Latency Period

Mesothelioma Latency Period

Mesothelioma is a non-communicable disease. There are certain characteristics of diseases that fall into this category:

• They are not caused by an infection; they result from prolonged exposure to a disease-causing agent like asbestos.
• They are chronic, meaning they last throughout a person’s lifetime and cannot be cured.
• They have a long latency period.

What is a Latency Period?

This is the time that elapses between exposure to the disease-causing agent and the development of the disease. During this period, the patient is what doctors refer to as asymptomatic, meaning the person does not show any of the signs or symptoms associated with the disease.

However, just because there aren’t any visible signs of the disease, that doesn’t mean it isn’t progressing. Non-communicable diseases progress very slowly, which is the reason there is such a long time frame between exposure to a disease-causing agent and the onset of the disease.

The Latency Period is Affected by the Level of Exposure

In non-communicable diseases, the latency period is dose-dependent. That means that the length of time between exposure and development of the disease is affected by how long the person was exposed. The more time the person spent around the disease-causing agent, the shorter the latency period. That’s why latency periods for these kinds of diseases are given in ranges.

Mesothelioma has the Longest Latency Period of Any of the Asbestos-Related Diseases

Patients can develop mesothelioma 20 to 60 years after being exposed to asbestos. That means that the majority of people who are diagnosed with this disease are between the ages of 40 to 80 years old.

In a study titled “Malignant Mesothelioma: a Clinical Study of 238 Cases”, published online December 16, 2010 in Industrial Health, two doctors from the Texas Occupational Medicine Institute reported their findings concerning 238 cases of mesothelioma, the majority of which were patients with an occupational exposure to asbestos.

The doctors found that the average latency period was a little less than 48 ½ years, and that women have a longer latency period than men. They also found that the longer the time the person was exposed to asbestos, the shorter the latency period.

The Latency Period May Also be Affected by the Level of Exposure

Researchers also believe that the intensity of the asbestos exposure has a direct effect on the length of the latency period.

In a study titled “Malignant Mesothelioma of the Pleura Among Seafarers”, published in the November-December 2005 edition of La Medicina del Lavoro (Laboratory Medicine), researchers examined autopsy results from 38 former sailors, ages 53 to 91 years old, from the Trieste-Monfalcone area in Italy who were diagnosed with mesothelioma. They worked at a variety of different trades including engine room and deck personnel.

When compared with shipyard workers, the number of asbestos bodies taken from lung sections of these sailors were less, meaning their exposure was less intense. The researchers found that these sailors had longer latency periods than the shipyard workers whose exposure intensity was greater.