Physical activity and patient-reported outcomes during a two-year lifestyle intervention for severely obese adults: The Haugland study
Abstract
Severe obesity is a chronic condition, which is associated with impaired quality of life
and health hazards. The direct cause of obesity is an imbalance in energy intake and
expenditure over time, but the underlying mechanisms include a complexity of
individual, inter-relational, social, environmental, and political factors. The prevalence
of severe obesity is growing in the adult Norwegian population, and the condition
gives access to the specialist health services. One treatment option is multi-component
lifestyle interventions, which include physical activity, change of diet, and cognitive
behavioural therapy. Although physical activity is a cornerstone of such interventions,
it is sparsely studied. How physical activity may be associated with subjective
phenomena like psychological, predisposing factors or quality of life before and during
lifestyle interventions is not known.
Therefore, the purposes of the study were 1) to examine associations between physical
activity and quality of life outcomes prior to a lifestyle intervention, 2) to examine
associations between change in the three psychological, predisposing factors perceived
behavioural control over physical activity, self-efficacy for physical activity in the face
of psychological barriers, and physical activity identity and change in physical activity
during a two-year lifestyle intervention, and 3) to examine associations between
change in physical activity and change in quality of life outcomes during a two-year
lifestyle intervention.
The study was part of the Haugland Obesity Study, which was a two-year prospective,
observational study on severely obese adults participating in a multi-component
lifestyle intervention. Residential periods constituted 15 weeks in total at the Red
Cross Haugland Rehabilitation Centre, Western Norway. Inclusion criteria were age
between 18-60 years and body mass index (BMI) ≥ 40 kg/m2 with or without
comorbidities, or ≥ 35 kg/m2 with comorbidities. Exclusion criteria were: referral to,
or, previous obesity surgery, severe cardiovascular disease, pregnancy, alcohol or
substance abuse, and mental illness or physical impairment that would compromise
adherence to the intervention. Ethical approval was obtained from the Regional Committee for Medical and Health Research Ethics for South-East Norway
(registration number 2010/159a).
Multi-component lifestyle interventions were understood as health promoting
activities. The socio-ecological PRECEDE-PROCEED model and its theoretical
underpinnings inspired the understanding of the processes of change, the associations,
and outcomes.
Physical activity was assessed using the ActiGraph GTIM accelerometer (ActiGraph,
Fort Walton Beach, FL, USA). The unit counts per minute was used for level of
physical activity. Psychological, predisposing factors were measured using
questionnaires on perceived behavioural control over physical activity, self-efficacy
for physical activity in the face of psychological barriers, and physical activity
identity. Quality of life was measured using a one-item question on life satisfaction,
the Medical Outcomes Study Short-Form 36 Health Survey (SF-36), and the ObesityRelated
Problems Scale (OP). Anthropometric data were collected by health staff.
Socio-demographic information was obtained from questionnaires. Data collection
took place four times: before, during, and at the end of the intervention between
February 2010 and October 2012.
A linear mixed model based on restricted maximum likelihood estimation with random
intercept for subjects was used in analyses for change over time, using least significant
difference from baseline. Linear regression analyses were performed to examine
associations between variables. Gender, age, and (change in) BMI were used as
control variables in the regression analyses.
Forty-nine individuals (37 women; 43.6 ± 9.4 years; BMI 42.1 ± 6.0 kg/m2
) consented
to participate in the study. At year two, 44.9% were lost to follow-up. Attrition
analyses did not reveal differences between completers and non-completers.
Regression analyses revealed that 1) level of physical activity was positively and
independently associated with life satisfaction and physical functioning (obtained from SF-36) but not mental health (obtained from SF-36) prior to the intervention, 2)
change in perceived behavioural control was positively and independently associated
with change in physical activity during the two years, but self-efficacy and physical
activity were not, and 3) change in physical activity was positively and independently
associated with change in life satisfaction, the physical and mental component
summary scores of SF-36, and obesity-specific quality of life.
The conclusions were that perceived behavioural control may be a valid target for
increase of physical activity in multi-component lifestyle interventions, and that
improvements in quality of life may have the potential to operate as a long-term
motivational factor for physical activity in lifestyle interventions for severely obese
adults. The findings should be further examined in larger samples and different
settings, and should preferably include establishment of a control group. The impact of
extra-personal factors on change of physical activity behaviour should also be
examined in recognition of the complexity of factors influencing individual healthrelated
behaviour.
Description
Dissertation for the degree philosophiae doctor (PhD) at the University of Bergen 2015.
Dissertation date: 15.04.2015
Has parts
Paper I: Jepsen R, Aadland E, Andersen JR, and Natvig GK. Associations between physical activity and quality of life outcomes in adults with severe obesity: a cross-sectional study prior to the beginning of a lifestyle intervention. Health and quality of life outcomes 2013;11(1):187. DOI: 10.1186/1477-7525-11-187Paper II: Jepsen R, Aadland E, Robertson L, Kristiansen M, Andersen JR, and Natvig GK. Factors and associations for physical activity in severely obese adults during a two-year lifestyle intervention. PeerJ 2014;2:e505. DOI: 10.7717/peerj.505
Paper III: Jepsen R, Aadland E, Robertson L, Kolotkin RL, Andersen JR, and Natvig GK. Physical activity and quality of life in severely obese adults during a two-year lifestyle intervention programme. Journal of Obesity. Accepted 23 December 2014. DOI: 10.1155/2015/314194