Calculations
Hurricane Helene hit landfall in Asheville, NC in late September 2024. The following October, the North Carolina Department of Public Health reported that 2,116 adults were diagnosed with cholera of which 87 people died. What is the case fatality rate?
(87/2116) x 100 = 4.1%
OR
(87/2116) x 10,000 = 411.2 cholera deaths per 10,000 in Asheville, NC in October 2024
Compares disease frequencies between groups
What is a contingency table? What is a 2x2 table?
Appears in every causal mechanism or pie
What is a necessary cause?
What is the burden of preeclampsia among pregnant women aged 25-44yrs?
What is a cross-sectional study? What is prevalence?
Narcissa surveyed 578 certified nursing assistants (CNAs) across Boston, MA on their experience working in nursing homes and 133 reported low job satisfaction due to workplace harassment by their superiors. What is the prevalence of CNAs who report low job satisfaction?
(133/578) x 100 = 23.0%
Measures the strength of an association between an exposure and disease
What is a relative measure?
The most important standard for causal inference
What is temporality?
What is the nature of the relationship between Boston's traffic patterns and its incidence of automobile accidents?
What is an ecological study? What is correlation?
A 5-year follow-up study looking at the impact of beta-blockers on heart rate included 4,041 hypertensive adults. By the end of the study, 2,505 adults experienced a heart rate that decreased by 25 bpm. What is the incidence of the lowered heart rate in this study population?
(2505/(4041x5)) x 1000 = 124.0 cases of lowered heart rate per 1,000 person-years
Measures the public health impact of a risk factor by quantifying the ______ disease that can be attributed to an exposure
What is excess of risk?
Causation and association differ in that association does not ______ that there is a direct causal relationship.
What is prove?
What are the odds of developing a substance use disorder (SUD) among individuals who were exposed to secondary severe drug abuse during their childhood compared to those who were not exposed to secondary severe drug abuse during their childhood?
What is a cohort study (prospective or retrospective)? What is an odds ratio?
In 2006, children in Arkansas experienced an outbreak of measles. Measles was diagnosed in 18 of 152 vaccinated children compared with 3 of 7 unvaccinated children. What is the risk of measles in vaccinated vs. unvaccinated children?
risk of measles among vaccinated: 18/152 = 0.118
risk of measles among unvaccinated: 3/7 = 0.429
rate ratio: 0.118/0.429 = 0.28
interpretation: vaccinated children had a 72% decreased risk of developing measles compared to unvaccinated
OR approximates the RR if the incidence of the outcome is low
What is the rare disease assumption?
Epidemiologists have used this technique to corroborate hypotheses with statements or evidence through crucial testing of competing hypotheses about a specific causal mechanism.
What is refutionism?
Is the combination of an oral drug and biweekly therapy sessions more or less effective than just biweekly therapy sessions in decreasing the risk of depression among US adolescents?
What is an RCT? What is cumulative incidence?
You're conducting a case-control study on the relationship between male-pattern baldness and CVD among men up to 55yrs old. Cases were men hospitalized for a heart attack and controls were men admitted to the same hospital for non-cardiac conditions. Of 446 men hospitalized for a heart attack, 251 had male-pattern baldness. Of men who were hospitalized with a non-cardiac condition in the same hospital, 331 had male-pattern baldness. What are the odds of male-pattern baldness among men hospitalized for a heart attack vs. men hospitalized for a non-cardiac condition?
(251x270)/(331x195) = 1.05
interpretation: the odds of male-pattern baldness among men who were hospitalized for a heart attack is 1.05 times the odds (or have a 5% increased odds) of male-pattern baldness among men who were hospitalized for a non-cardiac condition
A measure that could be used to quantify clinical significance and goes beyond just statistical significance
What is effect size?
You ran a cross-sectional study to investigate the burden of torn ACLs among women's soccer players at the NCAA level finding that these players have a strong, positive correlation with having a torn ACL (0.72). Now you'd like to understand the potential causal nature of the relationship, so you decide to run a prospective cohort study comparing women's soccer players aged 18-22yrs and women who do not play soccer of the same age group and assess the risk of a torn ACL. By doing so, you are trying to find out, had these women of this age group not been playing soccer, would they have torn their ACL which is the concept of _______.
What is the counterfactual?
What is the estimated proportion of newly insured low-income individuals in California that can be attributed to the Medicaid expansion by the ACA?
What is a case-control study? What is the attributable risk percent?