Cystic fibrosis (CF) is a hereditary autosomal recessive disorderaffecting the exocrine glands (mucous and pancreatic glands) in the body. It is a progressive condition and the most common deadly genetic disease affecting Caucasians (250, 251), although it
also occurs in other races. Cystic fibrosis is a disease that involves several organs in body by affecting the transport of sodium across cell membranes. This causes the production of abnormally thick mucus (252), leading to the blockage of the pancreatic
ducts, intestines, and bronchi. In the chest this often results in frequent respiratory
infection (251, 253).
Incidence and Prevalence
CF is the most common life-threating inherited conditions. It affects the white
population more than the black population. CF incidence varies depending on the
method of diagnosis (screening the new-born, from death certificates, or reports of
new case diagnosis) and origin of sample population raging from 1 in 2000 to 1 in
3000 live births in white population (254). According to the CF Foundation Patient
Registry in United State the incidence of CF was approximately 1 in 3,200 white and
cystic fibrosis (> 70,000 worldwide); around 1,000 new cases of CF are diagnosed
each year with > 75% of these people with CF are diagnosed by second birthday. In
the UK CF occurs in around one in 2,500 live births and around 10,000 people in the
UK have CF (256).
Diagnostic Criteria
The diagnosis of CF is mainly made on the basis of clinical signs and symptoms and
a sweat test (252) and can now often be confirmed with genetic analysis. Rosenstein
et al, reported that diagnosis of CF requires one criterion from each of the following
two groups (257, 258):
Group one:
Two occasions of sweat chloride concentration of >60 mmol/L. Two genetic mutations causing CF.
Disturbed chloride transport measured as an epithelial potential difference.
Group two:
Family history of CF.
Positive new-born screening.
Clinical symptoms; recurrent chest infection, weight loss, diarrheal, constipation, steatorrhoea, coughing, short of breathing and pulmonary
exacerbations and a bowel obstruction in newborn (meconium ileus)
.
In UK, children with CF are usually diagnosed shortly after birth during the
newborn screen blood test with the diagnosis then confirmed by sweat and genetic
Evaluation of Disease Activity
Cystic fibrosis is a complex disease and the severity of disease differs between
patients. Contributing factors to disease variation include: age of diagnosis, an
individual's health, nutritional status and the course of the disease and treatment have
an important role in disease outcomes (259, 260). Thus, severity of disease provides a
guide for the physician to adapt therapies. The Shwachman-Kulczycki score was the
first score to assess the severity of CF (261). CF severity tools scores are mainly
focused on 4 groups of variables: physiology, infection, inflammation, and radiology
(262). Forced expiratory volume in 1 second (FEV1) is the typical measure of lung function and a key predictor of life expectancy in people with CF (263).
Treatments Options for Cystic Fibrosis
There is currently no cure for children with CF, and they may need to take a range of
different medicine to help control the symptoms and prevent or reduce complications
(259). Specific treatment plans for each child with CF should be determined by close
work between family and medical professionals based on several factors such as: child
age, health, medical history, extent of the disease and child's tolerance for specific
medications, procedures, or therapies (260). Treatment options may include: Chest
physical therapies to help loosen and clear lung secretions (264). Medical treatment
such as antibiotics - the main treatment of the lung infections; mucus thinning
medicines like dornase alfa that make the mucus easier to cough up (265, 266); bronchodilators and anti-inflammatories treatment help to widen the airways,
decrease the inflammation, reduce the mucus section in lung and make breathing
easier; management of digestive problems that include: appropriate diet, digestive
mucus, stimulate coughing, and improve overall physical condition. Finally, those
with CF may need psychosocial support to help them deal with issues such as
surviving with CF, independence, fertility, and sexual issues.
Cystic Fibrosis Complications
Serious complications include: lung complications like chronic obstructive bronchitis, recurrent chest infection with pseudomonas aeruginosa (267), pneumonia and destruction of the lung tissue, bronchiectasis, fibrosis and emphysema (255) leading to respiratory insufficiency and cor-pulmonale. At this stage lung transplantation is the only possible treatment option (268). Children with CF are also at risk of the following common complications: malnutrition and vitamin deficiencies (269), liver disease,
meconium ileus (affects 1 in 7 newborn live birth), deficits in bone mineral density,
reduced female fertility and male fertility (270).
Possible Disease Effects of Integrated Movement Behaviours in Children with Cystic Fibrosis
Several studies show that exercise and daily habitual PA can improve health-related
quality of life (271-274), pulmonary function and aerobic fitness, and help in improve
bone mineral density in patients with CF (256), as well as reducing the rate of
hospitalisation and (275, 276). PA may help in improving airway clearance by
increasing trans-epithelial fluid transport and raising ventilation (277). Moreover, an
active lifestyle in children with CF might reduce even prevent decline in lung function
(272, 278, 279). Therefore, several bodies have recommended a minimum of 60
minutes of MVPA every day for children with CF (30, 87, 256, 280), These
applicable to children and adolescents with chronic disease (39, 281). Further,
increased time spent in SB has been associated with increased risk of co-morbidities,
reduced quality of life and increased mortality rate in adult life (282). Collectively,
sleep in children with CF had been inadequate in term of duration and quality. Some
studies had noted that children with CF had short sleep with more sleep disturbance
compared to healthy (129, 283, 284); reasons of short sleep could related to delay of
sleep time with early of wake-up time (284) or might related to frequent awakenings
episodes and more wake after sleep onset (129) or combination of the two. Overall,
the lifestyles of children with CF might be less active and more sedentary with
inadequate sleep (poor quantity and quality), and the reason for these compared to
healthy children and recommendations, possibly related to disease symptoms or
characteristics such as coughing or pain, or due to treatment regimen which is usually
complex with multiple medications and airway clearance and physiotherapies that
1.4. Aims:
The aims of the present study were to:
1. Complete a systematic review and meta-analysis (Chapters III) examining
whether children and adolescents with chronic disease meet the current MVPA
recommendations (79, 80, 281). Secondary aims were to examine the amount
of accelerometer-measured ST in children and adolescents with chronic
diseases, and to determine whether accelerometer measured MVPA and ST in
children and adolescents with chronic disease were different from those in
healthy control or comparison groups. (Paper I).
2. To complete a systematic review (Chapters IV) to determine obese children’s
and adolescents’ habitual amount of time spent in MVPA, and examine whether those living with obesity met the current MVPA recommendation for
health of a minimum of 60 minutes per day (9, 30). Secondary aims were to
examine time spent in accelerometer-measured SB by obese children and
adolescents, and to determine whether MVPA and SB in obese children and
adolescents were different from the non-obese peers (Paper II).
3. To complete a study (Chapters VI) investigating the 24 hour-movement
behaviours (Sitting/lying, PA, standing, and sleep) for 5-7 days in children with
common chronic childhood diseases and test whether there were differences
between children with chronic disease and their healthy peers, and whether
both meet the current sleep duration recommendations (Manuscript submitted
4. To complete a study (Chapters VII) investigating sleep quantity – particularly
sleep timing (sleep onset/offset), and sleep duration - and sleep quality in
children with chronic diseases and test whether these aspects of sleep in
children with chronic disease differed from healthy controls and whether both