Health and Medicine

p Epidemiology

The study of the distribution of diseases in populations and of factors that influence the occurrence of disease . Epidemiology examines epidemic (excess ) and endemic (always present ) diseases it is based on the observation that most diseases do not occur randomly , but are related to environmental and personal characteristics that vary by place , time , and subgroup of the population . The epidemiologist attempts to determine who is prone to a particular disease where risk of the disease is highest when the disease is most likely to occur and its trends over time what

br exposure its victims have in common how much the risk is increased through exposure and how many cases of the disease could be avoided by eliminating the exposure

Epidemiologic approach has helped to explain the transmission of communicable diseases , such as HYPERLINK "http /www .answers .com /cholera " \t "_top " cholera and HYPERLINK "http /www .answers .com /measles " \t "_top " measles , by discovering what exposures or host factors were shared by individuals who became sick . Modern epidemiologists have contributed to an understanding of factors that influence the risk of chronic diseases particularly cardiovascular diseases and cancer , which account for most deaths in developed countries today . Epidemiology has established the HYPERLINK "http /www .answers .com /causal " \t "_top " causal association of HYPERLINK "http /www .answers .com /cigarette " \t "_top " cigarette smoking with heart disease shown that HYPERLINK "http /www .answers .com /aids " \t "_top " acquired immune deficiency syndrome (AIDS ) is associated with certain sexual practices linked HYPERLINK "http /www .answers .com /menopause " \t "_top menopausal estrogen use to increased risk of HYPERLINK "http /www .answers .com /endometrial-cancer-2 " \t "_top endometrial cancer but to decreased risk of HYPERLINK "http /www .answers .com /osteoporosis " \t "_top " osteoporosis and demonstrated the value of HYPERLINK "http /www .answers .com /mammography " \t "_top " mammography in reducing breast cancer mortality . By identifying personal characteristics and environmental exposures that increase the risk of disease , epidemiologists provide crucial input to risk assessments and contribute to the formulation of public health policy

Descriptive epidemiologic studies provide information about the occurrence of disease in a population or its subgroups and trends in the frequency of disease over time

Analytic epidemiologic studies seek to identify specific factors that increase or decrease the risk of disease and to HYPERLINK "http /www .answers .com /quantify " \t "_top " quantify the associated risk . In observational studies , the researcher does not alter the behavior or exposure of the study subjects , but observes them to learn whether those exposed to different factors differ in disease rates (Greenberg , 2004 ,

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Clinical Research

This patient-oriented research , conducted with human subjects (or on material of human origin such as tissues , specimens and cognitive phenomena ) for which an investigator directly interacts with human subjects (Wills , 2003 ,

.13 References

Raymond S . Greenberg , Stephen R . Daniels , W . Dana Flanders , John William Eley , John R . Boring (2004 )- HYPERLINK "http /books .google .co .ke /books ?q subject 22Medical 22 " Medical Epidemiology

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