The frequency, cause and treatment of limb pain were ascertained in a cohort of children at six time points between the ages of 5 and 13 years. Data were collected using self-completion questionnaires sent to the chief carers of children in the Avon Longitudinal Study of Parents and Children. Reports of limb pain over the study period doubled from 15.1% of children aged 5 to 32.5% aged 13; 3.4% of children had limb pain at all time points, 43.4% never reported limb pain and 56.6% reported limb pain on at least one occasion. Growing pains were the most common ‘cause’ given for limb pains. Limb pain and growing pains were each associated with a family history of arthritis and rheumatism. Limb pain prevalence may have been under-reported in this study due to gradual attrition, particularly in the less educated mothers among whom the highest prevalence of limb pain was reported.
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Limb pains are one of the most common types of pain experienced by children. The prevalence of recurrent limb pain in children has been reported to be 33.6%.1 The majority of studies have shown that growing pains are the most frequently reported cause. Previous studies examining limb pain in children have mostly collected cross-sectional data only. We report longitudinal and cross-sectional frequencies of all types of limb pain and also the reported differences in causes and treatments in the same children over a 9-year period.
The Avon Longitudinal Study of Parents and Children (ALSPAC),2 is a population-based cohort study, designed to investigate the determinants of health and disease during childhood and beyond. Data were collected via self-completion questionnaires sent to the study child's chief carer at 5, 6, 7, 8, 11 and 13 years of age. Questions were asked about whether the child had often experienced pain in their arm(s) and/or leg(s). If yes, parents were asked to describe what they thought was the cause and whether any particular treatment(s) had helped. Descriptions of causes and treatments of limb pain were keyed as text and coded into numerical responses.
Cross-sectional analyses present the frequencies, causes and treatments of limb pain reported at each age. Longitudinal analyses concern those who responded to every limb pain question (n=4491; subsequently referred to as ‘the complete cases’). Associations between limb pain and growing pains at any time and child sex, maternal education, maternal age at delivery, parental and grandparental history of arthritis and rheumatism were tested using χ2 tests on the complete cases. All analyses were performed using SPSS V.15 (SPSS, Chicago, Illinois, USA).
Data on limb pain were available for 9380 children at 5 years (67.1% of 13 988 study children alive at 1 year) and 6502 at 13 years (46.5%). The frequency of limb pain doubled from 15.1% of children aged 5 to 32.5% aged 13 (table 1).
At each age, pains almost always involved the legs (>98%). The proportion of limb pains that included the arms increased from 17.3% at age 5 to 36.2% at age 13. When restricted to the 4491 children for whom the questions had been answered at each time point, it can be seen that only 43.4% were reported as having no limb pain, 56.6% as having limb pain at least once throughout the 9-year period and 3.4% of the children had limb pain at every age (table 2).
Up to three causes and treatments of limb pain were reported per child at each time point. Causes included specific and diagnosed conditions such as cerebral palsy, muscular dystrophy, arthritis and rheumatism and non-specific causes such as exercise/exertion and cramp (details are given in the supplementary material). The most common cause given for any type of limb pain was growing pains reported by the parents of 2435 children.
The proportion of children with limb pains for whom growing pains was given as a cause increased at each time point from 27.6% (n=391) at age 5 to the highest prevalence of 46.5% (n=983) at age 13. Treatments reported as being helpful for treating any type of limb pain and for growing pains are shown in the supplementary material.
The cumulative prevalence of limb pain was slightly higher in boys than girls (58.6% vs 54.6%; p=0.006), lower in children of mothers with university degrees compared with those with little education (49.7% vs 60.0%; p<0.0001) but had little variation with maternal age (p=0.026). There was little difference in the reporting of growing pains between boys (32%) and girls (29.5%; p=0.071), and were less likely to be reported by more highly educated and older mothers (p<0.0001 and p=0.002, respectively). Parental history of arthritis and of rheumatism were strongly associated with children with any type of limb pain (p<0.0001 and p<0.0001, respectively) and also growing pains (p=0.009 and p=0.002, respectively) (see supplementary material). Similar associations were seen for a history of arthritis/rheumatism in the grandparents.
In this, the largest longitudinal study of parentally reported frequent limb pain in children in Britain we have shown that limb pains were a common occurrence with 56.6% being reported with these pains at some stage between 5 and 13. The most often cited cause of limb pain given by the parents was referred to as growing pains, which was reported for 2435 children.
Growing pains have been associated with a variety of causes in the past including rheumatism, night cramps, hypermobile joints, psychosomatic pain and the restless legs syndrome.3 4 To our knowledge only one study has looked at a relationship between growing pains and family history of rheumatism and arthritis.5 The authors of that study found that children with growing pains (defined as persistent and non-arthritic) had a higher incidence of family history of all forms of rheumatism and arthritis. A similar association was seen in this study, and raises the question as to whether the affected children are at increased risk of developing these conditions in adulthood.
While it is likely that diagnosed conditions would have been given as a cause, undiagnosed pains would have been subject to the parent's own interpretation of what they thought had caused their child's limb pains, many parents preferred to state that the reason was unknown (n=722). Gradual attrition over the length of the study was 32.9% at 5 years and 53.5% at 13 years; in this analysis only 32% of study parents provided data at all six time points.
As in the majority of longitudinal studies the loss to follow-up in ALSPAC is negatively related to higher educational status. Since we have shown that recurrent limb pain was more prevalent when the mother was less well educated, the overall prevalence in the population is likely to be even greater than shown here.
Limb pain appears to be much more common than generally recognised. Whether the link with a family history of arthritis and rheumatism indicates that children with such pains in childhood and adolescence are at increased risk of developing these disorders themselves must await long-term follow-up of this and other cohorts.
We are extremely grateful to all the families who took part in this study, the midwives for their help in recruiting them, and the whole ALSPAC team, which includes interviewers, computer and laboratory technicians, clerical workers, research scientists, volunteers, managers, receptionists and nurses.
Funding The UK Medical Research Council, the Wellcome Trust and the University of Bristol currently provide core support for ALSPAC. Funding for this project was provided by the Arthritic Association. This publication is the work of the authors and JLB serves as guarantor for the contents of this paper.
Competing interests None.
Ethics approval Ethical approval for the study was obtained from the ALSPAC Law and Ethics Committee and the three local research ethics committees.
Provenance and peer review Not commissioned; externally peer reviewed.
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