Mwaka ES, Munabi IG, Buwembo W, Kukiriza J, Ochieng J.

Anatomy DepartmentMakerere University, School of Biomedical

Sciences

IntroductionSchoolbag are important for carrying

scholastic materials and lunch packs.Children carry heavy bags loaded with books.Recommended safe load limits 10%-15% of

body weight.Low back pain prevalence between 30%-50%.

Taimela,1997

Schoolbags associated with back painGrimmer, 2000

No studies describing the actual current use of schoolbags by pupils in Uganda

No data against which guidelines for weight limits can be set and for designing injury prevention programs.

Objectives The main objective of the study was to determine the

prevalence of back pain and describe its relationship with schoolbag use in children.

Specific objectivesTo determine the prevalence of low back pain in school

children.To determine the average schoolbag load carried by school

children and investigate its association with back pain. Comparisons were made between rural and urban school children.

To investigate schoolchildren’s subjective perceptions of their daily schoolbag loads, to ascertain whether an association exists between these sensations or the load itself and back pain.

MethodsCross-sectional descriptive study design532 children from 3 rural and 3 urban

primary school Parental informed consent and pupil assent

were sought.Questionnaire was used.Weight with and without the schoolbag was

taken and the difference recorded

VariablesOutcome variable was low back pain was

operationally defined as pain or discomfort in the low back region, from the lower rib curvature to the lower part of the seat region.

Predictor variables included: body weight, schoolbag weight, schoolbag weight as % of body weight, type of schoolbag, how the bag was carried, pupil perception of bag weight and comfort while wearing the bag, and activities done after school.

AnalysisData imported into Stata 10.0Responses were analyzed using frequency

distributions and descriptive statistics. Chi-square cross tabulations Nonparametric tests for trend Two- sample t test with equal variancesRegression analysis P<0.05 was significant.

ResultsFemales =294 (55.4%) and males = 237

(44.6%). Mean age 13.6 years (range10- 21 years +

1.66). The mean age of children from the urban

schools was 12.9 + 1.9 compared with 14.3 + 1.5 for the rural schools.

The overall mean weight of the school children was 46.82 kg + 9.1(range 28.5- 84.9kg). (Males 46 + 9.1, females 47.5+ 9.1).

Mean schoolbag weight was 3.78 kg + 1.97 (range 0- 12.3 kg).

Mean bag weight as a percentage of the body weight was 8.46% + 5.0 (range 0- 31.3%).

Urban pupils were carrying significantly heavier bags (mean 10.58% + 5.29) than rural school children (mean 6.59% + 3.82) (p<0.0001).

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10 15 20Age

Schoolbag weight as a percentage of body weight plotted against age

12 year old carrying a bag 23.5% of his body weight

164/532 pupils (30.8%) carrying bags which were more than 10% of their body weight

122 (74.4%) pupils were from urban schools and 42 (25.6%) from rural schools

.

Schoolbag useType of bag Urban (n= 254) Rural (278)

Backpack 203 (79.9) 102 (36.7)

Shoulder bag 45 (17.7) 78 (28.1)

Rack suck 0 (0) 20 (7.2)

OtherNo bag

6 (2.4)0 (0)

35(12.6)43 (15.5)

Bag features

Padded shoulder straps 237 (44.5)

Adjustable Shoulder straps

304 (57.1)

Chest strap 19 (3.6)

Waist belt 38 (7.1)

Padded back 144 (27.1)

Method of carriage n= 509

Both shoulder straps 264 (51.9)

One shoulder strap 146 (28.7)

Use of hip belt 3 (0.6)

Other method 38 (7.5)

Do not use bag 58 (11.4)

Type of school bag safety and comfort features, and method of bag carriage.

Only 24/532 (4.5%) routinelyUsed all the bag features.

