Sampling Frame and Disease Risk Assessment in Epidemiology

This article discusses the sampling frame for the Whitehall study and disease risk assessment methods used in epidemiology. It also covers the generalization and feasibility of the results and limitations of the studies. The subject is epidemiology, and the course code and college/university are not mentioned.

Running head: EPIDEMIOLOGY
Assessment 2
Name of the Student
Name of the University
Author Note

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Sampling frame for each phase of the Whitehall study
Sampling frame commonly refers to the source devise or material from which samples
are drawn. Thus, sampling frame incudes a list of individuals/houses/institutions that can be
sampled, within a population. The Whitehall study I included a sample that was selected from
British civil servants, all male during the 1960s. Approximately 19029 men from the selected
population, all aged between 40-69 years were recruited for investigation between the 1967-
1970s, for identifying the risk factors that lead to the incidence of cardiovascular diseases. No
women were included in the sampling frame for the first study. The Whitehall study II
selected participants from a new sampling frame that comprised of 10314 British civil
servant, comprised of men and women, aged 35-55 years. The cohort for the second study
included 3414 women and 6900 men. This study was conducted from 1985-1988 and
investigated the cause and degree of social gradients in morbidity in the new cohort.
Disease risk assessment
The study conducted by Breeze et al., (2001) resurveyed 400 survivors of the pilot
study conducted in 1997-1998. Data collection was conducted by distributing questionnaires
to the individuals that included questions on retirement and socioeconomic status, diagnosis
of diseases, and ability to carry out daily activities. Thus, the researches assessed the disease
risk by collecting information on 4 aspects of self-reported morbidity that encompassed poor
physical performance, mental health, general health and disabilities. Data analysis was
conducted by chi-square tests for determining univariate associations between the aspects.
Odds ratio estimation was done with the use of a logistic regression model.
Marmot et al., (1978) collected data for assessing the risks of coronary heart disease
by distributing London School of Hygiene Cardiovascular Questionnaire that focused on
several items, including employment grade. Use of this questionnaire can be cited as a correct

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method for defining the risks that might predispose a person to cardiovascular disorders such
as, angina pectoris. Putting forth questions related to respiratory symptoms, smoking history,
leisure activities, medical treatment and ECG were an effective data collection method. Data
analysis was conducted by age adjustment and multivariate analysis that involved an
observation and analysis of several statistical outcomes at one time. Calculation of the
relative increase in risks for major factors was an appropriate step for risk assessment.
The study conducted by Chandola et al., (2007) collected data for evaluating the
association between heart disease and work stress with the use of the job-strain questionnaire.
Use of this self-assessment questionnaire helped to determine the psychological and social
characteristics of the jobs that the respondents were engaged in. This helped to evaluate the
relative risk of exposure to different work setting for predicting coronary heart disease and
job related distress. Adding cumulative measures of work stress and use of the Cox
proportional hazard regression model helped to determine association between stress and
cardiovascular events.
Generalisation of results
Generalisation involves the process of drawing inference from certain observations
and is acknowledged as a major standard of quantitative research. The results of the findings
by Breeze et al., (2001) can be generalised to the entire population since multimorbidity was
found prevalent among individuals belonging to the lower socioeconomic sections of the
society. Owing to the fact that socioeconomic status creates an impact on the morbidity and
disability status of individuals, the findings that illustrated an association between SES in
retirement, disadvantage accumulation and poor health status can be generalised to a larger
population.

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The results by Marmot et al., (1978) can also be generalised since it established a link
between grade of employment and risks of cardiovascular diseases. Owing to the fact that
employment condition is a major social determinant of health, poor employment status will
lead to poverty and increase the chances of suffering from poor health.
Association between work related stress on CHD, as stated by Chandola et al., (2008)
can also be generalised since heavy workload, job insecurity and conflicts have already been
identified as psychological risk factors that increase the susceptibility of suffering from heart
disorders.
Feasibility
Feasibility of studies refer to practicality of certain methods or plan. The 45 and Up
cohort can be selected for conducting a risk assessment of cardiovascular disease. The cohort
was comprised of one in 10 men and women from the NSW, aged over 45 years. The cohort
was built with the aim of investigating healthy aeging among the selected individuals. Risk
assessment of cardiovascular diseases can be conducted among the cohort by distributing
self-reported questionnaires, since men have been found at a risk of CVD above 45 years of
age. However, prevalence of CVDs among women aged more than 55 years, might produce
bias in the results.
Moreover, lack of availability of clinical diagnostic results will also limit the
feasibility of the cohort. Use of the Australian Longitudinal Study on Women’s Health is not
reasonable since the new cohort formed in 2012-13 included 17000 women aged 18-23 years
and determined their physical and mental health, in addition to lifestyle factors and socio-
demographic factors. Unlikelihood of using this cohort for determining the risks of CVDs can
be established by the fact that only 4-10% of heart diseases occur before the age of 45.
Moreover, heart attacks and other cardiovascular abnormalities are twice as common in males

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as females, during the lifespan. Considering the fact that the cohort takes into account only
females, the results are likely to be biased upon conduction of the study.
Limitations
Ill health preceding low socioeconomic status, cumulation of psychological stress, and
material resource disadvantage could have resulted in variations in the outcomes of the
baseline and resurvey (Breeze et al., 2001). Limitations of the second research were
associated with self-selection of men belonging to the low employment grades that might
have resulted in obtaining stronger mortality gradient among the respondents (Marmot et al.,
1978). Other limitations were related to lack of consideration given to leisure related physical
activities, since the study was primarily based on men working in physically undemanding
occupations. Missing data in the Whitehall cohort, based on which the third study was
conducted was another major limitation that might have resulted in bias in the results that
showed association between work related stress and coronary heart disease (Chandola et al.,
2008).

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References
Breeze, E., Fletcher, A. E., Leon, D. A., Marmot, M. G., Clarke, R. J., & Shipley, M. J.
(2001). Do socioeconomic disadvantages persist into old age? Self-reported morbidity
in a 29-year follow-up of the Whitehall Study. American journal of public
health, 91(2), 277.
Chandola, T., Britton, A., Brunner, E., Hemingway, H., Malik, M., Kumari, M., ... &
Marmot, M. (2008). Work stress and coronary heart disease: what are the
mechanisms?. European heart journal, 29(5), 640-648.
Marmot, M. G., Rose, G., Shipley, M., & Hamilton, P. J. (1978). Employment grade and
coronary heart disease in British civil servants. Journal of Epidemiology &
Community Health, 32(4), 244-249.