1
Prevalence of Low Back Pain among Peasant Farmers in a Rural
2
Community in South south Nigeria
3
1
Birabi B.N., 2Dienye P.O., 2Ndukwu G.U.
4
1
Ezel Therapy, 27 Obagi Street, Port Harcourt, Nigeria.
5
2
Department of Family Medicine, University of Port Harcourt Teaching Hospital,
6
Nigeria.
7
Corresponding Author:
8
Dr Paul O. Dienye
9
Department of Family Medicine, University of Port Harcourt Teaching Hospital, Nigeria.
10
e-mail: pdienye@yahoo.com
11
Mobile: +2348033393806
12
13
Abstract
14
Low back pain (LBP) is an important cause of morbidity in the general population and in
15
many occupational settings including farming. It is the most common musculoskeletal
16
disorder affecting farmers. Many research and publications on LBP have been conducted
17
in the developed world but in the developing countries, they are few. In Nigeria, most
18
studies on LBP were conducted in the South Western geopolitical zone with little or none
19
reporting on the prevalence of LBP in the rural South south geopolitical zone of Nigeria.
20
This study is aimed to determine the prevalence and factors associated with LBP among
21
peasant farmers in this area.
22
23
Methodology
1
24
Community based cross sectional study.
25
Results
26
Three hundred and ten (310) apparently healthy adult farmers consisting of 132 males
27
and 178 females with age range of 18-58 years and a mean of 36.71±8.98 years were
28
sampled for the study. Two hundred and eight (67.10%) had LBP. It was more prevalent
29
in the 41-50 years age bracket (90.63%), males (77.27%), non obese (68.95%), tall
30
people (73.2%) and those that practiced farming for long duration. Severe low back pain
31
was linked to aging (51-60 years age group), the overweight/obesity and those with
32
height above average (1.60metres). The association between these factors and low back
33
pain was statistically significant (P<0.05).
34
Conclusion
35
Our study indicates that LBP is a prevalent health problem among rural peasant farmers.
36
Establishing cooperative societies to which loans can be given by the government to
37
commence mechanized farming can help to alleviate this problem significantly.
38
Key words
39
Low back pain, Rural farmers, South south Nigeria
40
Introduction
41
Low back pain (LBP) has been reported as an important cause of morbidity in the general
42
population and in many occupational settings including farming.1,2,3 It is the most
2
43
common cause of disability in developed nations4 and also the commonest
44
musculoskeletal disorder affecting farmers .5,6
45
LBP causes considerable levels of disability, producing significant restrictions on usual
46
activity and participation, such as an inability to work. 7 It is an important clinical, social,
47
economic, and public health problem affecting the population indiscriminately .8 The
48
economic, societal and public health effects of LBP appear tremendous considering the
49
fact that it incurs billions of dollars in medical expenditures each year.9 This economic
50
burden is of particular concern in poorer nations such as in Africa. This is because of the
51
already restricted health care funds which are directed toward epidemics such as malaria,
52
HIV and AIDS.10 The effect on the family is enormous being a very costly condition for
53
the individual and to society in terms of lost work output, sick days and reduced earning
54
power.
55
Studies in the developed countries have shown that the 12-month prevalence rate of LBP
56
among farmers was 23% in Finland11, 26.2% and 37% in the United States12,13 37% in
57
Ireland7 and 47% in Sweden14. Few studies conducted in the developing countries
58
reported much higher rates especially in South West Nigeria, 72.4 %
59
and Thailand, 56.2%.17
60
The major occupational risk factors associated with LBP have been identified as
61
poor/awkward work postures, bending, lifting and heavy physical work.
62
reported risk factors of LBP include Body Mass Index (BMI), smoking, age, gender, and
63
workload.15, 20,21
64
To our knowledge, no study reporting on the prevalence of LBP in the rural South South
65
geopolitical zone of Nigeria exists. This is a significant shortcoming particularly as the
15
, China, 64%
18,19
16
Other
3
66
residents are involved in a lot of farming activities which not only provides food and raw
67
material but also employment opportunities to a very large proportion of population. This
68
study was therefore undertaken to determine the prevalence and predisposing factors of
69
low back pain among peasant farmers in a rural community in South South Nigeria. This
70
study may assist in the understanding of global causes of LBP and its management in this
71
region.
