Temporal trends in chronic obstructive pulmonary disease mortality in Mexico, 1999-2014.

SETTING: Country of Mexico. OBJECTIVE: To determine mortality trends due to chronic obstructive pulmonary disease (COPD) in Mexico between 1999 and 2014. DESIGN: COPD mortality data for persons aged ≥40 years from 1999 to 2014 were obtained from the official website of the Mexican Ministry of Health. Age-standardised mortality rates (ASMRs) were calculated, and joinpoint regression analysis was used to identify trends over time. The annual per cent change (APC) was determined for each trend. RESULTS: A total of 313,962 COPD deaths (crude rate 66.3 per 100,000 population) was reported. Between 1999 and 2014, overall ASMRs decreased from 75.5 to 62.2/100,000 (APC -0.6, P = 0.03): from 94 to 74.7 (APC -0.8, P = 0.004) in males and from 59.7 to 51.8 (APC -0.2, P = 0.4) in females. CONCLUSIONS: COPD mortality rates in Mexico are slowly declining overall and among males. The reduction in smoking prevalence over time, and the new cigarette taxes and smoking laws implemented during the study period, have had no immediate impact on mortality. The lack of a decline in COPD mortality among females needs to be further investigated, particularly in rural areas, where the prevalence of biomass smoke exposure remains high.

Demographic risk factors of pulmonary colonization by non-tuberculous mycobacteria.

SETTING: British Columbia (BC), Canada. OBJECTIVE: To determine the risk factors for pulmonary colonization by non-tuberculous mycobacteria (NTM). DESIGN: Retrospective study of subjects colonized by NTM from 1990 to 2006. Subjects without mycobacterial disease and with at least three negative cultures served as controls. RESULTS: Mycobacterium avium complex (MAC) species were the most common NTM. Risk factors of colonization included age > or = 60 years (aOR 2.3), female sex (aOR 1.2), residency in Canada for at least 10 years (aOR 3.8), Canadian-born aboriginal (aOR 1.8), and Canadian-born non-aboriginal (aOR 1.4). Predictors of MAC colonization included White race (aOR 1.6) and residency in Canada for at least 10 years, which was the strongest predictor (aOR 6.7). Aboriginal origin was associated with non-MAC colonization (aOR 1.8), and Canadian-born people from the East/South-East Asian ethnic groups were protected from MAC colonization (aOR 0.2), all aOR P < 0.05. CONCLUSION: Older age, female sex, having been born in Canada, long residency in BC and White race predict pulmonary NTM colonization, while Aboriginal origin predicts non-MAC colonization. Further research is needed to identify environmental NTM sources in BC and to determine their relation to colonization and disease.

The incidence of pulmonary non-tuberculous mycobacteria in British Columbia, Canada.

SETTING: British Columbia Centre for Disease Control (BCCDC), Vancouver, Canada. OBJECTIVE: To determine the incidence of non-tuberculous mycobacteria (NTM) and to assess the impact of new laboratory techniques. DESIGN: Population-based study of all subjects with positive cultures for NTM from 1990 to 2006. RESULTS: Mycobacterium avium complex (MAC) was the most common NTM isolate (77%). The median incidence rates per 100 000 population in the total sample were respectively 6.7, 4.5 and <0.7 for all NTMs, MAC and all non-MAC species; for NTM-treated subjects the rates were respectively 1.6, 1.4 and <0.08; and for the NTM-colonised they were respectively 4.7, 2.7 and <0.5. In the period after the introduction of new laboratory techniques, all NTM isolates, the overall MAC rate and the MAC-colonised rate increased by respectively 24%, 35.4% and 76% (P < 0.05). All NTM isolates and rates for all NTMs, NTM-treated and M. tuberculosis subjects (used as comparison group) decreased over time (P < 0.05). CONCLUSION: The most common NTM species was MAC. Episodic increases in the number of isolates and incidence rates of subjects colonised with MAC are likely to be associated with the implementation of new laboratory techniques, which may represent an artefact. The decrease in rates of NTM-treated subjects is reassuring.

Risk of tuberculosis in screened subjects without known risk factors for active disease.

SETTING: Tuberculosis (TB) referral clinic in Vancouver, British Columbia, Canada. BACKGROUND: Screening for and treatment of latent TB infection (LTBI) in at-risk populations are the cornerstone of TB control in low-incidence countries. Persons at low risk often undergo the tuberculin skin test (TST) for reasons other than contact. Little information exists on the actual risk of TB in this population. OBJECTIVE: To determine the risk of TB in screened subjects without known risk factors. DESIGN: Retrospective descriptive analysis of demographics, TST reaction size and TB disease occurrence in 98333 low-risk subjects screened from 1990 to 2002. RESULTS: The average annual disease rate was 0.4 per 100000 population (cumulative rate 7.4/100000) from 1990 to 2006, and TB was diagnosed only in the foreign-born. Risk of TB in the foreign-born increased with larger TST reaction size (P < 0.03). Completion of treatment for LTBI was not documented for any of the subsequent active TB cases. CONCLUSION: In a low-risk screened population, active TB disease was found only in the foreign-born. Treatment of LTBI is not recommended in persons with a positive TST and no additional risk factors. Local screening programs should focus on populations with confirmed risk factors for disease.

