In the biomass exposure COPD group the rate of FEV1 decline is slower and shows a more homogeneous rate of decline over time in comparison with smokers. The rapid rate of FEV1 decline is a rare feature of biomass-induced airflow limitation.

IntroductionBiomass smoke exposure (BSE) is a recognized cause of COPD particularly in rural areas. However, little research has been focused on BSE in suburban areas.ObjectiveThe aim of this study was to determine the prevalence of COPD, respiratory symptoms (RS) and BSE in women living in a suburban area of Mexico City exposed to BSE.MethodsA cross-sectional epidemiological survey of a female population aged >35 years was performed using a multistage cluster sampling strategy. The participants completed questionnaires on RS and COPD risk factors. The COPD prevalence was based on the postbronchodilator forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) ratio. Of the 1,333 women who completed the respiratory questionnaires, spirometry data were obtained from 1,190, and 969 of these were scored as A–C.ResultsThe prevalence of BSE was 47%, and the estimated prevalence of COPD was 2.5% for the total population (n=969) and 3.1% for those with BSE only. The spirometry and oximetry values were significantly lower in women with greater exposure levels. The prevalence of RS (cough, phlegm, wheezing and dyspnea) was significantly higher in the women with BSE compared to those without exposure. We concluded that the association of COPD with biomass exposure is not only a rural phenomenon but also may be observed in the suburban areas of the big cities.

BackgroundPhysicians do not routinely recommend smokers to undergo spirometry unless they are symptomatic.ObjectiveTo test the hypothesis that there are a significant number of asymptomatic smokers with chronic obstructive pulmonary disease (COPD), we estimated the prevalence of COPD in a group of asymptomatic smokers.MethodsTwo thousand nine hundred and sixty-one smokers with a cumulative consumption history of at least 10 pack-years, either smokers with symptoms or smokers without symptoms (WOS) were invited to perform a spirometry and complete a symptom questionnaire.ResultsSix hundred and thirty-seven (21.5%) smokers had no symptoms, whereas 2,324 (78.5%) had at least one symptom. The prevalence of COPD in subjects WOS was 1.5% when considering the whole group of smokers (45/2,961) and 7% when considering only the group WOS (45/637). From 329 smokers with COPD, 13.7% were WOS. Subjects WOS were younger, had better lung function and lower cumulative consumption of cigarettes, estimated as both cigarettes per day and pack-years. According to severity of airflow limitation, 69% vs 87% of subjects were classified as Global Initiative for Chronic Obstructive Lung Disease stages I–II in the WOS and smokers with symptoms groups, respectively (P<0.001). A multivariate analysis showed that forced expiratory volume in 1 second (mL) was the only predictive factor for COPD in asymptomatic smokers.ConclusionPrevalence of COPD in asymptomatic smokers is 1.5%. This number of asymptomatic smokers may be excluded from the benefit of an “early” intervention, not just pharmacological but also from smoking cessation counseling. The higher forced expiratory volume in 1 second may contribute to prevent early diagnosis.

Chronic obstructive pulmonary disease (COPD) is a complex and multifactorial disease with a strong genetic component. Our objective is to identify the genetic variants associated with COPD risk and its severity in Mexican Mestizo population. We evaluated 1285 single-nucleotide polymorphisms (SNPs) of candidate genes in 299 smokers with COPD (COPD-S) and 531 smokers without COPD (SWOC) using an Illumina GoldenGate genotyping microarray. In addition, 251 ancestry informative markers were included. Allele A of rs2545771 in CYP2F2P is associated with a lower risk of COPD (p = 4.02E-10, odds ratio [OR] = 0.104, confidence interval [CI] 95% 0.05-0.18). When the COPD group was stratified by severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD; levels III + IV vs. I + II), 3 SNPs (rs4329505 and rs4845626 in interleukin 6 receptor [IL6R] and rs1422794 in a disintegrin and metalloproteinase domain 19 [ADAM19]) were associated with a lower risk of suffering the most severe stages of the disease. rs2819096 in the surfactant protein D (SFTPD) gene was associated with a higher risk of COPD GOLD III + IV (p = 7.79E-03, OR = 1.80, CI 95% 1.16-2.79). Finally, the haplotype in IL6R was associated with a lower risk of suffering from more severe COPD, whereas the haplotype in ADAM19 was associated with a higher risk (p = 7.40E-03, OR = 2.83, CI 95% 1.20-6.86) of suffering from the severe stages of the disease. Our data suggest that there are alleles and haplotypes in the IL6R, ADAM19, and SFTPD genes associated with different severity stages of COPD; in CYP2F2P, rs25455771 is associated with a lower risk of COPD.

Polymorphisms in MMP2 and MMP9 but not in MMP1 and MMP12 are associated with the risk of COPD in the Mexican mestizo population.