PUB 540 Describe the characteristics and design of a cohort study

As discussed by Friis & Sellers (2020) a cohort study is an observational study that goes from cause to effect. It is a longitudinal study that follows a group of subjects over time. The exposure of a particular disease is known to be positive and how the effects of this positive exposure manifest are observed. There are two points of observation, before disease onset and then at a follow up. By doing this, a measure of effect that certain risk factors related to disease outcome. This is the best type of study for population-based studies because more measures of association can be evaluated. This is an observational study versus an experimental study because no intervention is included; the aim is to simply observe cause and effect in a certain group to determine the incidence of disease, mortality rates among this group, which then can serve as a flag for the need for more resources to prevent high numbers of untoward outcomes.

Hoepner et al., (2016) participated in a cohort study that looks at the association between bisphenol A and adiposity in the inner city. Prenatal mothers had their BPA concentrations measures (n =375), children aged 3 (n=408), and children 5 years (n=518). The children in age groups 3 and 5 had their urine spot tested. The children were followed up every 3 months and followed till they were 5 years of age, and then every 6 months until 7 years of age. The mothers were followed differently during their pregnancy. They wanted to see if there was an association between higher BPA concentration before birth and adiposity. There was a positive association that high prenatal concentrations of BPA were associated with adiposity by age 7.

References

Hoepner, L. A., Whyatt, R. M., Widen, E. M., Hassoun, A., Oberfeld, S. E., Mueller, N. T., Diaz, D., Calafat, A. M., Perera, F. P., & Rundle, A. G. (2016). Bisphenol A and Adiposity in an Inner-City Birth Cohort. Environmental Health Perspectives, 124(10), 1644–1650. https://doi-org.lopes.idm.oclc.org/10.1289/EHP205

Friis, R. H., & Sellers, T. (2020). Epidemiology for public health practice (6th ed.). Jones & Bartlett Learning.

Great discussion above. I have come to discover that cohort studies are powerful tools to conduct research. Its not only differentiated from an experimental study but also other observational studies. Friis & Sellers (2019) explain that as a prospective or longitudinal study, a cohort study is distinguished from other observational research designs by the fact that it starts with a group of subjects who lack a positive history of the outcome of interest and are at risk for the outcome. By selecting study groups, cohort studies can be thought of as going from cause to effect. That is, the exposure(s) of interest is (are) determined for each member of the cohort at baseline or time of study; then, the group is followed through time to document the incidence of an outcome among the exposed and nonexposed members (Friis & Sellers, 2019).

Reference

Friis, R.H. & Sellers, T.A. (2021). Epidemiology for public health practice (6th ed.). Burlington,

MA: Jones & Bartlett Learning.

Click here to ORDER an A++ paper from our Verified MASTERS and DOCTORATE WRITERS PUB 540 Describe the characteristics and design of a cohort study:

One of the most influential tools used in epidemiology is a cohort study. According to the Center for Disease Control and Prevention reports the exposure and those who are unexposed to the disease of interest and tracks the participants to determine if they contract the disease of interest. In the words of Friis and Sellers cohort studies are observational, and longitudinal study that begins with people who have not been exposed but have a harmful outcome.

The 2020 KH Topic I choose to discuss the “Prospective Cohort Study of Mental Health During Imprisonment”. The aim of the scientific study was to determine how early detention or imprisonment of individuals can affect one’s mental health. This was accomplished by screening 3079 prisoners and examining their psychiatric symptoms ( Hassan, Harty, Jarrett, Jones, King, Lathlean, Lowthian, Mills, Thornicroft, Web, 2011). (DOI: 10.1192/bjp.bp.110.080333).

Approximately 978 prisoners exhibited psychiatric symptoms as early as the first week of incarceration. Those who remained in prison had follow-up interviews recorded at one and two. The results yielded data that depicted those psychiatric symptoms are prevalent during the first week of incarceration, but the presence tends to decline over a period. The overall study can be classified as observational because of the method used to collect data and type of data retrieved.

References:

Hassan L, Birmingham L, Harty MA, Jarrett M, Jones P, King C, Lathlean J, Lowthian C, Mills A, Senior J, Thornicroft G, Webb R, Shaw J. (2011). Prospective cohort study of mental health during imprisonment. Br J Psychiatry 198(1), 37-42. DOI: 10.1192/bjp.bp.110.080333

Setia M. S. (2016). Methodology Series Module 1: Cohort Studies. Indian journal of dermatology, 61(1), 21–25. https://doi.org/10.4103/0019-5154.174011

According to Himmelfarb.gwu.edu (2019) cohort study is a design where one or more samples (called cohorts) are followed prospectively and subsequent status evaluations with respect to a disease or outcome are conducted to determine which initial participants exposure characteristics (risk factors) are associated with it.

