Research on Association between Physical Activity and Health-Related Quality of Life

Running head: RESEARCH
Research
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1RESEARCH
Article 1:
Xu, H., Tang, L., Hu, Z., Gao, F., Yang, Y., Qin, L., & Luo, B. A. (2018). Association between
physical activity and health-related quality of life in elderly individuals with pre-diabetes in rural
Hunan Province, China: a cross-sectional study. BMJ open, 8(4), e019836. doi:10.1136/
bmjopen-2017-01983
Hypothesis: The research hypothesis was that physically active elderly individuals with
prediabetes would report higher HRQoL (health related quality of life) scores compared to those
who are physically inactive.
Research method and design: Cross sectional study design was used to investigate the relation
between HRQoL and physical activity among elderly individuals with prediabetes in rural China.
The research was conducted in rural areas of Yiyang city of Hunan province and representative
sample was selected by means of a screening programme.
Operational definition: A multistage cluster randomized sampling method was used to select
participants for the study and fasting blood glucose level for each participant was analyzed to
select individuals with prediabetes. HRQoL assessment for sample group was done using 36-
item Short Form Health Survey and the International Physical Activity Questionnaire was used
to assess physical activity. Total physical activity was calculated using sum of walking and
intensity of physical activity scores.
Dependent variable: Healthy related quality of life
Independent variables: Physical activity among elderly individuals

2RESEARCH
Confounding variables: Sociodemographics and anthropometric measurements like height,
weight, hip circumference, waist circumference and blood pressure.
Validity: Internal validity of a research is dependent on factors like selection bias, confounding
factors and lack of reliability of research instruments or tool. As self-administered questionnaires
were used for assessment of physical activity and HRQoL, there is a possibility of recall bias.
Recall bias is a major threat to the internal validty of a research (Dusetzina, Brookhart &
Maciejewski, 2015). Another factor influencing the internal validity of the study includes lack of
consideration of intensity and domain of physical activity. Evaluating this aspect was important
because different domains of physical activity also have an impact on HRQoL. In addition, use
of cross-sectional research design is also a major limitation as it failed to give idea regarding the
causal relation between the two variables. However, the study is generalisable because large
samples are used
Sampling procedure: Multistage cluster randomized sampling method was used to select
samples for the study. In the first stage, two countries were selected, in the second stage
township was selected. This was followed by selection by village and by means of elderly people
in the village.
Article 2:
Thiel, D. M., Al Sayah, F., Vallance, J. K., Johnson, S. T., & Johnson, J. A. (2017). Association
between physical activity and health-related quality of life in adults with type 2
diabetes. Canadian journal of diabetes, 41(1), 58-63.
http://dx.doi.org/10.1016/j.jcjd.2016.07.004