The impact of altitude on mortality from tuberculosis and pneumonia

To examine the association between altitude and mortality from tuberculosis (TB) and pneumonia-influenza in Mexico.

We analysed specific causes of death in Mexico according to death certificates for the period 1993-1997, totalling over 2,700,000 deaths and including nearly 23,000 attributed to TB and 115,000 to pneumonia and influenza. Thirty population subgroups were formed based on altitude of residence (six categories) and level of poverty (five categories). The effect of altitude on mortality was estimated through Poisson regression models, with adjustment for age, gender and socioeconomic status.

Adjusted death rates for TB decreased with altitude and increased for pneumonia-influenza. Compared to people living below 500 m above sea level, those living between 2000 and 2499 m had a 58% mortality rate for TB and a three-fold increase in mortality due to pneumonia-influenza, despite adjustment for poverty, age and gender.

The mortality rate for TB based on death certificates decreases with altitude of residence, whereas the opposite is observed for pneumonia and influenza.