health - epidemiology

morbidity

incidence and/or prevalence of a disease or all diseases in a population

epidemiology

investigates patterns of diseases among populations

mortality

death rate in a population which may be from all causes

incidence of disease

new cases of diseases (specified time in a defined population)

prevalence of disease

total number of people with the disease (specified time in a defined population)

incidence equation

number of new events / population at risk of event in specified period

prevalence equation

incidence x duration

cholera

intestinal infection of Vibrio cholerae

mechanisms of cholera disease

hijacks production of cyclicAMP → exaggerated release of Cl- from intestinal cells to lumen → H2O follows Cl- → massive diarrhea → up to 2L H2O lost every hour

ghost map story

first ideology of epidemiology — importance of people, time & place

non-modifiable risk factor

risk factors that we cannot control (e.g. sex, age, etc.)

modifiable risk factor

risk factors that we can control (e.g. smoking, blood pressure, cholesterol levels)

incidence, prevalence, & mortality per day count

calculate everything day by day (prevalence & incidence are not necessarily permanent states - mortality is permanent)

framingham study

world’s first big data study about 10-year risk of fatal cardiovascular event (longitudinal & cohort)

framingham study variables

smoking, sex (males much higher chance), systolic blood pressure, age, and cholesterol levels

excess deaths meaning

compare the incidence of daily deaths presently with the incidence of dying of the same periods of previous years.

covid-19 test positive per day in the netherlands

second wave is larger but could be because tests got more widespread/used as the pandemic went on & the actual number of Covid-19 positive people in the first wave was most likely much higher

persons being hospitalized per day in the netherlands

first peak is higher but sharper, second peak is lower but more spread out → so they may be around the same amount (equally severe) + that the number of actual positive cases was underestimated.

deaths per day in the netherlands due to covid-19 — was the variant in the first wave worse?

no, we cannot know since it could just be that the medical centers were more prepared & could treat patients better — could be that they were equally severe or maybe the second variant was worse -- but treatment got better either way

5 categories of problems with data

absence of information, inconsistent information, case ascertainment, diagnostic criteria, and variable formats for data

case - mortality in iraq problems with data

absence + inconsistent information due to poor state infrastructure, most deaths not reported to morgues & hospitals, and political control

iraq mortality case method to collect data

1 sampling cluster per 500,000 people for each city → 1 cluster from selected household -- then survey nearest 39 other households → interview regarding loss in household → information on deaths from around 2K households containing 12K persons collected → ssume that this is representative of the whole country

noncompaction cardiomyopathy case problems

inconsistent information, case ascertainment (no epidemic, just increased awareness and better diagnostics), diagnostic criteria (are different between techniques - e.g. pathology, echocardiography  & MRI)