Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Jul 10;8(7):e68102.
doi: 10.1371/journal.pone.0068102. Print 2013.

Seasonal variations in notification of active tuberculosis cases in China, 2005-2012

Xin-Xu Li  1 , Li-Xia Wang, Hui Zhang, Xin Du, Shi-Wen Jiang, Tao Shen, Yan-Ping Zhang, Guang Zeng
Affiliations

Seasonal variations in notification of active tuberculosis cases in China, 2005-2012

Xin-Xu Li et al. PLoS One. .

Abstract

Background: Although seasonal variation in tuberculosis (TB) incidence has been described in many countries, it remains unknown in China.

Methods: A time series decomposition analysis (X-12-ARIMA) was performed to examine the seasonal variation in active TB cases nationwide from 2005 through 2012 in China. Seasonal amplitude was calculated for the evaluation of TB seasonal variation.

Results: A total of 7.78 million active TB cases were reported over a period of 8 years. A spring peak (April) was observed with seasonal amplitude of 46.3%, compared with the winter trough (February). Most cases in provinces with subtropical and tropical monsoon climate showed lower amplitudes than those in temperate continental, plateau and mountain climate regions. The magnitude of seasonality varied inversely with annual average temperature, r (95% CI) = -0.71 (-0.79, -0.61). The seasonal amplitudes were 56.7, 60.5, 40.6, 46.4 and 50.9% for patients aged ≤14, 15-24, 25-44, 45-64, and ≥65 years, respectively. Students demonstrated greater seasonal amplitude than peasants, migrant workers and workers (115.3% vs. 43.5, 41.6 and 48.1%). Patients with pulmonary TB had lower amplitude compared to patients with pleural and other extra-pulmonary TB (EPTB) (45.9% vs. 52.0 and 56.3%). Relapse cases with sputum smear positive TB (SS+ TB) had significantly higher seasonal amplitude compared to new cases with sputum smear positive TB (52.2% vs. 41.6%).

Conclusions: TB is a seasonal disease in China. The peak and trough of TB transmission actually are in winter and in autumn respectively after factors of delay are removed. Higher amplitudes of TB seasonality are more likely to happen in temperate continental, plateau and mountain climate regions and regions with lower annual average temperature, and young person, students, patients with EPTB and relapse cases with SS+ TB are more likely to be affected by TB seasonality.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Seasonal decomposition of active tuberculosis cases per month in the mainland of China, 2005–2012.
Original series (A) with trend cycle (B), seasonal component (C), and irregular component (D).
Figure 2
Figure 2. Peak/trough month, seasonal amplitude (%) (95% Confidence Interval) and hotspots of amplitude of active tuberculosis cases by province in the mainland of China, 2005–2012.
Figure 3
Figure 3. Climate zones in China.
Figure 4
Figure 4. Correlation of seasonal amplitude of active tuberculosis cases and annual average temperature by province in the mainland of China, 2008–2012.
Source of meteorological data: National Climate Center of China (http://ncc.cma.gov.cn/cn/). Abbreviations: CI, confidence interval.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Mabaera B, Naranbat N, Katamba A, Laticevschi D, Lauritsen JM, et al. (2009) Seasonal variation among tuberculosis suspects in four countries. International Health 1: 53–60. - PubMed
    1. Chan TY (1999) Seasonal variations in vitamin-D status and the incidence of tuberculosis in different countries. Respiration 66: 196. - PubMed
    1. Martineau AR, Nhamoyebonde S, Oni T, Rangaka MX, Marais S, et al. (2011) Reciprocal seasonal variation in vitamin D status and tuberculosis notifications in Cape Town, South Africa. Proc Natl Acad Sci U S A 108: 19013–19017. - PMC - PubMed
    1. Nagayama N, Ohmori M (2006) Seasonality in various forms of tuberculosis. Int J Tuberc Lung Dis 10: 1117–1122. - PubMed
    1. Luquero FJ, Sanchez-Padilla E, Simon-Soria F, Eiros JM, Golub JE (2008) Trend and seasonality of tuberculosis in Spain, 1996–2004. Int J Tuberc Lung Dis 12: 221–224. - PubMed