All had scholastic materials inthe bags, 28.3% had lunch Packs/ water bottles

Mode of transport

Urban (n= 251)

Rural (276)

Walking 137 (54.6) 240 (87)

Bicycle 1 (0.4) 9 (3.2)

Car 64 (25.4) 7 (2.5)

Taxi/ Bus 36 (14.3) 18 (6.5)

Motorcycle 13 (5.2) 2 (0.7)

Time spent carrying bag to school

n= 252 n= 276

<5 minutes 71 (28.2) 37 (13.4)

5- 10 minutes 75 (29.8) 57 (20.7)

11- 20 minutes 34 (13.5) 22 (8)

21- 30 minutes 31 (12.3) 42 (15.2)

>30 minutes 41 (16.6) 118 (42.7)

Time spent carrying bag from school

n= 252 n= 276

<5 minutes 67 (26.6) 30 (10.9)

5- 10 minutes 41 (16.3) 34 (12.3)

11- 20 minutes 37 (14.7) 29 (10.5)

21- 30 minutes 37 (14.7) 51 (18.5)

>30 minutes 70 (27.8) 132 (47.8)

Mode of transport and time spent carrying the school bag

•77.7% walked to school•57.4% carried bags for <20 mins

•Duration of school bag carriage between urban and rural pupils p< 0.0001

Only 101/532 (19%) had lockers

Body pain 448/532(88.2%) had pain or discomfort in

the body over the previous 2 weeks.Pain greatest in the neck (24.5%), shoulders

(42.1%), upper back (35.7%) and the lower back.

201/532 (37.8%) had low back pain.Females were more significantly affected

(odds ratio 0.54, 95% CI 0.37- 0.79).

Urban(n= 253) Rural (n= 278)

Odds ratio 95% CI

Sitting for long 18 (7.1%) 26 (9.4%) 0.90 0.46- 1.74

Walking for long 33 (13) 16 (5.8) 2.67 1.38- 5.16

Carrying the bag 92 (36.4) 96 (34.5) 1.24 0.83- 1.85

Writing 1 (0.4) 3 (1.1) 0.43 0.04- 4.22

Sports/ playing 13 (5.1) 11 (4.0) 1.1 0.47- 2.56

Comparison by sex Back pain No back pain

Male 66 (27.8) 171 (72.2) 0.45 0.31- 0.65

Female 135 (45.9) 159 (54.1)

Significant associations with LBP•Walking for long periods (z= 6.95, r= 0.30, p< 0.0001).•Type of school bag carried (z= -3.39, 95% CI -0.76 to -0.20, P= 0.01).•Method of schoolbag carriage (95% CI 1.798- 1.954, p< 0.0001).

Factors associated with low back pain

Low back pain cont’dActivities done after school did not have a

significant effect on back pain. (p= 0.37). 212/523 (40.5%) on average spent between 2- 4

hours seated every evening and this significantly affected the occurrence of low back pain (z=-3.063, r= -0.137 p= 0.02).

48/532 (9.3%) had ever missed school148/518 (28.6%) had ever had to rest or not play

sports 36 / 520 (6.9%) had ever been taken to the

doctor because of back pain.

Pupils perceptions

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Light Medium Heavy

•119/305 (38.5 %) did not like their bags

•Medium (242/532, 49.9%)

•Heavy (193/532, 39.8% (p<0.0001)

•49.8% felt uncomfortable ( pupils with pbw >10% p<0.0001

•Rural pupils twice as likely to complain of LBP Odds ratio 2.76 95% CI 1.90577 - 4.00581).

DiscussionPain in the neck, shoulders and back is

associated with carrying heavy loads.Heavy school bags result in postural changes

at the head and trunk leading to repetitive strain injuries to the growing body.

Professional bodies put limits at 10%- 15% of body weight.

What sort of bag should school children carry?BackpackWide, padded shoulder straps for comfort

and greater distribution of weight across the shoulders.

Adjustable straps to allow varied placement of the backpack on the user’s back

Padded back for comfort and protectionMultiple compartments for distribution of

load.Proper use: Two straps

How you recognize a heavy schoolbag?Key signs that bag is heavy: struggling to put

on or take off the schoolbag, postural mal-alignment (forward head and/or trunk flexion or lateral listing), and pain and/or paresthesia associated with wearing the schoolbag.

When a child complains that the bag is heavy take him/her seriously!

Parents seldom check the weight and contents of children’s schoolbags.

ConclusionA significant number of pupils in the urban

schools had school bags that were more than 10% of their body weights and significantly heavier than the school bags of older pupils in rural schools.

The prevalence of LBP was 37.8%.Association was observed between low back

pain and; type of schoolbag, method of bag carriage, and the time spent sitting after school.

RecommendationsParents remain the best advocates for safety

promotion and should represent the group most likely to help to significantly reduce the number of schoolbag related injuries by checking backpack weights and contents

Provision of lockers and functional libraries.Recommended schoolbags should be

backpacks with ergonomic features designed to improve safety and comfort.