Public Health Essentials

88 flashcards by MentisLibrary

The vocabulary of population health: incidence and prevalence, the study designs and what each can and cannot prove, the bias types that ruin results, screening test statistics, the levels of prevention, and the biostatistics behind p values and confidence intervals.

What is epidemiology?
The study of how disease and health states are distributed in populations and what determines that distribution
What is incidence?
The number of new cases arising in a population over a defined period
What is prevalence?
The proportion of a population that has a condition at a given moment or over a period
How are incidence and prevalence related?
Prevalence is roughly incidence multiplied by average duration of disease
What is an attack rate?
The proportion of an exposed group that develops disease during an outbreak
What is the case fatality rate?
The proportion of people with a disease who die from it
What is the mortality rate?
The number of deaths in a population over a defined period, usually per 100,000 people per year
What is the difference between morbidity and mortality?
Morbidity is illness and disability, while mortality is death
What is the infant mortality rate?
Deaths of infants under one year of age per 1,000 live births in a year
What is life expectancy at birth?
The average number of years a newborn would live if current age specific mortality rates stayed constant
What is a disability adjusted life year?
One DALY represents one year of healthy life lost, combining years lost to early death and years lived with disability
What is a quality adjusted life year?
A year of life weighted by its quality, where 1.0 is a year in perfect health and 0 is death
What is a randomized controlled trial?
An experimental study in which participants are randomly assigned to intervention or control
Why is randomization so powerful?
It balances confounders, including ones nobody thought to measure, across study groups
What is blinding in a clinical trial?
Concealing group assignment from participants, investigators, or both, to prevent expectation from shaping results
What is a cohort study?
An observational study that follows exposed and unexposed groups forward in time to compare who develops the outcome
What is a case-control study?
An observational study that starts with people who have the outcome and looks backward at their past exposures
Which study design is best for a rare disease?
A case-control study, because it starts by recruiting the cases rather than waiting for them to occur
Which study design is best for a rare exposure?
A cohort study, because investigators can deliberately recruit the exposed group
What is a cross-sectional study?
A study measuring exposure and outcome at the same single point in time
What is an ecological study?
A study comparing populations rather than individuals, using group level averages
What is a case report or case series?
A description of one patient or a small group with an unusual presentation or outcome
What is a systematic review?
A review that uses a prespecified protocol to find, appraise and synthesize all studies addressing one question
What is a meta-analysis?
A statistical combination of results from multiple studies into a single pooled estimate
What is the hierarchy of evidence?
A ranking from expert opinion and case reports at the bottom through observational studies to randomized trials and systematic reviews at the top
What is relative risk?
The risk of the outcome in the exposed group divided by the risk in the unexposed group
What is an odds ratio?
The odds of exposure among cases divided by the odds of exposure among controls
What does a relative risk of 1.0 mean?
No association between the exposure and the outcome
What is attributable risk?
The excess risk in the exposed group that can be attributed to the exposure
What is the number needed to treat?
The number of people who must receive a treatment for one additional person to benefit