Question

Describe the characteristics and design of a cohort study. Based on a disease or health condition identified from the 2020 LHI Topics" on the Healthy People 2020 website, or an article from the GCU library, discuss a real example of a cohort study (include the link to the article in your post to the forum). Include the participants, exposures or treatment groups, timeframe, and outcomes that were measured. Why is a cohort study described as an observational study rather than an "experimental study design? Reply

Answer 1

#. Cohort studies are the species of observational study most closely related to experiments.

HOWEVER, instead of assigning subjects to exposure groups, we can only observe the level of exposure that already exists

Cohort - group of people that have characteristics in common.

Prospective (Traditional) cohort exists in the present.

Retrospective (uses secondary data) cohort existed in the past.

#. Design of Cohort study

Target Population

v

Cohort: People without the disease in question

v

1. Exposed. 2. Not Exposed

v

Exposed: a. disease b. no disease

Not Exposed: c. disease d. no disease

#. Example of a cohort study based on a health condition :-

- Study on obesity :-

Prospective cohort study of overweight and obesity among rural Indian adults : sociodemographic predators of prevalence , incidence and remission .

- Design

Prospective cohort study.

- Setting

Birbhum Health and Demographic Surveillance System, West Bengal, India.

- Participants

Self-weighted sample of 24 115 adults (men: 10915, women: 13200) enrolled in 2008 were followed up for body mass index (BMI) reassessment in 2017.

- Primary and secondary outcome measures

Measured BMI was categorised as: underweight (<18.5 kg/m2), normal weight (18.5–22.9 kg/m2) and overweight including obesity (≥23 kg/m2; hereinafter overweight). Incident overweight was defined as transition from normal weight in 2008 to overweight in 2017, whereas if overweight individuals in 2008 measured normal BMI in 2017, it was classified as remission from overweight.

- Results

In 2008, 10.1% of men and 14.6% of women were overweight, whereas 17.3% of men and 24.7% of women were overweight in 2017. At the same time, in 2017, 35.6% of men and 33.3% of women were underweight. Incident overweight was 19.0% among men and 27.2% among women, whereas remission among men was higher (15.4%) than women (11.5%). Women were more likely to be overweight in 2008 and to experience incident overweight than men. For men and women, education level and wealth were positively associated with prevalence and incidence of overweight. Remission from overweight was less likely in Sainthia, a business hub in the district, as compared with Mohammad Bazar, a more rural area.