[Hypersensitivity pneumonitis in Mexico City].
OBJECTIVE
To investigate the association between the urban area of origin of patients and the prevalence of hypersensitivity pneumonitis (HP), induced by avian antigens.


METHODS
A case-control study was conducted in 1999 at the National Institute of Respiratory Diseases (NIRD). Cases were 109 consecutive HP patients and controls were 184 patients: 39 with idiopathic pulmonary fibrosis (IPF), 63 with pulmonary tuberculosis (PTB), and 82 with asthma. Mexico City and surrounding counties (SC) were divided into 5 geographical areas: 1) Downtown; 2) North-East (NE); 3) South-East (SE); 4) North-West (NW) and 5) South-West (SW). Statistical analysis consisted of calculation of disease prevalence by urban area; associations were assessed with odds ratios and 95% confidence intervals. Multivariate analysis with multiple logistic regression was performed to adjust for age, gender and socioeconomic level.


RESULTS
Eighty HP cases were located in the NE southernmost and SE northernmost areas of Mexico City (48 and 32, respectively) (OR = 3.86; 95% CI 2.17-6.96). Thirty-six controls with asthma came from the SW area, (where NIRD is located) (p < 0.05), and four from SC. Controls with PTB and IPF were scattered throughout the study area.


CONCLUSIONS
The NE southernmost and SE northernmost areas were associated with HP. The cause of HP may not be geographical; a garbage dump used to be located in this area, suggesting that exposure to organic particles might contribute to the development of HP in susceptible individuals.
Carrillo-Rodríguez
J G
JG
Clínica de Enfermedades Intersticiales del Pulmón, Instituto Nacional de Enfermedades Respiratorias (INER), México. josecr@data.net.mx
Sansores
R H
RH
Castrejón
A
A
Pérez-Padilla
R
R
Ramírez-Venegas
A
A
Selman
M
M
D000328:Adult; D000542:Alveolitis, Extrinsic Allergic / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D012959:Socioeconomic Factors; D014505:Urban Population