72
METHODS
73
SETTING
74
This study was conducted among the inhabitants of Ebubu farm settlement. This
75
settlement was established for Nigerians who were repatriated from the Equatorial
76
Guinea. The inhabitants were basically farmers with few traders, artisans, school
77
teachers, clergymen and civil servants who worked in the local government council
78
headquarter in Eleme. The farmers in Ebubu were chosen for this study because they
79
were quite homogeneous with regard to lifestyle, cultural norms, and farming type. This
80
community is about 60 kilometers from Port Harcourt, the capital of the oil rich Rivers
81
State of Nigeria. It is basically a rural settlement with no electricity, pipe-borne water and
82
health facilities. It has a population of about 10,000 people.
83
STUDY DESIGN
84
The study was a cross-sectional study.
85
SELECTION
4
86
Inclusion criteria: All adult full time farmers between the age of 18 and 58 years who
87
gave their consent after the content of the study were explained to them.
88
Exclusion criteria: The farmers excluded from the present study included those that
89
were no longer active in farming, had other health conditions that may interfere with the
90
present study results such as renal failure, symptomatic heart disease, spinal injuries or
91
surgery, involved in other occupations that may predispose to low back pain such as
92
masons, automobile mechanics and those below the age of 18 years.
93
SAMPLE SIZE
94
The study was designed to detect a 5% difference in the prevalence of low back pain,
95
with an alpha error of 5%, acceptable beta error of 20% ( a statistical power of 80%); and
96
using the prevalence of 72.4% in a study by Fabunmi;15 the determined minimum sample
97
size was 307, which was approximated to 310.
98
SAMPLING METHOD
99
A commonly used two-stage cluster sampling scheme, the “30 x 7” sampling was used in
100
this study. It was developed by the World Health Organization with the aim of
101
calculating the prevalence of immunized children within ± 10 percentage points of the
102
true proportion, with 95% confidence. That is, if the true prevalence was 40%, one would
103
expect an estimate between 30% and 50% when using the 30x7 method. This sampling
104
scheme is thought to be sufficient for most sampling of community health factors and has
105
been adopted for other purposes such as rapid needs assessments with no (or only slight)
106
modification. 22
5
107
In this study, based upon 2006 Nigerian population census tract data,23 one hundred and
108
twelve clusters in the community were delineated out of which 31 clusters were randomly
109
selected. House addresses within the clusters were utilized to create a new sampling
110
frame from which ten random addresses were selected for each of them. These addresses
111
represented a cluster from which data regarding low back pain were collected. In all, 310
112
houses were sampled from which a farmer within the age bracket of 18 and 58 years was
113
selected from each of the houses by balloting.
114
DATA COLLECTION
115
The study protocol was approved by the ethics committee of the University of Ibadan.
116
Four community health extension workers were recruited as research assistants and
117
trained for two weeks for the purpose of this study. Before interviewing the subjects, the
118
objectives of study were explained to them by the research assistants who also obtained
119
consent from them. They were reassured that the data would be used for research
120
purposes only.
121
A pre-tested questionnaire designed by the authors specifically for this research was used
122
for each subject. The questionnaire solicited information on low back pain which was
123
defined as an ache, pain or discomfort in the area between the 12th ribs and gluteal folds1
124
(a shaded area on a body diagram shown to the subjects). Subjects were asked if they had
125
experienced low back pain in the preceding twelve months. Data on socio demographic
126
characteristics and individual factors such as gender, age and duration of farming were
127
also obtained from the subjects. All questionnaires were scrutinized and detected
128
mistakes corrected by the researchers.
6
129
CLINICAL ASSESSMENT
130
Clinical history consisting of the following; duration of symptoms, mode of onset of
131
symptoms, knowledge of causes of low back pain and care seeking practices were sought
132
for and recorded. The severity of LBP was classified as mild, moderate and severe using
133
the method described by Alcouffe et al.24 In their description, subjects with low back pain
134
without radiation to the knee were described as mild cases, those with low back pain
135
radiating above the knee were described as moderate cases and those with low back pain
136
radiating below the knee described as severe cases. Their weight was measured in
137
kilogram with a calibrated and validated Hanson bathroom scale. Height was measured in
138
meters using the Leicester height measuring stadiometer. From these measurements, their
139
Body Mass index (BMI) was calculated and classified as desirable weight <25kg and
140
overweigh/obese > 25kg. To assess the effect of height on low back pain, their heights
141
were dichotomized into above and below average, the average height of Nigerians being
142
taken as 1.60m.25 They were educated on work ergonomics and the use of nearby health
143
facilities.
