Cardiovascular disease in cerebral palsy
these findings in the context of the general population.
A longitudinal study completed in older adults (mean
age 60 ± 9 years) found that cfPWV increased from
9.6 to 10.4 m/s in a 4–6-year time-period (20). Com-
parably, we found a modest increase in cfPWV from
6.2 to 6.9 m/s in a similar time period (i.e. 4 years),
but in a much younger cohort of individuals with CP
(mean age 31.2 ± 15.0 years at baseline). In addition,
there is well-established literature demonstrating that
advancing age is the strongest predictor of increases
in cfPWV (18, 21), and we previously found age to
be significantly associated with cfPWV in a cross-
sectional analysis of 42 adults with CP (8). However,
our current multiple regression analysis did not reveal
age to be associated with rate of change in cfPWV in
the present study, which, in addition to younger age at
baseline, might be explained by a combination of the
small magnitude of observed changes in cfPWV and
the small sample size. Similarly, cIMT increases with
age due to changes to the structural components of the
arterial wall, particularly thickening of both the intima
and media layers; in the general population, cIMT
increases by approximately 3-fold between the ages
of 20 and 90 years (22). The 1 st Screening for Heart
Attack Prevention and Education (SHAPE) Program
identified an individual to be at high risk for subclinical
atherosclerosis when a cIMT ≥ 1 mm is present (23).
Considering the information in the SHAPE guideline,
2 individuals in the present study were at high risk for
subclinical atherosclerosis from cIMT alone. A study in
a cohort of 70-year-old Swedish adults found that cIMT
significantly increased from 0.88 to 0.95 mm over a
5-year period (24). The present study found a larger
relative increase in cIMT compared with the Swedish
cohort. Also, age was a strong significant predictor of
cIMT change in our study, which is consistent with
what is known in the general population and further
supports our findings from cross-sectional work (8). In
addition to age, another important variable to consider
when examining CVD risk is hormonal development.
Specifically, literature has shown that estrogen might
have a cardioprotective effect on the cardiovascular
system (25); however, this topic remains controversial
(26). While this was the first longitudinal study that
examined cardiovascular health in individuals with CP
and demonstrated change over time, we recommend
investigating the effect of age and sex, in particular
metabolic and hormonal effects on cardiovascular
health, in future studies.
Few studies have examined longitudinal changes in
brachial artery FMD from adolescence to adulthood. A
study in children and adolescents with type 1 diabetes
mellitus observed a significant decrease in FMD in ap-
proximately a 3-year follow-up period (27); whereas no
529
significant change in FMD was observed after a 5-year
follow-up study in older adults (24). The latter study
observed a significant inverse relationship between
change in FMD and change in LDL-cholesterol (24),
whereas the former study observed an inverse relation-
ship between glycaemic control and FMD (27). It is
plausible that metabolic markers could be associated
with change in FMD in individuals with CP; however,
we did not measure these in the current study. At the
very least, we know that age and gross motor function
were not significantly associated with change in FMD
in the present cohort. Given the recent work by Peter-
son et al. (28) and Ryan et al. (29) pointing towards
adolescents and adults with CP having an elevated risk
of cardiometabolic disease, it is important for future
work to include cardiometabolic markers to advance
our understanding of the regulation of endothelial fun-
ction in this population. Indeed, we did observe a (non-
significant) increase in waist circumference; however,
our modest sample size limited our ability to include
waist circumference as an independent predictor in li-
near regression analysis. Finally, a significant decrease
(1.1E–3 mmHg –1 ) in carotid artery distensibility bet-
ween baseline and follow-up assessment was observed
in our cohort. In a large cohort of men and women free
of CVD (45–84 years old), carotid artery distensibility
decreased by 0.41E–3 mmHg –1 over a mean period of
9.4 years, and SBP was associated with accelerated
stiffening (30). A larger decrease in distensibility that
was not associated with age or gross motor function
was observed. Taken together, our findings provide
initial support for the argument that individuals with
CP experience accelerated ageing for disease progres-
sion, specifically non-traditional CVD risk factors, in
comparison with the general population. In light of
recent research that identified young adults with CP
at increased risk of CVD compared with age-matched
controls from the general population (31), early de-
tection of the development of CVD, particularly by
assessing non-traditional risk factors for CVD, can
lead to more effective strategies for the prevention of
CVD in this population.
Study limitations
There are important limitations to address in this cohort
study. The main limitation was the small sample size.
While the sample size of 28 individuals did allow us to
examine longitudinal changes in CVD risk factors in
the total group, we were unable to determine whether
other factors (e.g. waist circumference and sex hor-
mones) were associated with the observed changes
in CVD risk variables. Secondly, the large age range
would have been best examined in age groups with a
J Rehabil Med 51, 2019