strokedata_smallSample {causalPAF}R Documentation

Fictional ischemic stroke data case control data with risk factors, exposures and confounders

Description

A fictional standardized international study of ischemic stroke cases and controls in 32 countries in Asia, Europe, Australia, the Middle East and Africa. Information on key causal and modifiable risk factors for stroke are included. The risk factors included are healthy eating score (in tertiles), physical inactivity (yes/no), smoking behaviour (current smoker or ex/no smoker), alcohol intake (no alcohol, moderate consumption, high consumption), an indicator for stress, ApoB/ApoA lipid ratio (in tertiles), pre-existing hypertension or high measured blood pressure (yes/no), waist hip ratio (in tertiles), cardiac risk factors such as atrial fibrillation or flutter (yes or no) and a diagnosis of diabetes mellitus or elevated HbA1c(yes/no). One needs to assume a causal graph describing the causal relationships between confounders, risk factors and disease to implement the methods in the 'causalPAF' package. To do this, it is helpful to divide the risk factors and exposures into categories depending on whether they are descriptive of an individual’s behaviour SB = Smoking, Alcohol intake, inactivity, diet and stress, their physiology SP = High blood pressure, ApoB/ApoA ratio, Waist hip ratio and what might be regarded as preclinical disease SD = Cardiac risk factors, Pre-clinical diabetes. We also consider a set of variables that might be confounders (joint causes of the risk factor and stroke) for all the listed risk factors. This set of confounders, SC consist of the individuals and their parents’ education level (in 5 levels from no-education to holding a college Degree), age, gender and region. Here we make the simplifying assumption that disease develops in a stage-wise fashion, each stage being represented by one of the sets of variables just described with variables in earlier stages having causal effects on variables contained in later stages, but not vice-versa. The ordering of stages is indicated by the sequence, SC , SB , SP , SD , Y , and summarized by the causal graphs in (O’Connell and Ferguson 2020) <https://doi.org/10.1101/2020.10.15.20212845> and (Ferguson, O’Connell, and O’Donnell 2020) https://doi.org/10.1186/s13690-020-00442-x .

Usage

strokedata

Format

A data frame with 5000 rows and 21 variables in columns. Each row representing either a fictional individual stroke case or control:

regionnn7

Region (number, 7 categories)

case

Case status (number, 1=cases, 0=controls)

esex

Gender (number, 1=female, 2=male)

eage

,Age based on both DOB and eage (number)

htnadmbp

High blood pressure, Hx HTN/Adjusted BP>140/90 at admission (number, 0=No, 1=Yes)

nevfcur

Smoke history(2lev) (number, 1=Never/Former, 2=Current)

global_stress2

Global Stress, (number, 1=None/some_periods, 2=Several/Perm. periods)

whrs2tert

Tertile of standing waist_to-hip ratio, WHR (number, 1=Tertile1, 2=Tertile2, 3=Tertile3)

phys

Leisure-Physical activity (number, 1=mainly inactive, 2=mainly active)

alcohfreqwk

Alcohol history and frequency(3) (number, 1=Never/Former, 2=Low/Moderate, 3=High intake/Binge)

dmhba1c2

clinically diagnosed diabetes mellitus or measured Hba1c level at least 6.5 - yes or no, Hx DM/HbA1c greater than or equal to 6.5 per cent (number, 1=No, 2=Yes)

cardiacrfcat

History of risk factors for heart disease - yes or no, Hx Cardiac Risk Factors (number, 1=No, 2=Yes)

ahei3tert

Diet: AHEI diet score (in tertiles) Tertile of Total AHEI Score (not including alcohol), (number, 1=Tertile1, 2=Tertile2, 3=Tertile3)

apob_apoatert

Lipids: Apolipoprotein B/Apolipoprotein A1 ratio (in tertiles) (number, 1=Tertile1, 2=Tertile2, 3=Tertile3)

subeduc

Education (number, 1=None, 2=1-8, 3=9-12, 4=Trade School, 5=College/University)

moteduc

Mother education (number, 1=None, 2=1-8, 3=9-12, 4=Trade School, 5=College/University, 6=unknown)

fatduc

Father education (number, 1=None, 2=1-8, 3=9-12, 4=Trade School, 5=College/University, 6=Unknown)

subhtn

Blood pressure Hx HTN (number, 1=No, 2=Yes)

whr

Waist-to-hip ratio ( number as continuous variable)

apob_apoa

Lipids: Apolipoprotein B/Apolipoprotein A1 ratio (number as continuous variable)

weights

To fit these models to case control data, one needs to perform weighted maximum-likelihood estimation to imitate estimation using a random sample from the population. We chose weights of 0.0035 (for each case) and 0.9965 (for each control), reflective of a yearly incidence of first ischemic stroke of 0.35 per cent, or 3.5 strokes per 1,000 individuals. These weights were chosen according to average incidences across country, age group and gender according to the global burden of disease.


[Package causalPAF version 1.2.4 Index]