144
STATISTICAL ANALYSIS.
145
The information obtained from the questionnaires were transferred into Microsoft excel
146
spread sheet for analysis which was done using statistical package for social sciences
147
(SPSS) version 15 and Microsoft Excel. Results were presented as frequency tables,
148
means, percentages, chi square and odds ratio using 95% confident interval and p<0.05.
149
RESULTS
7
150
Three hundred and ten (310) apparently healthy adult farmers consisting of 132 males
151
and 178 females with age range of 18-58 years and a mean of 36.71±8.98 years were
152
sampled for the study. Two hundred and eight (67.10%) had LBP. Considering
153
sociodemographic characteristics, LBP was more prevalent in the 41-50 years age bracket
154
(90.63%) and least in the subjects less than 30 years of age (31.37%). The association of
155
age with LBP was statistically significant (p= 0.000).There was also a significant
156
association between gender and LBP (p = 0.001), the prevalence being higher among the
157
males (77.27%). Most of the subjects (73.77%) had attained secondary education level
158
but the association of educational level with low back pain was not statistically
159
significant (p=0.59)(Table 1).
160
spanned between five years and 38 years with a mean 17.02±9.43 years (Table 2).
161
Height was significantly associated with low back pain in this study (p=0.000) with
162
majority of the subjects (73.2%) with low back pain in this study being less than
163
1.6meters tall (RR=1.213, 95% CI= 1.008-1.489) (Table 3). A large percentage (68.95%)
164
of the farmers with desirable weight and 59.68% of overweight farmers had low back
165
pain. The association between overweight and LBP was not statistically significant
166
(p=0.164). The farmers with desirable weight were more likely to have low back pain
167
(RR=1.155, 95% CI= 0-935-1.497) (Table 4).
168
Severe low back pain was linked to aging (51-60 years age group), the
169
overweight/obesity and those with height above average (1.60metres). The association
170
between these factors and low back pain was statistically significant (P<0.05)(Table 5).
Their duration of farming practice was found to have
171
8
172
Table 1: Socio-demographic Characteristics of Farmers
173
Characteristics
174
Age
175
<30
32(31.37)
176
31-40
177
Total(%)
χ2
p-value
70(68.63)
102(32.90)
89.76
0.000
102(82.93)
21(17.07)
123(39.68)
41-50
58(90.63)
6(9.37)
64(20.65)
178
51-60
16(76.19)
5(23.81)
21(6.77)
179
Sex
180
Males
102(77.27)
30(22.73)
132(42.58)
10.78
0.001
181
Females
106(59.55)
72(40.45)
178(57.42)
182
Education
183
Nil
71(67.62)
34(32.38)
105(33.87)
1.96
0.59
184
Primary
83(63.85)
47(36.15)
130(41.94)
185
Secondary
45(73.77)
16 (26.23)
61(19.68)
186
Tertiary
9(20.45)
5(79.55)
14(4.52)
LBP + (%)
LBP -(%)
187
188
189
190
191
192
9
193
Table 2: Distribution of farmers by the no. of years they practiced farming
194
Age (Yrs) LBP(%)
No LBP(%)
Total(%)
χ2
p-value
195
5-10
42(38.18)
68(61.82)
110(35.48)
66.5
0.000
196
11-15
39(78.0)
11(22.0)
50(16.13)
197
16-20
42(89.36)
5(10.64)
47(15.16)
198
21-25
42(85.71)
7(14.29)
49(15.81)
199
31-35
18(78.26)
5(21.74)
23(7.42)
200
26-30
25(80.65)
6(19.35)
31(10.00)
201
Total
208(67.10) 102(32.90)
310(100.0)
202
203
204
205
206
207
208
10
209
Table 3: Distribution of farmers by their height
210
Height (m)
LBP(%)
No LBP(%)
Total(%)
χ2
211
1.46-1.50
10(58.82)
7(41.18)
17(5.48)
15.02
212
1.51-1.55
65(75.58)
21(24.42)
86(27.74)
213
1.56-1.60
75(69.44)
33(30.56)
108(32.61)
214
1.61-1.65
35(68.63)
16(31.37)
51(16.45)
215
1.66-1,70
6(40.00)
9(60.00)
15(4.84)
216
1.71-1.75
12(63.16)
7(36.84)
217
1.76-1.80
5(35.71)
9(64.29)
218
Total
208(67.10)
102(32.90)
p-value
0.02
19(6.13)
14(4.52)
310
219
220
Table 4: Distribution of the farmers by their Body Mass Index (BMI)
221
BMI
222
Desirable (<25 171(68.95) 77(31.05)
223
Overweight/
224
Obesity (≥25)
225
