Association between Alcohol Consumption and Cardiovascular Disease

This study aims to establish the association between alcohol consumption and cardiovascular disease development. It explores the different phenotypes of cardiovascular diseases and their correlation with alcohol consumption. Previous research articles are used to provide background information and address unanswered questions.

Cardiovascular Disease
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Introduction:
It is evident that association between the alcohol consumption and development of
cardiovascular disease is complex and controversial. Previously numerous systematic reviews
and meta-analysis were published to establish association between the alcohol consumption
and development of cardiovascular disease. Most of the studies established that non-drinking
population exhibited better cardiovascular health profile as compared to the alcohol drinking
people. Moreover, these studies also established grading like moderate and severe
cardiovascular diseases based on the amount of alcohol consumption. Alcohol consumption
at the moderate and high level produced moderate and high risk of morbidity and mortality
due to cardiovascular diseases. Cardiovascular diseases are complex diseases comprising of
different phenotypes. However, most of the studies put efforts to establish association
between the alcohol consumption and cardiovascular disease development. Very few studies,
were carried to out to establish association between the cardiovascular diseases with different
phenotypes and alcohol consumption. However, some of the studies has not been completed
yet. Moreover, some electronic database revealed that there is heterogenous association
between the alcohol consumption and cardiovascular disease development. It indicates there
can be robust association between the alcohol consumption and different phenotypes of the
cardiovascular diseases (Bell, Kivimäki, and Batty, 2015). Hence, this study was undertaken
with large pool of data to establish association between the alcohol consumption and
cardiovascular disease.
In this research, multiple research articles were used which have significant importance to
understand the background of the study, to establish objectives of the study and address the
questions which remain unanswered in the previous studies. Previously published article on
the current research topic would be helpful in improving information related to research
topic, filling the research gap, opening up questions which were not addressed previously,
identifying requirement of further research and placing the current research in the context of
existing literature. Articles which report association between the alcohol consumption and
cardiovascular diseases are important in this research because these articles are helpful in
addressing the research question (Mukamal and Rimm, 2008; Roerecke and Rehm, 2012;
Roerecke and Rehm, 2014). Previous article can be also be useful for identifying themes for
further literature search and determining the robust end point for incorporation in the
research. Existing articles can also be useful in the identification of accurate key words. This
study was developed based on the literature search. Identification of key words is most
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significant aspect in this study for further research. Existing articles proved helpful in
comparing and contrasting existing research, which helped in developing objective of the
current research. Previous research articles helped in sharpening the research focus (Movva
and Figueredo, 2013; O’Keefe, Bybee, and Lavie, 2007; Brien, Ronksley, Turner et al., 2011;
Mathews, Liebenberg, and Mathews, 2015).
Previously published articles were used as basis for this study because these articles provided
following information : information related to the risk and benefits of alcohol consumption in
cardiovascular patients, relationship of drinking pattern and amount of alcohol with
cardiovascular diseases, association of alcohol consumption with the selective and non-
selective cardiovascular diseases, effect of alcohol consumption on the biological markers of
the cardiovascular diseases, mechanisms of alcohol consumption for the development of
cardiovascular diseases and effect of alcohol consumption of cardiovascular disease burden.
Information collected from the previously published articles is useful in deciding various
measures for this study. These measures includes : selection of 12 cardiovascular diseases
with different phenotypes, selection of patients with different drinking pattern, differentiation
of patients based on quantity of alcohol consumption and categorising of patients as current
drinkers, previous drinkers, chronic and occasional drinkers (Fernández-Solà, 2015;
Mukamal and Rimm, 2008; Roerecke and Rehm, 2012; Roerecke and Rehm, 2014; Ronksley,
Brien, Turner et al., 2011).
This study was based on the results of previous research. Previous research provided
background for developing clinical research question. Previous research was associated with
certain limitations. These limitations include whether it is necessary to consider current
drinkers, previous drinkers and moderate drinkers. In most of the studies, it was not clarified
whether reported results were due to consideration of specific type of drinkers or combination
of the different types of drinkers. There is possibility of overestimation of prevalence of
cardiovascular disease, if previous drinkers and current drinkers are merged together.
Though, previous drinkers develop cardiovascular disease; its phenotype would be definitely
different from the phenotype of the cardiovascular disease developed due to current alcohol
drinking. Moreover, in previous studies it has been established that onset of the
cardiovascular condition is associated with the reduced or stopped consumption of the
alcohol. Hence, non-drinkers can be considered are at risk of cardiovascular conditions
development. Moreover, previous studies established that moderate alcohol consumption can
prevent certain cardiovascular diseases. Hence, these studies underestimated association
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between the alcohol consumption and cardiovascular disease. Most of these findings are
confounding. It is necessary to address all these questions to establish robust association
between the alcohol consumption and cardiovascular disease. It is essential to consider both
agreements and disagreements from the previous studies for building current studies.
