Tuberculosis among Tibetan immigrants from India and Nepal in Minnesota, 1992-1995.
OBJECTIVE
To study screening outcomes among a group of Tibetan immigrants at high risk for developing active tuberculosis (TB) after arrival in Minnesota.


METHODS
Retrospective cohort study.


METHODS
A total of 191 Tibetan immigrants undergoing medical screening.


METHODS
Occurrence and treatment outcomes of active TB.


METHODS
A health maintenance organization and a public TB clinic in Minneapolis, Minn.


RESULTS
Positive (induration, > or =10 mm) tuberculin skin test results were documented in 98% of Tibetans, compared with 44% of Vietnamese, 10% of Hmong, and 51% of Russian refugees in Minnesota (P<.001 for each group). Sixteen active cases (8.4%) were confirmed by isolation of Mycobacterium tuberculosis; however, 5 (31%) were culture-negative on initial screening in Minnesota. Seven cases (44%) were diagnosed during initial screening efforts, and 9 cases (56%) were diagnosed a mean of 19 months (range, 10-27 months) after their initial medical evaluation. Of these 9 cases, 6 (38% of all Tibetan cases) had isolates resistant to 1 or more antituberculous drugs, and 3 (19% of all Tibetan cases) were multidrug resistant (MDR TB). All 3 MDR TB cases were culture-negative on initial screening; these cases constituted 75% of the MDR TB isolates in Minnesota in 1994. The presence of MDR TB was associated with a known history of active TB in Asia (P<.02). Any abnormality on chest radiograph noted either during the Immigration and Naturalization Service screening evaluation in India (relative risk [RR], 5.2; P=.006) or on arrival in Minnesota (RR, 6.8; P=.005) was associated with an increased risk of subsequent active TB.


CONCLUSIONS
Tuberculosis infection is nearly universal among Tibetans settling in Minnesota. A single screening evaluation failed to detect the majority of TB cases among Tibetans. Even in the face of negative M tuberculosis cultures, persons with a history of active TB require particularly close follow-up.
Truong
D H
DH
Division of Epidemiology, University of Minnesota School of Public Health, Minneapolis 55454-1015, USA.
Hedemark
L L
LL
Mickman
J K
JK
Mosher
L B
LB
Dietrich
S E
SE
Lowry
P W
PW
D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D015331:Cohort Studies; D016358:Contact Tracing; D004641:Emigration and Immigration; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D008297:Male; D008400:Mass Chest X-Ray; D008403:Mass Screening; D008910:Minnesota / Q000453:epidemiology; D009390:Nepal / Q000208:ethnology; D012036:Refugees; D012189:Retrospective Studies; D012307:Risk Factors; D018609:Tibet / Q000208:ethnology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology* / Q000517:prevention & control
D000995:Antitubercular Agents