Host factors in TB

Host factors in TB disease are various factors/attributes of the host(person who is developing TB disease/infection).

The various host factors are as follows:

• Age: TB can affect people of any age. Young adults (15-30 years of age) are seen to have high rates of disease in India. Children and the elderly are also key and vulnerable population for the contraction of the disease. 
• Gender: TB affects all genders, but males have higher disease rates, probably owing to higher levels of exposure to the bacteria in occupational settings. 
• Immunity status: Individuals with compromised immunity status, like those on corticosteroid therapy/ immunosuppressants after organ transplant, HIV infection, diabetes mellitus etc., are more prone to TB infection and disease.
• Nutritional status: Undernutrition causes weakening of the immune system and hence predisposes to TB. Risk of TB increases by about 14% with each unit reduction in Body Mass Index (BMI).
• Previous TB infection: Individuals who are close/ household contact persons of confirmed pulmonary TB patients; individuals residing in TB high-prevalence regions; key and vulnerable population like healthcare workers, homeless people, HIV infected etc., have high chances of being already infected with TB and hence, would progress to disease.

Resources

• India TB Report 2021, Central TB Division, MoHFW, Government of India. 
• TB Risk Factors, Centers for Disease Control and Prevention.

Assessment