RR=1.155, 95% CI= 0-935-1.497
LBP(%)
37(59.68)
No LBP(%)
25(40.32)
Total(%)
χ2
p-value
248(80.0)
1.92
0.164
62(20.0)
11
226
227
Table 5: Personal characteristics and intensity of low back pain
228
Characteristics
229
Age (yrs)
230
< 30
23(68.75)
7(21.88)
231
31-40
75(73.53)
232
41-50
233
51-60
234
Sex
235
Males
236
Females
Total
χ2
2(6.25)
32
*13.51
23(22.55)
4(3.92)
102
35(60.34)
18(31.03)
5(8.62)
58
6(37.50)
5(31.25)
5(31.25)
16
68(66.67) 25(24.51)
9(8.82)
102
71(66.98) 28(26.42)
7(6.60)
106
237
BMI (Kg/m2)
238
Desirable (<25) 121(70.76) 42(24.56)
8(4.68)
171
239
Overweight/
240
Obesity (≥25)
18(48.65) 11(29.73)
8(21.62)
37
241
Height(m)
242
≤ 1.60
106(70.67) 39(26.00)
5(3.33)
150
243
> 1.60
33(56.90) 14(24.14)
11(18.96)
244
* Yate’s correction applied
Mild (%)
Moderate (%) Severe (%)
p-value
0.04
0.48
0.82
13.90
0.001
14.53 0.000
58
245
246
247
12
248
DISCUSSION
249
The prevalence of LBP among the rural farming population in this study is 67.10%. This
250
is lower than findings in Iju-Odo, South West Nigeria (72.4%)15 but higher than that
251
reported in studies in Igbo Ora, South West Nigeria (40%)21 and farmers in in the
252
developed countries such as Finland, US, Ireland and Sweden.1,11-14 Although the Ebubu,
253
Igbo Ora and Iju-Odo farmers belong to the same racial group and use similar farming
254
techniques, the dissimilarity in the prevalence in the different locations could have arisen
255
from possible differences in the descriptions of LBP by the researchers
256
techniques, sample size and personal factors related to work, such as high work stress,
257
low job satisfaction, financial constraints, health-related problems, low social class and
258
worries about the future which have all been linked with LBP in previous studies. 27 The
259
variation of prevalence might be due to the distinction of study populations, farming
260
methods or the relative presence of physical, psychosocial and individual risk factors of
261
LBP.28,29,30
262
The difference in the prevalence of LBP in our study and the farmers in the developed
263
countries could have emanated from the modalities of farming practice in the locations.
264
Rural farming activities in Nigeria require considerable physical stress which may
265
predispose to LBP.
266
practice mechanised farming which is less physically demanding.
267
The increasing prevalence of low back pain with age, reaching a peak at 41-50 years age
268
bracket agrees with the range of 35 to 55 years maximal age of occurrence in the review
269
by Biering- Sorenson.
21, 31
32
26
, sampling
The situation in the developed countries is different since they
Opinions on the association of age with LBP are diverse.
33
13
27,32
Some literature
271
prevalence with age while others showed reducing prevalence.
272
opinions could have possibly arisen from the wide range and variety of definitions of
273
back pain which might have influenced the measurement of study outcomes.36 Increasing
274
prevalence with age appears more plausible considering the fact that the prevalence of
275
osteoarthritis, disc degeneration, osteoporosis and spinal stenosis; which cause LBP have
276
been known to increase with age.
277
occurs is more likely to continue with minimum chance of recovery, hence the increasing
278
prevalence with age is not surprising.38
279
The increasing prevalence of LBP with age has potentially considerable implications for
280
public health in the coming years as many countries will experience a substantial increase
281
in the number and proportion of aged people. This suggests at the very least that more
282
attention should be paid to back pain in older people as well as the working class
283
Low back pain was significantly more prevalent among the males than females in this
284
study. Some studies have reported that female gender
285
whereas other studies report no association.
