Morbidity

The term morbidity is generally used with the intention of expressing the frequency with which a given disease occurs in the population. In this sense, to say that a disease is one of the most common causes of morbidity means to underline its widespread diffusion in the population. On the other hand, rare diseases are characterized by very low morbidity.

This interpretation of the term reflects in all respects the meaning of "morbidity", the two words being often used as synonyms, especially in epidemiology. In occupational medicine, however, the term morbidity refers to the "lost work activity due to a disease; this parameter is calculated by running the percentage ratio between the days of absence from work due to its cause and the number of expected working days for the group of subjects considered.

The cold, for example, is an associated disease:

• very high morbidity (or very high morbidity if the two terms are used interchangeably, therefore considering them as the ratio between the number of sick subjects and the total population)
• and low morbidity (if considered as the number of working days lost due to the disease, which being mild, does not generally prevent people from going to work).