Introduction to Epidemiology: HPV, Cervical Cancer, and Public Health

This assignment solution delves into the epidemiology of human papillomavirus (HPV) and its connection to cervical and bladder cancer. It explores calculating and interpreting positive predictive values in screening programs, emphasizing the selection of appropriate tests like cytology. The document also addresses the importance of considering HPV-vaccinated women in screening, adjusting screening ages, and the impact of false-negative outcomes. Furthermore, the assignment examines primary and specific prevention strategies, analyzes odds ratios related to bladder cancer risk, and discusses the latent and incubation periods of infectious diseases. It also covers sentinel surveillance, disease control measures, and confounding factors. The solution provides a comprehensive overview of epidemiology principles related to HPV and cancer prevention, offering valuable insights into public health strategies and risk assessment.

INTRODUCTION TO
EPIDEMIOLOGY

TABLE OF CONTENTS
INTRODUCTION...........................................................................................................................1
QUESTION 1...................................................................................................................................1
a. Calculating positive predictive value (PPV).......................................................................1
b. Interpretation of the value of PPV......................................................................................2
c. Stating the test which needs to be selected for the purpose of screening...........................2
d. Presenting the test needs to be administered for screening program..................................2
e..............................................................................................................................................2
f...............................................................................................................................................2
QUESTION 2...................................................................................................................................3
QUESTION 3...................................................................................................................................3
QUESTION 4...................................................................................................................................3
QUESTION 5...................................................................................................................................4
QUESTION 6...................................................................................................................................5
QUESTION 7...................................................................................................................................5
QUESTION 8...................................................................................................................................5
QUESTION 9...................................................................................................................................6
QUESTION 10.................................................................................................................................6
QUESTION 11.................................................................................................................................6
CONCLUSION................................................................................................................................6
REFERENCES................................................................................................................................7

INTRODUCTION
Epidemiology refers to studying and examining causes, patterns and effect of chronic
disease conditions. In healthcare studies, it helps to make effective policy decisions and practices
by detecting risk causing factors and targeted at introducing preventive healthcare. Thus, it is
primary concerned with studying the determinants of health-related events and use its results to
introduce the best solution for controlling and preventing the healthcare problems. HPV
particularly HPV-16 & HPV-18 are the types of virus that causes cervical cancer. Thus, the
current study targeted at exploring key issues surrounding human papillomavirus (HPV).
QUESTION 1
a. Calculating positive predictive value (PPV)
On the basis of cited case situation, by using the values of cytology positive predictive
value has been calculated. Further, given case scenario presents that prevalence of cervical
cancer in the women accounted for 0.6 or 60%. By considering this, it has been assessed that
women who have disease of cancer implies for 60, whereas remaining fall into the category of
non-disease. Further, sensitivity and specificity accounts for 61.6% & 96%.
G
Disease Non-disease Total
Positive True positive (a) 37 False positive (FP) 2 39
Negative False negative ©
23
True negative (TN) 38 61
Total Total diseased
(a+c) 60
Total normal (b+d) 40 100
NPV = sensitivity * (1 – prevalence) / (1 – sensitivity) * prevalence + specificity * (1 –
prevalence)
PPV = sensitivity * prevalence / sensitivity * prevalence + (1 – specificity) * (1- prevalence)
A / (A + B) * 100
= 37 / 39 * 100
= 95%
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b. Interpretation of the value of PPV
By doing assessment of positive predictive value, it has been identified that 95% is the
probability in relation to the subjects that have positive screening. Hence, it has been assessed
that women who truly have disease of cancer accounted for 95%.
c. Stating the test which needs to be selected for the purpose of screening
In order to identify positive predictive value, cytology aspect is considered. The rationale
behind the selection of element is that it provides high level of assistance in testing the level or
diagnoses cancer. In the context of cytology, with the motive to diagnose disease high level of
emphasis is laid on single cells and small clusters (Types of cytology tests used to look for
cancer, 2017). Cytology provides high level of assistance in diagnosing some specific types of
cancer. This is one of the main reasons due to which screening test is performed by taking into
account the aspect of cytology.
d. Presenting the test needs to be administered for screening program
In the context of future screening, there is a need to consider HPV vaccinated women
because such aspect does not protect against HPV which is one of the major causes of cervical
cancer (The Renewed National Cervical Screening Program, 2017). Thus, this factor or element
needs to be considered which in turn provides high level of assistance in assessing the extent to
which women are suffering from the disease of cervical cancer.
e.
By doing assessment, it has been identified that the age of screening needs to be inclined
from 18 to 25 years. Along with this, women who are in the age of 70 to 74 years also need to be
invited because they also have greater chances in relation to cancer. Along with this, by
including HPV vaccinated women, analysts would be able to fair view in relation to women who
are suffering from cancer.
f.
