Children and adolescents who have decreased mobility due to spina bifida may be at increased risk for the components of metabolic syndrome, including abdominal obesity, insulin resistance, and dyslipidemia due to low physical activity. Like their nondisabled peers, adolescents with spina bifida that develop metabolic risk factors early in life have set the stage for adult disease. Exercise interventions can improve metabolic dysfunction in nondisabled youth, but the types of exercise programs that are most effective and the mechanisms involved are not known. This is especially true in adolescents with spina bifida, who have impaired mobility and physical function and with whom there have been few well-controlled studies. This paper highlights the current lack of knowledge about the role of physical activity and the need to develop exercise strategies targeting the reduction of cardiometabolic risk and improving quality of life in youth with spina bifida.
Spina bifida (SB) is a congenital abnormality characterized by the incomplete closure of the spinal column. The majority (>90%) of cases are classified as meningomyelocele, in which the spinal cord protrudes through the spinal column, resulting in nerve damage and physical disabilities including lower limb paralysis and disrupted bladder or bowel function. Widespread public advertising and clinical advocacy campaigns have been used to promote the intake of adequate dietary folic acid during pregnancy, since this strategy has been shown to reduce the risk of developing SB. Nevertheless, the current prevalence of SB in the United States is estimated to be close to 1 in 1,000 pregnancies [
As a result of improved surgical treatments and early medical care, children with SB can expect longer lives today than in the past [
The purpose of this narrative review is to describe the current scientific literature on cardiometabolic risk in youth with SB and the potential for structured exercise intervention programs to improve health and function in that population. The volume of existing literature in this area is relatively small and therefore neither a structured systematic review of the evidence, nor a meta-analysis of the results of multiple exercise studies was feasible. Thus, our goal is to outline what is known about the potential cardiometabolic consequences of SB, to highlight both the strengths and weaknesses of selected studies, to identify gaps in knowledge, and to suggest future directions that would produce the type of evidence that will ultimately guide improved clinical care and lifestyle recommendations for people with SB. Our review of the literature covers primarily papers published with in the past 25 years that could be identified through PubMed and cross-referencing citations of published papers. We included some studies with small sample sizes because so little has been published to date, but excluded individual case studies. Although the focus of this narrative review is on SB, we have included selected results obtained from studies of SCI and childhood obesity because of their relevance to understanding the potential consequences of physical disability, deconditioning, and cardiometabolic risk in youth with SB.
Although the prevalence of diabetes and cardiovascular disease in the SB population is not known, children and adults with SB may be at increased risk for metabolic and vascular dysfunction because of their body composition, physical function, and clinical blood test results (Table
Summary of published outcomes for body composition, physical function, and metabolic and vascular risk factors in people with spina bifida (SB).
Outcome | Increased in SB | Decreased in SB | Not different in SB |
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Body mass index, for age and sex | - Non-amb children [ |
- Amb and non-amb children [ | |
- Amb children [ |
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- Children and young adults [ |
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- Amb and non-amb adults [ |
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- Children [ |
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Total body fat (%) | - Non-amb children [ |
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- Children and young adults [ |
- Amb children [ |
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- Children [ |
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Abdominal fat (%) | - Children and young adults [ |
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- Obese children [ |
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Lean body mass (%) | - Children [ |
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Aerobic capacity | - Non-amb children [ |
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- Amb children [ |
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- Non-amb children and young adults [ |
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- Amb children and young adults [ |
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- Amb children [ |
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Muscle strength | - Non-amb children [ |
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- Amb children [ |
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- Non-amb children and young adults [ |
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- Amb children and young adults [ |
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Absolute energy cost of walking or wheelchair use | - Non-amb children and young adults [ |
- Amb children and young adults [ | |
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Requirement of physical reserve for activities of daily living | - Non-amb children and young adults [ |
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- Amb children and young adults [ |
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Total daily physical activity | - Amb children [ |
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- Non-amb children [ |
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- Amb children [ |
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- Non-amb children and young adults [ |
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- Amb children and young adults [ |
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Glucose | - Children and young adults [ |
- Obese children [ |
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Insulin | - Children and young adults [ | ||
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HOMA-IR | - Obese children [ |
- Children and young adults [ | |
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Total cholesterol | - Amb and non-amb girls [ |
- Children and young adults [ | |
- Amb and non-amb girls [ | |||
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LDL-cholesterol | - Children and young adults [ | ||
- Amb and non-amb girls [ | |||
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HDL-Cholesterol | - Children and young adults [ | ||
- Amb and non-amb girls [ | |||
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Triglycerides | - Amb and non-amb children [ | ||
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Homocysteine | - Amb and non-amb children [ |
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Blood pressure | - Amb and non-amb children and young adults [ |
- Obese children [ |
All comparisons refer to outcomes for people with SB relative to people without SB. Results from people with SCI or other spinal disorders are not included in this table according to the descriptions presented in the individual studies. *Comparison is relative to published or unpublished values from prior studies; all other investigations used a specifically recruited comparison group within their study design. Amb: ambulatory; Non-amb: nonambulatory. If not specified, ambulatory status was not stated in the cited study. In some studies “amb and non-amb” designation is used because the results for ambulatory and nonambulatory participants were not presented separately. The designation for children and adults in the cited studies is defined as <18 or ≥18 years old, respectively. In some studies, results from children and adults were not presented separately.