Agreements and disagreements in the previous studies might be due to certain limitations of
the studies like lack of expertise researchers, inadequate discussion among researchers and
improper interpretation of the findings (Berkman, Sheridan, and Donahue, 2011). Moreover,
recruitment of inadequate number of participants might lead to disagreement or deviation
from the existing theory and practice (Liu, Shen, and Ning, 2017). Hence, all these aspects
were addressed in this study to make agreement on findings from the previous studies.
It has been hypothesized that higher alcohol consumption is associated the development of
cardiovascular diseases with different phenotypes.
This study is beneficial in improving both basic and scientific knowledge; however, this is
not useful in providing applications to solve practical problems. This study is useful in
improving the scientific and clinical knowledge about the different phenotypes of
cardiovascular diseases. Accurate correlation between the different categories of the alcohol
consumption and cardiovascular diseases can be understood (Orozco-Beltran, Gil-Guillen,
and Redon, 2017). It is also useful in improving the knowledge about the distribution of
cardiovascular diseases among different grades of alcohol consumption. This study provides
information related to the correlation between the alcohol consumption and its association
with cardiovascular diseases; however, it does not provide information about the mechanism
of alcohol in producing cardiovascular diseases with different phenotypes. This study
improves knowledge about the endpoints for the development cardiovascular diseases.
Knowledge about the differential endpoints of the cardiovascular diseases with different
phenotypes is important because most of the cardiovascular diseases are with overlapping
symptoms (Prabhakaran, Jeemon, and Roy, 2016). This knowledge facilitates accurate
correlation of the alcohol consumption and cardiovascular diseases with different phenotypes.
Since, this study was conducted through recruitment of large number of participants; this
study can be used as prototype study for conducting future studies with enrolment of large
number of participants. One of the major hurdle in conducting study with large number of
participants is to collect data for the large number of participants. Hence, this study provided
the solution for collection of data for the large number of participants. This study suggested
that electronic data from the previously conducted or ongoing studies can be utilised.
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Methods:
In this study, implemented study design was population-based cohort study. This cohort study
is linked to the electronic health records of primary care, hospital admissions and mortality in
1997 – 2010. Setting selected for this study was CALIBER (ClinicAl research using LInked
Bespoke studies and Electronic health Records). In this study, temporal association between
the alcohol consumption and development of cardiovascular diseases should be explored.
Hence, population-based cohort study is appropriate study design for this study because this
study provides temporal sequence between the exposure and outcome. Subjects are
considered as the disease free prior to exposure and their diseased status assessed after the
exposure. In cohort studies, subjects are categorised into diseased and non-diseased and
collected information related to their prior exposure. These types of studies are useful in
establishing relationship between the past exposure and diseased state (Song and Chung,
2010). In the current study also, association of past drinkers and cardiovascular diseases
should be established because it has been established that stopping of alcohol drinking lead to
the onset of the cardiovascular disease. However, these types of designs can give cofounding
finings because subject might not provide accurate information about the past exposures
(Sessler and Imrey, 2015a). In this study, incidence of cardiovascular disease with different
phenotypes should be established with alcohol consumption. Cohort studies are beneficial in
calculation of incidence through calculation of absolute risks (incidence), relative risk (risk
ratio or rate ratio), risk difference and attributable proportion (attributable risk %). Absolute
risk or incidence can be effectively calculated in this study with respect to the alcohol
exposure and respective phenotype of the cardiovascular disease (Sessler and Imrey, 2015b).
Relative risk ratio can be calculated in this study to differentiate between risks of
cardiovascular diseases for subjects with non-drinkers, previous-drinkers, occasional
drinkers, moderate drinkers and high-drinkers. Calculation of the relative risks is helpful in
eliminating the risk of wrong calculation because risk can be calculated individually instead
of calculating combined risks. Calculation of risks as the combined risk can overestimate
prevalence of the disease. Cohort studies are useful in establishing relationship between the
rare exposures and diseases state. Cohort studies are useful in establishing association
between single exposure and multiple outcomes. In the current study also, it is essential to
establish relationship between alcohol consumption and cardiovascular diseases with
different phenotypes. Selection bias can be effectively eliminated in cohort studies.
Possibility of biased results is less in cohort studies because outcomes of exposures might not
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be in the favour of participants; moreover, outcome is not evident at the baseline (Boyko,
2013).
Though cohort study design is appropriate for this study, this study design is associated with
certain limitations. In this study, large number of subjects should be followed for the longer
duration. Since, this is a long duration study; multiple resources are necessary. Hence, this
study was expensive and time consuming. This study design is beneficial in recruitment of
large number of subjects. Hence, subjects with heterogenous characteristics can be recruited
to obtain variable outcome. Large sample size is the significant component of this study
because it would be difficult to identify multiple risk factors in a study with smaller
population size (Berbano and Baxi, 2012). Data was retrieved from the validated electronic
health record databases; hence, it proved further validity of the findings of the study.
