Table 2. Variables correlated with the annual change in TB incidence rate in 134 countries over 1997–2006, by country groupa,b.
| Variable | Sub-Saharan Africa | Central and eastern Europe | High-income countries | Eastern Mediterranean | Latin America and the Caribbean | South-east Asia and the western Pacific | All country groups |
|---|---|---|---|---|---|---|---|
| Composite development | |||||||
| Human development index | –0.60 | –0.20 | |||||
| Economy | |||||||
| Corruption perception index | –0.52 | ||||||
| GDP per capita | –0.61 | +0.34 | –0.21c | ||||
| Annual change in GDP | |||||||
| People with income < 1 PPP$ | |||||||
| People with income < 2 PPP$ | +0.43 | ||||||
| Income inequality | |||||||
| Population | |||||||
| Population aged ≥ 15 years | |||||||
| Urban population | |||||||
| Percentage of foreign-born TB patients | +0.47c | ||||||
| Behavioural and biological risk factors | |||||||
| Diabetes in people aged 20–79 years | –0.47c | ||||||
| Undernourished people | +0.36 | +0.31 | |||||
| Adult male smokers | |||||||
| Adult female smokers | –0.45 | ||||||
| HIV prevalence | +0.41 | ||||||
| HIV prevalence in TB patients | +0.26 | ||||||
| People with improved water source | –0.41c | ||||||
| People with improved sanitation | –0.40c | –0.43c | –0.26 | ||||
| People using solid fuels | +0.30 | ||||||
| Health services | |||||||
| Total health expenditure per capita | –0.66c | ||||||
| Government health expenditure per capita | –0.63 | ||||||
| Total health expenditure as % of GDP | –0.23 | –0.53c | |||||
| Health workers per 1000 population | +0.33 | ||||||
| Under-5 mortality | +0.36c | ||||||
| Annual change in under-5 mortality | +0.39 | +0.35 | –0.29c | +0.25c | |||
| TB control programmes | |||||||
| Expenditure on TB control per capitad | +0.49c | ||||||
| Expenditure per TB control per patientd | |||||||
| New TB cases detectedd | |||||||
| New smear+ TB cases detectedd | –0.32c | ||||||
| Treatment success in DOTS cohortsd | |||||||
| New TB cases successfully treatedd | |||||||
| New smear+ TB cases successfully treatedd | |||||||
GDP, gross domestic product; PPP$, purchasing power parity dollar; TB, tuberculosis. a The countries in each group are listed in Appendix B (available at: www.who.int/tb/publications/en/). b The numbers are values of r² for associations that were significant in univariate linear regression (r² > 0.20; P < 0.05). Cells are blank where there was no significant association. c Variables that yielded significance and were retained in a minimal multivariate model. d This variable is a measure of the intensity of TB control.