- Top of page
- What this paper adds
Aim The aim of this study was to investigate the effect of gastrostomy tube feeding on body protein and bone mineralization in malnourished children with cerebral palsy (CP).
Method Children aged between 4 and 18 years with spastic quadriplegic CP (Gross Motor Function Classification System level V) were recruited from the Children’s Hospital at Westmead to participate in this prospective cohort study. The children had measurements of anthropometry (weight, height, and skinfold), bone mineral content (BMC) by dual-energy X-ray absorptiometry, and total body protein (TBP) by neutron activation analysis before and after gastrostomy tube feeding. Comparison data were collected prospectively from age-matched healthy children and extracted from databases for this study.
Results A total of 21 children (nine females, 12 males) participated in the study (median age 8y 5mo; interquartile range [IQR] 6y 9mo–11y 10mo). The median length of time of gastrostomy feeding was 19.4 months (IQR 7.7–29.9mo). Significant (p<0.05) improvements were found in the median values for weight (15.4–23.3kg), weight standard deviation scores (SDS; −4.8 to −3.0), height (105.4–118.3cm), per cent body fat (10.7–16.3), TBP (2.4–3.4kg), TBP per cent predicted for height (83.4–99.0), and BMC (469–626g). No significant increases were found in height SDS, TBP per cent predicted for age, or BMC SDS for age or height.
Interpretation Malnourished children with quadriplegic CP showed significant increases in body fat and protein with gastrostomy tube feeding. No significant change in bone mineralization predicted for age or height was observed.
Despite the many studies reporting a high incidence of malnutrition in children with severe cerebral palsy (CP), there have been limited studies investigating the effects of nutritional intervention on body composition parameters. The few studies that have been carried out have investigated only changes in growth parameters (weight and height) and body fat, with no exploration into the effects of weight gain on body protein and bone mineralization.1–7
Patients with severe CP have severe muscle atrophy due to neurological injury and disuse, but this is also compounded by malnutrition and poor growth. Moreover, neurological injury may limit protein accretion associated with nutritional rehabilitation. We have previously published studies demonstrating a severe reduction in body protein in children with spastic quadriplegic CP.8,9 Bone disease is also an important consideration in this group, as previous studies have demonstrated large reductions in bone density with an increased fracture rate.10–15
An important question in the nutritional restitution of malnourished patients with CP is whether improved weight gain results in improvement in protein mass and bone mineralization and/or whether it just leads to accumulation of body fat. Thus, the aims of this study were to determine if nutritional rehabilitation via gastrostomy feeding of patients with spastic quadriplegic CP improved total body protein and increased bone mineralization.
- Top of page
- What this paper adds
The baseline and repeat measures of study variables of the 21 children (nine females, 12 males) are shown in the tables. Baseline measures of height – height SDS (Table I), TBP percentage of that predicted for height (Table II), and BMC for height SDS (Table III) – were unavailable for seven of the children (four females, three males) because the measurement of knee height was not part of the study protocol at the time of their participation in the study. Paired skinfold measurements were unavailable in two patients. Therefore, the tables depict participants with both baseline and repeat measures for each parameter.
Table I. Baseline and repeat measures of body composition after nutritional rehabilitation
| ||Baseline||Repeat||p value|
|Age, y:mo||8:5 (6:9 to 11:10)||10:4 (8:9 to 14:0)||<0.05|
|Weight, kg||15.4 (12.0 to 20.5)||23.3 (16.6 to 25.9)||<0.05|
|Weight SDS||−4.8 (−6.7 to −3.1)||−3.0 (−5.2 to −1.7)||<0.05|
|Height, cma||105.4 (99.3 to 121.5)||118.3 (114.2 to 127.9)||<0.05|
|Height SDSa||−3.9 (−4.7 to −2.0)||−3.5 (−4.2 to −1.7)||ns|
|PBFskin,%b||10.7 (6.4 to 12.9)||16.3 (12.3 to 24.2)||<0.05|
Table II. Effect of nutritional rehabilitation on total body protein (TBP)
| ||Baseline||Repeat||p value|
|TBP, kga||2.4 (1.6–3.2)||3.4 (2.8–4.0)||<0.05|
|TBP for age, %a||51.9 (44.9–62.9)||58.0 (45.0–75.0)||ns|
|TBP for height, %b||83.4 (72.3–96.0)||99.0 (92.0–117.9)||<0.05|
Table III. Effect of nutritional rehabilitation on bone mineral content (BMC)
| ||Baseline||Repeat||p value|
|BMC, g|| 469 (374 to 632)|| 626 (509 to 736)||<0.05|
|BMC for age SDS||−2.3 (−3.3 to −1.7)||−2.5 (−3.6 to −1.7)||ns|
|BMC for height SDSa||−0.6 (−1.0 to −0.1)||−1.1 (−1.5 to −0.3)||ns|
The median time difference between baseline and repeat testing was 20.6 months (IQR 11.3–34.4mo). In 13 of the children, there was a median time delay of 5.3 months (IQR 3.9–12.8mo) between having the baseline measurement and insertion of a gastrostomy tube; therefore, the median length of time of actual gastrostomy tube feeding was 19.4 months (IQR 7.7–29.9mo).
Baseline characteristics indicate significant degrees of stunting, weight deficit, and reduced body fat in this group of children with CP. However, after an extended period of gastrostomy feeds, there was a significant increase in all body composition parameters measured by anthropometry, including body fat. Mean body weight increased by approximately 50%. There was also a significant increase in weight SDS, although height standard deviation did not alter. These results indicate that gastrostomy feeding did improve nutritional status.
