Module #9: Lectures 1-3

what were the STROBE recommendations designed for?

- in recognition of the difficulty in appraising study strengths and weaknesses if key information is missing from the study report. - for observational studies

what do prognostic research questions involve identifying?

- risk factors and protective factors for a health outcome - outcome can be dichotomous or measured on a continuous scale

STROBE checklist:

1. title and abstract 2.Intro/Background 3.Methods: Study design, setting, participants 4.Methods- data sources/ measurement, and minimizing biases 5. Methods- study size, quantitative variables, and statistical methods 6.Results- participants and descriptive data 7. Results- outcome data and main results 8. Discussion- key results, limitations, interpretation, generalizability 9. Other- source of funding

how many items are in the STROBE recommendations?

22 items

A linear regression analysis generated an R2 value of 0.33. Which one statement is a correct interpretation of this R2 value?

33% of the variation in the outcome is explained by the linear regression model.

A linear regression analysis generated an R2 value of 0.56. Which one statement is a correct interpretation of this R2 value?

56% of the variation in the outcome is explained by the linear regression model.

Which one of the following describes a case-control study design?

A study was done to determine risk factors for developing anorexia nervosa (an eating disorder). Fifty adolescents who were diagnosed with anorexia nervosa, and 50 control persons who attended school in the same district as cases, but who tested negative for anorexia nervosa, were all interviewed regarding several exposures, including their dietary patterns, exercise history, body image, and social media use, since the beginning of secondary school to the present time.

Which one of the following describes a prospective cohort study design?

A study was done to determine risk factors for developing anorexia nervosa (an eating disorder). Five hundred adolescents were enrolled upon completion of 6th grade, at which time baseline data were collected on several exposures such as dietary patterns, exercise history, body image, social media use, etc., and then they were assessed yearly throughout their secondary school years to see who developed the study outcome of anorexia nervosa.

Which one of the following describes a cross-sectional study design?

A study was done to determine risk factors for developing anorexia nervosa (an eating disorder). Five hundred adolescents were randomly selected from within a specific school district and at the time of screening for anorexia nervosa (an eating disorder) they were interviewed regarding their present dietary patterns, exercise practices, body image, and social media use.

Which of the following famous prospective cohort studies aims to enroll 1 million or more participants who reflect the rich diversity of America?

All of Us Study

You have defined your study aim as to identify risk factors for developing hip fracture in adults aged 60-80 years old. Which of the following study design description best fits the prospective cohort study design?

At the start of the study, enroll adults aged 60-80 years old without hip fracture history based on specific inclusion and exclusion criteria. Collect data on several risk factors such as diet, exercise, and smoking habits at baseline and every 6 months for 10 years, and monitor hip fracture events during this time frame.

You have defined your study aim as to identify risk factors for developing hip fracture in adults aged 60-80 years old. Which of the following study design description best fits the case-control study design?

At the start of the study, identify cases of adults who experienced hip fracture between the ages of 60-80 years old and controls who come from the same community as cases but without a hip fracture event, and collect data on both groups with regards to their past diet, exercise, and smoking histories.

Which one of the following is an example of a prognostic research question?

Do lifestyle factors in midlife predict bone mineral density 10 years later?

The Nurses' Health Study is one of the largest prospective cohort studies in the U.S. What was the original study aim when the Nurses' Health Study was initially launched?

Examine the safety of oral contraceptives

T/F: cross-sectional studies prove causation.

False

T/F: cross-sectional studies are not cost and time efficient

False- they are time and cost efficient which makes them good for exploration of exposures associated with outcomes

Which one of the following statements accurately describes advantages of the prospective cohort study design as compared to the cross-sectional study design?

In the prospective cohort study design, the exposure precedes the outcome.

Is this a linear or logistic question? " How much calendar time of active use can be expected after hip replacement?"

Linear

Which one of the following statements is true about using multiple variable linear regression analysis for answering prognostic research questions?

Linear regression analysis is most appropriate for answering prognostic research questions when the outcome variable is measured on a continuous scale, such as body mass index.

is this a prognostic research question Y/N: Is physical therapy superior to rest for healing a sprained ankle?

No

Which one of the following statements is NOT true about the STROBE Recommendations:

The STROBE checklist was created to improve the completeness of reporting of experimental research studies

Which one of the following statements is true about the STROBE Recommendations:

The STROBE checklist was created to improve the completeness of reporting of observational research.

Which one of the following statements is NOT true prospective cohort study design?

