Predictors of Mycobacterium tuberculosis infection in international adoptees

The objective of this study was to measure the factors that are associated with Mycobacterium tuberculosis infection in international adoptees.

A retrospective chart review was conducted on 880 international adoptees who presented to the International Adoption Clinic at the University of Minnesota between 1986 and 2001. Five tuberculin units of purified protein derivative were placed intradermally on the left forearm. The largest diameter of induration was measured in millimeters between 48 and 72 hours. Nutritional status was assessed using anthropometric measures at initial screening. Data on age, birth country, and year of adoption were assessed.

Adoptees (mean age: 26 months; range: 1-200 months; 62% female) came from 33 birth countries. Twenty-eight percent and 5% had evidence of chronic and acute malnutrition, respectively. Twelve percent had evidence of M. tuberculosis infection. The odds of M. tuberculosis infection increased 7% for each subsequent year during the period studied, increased 142% with each additional year of age for children < or = 24 months of age at baseline screening, and increased 15% with each additional year of age for children > 24 months of age at the time of evaluation. Tuberculin skin test induration response was not associated with nutritional status or birth region.

Our study demonstrated a high prevalence of M. tuberculosis infection and malnutrition in internationally adopted children, placing them at considerable risk for progression to tuberculosis disease. These findings also support current guidelines recommending completion of tuberculin screening immediately after adoption.