[D] If the inadequate collection of cell, inflammatory cells obscuring abnormal cells
which increases the rate of False Negative outcomes in Screening test that there will be Negative
Predictive value for such screening test. Hence, it will influence the causes for cancer as well as
it will affect the large numbers of population. Thus, the test in-able people for getting the
adequate information which are in context with making the improvements in educational level as
well as lowering down the risks of such diseases.
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“Pap smear” also known as pap test which is a method of testing cervical cancer in
women. The process includes collection of cells from lower, narrow and end uterus. Thus, the
result may give negative prediction if inadequate and small number of cells are collected.
Moreover, inflammatory cells obscuring abnormal cells improve the risk of negative results.
QUESTION 2
In accordance with preventing the cervical cancer in the state there is need to monitor
primary outcome by providing vaccination, facilitated to Women at risk. Hence, [C] is the
appropriate answer for such question. Thus, it is a sexually transmitted infection mainly caused
in women.
QUESTION 3
[1] Primary Prevention: HPV prevention is a kind of primary prevention as it is the first
vaccination introduced to prevent people from cancer. It is considered as one of the most
powerful and effective method to fight against cancer.
[2] Example of Specific Prevention: HPV screening including Pap smear cytology test
and HPV PCR test are the example of specific prevention. The key aim of the HPV screening is
to find out abnormal cells which can develop into cancer if they are not treated properly and
timely.
QUESTION 4
A.
In the study, overall 19 cases with 926 bladders cancers and 219 control cases were being
studied. In the forest plot, 2 automatically excluded because of the absence of HPV in both the
cases and control. However, out of remaining seven, only 1 study conducted by Shibutani depict
negative (opposite) relationship at odds ratio of 0.25(CI @ 95%, 0.09 – 0.65). However, all the
remaining 16 studies found positive relation by indicating that HPV infection increases the
chance of bladder cancer or vice-versa. It is because, in the forest plot, all line crossed “line of
null effect”.
B.
Overall odds ratio is determined to 2.84 (CI, 1.39 – 5.80) which reported statistically
significant relationship between HPV infection and possibility of bladder risk. In other words,
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people with HPV infection have high risk of bladder cancer compared to the people who are not
HPV infectious.
C.
No, it is not appropriate to use the overall summary estimate of odds ratio to interpret the
results for assessing association between both the variables. It is because, it provides combined
results by pooling all the individual studies together. Thus, it might be possible that an individual
study does not show significant relationship between HPV infection and bladder risk but have a
significant influence over pooled result which is not considered by overall odds ratio. In the
study, it can be seen that 1 study at OR 0.25 (CI @ 95%, 0.09-0.65) did not show favourable
relationship, still, it has a significant influence by having a weight of 8.51% on pooled results.
D.
Heterogeneity have been tested by χ2 value under Q test and found significant if, it is
less than 0.05 (P<0.05) or vice-versa. Taking into consideration its results, random effect model
was applied to examine pooled results of odds ratio. Heterogeneity has been derived for HPV
type, histological type, and HPV DNA detection method, date of publication, region and DNA
specimen (Li and et.al., 2011).
E.
Newcastle-Ottawa Scale (NOS) might be used by the authors to examine the quality of
studies used in the research. It helps to evaluate design, content validity and ease of use for meta-
analysis and found best in case-control studies.
QUESTION 5
Latent Period took Long time than Incubation than there will be chances of passing of
infection over people before they become sick because it is the initial symptoms of a viral
infection. Hence, this disease starts from the point when the pathogen enters in the host which
reflects the moment of exposure. Thus, after such event Pathogen starts to move towards the
targeted organs hence, such incidents incurred the Legionella which will target lungs. Moreover,
the person will suffer from the lung cancer as the lungs get highly damaged due to such longer
period. Hence, the duration between Exposure and Infection will be known as the Latent time
which describes that there will be infection in the hosts while on the other side the period
between Onset and exposure of the clinical Symptoms are known as Incubation period in which
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there are chances of hosts to get infection (Incubation period, Latent period and Generation
time, 2017). Hence, it all depend over the movement of Pathogen which varies in different stages
or various levels.
QUESTION 6
[a] in context with the department of health set up HIV providing Antenatal care clinics
are worked as a Sentinel Surveillance. Hence, this in turn helps in preventing the life-threatening
diseases in India such as HIV AIDS which are denoted as the high rated risks for patients who
are suffering from diseases. Thus, this organisation or health and care scheme helps in
facilitating information to understand and obtain essential knowledge in relation with managing
such risk as well as adequate factors to control such risk. Hence, it improves the attention of
popularization in context with preventing them from such serious diseases. Hence, such
prevalence was based on the mortality, incidence over the findings from HIV Sentinel
Surveillance program which were operated at mass level. However, the surveillance program
incurred only twice in the year which will be helpful in having the in-depth analysis and
modelling (McConnico and et.al., 2017). The use of Surveillance data as well as Epidemiological
Research are utilised for operational tasks which in turn made surveys over the large numbers of
population specially women in context with educating them towards HIV and the relevant
diseases.