The health condition I have identified is environmental quality. Healthypeople.gov (2022) discusses how the Air Quality Index (AQI) reports daily air quality from a value of 0 to 500, considers values greater than 100 to indicate unhealthy levels of air pollution. It was reported that between 2006–2008 and 2016-2018, potential exposure to unhealthy air quality (measured as the number of AQI-weighted people days) decreased 43%, from 7.603 to 4.296 billion, exceeding the HP2020 target (Healthypeople.gov, 2022).

The link to the article is https://www.healthypeople.gov/2020/leading-health-indicators/2020-lhi-topics/Environmental-Quality/data

As stated on Healthypeople.gov (2022) between 2005–2008 and 2013-2016, exposure to secondhand smoke among children aged 3–11 years was conducted and it was discovered that there was a decrease of 27.0%, from 52.2% to 38.1%, exceeding the HP2020 target. In 2013-2016, several groups of children in specific demographic categories had the lowest rates of secondhand smoke exposure, including Asian children, those born outside the U.S., those with private health insurance, and those in families with incomes at 500% or more of the poverty threshold (Healthypeople.gov, 2022).

Friis & Sellers (2021) explain that a cohort study as an observational study design makes use of careful measurement of patterns of exposure and disease in populations to draw inferences about etiology while an experiment study design would be impractical and, in some instances, unethical.

References

Friis, R.H. & Sellers, T.A. (2021). Epidemiology for public health practice (6th ed.). Burlington,

MA: Jones & Bartlett Learning.

Healthypeople.gov (2022). Environmental Quality. Retrieved from https://www.healthypeople.gov/2020/leading-health-indicators/2020-lhi-topics/Environmental-Quality/data

Himmelfarb.gwu.edu (2019). Study Design 101. Retrieved from https://himmelfarb.gwu.edu/tutorials/studydesign101/cohorts.cfm#:~:text=Definition,factors)%20are%20associated%20with%20it.

The link to the article is https://www.healthypeople.gov/2020/leading-health-indicators/2020-lhi-topics/Environmental-Quality/data

References

Friis, R.H. & Sellers, T.A. (2021). Epidemiology for public health practice (6th ed.). Burlington,

MA: Jones & Bartlett Learning.

Healthypeople.gov (2022). Environmental Quality. Retrieved from https://www.healthypeople.gov/2020/leading-health-indicators/2020-lhi-topics/Environmental-Quality/data

Himmelfarb.gwu.edu (2019). Study Design 101. Retrieved from https://himmelfarb.gwu.edu/tutorials/studydesign101/cohorts.cfm#:~:text=Definition,factors)%20are%20associated%20with%20it.

Cohort studies are studies that monitor research participants for longer period of time (Barrett & Noble, 2019). It recruits and follow participants who has the same characteristics such as demographic information. During the study, impact of variable will be determine by allowing some cohorts to be exposed to risk factors and measure the outcome after some time of monitoring. Cohort studies are critical in epidemiology due to the ability to identify factors that may increase or decrease the possibility of developing a disease (Barrett & Noble, 2019).

An example of real cohort study that represent one of the health condition in “2020 LHI Topics” was about mental health during imprisonment (2011)(DOI: 10.1192/bjp.bp.110.080333). The goal of the study is to determine the prevalence and predictors of psychiatric symptoms during the early detention of prisoners. The 3079 prisoners were screened for mental health issue within 3 days but there are 980 prisoners that were interviewed and exposure is the early week being in prison (Hassan et al., 2011). Participants remaining in the prison were followed up after 1 month and 2 months. The result shows symptoms are prevalent during the first week being detained that declines over time with men unlike women. It is an observational study due to different groups were observed to attained the objectives of the study.

Reference

Barrett, D. & Noble, H. (2019). What are cohort studies? Evidence-Based Nursing 2019;22:95-96. Retrieved from http://dx.doi.org/10.1136/ebnurs-2019-103183

The characteristic feature of a cohort study is that the investigator identifies subjects at a point in time when they do not have the outcome of interest and compares the incidence of the outcome of interest among groups of exposed and unexposed (or less exposed) subjects.(Healthy people 2020)

An example of cohort study l choose is Injury and Violence. Unintentional injuries and violence-related injuries can be caused by a number of events, such as motor vehicle crashes and physical assault, and can occur virtually anywhere.(healthy people 2020) No matter what the circumstances of the event are, injuries can have serious, painful, and debilitating physical and emotional health consequences, many of which are long term or permanent, including:

Hospitalization
Brain injury
Poor mental health
Disability
Premature death

While their extent, severity, and impact may vary, injuries from any cause can significantly influence the physical, mental, and economic well-being of individuals, families, and communities nationwide.

Reference:

Natour, J., Cazotti, L., Ribeiro, L., Baptista, A., & Jones, A. (2015). Pilates improves pain, function and quality of life in patients with chronic low back pain: a randomized controlled trial. Clinical Rehabilitation, 29(1), 59-68. https://doi.org/10.1177/0269215514538981

PUB 540 Describe the characteristics and design of a cohort study