupationally exposed
to cement dust (mean years of exposure 9.9 ±5.6 years).
Fifty age and gender matched non -exposed individuals
were monitored as controls. Haematologicalvalues
obtained from subjects were compared with that of
controls and the difference analyzed statistically. The
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effect of socio-demographic factors were also be
compared statistically.
Eligibility Criteria
All consenting adult male (> 18 years) who have been
occupational exposed to cement dust (1-24 years), who
had no previous history of haematological condition,
who had not been transfused in the last 3 months were
enrolled into this study. Exclusion criteria included; age
< 18 years, non-exposure to cement dust, history of
haematological co-morbidities, red cell transfusion in the
last 3 months and failure to give written informed
consent after counselling.
Informed consent and ethical clearance
Written informed consent was obtained from all
participants recruited into this study (controls and
subjects). Ethical clearance was obtained from the
ethical review board of the Ethical committee of the
Faculty of Medical Laboratory Science Hospital Sokoto,
Nigeria.
Study Area
This present research work was carried out at the
Department of HaematologyUsmanuDanfodiyo
University Teaching Hospital Sokoto State, Nigeria. The
hospital is a tertiary health hospital in the Northwest
geopolitical zone of Nigeria offering routine quality care
to residents of Sokoto metropolis and neighbouring
states of Zamfara and Kebbi. Sokoto State is located in
the extreme North Western part of Nigeria near to the
confluence of the Sokoto River and the Rima River.With
an annual average temperature of 28.3 °C (82.9 °F),
Sokoto is, on the whole, a very hot area. However,
maximum daytime temperatures are for most of the year
generally under 40 °C (104.0 °F).
The warmest months are February to April when
daytime temperatures can exceed 45 °C (113.0 °F). The
rainy season is from June to October during which
showers are a daily occurrence. There are two major
seasons, wet and dry which are distinct and are
characterized by high and low malarial transmission
respectively. Report from the 2007 National Population
Commission indicated that the state had a population of
3.6 million 5
.
Statistical analysis
Statistical analyses were conducted using SPSS (version
11; SPSS Inc., Chicago, IL) software. Data were
expressed as mean ± standard deviation. Comparisons
between exposed subjects and non-exposed controls
were made using the Student's t-test for parametric data
and the Mann-Whitney test for non-parametric data.
Descriptive analyses of percentages of categorical
variables were reported. An alpha value of < 0.05
denoted a statistically significant difference in all
statistical comparisons. Correlation was compared using
a version of linear regression.
Study population
Subjects (100) for this case control study were recruited
from among the staff working in Cement Company of
Northern Nigeria a cement manufacturing factory in
Sokoto Nigeria. The need to meet the increasing demand
for cement for construction has led to the increased
number and production capacity in most cement
companies in Nigeria. Age and gender matched non-
exposed individuals were monitored as controls (50).
Sample collection
Three milliliters of blood sample was drawn aseptically
with MonovetteVacutainer blood collection system
(Sarstedt, Germany) from the median antecubital vein
for all the subjects into
dipotassiumethylenediaminetetracetic acid (K2EDTA)
anticoagulated blood containers. The EDTA
anticoagulated sample was used for the determination of
Packed Cell Volume using a microhaematocrit
centrifuge (Hawksley, UK). Platelet count and Total
White Cell count was determined using standard manual
methods using a Neubauer chamber. Despite the recent
technical development of scientific laboratories and the
development of automated blood counter, Neubauer
chamber remains the most common method used for
blood cell counting particularly in resource-limited
settings around the world. ESR was determined using the
Westergreen method. The standard operating procedures
as prescribed by the manufacturers was strictly followed.
Standard methods as described by Dacie and Lewis
6
were used for all haematological analysis.