QUESTION 7
[C] This infectious disease control measures are not directed by eliminating the host.
Hence, it will be due to the disease controls measurements which are directly eliminating the
Reservoir or Vectors, interruption transmission which in turn helps in protecting the host but did
not eliminate it (Gervasi and et.al., 2017).
QUESTION 8
[B] In consideration with preventing the primary stage of disease there must be selection
of the risk factors which are most Prevalent in the mass people. Hence, it will be concluded that
the diseases caused by two modifiable risk factors which are most prevalent in population so this
will be the necessary to control such operations (Blencowe and et.al., 2016).
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QUESTION 9
[D] The Attributable burden of a disease due to risk factor is always larger than the
burden due to other risk factors. Hence, it is due to preventing the infections from such life-
threatening diseases (Yang and et.al., 2016). Thus, in accordance with the Global Burden of
Disease which have transformed global understanding as well as helps in producing the high
attributable burden diseases over the current burden as if the risk factors do not exist.
QUESTION 10
[A] Confounding occur when a diseased individual is exposed in the group which are
differed in the important ways from the unexposed group. Hence, the confounding factors may
result in high risk coronary heart diseases which are generally caused by smoking and alcohol
consumption. Thus, such disease affects in observing the variations within population even when
no certain variation exists. It affects the underestimation of such effects as well as over
estimation of several effects (Greenland, Daniel and Pearce, 2016). However, it can be said that
it will generally occur when the exposure of the disease among the population group which
results in spreading the disease very promptly.
QUESTION 11
[C] The publication bias exists under-estimation of association in between outcomes and
exposures. Thus, in Urology the Meta analyses brings systematic reviews for well designing and
executing the randomized controlled trials which facilitated the high level of evidence in context
with supporting the Therapeutic interventions and Diagnostics. Hence, it can be said that the
publication of the bias exists within meta analysis or systematic reviews are commonly results in
under estimation of the exposure on such outcomes.
CONCLUSION
On the basis of above study, the epidemiology facilitated the analysis of pattern and
causes of health diseases in the population. Hence, it will also help the individuals in making the
productive efforts for identifying the risk factors of such targeted diseases. Hence, which in turn
will be beneficial for the Government of various nations in making the preventions from such
obstacles. Further, with the help of screening tests a person will be helpful in obtaining the
adequate treatments and preventions from such problems.
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REFERENCES
Books and Journals
Blencowe, H. and et.al., 2016. National, regional, and worldwide estimates of stillbirth rates in
2015, with trends from 2000: a systematic analysis. The Lancet Global Health. 4(2).
pp.e98-e108.
Gervasi, S. S. And et.al., 2017. Linking Ecology and Epidemiology to Understand Predictors of
Multi-Host Responses to an Emerging Pathogen, the Amphibian Chytrid Fungus. PloS
one. 12(1). p.e0167882.
Greenland, S., Daniel, R. and Pearce, N., 2016. Outcome modelling strategies in epidemiology:
traditional methods and basic alternatives. International journal of epidemiology. 45(2).
pp.565-575.
McConnico, C. and et.al., 2017. Systems Mapping of Sexually Transmitted Infection Services at
Three Clinical Sentinel Surveillance Sites in South Africa: Opportunities for Integrated
Care. Journal of the Association of Nurses in AIDS Care. 28(1). pp.154-164.
Yang, J. and et.al., 2016. The burden of stroke mortality attributable to cold and hot ambient
temperatures: Epidemiological evidence from China. Environment international. 92.
pp.232-238.
Online
Incubation period, Latent period and Generation time. 2017. [Online]. [Available
through] :<https://wiki.ecdc.europa.eu/fem/w/wiki/incubation-period-latent-period-and-
generation-time>.
The Renewed National Cervical Screening Program. 2017. [Online]. Available through:
<http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/content/future-
changes-cervical>.
Types of cytology tests used to look for cancer. 2017. [Online]. Available through:
<https://www.cancer.org/treatment/understanding-your-diagnosis/tests/testing-biopsy-
and-cytology-specimens-for-cancer/cytology-types.html>.
PDF
Li, N. and et.al., 2011. Human Papillomavirus Infection and BladderCancer Risk: A Meta-
analysis.. [PDF]. [Available through]
:<https://www.ncbi.nlm.nih.gov/pubmed/21673031>.
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