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

This research article investigates the association between physical activity and health-related quality of life in elderly individuals with pre-diabetes and adults with type 2 diabetes. The study design, operational definition, dependent and independent variables, confounding variables, validity, and sampling procedure are discussed. The article also proposes two possible research methods and designs to investigate the association between physical activity and HRQoL.

Running head: RESEARCH
Research
Name of the student:
Name of the University:
Author’s note

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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

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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

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Hypothesis: The research hypothesis was that people who meet recommendations for physical
activity will have better HRQLs compared to those who do not.
Research method and design: The research was done using data from the Alberta Caring for
Diabetes cohort study. Self reported questionnaire was mailed to patients living in Alberta and
physical activity level was measured using Godin Leisure Time Physical activity Questionnaire.
HRQL was assessed using the Medical Outcomes Study (MOS) 12-Item Short-Form Health
Survey version 2 (SF-12) and the 5-level EuroQol 5-Dimensions (EQ-5D-5L) questionnaire.
Operational definition: As the main purpose of the study was to examine the association
between physical activity recommendation and HRQL, participants were grouped into two
groups. The criteria was to assess whether they accrued 150 minutes of moderate-vigorous
physical activity (MVPA) or not. The association between physical activity and HRQL was
further assessed using multivariable linear regression models.
Dependent variables: HRQL is the independent variable for the study
Independent variable: Independent variable for the study included level of MVPA
Confounding variable: This included data on age, sex, ethnicity, annual house hold income,
employment status, smoking duration and number of co-morbidities.
Validity: The internal validity of the study is affected by the use of self-reported questionnaire
which increases the possibility of recall bias and affects the reliability of research outcome.
Another factor affecting the validity of the research is its research design. Although the study
used population based cohort study to select sample group, however use of cross-sectional data
influenced the credibility of the work. The research instruments used were all evidence based

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questionnaire. However, still possibility of bias has been found because research tool did not
collected objective data. Instead data was recorded by means of self-administered questionnaire.
Sampling procedure: The sample was selected using purposive sampling technique. The
English speaking individual with type 2 diabetes and older than 18 years was used as a criteria to
select research participants. The recruitment was done over the past 2 years and self-
administered questionnaires were mailed to those who gave consent for participation in research.
________________
Example research question: Does adequate amount of physical activity lead to better health
related quality of life for people?
Possible research methods and design: To get answers to the above research question, the
following research method could help to identify relevant association between the two variables:
1. Randomized controlled trial: Research participants can be randomly allocated to
physical activity group and those without physical activity. Physical activity group can be
engaged in recommended levels of physical activity and the control group work on their
own. After the implementation of the intervention, the assessment can be done regarding
change in health status and HRQoL of research participant using validated tool. The
primary outcome measure would be improvement in HRQL level.
Duration of the intervention: To show improvement in HRQoL, the intervention can be
implemented for at least six months period. This time is essential to ensure that structured
physical activity regimen is adequately acquired and adhered to by the research participants. By
this time period, people are likely to acquire health lifestyle gradually and understand the

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benefits of physical activity of weight loss, raised HDL cholesterol, low serum cholesterol,
glucose and blood pressure too. By keeping six months period, participants can be assessed at
baseline as well at six months follow-up. Hence, accurate data related to changes in HRQoL
following the intervention can be achieved.
Measurement of independent variable: The independent variable of physical activity and
compliance to the physical activity regimen needs to be measured too. This measurement will
depend on the type of physical activity implemented for the target population group. Devices like
pedometers can be used if the purpose is to track number of steps taken by a person each date.
The advantage of using this device is that it eliminates the risk of any bias as electronic data can
be monitored for individual client without any risk for misinterpretation of data.
However, if the physical activity intervention has many types of exercise or physical
activity routine, then self-assessment questionnaire can also be used to track improvement in
physical activity and adherence to the program. For example, in relation to conducting research
with the selected PICOT question, International Physical Activity Questionnaires (IPAQ) can
also be used to measure physical activity and track adherence to the program. IPAQ is a well-
recognized tool that consists of 4 questionnaires. This type of self-reported questionnaires mainly
measures the duration and frequency of physical activity. There are several advantage of using
such tools in research. This includes identifying different categories of physical activity level,
cost-effectiveness and ease of administration. However, the tool is dependent on participant’s
recall ability (Sylvia et al., 2013).
Method of measuring physical activity in the control group: Yes, physical activity in the control
group would be measured in the same way like that of intervention group because in an

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randomized controlled trial, all things should remain the same apart from the intervention.
According to Rosenberger and Lachin (2015), the credibility of a RCT trial is understood by the
equal treatment of groups in the trial. Hence, apart from the intervention and comparator
treatment, other things should remain the same for treatment and control group.
Details about the study population: To assess the impact of physical activity on health related
quality of life, I would take research participants with diabetes. The age group for the
participants will include 30-55 years. Participants with a common health issue have been taken to
evaluate the impact of physical activity on diabetes related outcome of patient. The main purpose
of implementing physical activity intervention is to reduce risk of disease and promote healthy
lifestyle in people. Hence, taking participants with a common illness would serve the purpose of
investigation.
2. Observational studies: Observational studies can also be used to assess the association
between physical activity and HRQoL. Merriam and Tisdell (2015) supports that well-
designed observational studies play a role in providing similar results like that of
randomized controlled trial. For example prospective study can be used to get answer to
the research question. Participants selected for the study may include people with
diabetes or in general adults with obesity. The participants for the study can be provided
with a 3 month individualized physical activity intervention and follow up related to
HRQoL can be taken by prospectively. To reduce the possibility of recall bias, two tools
can be used to collect data. The first will include COOP questionnaire tool for self-
assessment of HRQoL and the second will include analysis of physical fitness using 2-km
walk test.

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References:
Dusetzina, S. B., Brookhart, M. A., & Maciejewski, M. L. (2015). Control outcomes and
exposures for improving internal validity of nonrandomized studies. Health services
research, 50(5), 1432-1451.
Merriam, S. B., & Tisdell, E. J. (2015). Qualitative research: A guide to design and
implementation. John Wiley & Sons.
Rosenberger, W. F., & Lachin, J. M. (2015). Randomization in clinical trials: theory and
practice. John Wiley & Sons.
Sylvia, L. G., Bernstein, E. E., Hubbard, J. L., Keating, L., & Anderson, E. J. (2013). Practical
guide to measuring physical activity. Journal of the Academy of Nutrition and
Dietetics, 114(2), 199-208.
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
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