Seasonality of active TB notification from 2005 to 2014 in Xinjiang, China
Abstract
Objectives
Xinjiang is one of the
highest TB-burdened provinces of China. A time-series analysis
was conducted to evaluate the trend, seasonality of active TB in
Xinjiang, and explore the underlying mechanism of TB seasonality
by comparing the seasonal variations of different subgroups.
Methods
Monthly active TB cases from
2005 to 2014 in Xinjiang were analyzed by the X-12-ARIMA
seasonal adjustment program. Seasonal amplitude (SA) was
calculated and compared within the subgroups.
Results
A total of 277,300 confirmed
active TB cases were notified from 2005 to 2014 in Xinjiang,
China, with a monthly average of 2311±577. The
seasonality of active TB notification was peaked in March and
troughed in October, with a decreasing SA trend. The annual
77.31% SA indicated an annual mean of additional TB cases
diagnosed in March as compared to October. The
0–14-year-old group had significantly higher SA than
15–44-year-old group (P<0.05). Students had the highest
SA, followed by herder and migrant workers (P<0.05). The
pleural TB cases had significantly higher SA than the pulmonary
cases (P <0.05). Significant associations were not observed
between SA and sex, ethnic group, regions, the result of sputum
smear microcopy, and treatment history (P>0.05).
Conclusion
TB notification in
Xinjiang shows an apparent seasonal variation with a peak in
March and trough in October. For the underlying mechanism of TB
seasonality, our results hypothesize that winter indoor crowding
increases the risk of TB transmission, and seasonality was
mainly influenced by the recent exogenous infection rather than
the endogenous reactivation.
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Source:
PLOS ONE
