What Is the Illness Rate?

Incidence rate refers to the frequency of new cases of a certain disease in a certain population within a certain period of time. It is a measurement index that reflects the impact of the disease on the health of the population and describes the distribution of the disease.

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Incidence rate refers to the frequency of new cases of a certain disease in a certain population within a certain period of time. It is a measurement index that reflects the impact of the disease on the health of the population and describes the distribution of the disease.

Incidence can be used to reflect the impact of disease on population health. A high incidence indicates that the disease has a large impact on health, and a low incidence indicates that the disease has a small impact on health. Incidence can be used to describe the distribution of the disease. By comparing the incidence of a disease with different characteristics of the population, the cause of the disease can be explored and the control measures evaluated. ^[1]

Incidence rate = (number of new cases of a disease in a certain population in a certain period of time / number of exposed population in the same period) × K

K = 100%, 1000 , 10,000 / 10,000 or 100,000 / 100,000.

The unit of observation time can be determined according to the nature of the disease and the problem under study, and is usually expressed in years. ^[1]

The numerator is the number of new cases in a certain period (year, quarter, month). If a person has multiple onsets during the observation period, they should be recorded as the number of new cases, such as influenza and diarrhea. For some diseases whose time of onset is difficult to determine, the time of initial diagnosis can be regarded as the time of onset, such as

The denominator is the number of people exposed at the same time. The exposed population refers to the people who may have the disease in the observation area. For those who are unlikely to have the disease again (such as already infected

Incidence rate can be calculated according to different characteristics, such as age, gender, occupation, ethnicity, marital status, race, etiology, etc., which is called incidence rate. ^[1]

Because the incidence level is affected by many factors, when comparing different data, there may be differences in the composition of age, gender, etc., and the incidence should be standardized. ^[1]

The numerator of the prevalence is the number of new and old cases of a disease in a certain population at a certain time. Regardless of whether it is new or old, as long as the disease is not cured within a certain time, it is recorded as the number of cases. The numerator of the incidence is the number of new cases in the exposed population over a certain period of time. Any new occurrence of a disease in any of the exposed population is called a "new case" ^[2] .

The prevalence is the frequency of the disease obtained from a cross-sectional survey and is usually used to reflect the prevalence of chronic diseases with a long course of disease and the degree of impact on the health of the population. The morbidity is the frequency of the disease obtained from the morbidity report or cohort study, which is usually used to reflect the occurrence of new cases. ^[1]