Result
The PCV was significantly lower among exposed
subjects compared to non-exposed (31.1 ± 3.3 versus
40.7 ± 3.8), p=0.001. Platelet, WBC and ESR were
significantly higher among exposed subjects (262 ± 57.2,
15.5 ± 11.9 and 13.2 ±1.7) compared to non-exposed
controls (204 ±36.7, 12.9 ± 10.2 and 10.4 ± 1.3)
respectively. Table 1 show the mean and standard
deviation of PCV; ESR; WBC and PLTC of exposed
subjects and non-exposed control. We observed a
significant positive correlation between age of exposure
and WBC (r= 0.48). Tables 2 show the mean and
standard deviation of PCV; ESR; WBC and PLTC of
exposed workers according to their years of exposure.
We observed an age dependent higher PCV and ESR
among non-exposed controls as well as a lower age-
related lower WBC and platelet count. Table 3 show the
mean and standard deviation of PCV; ESR; WBC and
PLTC of unexposed (control) according to their age
group.We did not observe any age-related differenced in
the mean haematological values of exposed workers.
Table 4 show the mean and standard deviation of PCV;
ESR; WBC and platelet count of exposed workers
according to their age groups.
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Table 1: Mean and standard deviation of PCV; ESR; WBC and PLTC of exposed and control compared.
Subject
Groups F PCV (%) ESR (mm in 1hr) WBC (x109
/l) PLCT (x109
/l)
Exposed 100 31.1±3.3 13.2±1.7 15.5±11.9 262±57.2
Unexposed 50 40.7±3.8 10.4±1.3 12.9±10.2 204±36.7
P – value 0.001 0.01 0.01 0.001
Table2: Mean and standard deviation of PCV; ESR; WBC and PLTC of exposed workers according to their years
of exposure.
Years of exposure F PCV (%) ESR (mm in 1hr) WBC (x109
/l) PLCT (x109
/l)
1 – 4 17 29.4±2.2 13.8±1.3 12.3±0.6 239±63.2
5 – 9 40 30.9±3.5 13.2±1.3 11.8±1.1 257±71.4
10 – 14 27 41.1±6.2 13.2±2.0 11.9±1.1 291±61.9
15 – 19 5 33.0±2.8 14.0±1.7 12.4±0.6 267±72.5
20 – 24 9 35.8±4.2 14.6±0.5 12.7±0.6 215±47.7
25 – 29 2 27.5±0.7 13.5±0.7 12.7±0.4 315±10.8
Table 3: Mean and standard deviation of PCV; ESR; WBC and PLTC of unexposed (control) according to their
age group.
Age Groups (years) N PCV (%) ESR (mm in 1hr) WBC (x109
/l) PLCT (x109
/l)
20 – 24 16 39.5±4.8 10.1±1.1 8.8±8.2 219±54.4
25 – 20 19 40.2±3.4 10.2±1.3 7.6±11.6 212±82.8
30 – 34 15 40.9±3.2 10.8±1.4 7.4±8.9 196±22.3
Table 4: Mean and standard deviation of PCV; ESR; WBC and PLTC of exposed workers according to their Age
Group.
Age group (years) F PCV (%) ESR (mm in 1hr) WBC (x109
/l) PLCT (x109
/l)
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21 – 25 11 30.5±3.9 13.2±2.3 11.7±1.4 279±76.5
26 – 30 52 30.4±2.9 13.2±1.9 11.8±1.0 257±70.8
31 – 35 21 30.5±2.4 13.5±1.7 12.1±1.0 285±64.9
36 – 40 8 35.5±4.0 14.6±0.5 12.7±0.5 228±56.6
41 – 45 8 30.3±5.5 13.4±1.3 12.4±0.8 264±53.8
Discussion
Occupational exposure to cement dust may enter into the
systemic circulation and affect essentially all the organs
of body as well as the different tissues including heart,
liver, spleen, bone, muscles and hairs and ultimately
affecting their micro-structure and physiological
performance 7
.