Acceptability and generalizability of the collected data would be more, if data collected
through the validated database (Wells, Gupta, Smith et al., 2019). Cohort usually is a group
of people who does not have the disease at the start of the study. Hence, groups with different
characteristics can be corelated with the disease severity and intensity. In this study also,
groups with different traits like non-drinkers and former and occasional drinkers can be
corelated with respective cardiovascular disease severity and intensity. It is necessary to
differentiate current non-drinkers in non-drinkers and former and occasional drinkers because
there is possibility that non-drinkers and former and occasional drinkers exhibit different
disease severity and intensity. Hence, accurate outcome can be obtained for each class of
people. Alcohol consumption produces health effects for the longer duration. Hence, this
study is more beneficial in this case because this study identifies effects on current drinkers
and previous drinkers.
In this study, large number of participants (1 937 360) were recruited. These large number of
participants with variable traits of alcohol consumption would be helpful in obtaining large
pool of data. Moreover, recruitment of large number of participants would be helpful in
obtaining clinically and statistically significant information (Berbano and Baxi 2012).
Variable inferences can be made through the recruitment of large number of participants with
variable nature of drinking habits. Data was obtained for the participants from the Clinical
Practice Research Datalink (CPRD) which is validated source of patient information. Hence,
accurate conclusions can be made due to valid patient data source (Wells, Gupta, Smith et al.,
2019). Since, this study was followed for the duration of six years; large quantity of data was
obtained. Patient data was obtained for the patients of primary care, hospital admissions and
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mortality; hence, data was obtained for the patients with varied disease severity. Moreover,
patients above 30 years of age were recruited in this study because these patients are more
prone to cardiovascular disease development. Recruited patients were representatives of the
UK population in terms of age, sex and ethnicity; hence, obtained findings can be generalized
throughout the UK population.
General practitioners and practice nurse collected self-reported data for alcohol consumption.
There is potential bias in this type of data collection because participants might provide
wrong data. Codes were given for the different categories of alcohol drinkers. Coding helped
in easy identification of the participants with respective category of drinking. Coding to the
different categories of alcohol consumption is appropriate in this study because it helped in
corelating disease severity with different categories of alcohol consumption. Both primary
and secondary endpoints were measured in this study because primary endpoints helped in
answering the research question and secondary outcomes proved as basis for the primary
outcomes. Both primary and secondary outcomes are appropriate for this study because it
provide robust and valid data. Covariates were included during the data analysis for
improving the accuracy of the outcomes. Covariates are usually not affected by the
intervention; however, covariates can provide variable results for the exposure (Cameron,
Fireman, Hutton et al., 2015). Hence, accuracy of the outcome can be improved through
incorporation of the covariates. Multivariable Cox proportional hazard models is appropriate
model in this study because this model is helpful in addressing the effect of several known
covariates on patient prognosis (Kransdorf, Loghmanpour, Kanwar et al., 2017). Multiple
factors with variable intensity might be responsible for the occurrence of cardiovascular
diseases. Two groups of patients with variable characteristics but with same exposure like
alcohol consumption can be effectively analysed using this multivariate statistical modelling.
Schoenfeld residual plot was appropriate in this study because it is helpful in identification of
the proportional hazard of cardiovascular disease with respect to participants with respect to
different categories of alcohol consumption.
Results:
From the results, it is evident that there is J shaped association between the alcohol
consumption and risk of cardiovascular disease. This type relationship between the alcohol
consumption and cardiovascular disease indicate that there should be less consumption of
alcohol to reduce risk of cardiovascular disease development (Rahman and McEvoy, 2017).
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Results demonstrated that non-drinkers are at higher risk of cardiovascular disease
development; however, no difference in risk was observed between the heavy and moderate
smokers. Observed high risk in the non-drinkers might be due to more vulnerability for the
disease development as compared to the heavy and moderate drinkers. There should be
definite difference in risk among heavy and moderate drinkers; however, observed similar
effect might be due inaccurate classification as heavy and moderate drinkers. From the
results, it is evident that risk of cardiovascular disease is variable among the different
categories of participants like non-drinkers, previous drinkers, moderate and heavy drinkers.
Relationship has been established among the different categories of subjects and respective
cardiovascular disease phenotype. Variable relationship has been observed for different
categories of alcohol drinkers for different phenotypes of the cardiovascular diseases. It
indicates susceptibility of the different phenotypes of cardiovascular diseases is different for
different level of alcohol consumption. Cardiovascular diseases are complex diseases with
subtypes for few of the phenotypes of these diseases (Mathews, Liebenberg, and Mathews,
2015; Fernández-Solà, 2015). There was no heterogenicity observed in risks for subtypes of
the individual phenotype of cardiovascular disease.
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