Total body protein by neutron activation analysis
Nutritional rehabilitation resulted in a significant increase in TBP between baseline and repeat testing (Table II). A significant increase was also demonstrated in TBP as a percentage of that predicted from comparison data for height between baseline and repeat testing. However, there was no significant change in TBP expressed as percentage of that predicted from comparison data for age.
Bone mineral content by DXA
Nutritional rehabilitation resulted in a significant increase in BMC between baseline and repeat testing; however, there was no significant change in BMC SDS for age or height.
- Top of page
- What this paper adds
This prospective nutritional rehabilitation study revealed that significant weight gain in gastrostomy tube-fed children with CP produced significant increases in height, measures of fat mass, TBP, and BMC. These children also demonstrated significant improvements in their SDS for weight and for TBP expressed as a percentage of that predicted for height from comparison data, indicating that nutritional rehabilitation of malnourished patients with CP does result in increased body protein accretion.
There have been several longitudinal nutritional rehabilitation studies of children with CP,1–7 although only three of these studies were prospective.2,6,7 Three studies were retrospective reviews of the medical records,1,3,5 and one did not state how the data were collected.4 All of the above studies reported measures of weight and/or height, with only three including some basic skinfold anthropometry.2,6,7 None of the studies included a direct measure of body protein or BMC. The use of simple anthropometry alone to assess nutritional status in children and adults with CP is problematic, given the difficulties of obtaining accurate height measurements as well as the presence of reduced skeletal muscle mass from central nervous system injury and disuse.
Interestingly, nutritional rehabilitation in our study did not result in an increase in height SDS. This has also been reported in several other retrospective studies in children with neurological disabilities.1,3–5 The lack of improvement in height SDS is most likely a result of multiple factors, including the lack of weight-bearing activity and poor growth secondary to central nervous system injury. Immobilization, or disuse, during growth can also lead to reduced growth in bone length and, subsequently, a lack of growth in height.29
In three prospective studies of nasogastric and gastrostomy tube feeding in children with severe CP, it was found that, in addition to significant weight gain, the children demonstrated significant increases in their triceps skinfold thickness and, in one study, upper arm muscle area.2,6,7 This finding of an increase in upper arm muscle area suggests an increase in body protein; however, because upper arm muscle area is an indirect measure of body protein and is derived from the measurement of the triceps skinfold thickness and mid-upper arm circumference, this may have simply reflected an increase in fat stores.
The current study is, to our knowledge, the only study to report longitudinal data on TBP in children with CP. However, our centre has measured longitudinal changes in TBP in healthy comparison children.30 Compared with the healthy children, TBP gain per year was lower in the gastrostomy tube-fed children with CP (481g/y vs 406g/y respectively), yet the latter showed significant improvements in their TBP as a per cent of that predicted for height, demonstrating a catch-up in body protein for their size. Although there was no statistically significant increase in TBP as a percentage of that predicted for age, our previously published cross-sectional study demonstrated a significant negative correlation between age and TBP as a percentage of that predicted for age (i.e. as children with CP aged, there was an increasing divergence in body protein between the children with CP and the comparison group).8,9 It may be hypothesized from the results of this study that this divergence in body protein for age may be halted with adequate nutrition. Thus, this study demonstrated that significant increases in body protein can be achieved by gastrostomy tube feeding in children with severe CP.
Aside from the current study, there has been only one other longitudinal study of bone mineralization in children with CP.31 Although the authors were not conducting a nutritional rehabilitation study, they did find that a better nutritional status, as assessed by the triceps standard deviation score, was associated with greater change in BMD per year in 69 children with moderate to severe spastic CP. The study also reported that BMD SDS decreased over time in spite of overall increases in BMD, whereas, in the current study, it was found that there was no significant change in BMC SDS for age or height with gastrostomy tube feeding. However, the results are difficult to compare with the current study because the authors measured rate of change in areal BMD in the distal femur and lumbar spine, rather than in total body BMC, as in this study, no adjustments were made for body size, and they conducted an observational rather than an interventional study.
Despite overall increases in BMC, no improvements in BMC SDS for age or height were observed in our study. This is probably because of the need for both physical activity and nutrition for normal growth and development of bone.29 Consequently, in children with CP, it is unlikely that any significant improvements in BMC SDS will be seen with adequate nutrition alone, but longer-term studies will be required to clarify this. It is important to note, however, that, although there were no significant improvements in BMC SDS, these scores did not significantly decrease over the course of nutritional rehabilitation. Previous studies of bone mineralization in children with severe CP have demonstrated a decline in BMC and BMD SDS with increasing age,9,13,31,32 a pattern that is similar to what we describe for TBP (see above). Furthermore, a significant positive relation between BMC and measures of body protein (lean tissue mass) has been shown to exist in typically developing children as well as in children with severe CP.9,16 This implies that low body protein may predispose children with CP to low bone mineralization.
There are a number of limitations to this study. A small number of patients were recruited with CP, although data from a large number of typically developing children were available for comparison. Interpretation of the results is also confounded by the dilemma of how to normalize the study parameters given the difficulties of attaining accurate measurements of height and bone density in children with CP and the contribution of central nervous system injury and lack of physical movement to the lack of development of lean mass. However, these are the realities of working in such a clinic. Further studies of longer duration will be required to determine if maintenance of adequate nutritional status in spastic quadriplegic CP will ameliorate or halt the decline in BMC standard deviation seen with increasing age. Ideally, these questions would be best answered in a randomized controlled trial. We attempted to perform such as study but failed to recruit any patients over a 12-month period because of lack of caregiver consent to randomization.