286
predisposed to LBP than males because of risk factors such as pregnancy, young maternal
287
age at first birth, duration of oral contraceptive use and use of estrogens during
288
menopause. These factors result in hormonal changes which cause a global laxity in
289
muscles and ligaments of the back hence compromising the stability of the spine with
290
resultant pain.
291
even though surprising, has been similarly reported by other researchers.
292
for this disparity could be attributed to the fact that it is the responsibility of the men to
41
have reported no association but some
15,34
270
37
have shown increasing
33-35
The diversity of
It has also been postulated that back pain, once it
40
39
increases the risk of LBP,
The females are naturally more
The higher prevalence of LBP among the male farmers in this study
15
The reason
14
293
fend for their families. An important fact about these rural farmers is that they are either
294
self-employed or employed on ”task work” by a master. Since one day off work implies
295
income lost, time maximisation on the farm with high income is consequently the work
296
culture. This time maximisation result in the subjection of their back muscles to repetitive
297
stress which has been identified as an important cause of low back pain. 42 This can also
298
explain the prevalence of low back pain increasing with the number of years of practicing
299
farming occupation found in this study. A similar finding was reported among the peasant
300
farmers in Iju-Odo, South West Nigeria. 15
301
Height was found in this study to be significantly associated with low back pain.
302
Although positive and negative results have been reported in studies considering
303
association between height and LBP or sciatica, 43 a proposed mechanism involved in the
304
lumbar pathology is the role of lumbar disc height.44 Natarajan et al45 suggested that taller
305
people have more potential for instability under external loading, because higher discs are
306
exposed to much higher risk of failure.
307
alterations of facet joints in patients with lumbar disc hernia were more evident in the
308
taller patients.
309
could have major implications in public health policies. Effort has to be made towards
310
specific prevention of LBP among tall people. This could be similar to the provision of
311
standing aids to tall Japanese cooks to minimize the discomfort of LBP.47
312
This study demonstrated no significant association between low back pain and BMI
313
though farmers with normal BMI were more predisposed to LBP. This corroborates with
314
the findings by Hildebrandt48 and Kelsey et al.
46
An anthropometric study also found that
The significant association of height with low back pain in this study
49
This finding is surprising since obese
15
315
people are subject to increase mechanical demands and detrimental metabolic factors
316
which have been suspected of causing low back pain through excessive wear and tear.
317
A possible explanation of our finding could be that the farmers with normal BMI are
318
more liable to hard work for longer periods because of their healthy nature. This may be
319
predisposing to LBP.
320
Statistically significant association was found between severity of LBP and age, height
321
and BMI in this study. This corroborates partially with some of the findings by Stranjalis
322
et al.51 They found that the frequency and severity of low back pain were related to
323
several socio-demographic factors such as age and sex at a statistically significant level. 51
324
Sex, age, and kind of job presented a significant association with risk of low back pain
325
independently from other socioeconomic factors. Sex in our study, contrary to their
326
findings was not significantly associated with the severity of low back pain. Differences
327
in the characteristics of the sample populations could have been responsible for this
328
disparity. The severity of low back pain in our study could be attributed to the
329
degenerative effect of aging, higher discs which have potential for instability under
330
external loading and the mechanical demands resulting from obesity.
331
Information bias was an important limitation to the study. Farmers might over-report in
332
order to gain sympathy hence obtain financial benefits, since farming is observed as a
333
very difficult job. Explanation to the participants that over-reporting will not help the
334
study to discover their health problems and make recommendations to health authorities
335
helped in overcoming it.
50
336
16
337
CONCLUSION AND RECOMMENDATION
338
Our study indicates that back pain is a prevalent health problem among farmers on small
339
operations or family farmers. Encouragement of the rural peasant farmers to forms
340
cooperative societies to which loans can be given by the government to commence
341
mechanized farming can help to alleviate this problem significantly. Primary care
342
physicians in the services to the people in there are of practice to reduce belief in
343
witchcraft and complacency in reporting occurrence of low back pain to health
344
authorities. Chronic LBP is costly to manage due to recurrent and debilitating nature of
345
the condition. The findings of this review indicate that primary prevention should be
346
considered an African priority due to the already constrained economic resources for
347
overall health care. The school setting may therefore be appropriate to teach young
348
people good spinal health habits, and future research should incorporate spinal health
349
promotion strategies for schools in Africa.
350
351
352
353
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