Epidemiology

So right now im procrastinating, I have a very important test in a few hours, 10% in a paper I need to pass with 90+% to shave a few years of my degree. Only problem. Its boring. Not boring oh dam nothing exciting happened today. No boring, in a banging my head against a wall would be more interesting.

Basically I'm about to blog about Epi as a form of study to kinda keep myself interested!
Epidemiology is basically counting people, counting sick people, and then counting dead people when they die. The whole idea is that if we know whats causing people to die, and its preventable then we can do something about it. Eg. on a fiscal level implement health reforms invest in new treatments, or improve social services.
Ultimately its about using data to save lives. Good idea, easy concept, often intuitive.
For example the main determinants of an individuals health are, Socioeconomic, cultural and environmental conditions -> Living and Working conditions -> Social and Community influences -> Individual life style factors -> Age, sex, & hereditary factors. ie these things all effect the individuals health, which is defined at "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity." by the World Health Organization.
The data is collected in many ways, such as routine data collection, registries or reports. The quality of data depends on its source and the likelihood that it is incorrect or has a form of bias.
NOIDs (Notifiable infectious diseases) are diseases that medical clinicians have a moral and legal obligation to contact health monitors. This is an example of passive surveillance which is one of three types of surveillance used to monitor health, the others being sentinel and active. With Active being when monitoring services are actively tracking down information about incidence and prevalence whilst sentinel is when key sites are monitored, eg. emergency rooms in key hospitals.
There are several different types of studies used in epidemiology to figure out whats going on. One example is cohort studies. These studies follow a population and measure potential risk factors of a disease. These studies can be done historically using routinely collected data already available or be Prospective or concurrent, selecting a population and following them until a conclusion can be made about the outcome examples of this study include the Dunedin Multidisciplinary study, and the British Doctor study.
Other types of studies include ecological (correlational) studies which compare larger scale populations based on environmental factors such as pollution or sunlight hours, and are suitable for discovering basic level causes but sometimes results on a population level fail to hold true at an individual level. These types of studies are good for hypothesis generation.
Another study type is a cross sectional study. These studies provide a snapshot of the health of a population, but are useless at providing incidence data as they only truly capture prevalence information, this means its good for stable diseases ie. You have it and can't lose it. but not for diseases with a short prevalence.

Sigh, Study.... Shot me now!