This present study investigated the effect of occupational
exposure to cement dust on some haematological
parameters in order to test the hypothesis that exposure
to cement dust may perturb the haemopoietic system of
exposed workers. In this study, we observed that the
PCV was significantly lower among exposed subjects
compared to non-exposed controls. Our finding is
consistent with previous report by Mojiminiyi and co-
workers 8
, Mohan and colleagues 9
as well as Jude and
co-workers 10
but at variance with report of Ogunbilije
and colleagues 11
in Ibadan Nigeria who observed that
PCV was significantly higher among exposed workers
compared to unexposed controls. The relative low
number of subjects (45) included in this study may have
skewed this observation. Low packed cell volume is
indicative of a low amount of red blood cells per unit
volume and anaemia. Low PCV observed among staff
occupational exposed to cement dust may be an
indication that cement dust exposure may perturb
erythropoiesis.
It was observed in the study that there was an increase in
white blood cell count regardless of the period of
exposure. High white cell count represents a primary
disorder of leukocyte production or may reflect a
secondary response to some disease process or toxins.
White cell count is often seen as a biomedical marker for
inflammatory response 12
. Changes in the number of
circulating leukocytes can represent a primary disorder
of leukocyte production or may reflect a secondary
response to some disease process or toxin 13
.
In this present study, we observed that the mean platelet
count was significantly higher among exposed workers
compared to non-exposed controls. Our finding is at
variance with previous reports among exposed workers
in Nigeria and India respectively, which observed a
reduced platelet count among exposed workers
compared to non-exposed controls 8, 14
. The lower study
populations of 23 and 30 occupational exposed workers
may have skewed the findings with regards to platelet
count in both studies. In our study we investigated 100
occupationally exposed workers.
Higher platelet count observed among subjects
occupational exposed to cement may be associated with
inflammation. High platelet count have been associated
with infections. Platelet count can also potentially
increase when a relatively large amount of body tissue is
damaged either by exposure to toxins, following surgery
or after an accident. This is often part of the body’s
natural defence mechanism to ensure adequate clot
formation and prevent of life threatening haemorrhage.
We observed a significantly higher ESR among exposed
staff compared to un-exposed controls. The ESR is a
simple, inexpensive and it is especially valuable for
diagnostic and prognostic purposes in silent illness
including chronic diseases. The erythrocyte
sedimentation rate (ESR), also called a sedimentation
rate or Westergren ESR. It is the rate at which red cell
sediment when contained in a vertical tube over an hour
period. It is a common and non-specific haematology
test often used as a measure of inflammation. The ESR
remains fairly constant in healthy persons and is affected
by properties of the erythrocytes and plasma and by
mechanical or technical factors 15
. In general, the ESR is
high when there is an infectious disease or a significant
amount of tissue necrosis. It may also be increased in
localized infections, tuberculosis, and malignant tumors
with necrosis. High ESR is often associated with an
infectious disease or a significant amount of tissue
necrosis. It may also be increased in localized infections,
tuberculosis, and malignant tumours with necrosis 16
.
We observed a significant positive correlation between
age of exposure and WBC (r= 0.48). This finding
indicates that there may be a long-term direct association
between cement dust exposure and functional
impairment among the cement factory workers 17
.
A previous report among a cohort of Portland cement
workers in Italy indicated that long-term exposure to
cement dust had a statistically significant reduced risk of
overall mortality and of all cancers and mortality. The
study confirmed an increased risk of respiratory system
cancer only in the subgroup with previous work
exposure in a cement/asbestos plant 18
. This finding re-
emphasises the need for continuing follow-up of all
exposed populations to document the long-term
consequences 19
. There is increasing advocacy that
control measures be adopted to reduce the dust and
workers should be encouraged to use respiratory
protection devices during their working time 20
.
Conclusion
This present has shown that occupational exposure to
cement dust has a significant effect on some
haematological parameters. We recommended that
6. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-704)
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workers occupational exposed to cement dust be
provided with appropriate personal protective equipment
and respiratory protection devices (aprons, mask and
goggles) to reduce the effect of exposure. Worker should
have periodic medical examinations to include the
evaluation of haematological profile. These measures
can potentially mitigate against the effects of
occupational hazards of cement dust.
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