In addition to increased body fatness, children and young adults with SB typically are reported to have reduced aerobic fitness and muscular strength [
As a result of low aerobic capacity and muscle strength, activities of daily living may be relatively more difficult for people with SB. Bruinings et al. [
Given the increased presence of obesity and decreased physical activity and physical function, it is plausible to expect that the components of metabolic risk would be adversely affected by the presence of SB. There are, however, only a few studies that have measured the components of metabolic syndrome or associated risk factors in children or adults with SB. The available reports showed that fasting glucose, insulin, cholesterol, triglycerides, and blood pressure were, on average, not different in people with SB compared to either non-SB control groups or published normal values (Table
Although the group means reported in most of the studies cited above revealed little or no differences between people with and without SB, the results require confirmation in larger studies, and there is still reason for concern. For example, assessment of vascular function in a small group of men with SB demonstrated that arterial diameters were reduced and sheer stress on the vascular wall was increased compared to nondisabled controls, a result that is predictive of endothelial dysfunction [
Although the etiology of their disabilities is clearly different from SB, people with limited use of their legs due to spinal cord injury (SCI) and who rely on wheelchairs for mobility face many of the same health concerns as people with SB. In the United States, there are >1.2 million people with spinal cord injury (SCI) and ~1,500–2,000 new pediatric cases of SCI per year [
Although there are relatively few studies of metabolic risk factors in adults with SB, there are relevant data in the SCI population that could be used to predict longer-term health risks in the SB population. For example, a recent analysis of 134 Swedish adults with SCI revealed that one-third of people met the criteria for cardiovascular risk intervention based on the Framingham Risk Equation and the Systemic Coronary Risk Evaluation models, which include measures of cholesterol, blood pressure smoking, age, and sex [
The potential metabolic risk in children with SB resembles in many ways the current problem of obesity and sedentary lifestyle in all adolescents. According to body mass index criteria for obesity (≥the 95th percentile for age and sex) ~18% of children in the United States are obese [
It is well established that exercise, alone or in combination with dietary strategies aimed to reduce body weight, can be effective for the prevention of diabetes and metabolic syndrome in nondisabled children and adults [
Recent work suggests that some adolescents with SB can successfully participate in sports and should be encouraged to do so for psychosocial reasons [
To date, physical therapy strategies employed with people affected by SB have focused on muscle strengthening exercises and orthopedic supports and assistive devices meant to aid ambulation and postural control [
The first study to our knowledge to report the feasibility and effectiveness of exercise in SB was published by Ekblom and Lundberg in 1968 [
More recently, de Groot et al. [
The value of considering exercise intervention programs for people with SCI is that there have been far more studies conducted compared to the situation for SB [
In summary, although it may seem intuitive that exercise should be a cornerstone of healthy lifestyle recommendations for SB patients, there are so few studies on the effects of exercise in this population that it is unclear whether specific types of activity are more effective than others. Recent exercise recommendations have been developed for adults with SCI and consist of at least 20 min of moderate-to-vigorous intensity aerobic activity performed two times per week, and strength training exercises performed two times per week, comprised of three sets of 8–10 repetitions of exercises targeting each major muscle group [
The authors have no conflict of interests to declare.
This project was supported by National Center for Research Resources grants P20-RR024215 to K.R. Short. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.