The prospective cohort is an experimental study design

The Nurses' Health Study is one of the largest prospective cohort studies in the U.S. What was the response rate in the original Nurses' Health Study?

The response rate was very high in the original Nurses' Health Study.

Which one of the following is an example of a prognostic research question?

What are the risk factors for developing cardiovascular disease?

Which one of the following is an example of a prognostic research question?

What are the risk factors for developing type 2 diabetes?

What is the simple linear regression equation?

Y= a+bX Y= predicted value for outcome variable a= intercept or consonant from - to+ infinity b= slope of the regression line from - to + infinity X= value for the predictor variable

is this a prognostic research question Y/N: Do dietary patterns predict breast cancer diagnosis?

Yes

is this a prognostic research question Y/N: Do lifestyle factors in midlife predict bone mineral density 10 years later?

Yes

prognostic

a forecast or prediction

The All Of Us Study

a soon to be famous study that aims to engage a cohort of 1 million or more participants who reflect the rich diversity of America

what is multiple variable linear regression?

analysis that is a common statistical analysis approach for examining multiple exposures in answering prognostic research questions using prospective cohort or cross-sectional study designs where the outcome is measured on a continuous scale.

Identify the covariate in the following research question: 'Do middle-aged adults with higher intake of non-starchy vegetables have lower plasma cholesterol levels in a model adjusted for body mass index?'

body mass index

methods- data sources/measurement, and minimizing biases

clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers

hierarchy of study design strongest to weakest:

cohort--- case-control--- cross-sectional

Intro/Background:

explains scientific background and states specific objectives, including any prespecified hypotheses

in cohort studies, the independent variables are considered to be the _____, and the dependent variable is the ______.

exposures; outcome

T/F: prospective cohort study's prove causation

false

what makes something on the multiple linear regression statistically significant?

if the confidence interval does NOT include zero between the numbers ex- (0.5-0.9)

Identify the exposure variable in the following research question: 'Do middle-aged adults with higher intake of non-starchy vegetables have lower plasma cholesterol levels in a model adjusted for body mass index?'

intake of non-starchy vegetables

In which part of a research article would you look to see if the authors included appropriate details regarding study data sources and details of variable measurements?

methods

Identify the study population in the following research question: 'Do middle-aged adults with higher intake of non-starchy vegetables have lower plasma cholesterol levels in a model adjusted for body mass index?'

middle-aged adults

What is a case-control study?

observational study where 2 groups that have different outcomes: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls).

The Framingham Heart Study

one of the oldest cohort studies that's goal was to identify the common factors that contribute to cardiovascular disease (CVD)

prognostic research asks if we can predict an _______ (a positive or negative health condition) from one or more _______

outcome; exposures

Identify the outcome variable in the following research question: 'Do middle-aged adults with higher intake of non-starchy vegetables have lower plasma triglyceride levels in a model adjusted for body mass index?'

plasma triglyceride levels

Methods: Study design, setting, participants

present key elements of study deign early in the paper and describe the setting, locations, relevant dates, including period of recruitment, exposure, follow-up and data collection - give eligibility criteria for cohort study and the sources and methods of selection of participants

cross-sectional study

prone to bias because exposures are measured at the same time as the outcomes or via recall

What is R squared?

proportion of variation in the outcome that is explained by the linear regression model can be interpretated by making it a %

Which of the following is the correct order, from strongest to weakest, in terms of strength of observational study designs for answering prognostic research questions?

prospective cohort > case-control > cross-sectional

what kind of prognostic research question is the strongest observational study design design?

prospective cohort followed by case control study and then cross-sectional study design

what format will the prognostic question be in for the outcome?

quantitative variable format, statistical test being used also determines format

prospective cohort study

start by measuring the exposure of interest- they precede the outcome (+) - they are time and cost intensive which is a (-)

what is linear regression commonly used for?

to analyze prognostic research data when the outcome is measured on a continuous scale or other numerical data

when is logistic regression most commonly used?

to analyze prognostic research data with a dichotomous (binary) outcome -example: type 2 diabetes (yes/no) ALL ANSWER YES?NO QUESTIONS

What was The Nurses Health Study: a famous prospective cohort study aim?

to examine the safety or oral contraceptives and is associated with negative health outcomes - it was one of the largest cohort studies in the United States with 250,000 people involved

What is the All of Us Study's goal?

to provide insights into individual differences to tailor prevention care

What are the STROBE recommendations?

used to appraise completeness of observational research studies