High latent tuberculous prevalence in old age homes responsible for high rate of active tuberculosis

The high prevalence of latent tuberculous in old age homes is responsible for the high rate of active tuberculosis due to reactivation.

In a recent article published in the International Journal of Tuberculosis and Lung Disease, scientists in the People’s Republic of China conducted a coss-sectional study to “determine the prevalence of tuberculous infection and the predictors of positive tuberculin reactivity in old age home residents in Hong Kong.

“A questionnaire-interview and review of medical records were carried out, together with measurement of weight and height/arm span and assessment of nutritional status. A one-stage tuberculin skin test (TST) was performed using two units of PPD RT23. An induration {{>=}}10 mm was considered as positive.”

“Of 3682 residents (71.7% participation, mean age 82 years) who agreed to undergo a TST, 46.3% had a positive reaction. Factors associated with a significantly higher risk of a positive TST included being male, an ex- or current smoker and having a past history of tuberculosis (TB),” researchers said.

“Factors associated with reduced positive tuberculin reactivity included older age groups (>70 years), a history of cancer and chronic obstructive pulmonary disease and low body mass index quartiles.

“In old age homes, the high prevalence of latent tuberculous infection is responsible for the high rate of active TB due to reactivation,” reported M. Chanyeung and colleagues at Queen Mary Hospital in Hong Kong.

The authors concluded, “Early diagnosis and treatment are necessary to prevent transmission of disease in these crowded environments with susceptible individuals.”

Chanyeung and colleagues published their study in International Journal of Tuberculosis and Lung Disease (Prevalence and determinants of positive tuberculin reactions of residents in old age homes in Hong Kong. Int J Tuberc Lung Dis, 2006;10(8):892-898).

Additional information can be obtained by contacting M. Chanyeung, Queen Mary Hospital, 4-F Professorial Block, Hong Kong, Hong Kong, People’s Republic of China.

The publisher of the International Journal of Tuberculosis and Lung Disease can be contacted at: International Union Against Tuberculosis Lung Disease (I U a T L D), 68 Boulevard Saint-Michel, 75006 Paris, France.