The prevalence and predictors of tuberculin positivity in subjects screened for reasons other than contact investigation.

BACKGROUND: No previous studies have estimated the rates of tuberculin positivity (TP) in noncontact populations within the same community, which is important for prioritizing and implementing preventive measures. OBJECTIVES: To estimate the prevalence and predictors of TP in noncontact populations. METHODS: A retrospective analysis of tuberculin results of noncontact populations screened in British Columbia from 1990 to 2002 was conducted. RESULTS: The period prevalence of TP in 59,791 screened subjects was 12.7% (95% CI 12.4% to 13.0%), 30.4% (95% CI 28.2% to 32.7%) and 60.9% (95% CI 60.3% to 61.6%) for Canadian-born non-Aboriginals (CBNAs), Canadian-born Aboriginals (CBAs) and foreign born (FB), respectively. After controlling for age and sex, independent predictors of TP included Bacille Calmette-Guérin (BCG) vaccination (OR 19.6, 95% CI 17.9 to 21.5), country of birth (CBA: OR 2.87, 95% CI 2.44 to 3.37; FB: OR 3.67, 95% CI 3.34 to 4.03) and the following populations: correctional centre residents (OR 4.14, 95% CI 1.87 to 9.15), residents of long-term care and community care facilities (OR 1.79, 95% CI 1.44 to 2.23), immigrants (OR 1.75, 95 % CI 1.50 to 2.04), health centre employees (OR 1.71, 95 % CI 1.56 to 1.88), volunteers (OR 1.38, 95% CI 1.14 to 1.68), self-referred healthy subjects (OR 1.30, 95% CI 1.15 to 1.48) and students (OR 1.27, 95% CI 1.19 to 1.35). CBAs, FB and male subjects were less likely to react to tuberculin than CBNAs and female subjects among those vaccinated with Bacille Calmette-Guérin (P<0.05). CONCLUSIONS: Rates of TP correlate with disease rates by sex and origin. The continuation of tuberculin screening programs is warranted in noncontact populations with high TP rates, where unknown exposure to active cases is more likely to occur. Further research is needed to determine the reasons why a higher response to tuberculin occurs in BCG-vaccinated women and CBNAs.

Risk of tuberculosis in children from smear-negative source cases.

SETTING: British Columbia, Canada. OBJECTIVE: To determine the frequency of smear-negative tuberculosis (TB) transmission events from adults to children in epidemiologically linked pairs and to determine the predictors for identifying the source case. DESIGN: We extracted demographic, clinical and mycobacteriology information of 190 children with TB and their 83 source cases reported from 1990 to 2001 in the province of British Columbia. Smear-negative transmission events from adults to children were determined by identifying the smear results of epidemiologically linked source cases. We compared the sex, age, ethnicity, contact history, site of disease and tuberculin skin test (TST) results of children who had a source case identified with those who had not. RESULTS: Smear-negative source cases transmitted the disease to 10% of children (95%CI 5-17). Aboriginals (OR 4.9, 95%CI 1.5-13.4), those with primary TB (OR 7.3, 95%CI 3.3-16.0) and those with a positive TST (OR 2.9, 95%CI 1.2-7.0) were independent predictors for source case identification. CONCLUSION: This study suggests lower rates of transmission of disease to children from smear-negative sources compared to other studies involving all ages. Ethnicity of children, site of disease and a positive TST predict source case identification.

Wood smoke exposure and lung adenocarcinoma in non-smoking Mexican women.

OBJECTIVE: To determine the association between long-term exposure to wood smoke from cooking and lung adenocarcinoma in non-smoking Mexican women. METHODS: We reviewed records of hospitalized patients at a chest referral hospital in Mexico City and identified 113 histologically proven lung adenocarcinoma cases in non-smoking women. Four control groups of non-smoking women were also selected: 99 patients with pulmonary tuberculosis (PTB), 110 with interstitial lung disease (ILD), 64 with miscellaneous pulmonary conditions (MISC), and the three control groups combined (COMB) (n = 273). RESULTS: Exposure was assessed on the basis of questionnaire responses at the time of hospital admission. Exposure to wood smoke for more than 50 years, but not for shorter periods, was associated with lung cancer after adjusting for age, education, socio-economic status and environmental tobacco smoke (ETS) exposure. Adjusted odds ratios from the multivariable logistic regression models were 1.4 (95%CI 0.6-2.0) for cases vs. TB controls, 1.9 (95%CI 0.9-4.0) for cases vs. ILD controls, 2.6 (95%CI 1.0-6.3) for cases vs. MISC controls and 1.9 (95%CI 1.1-3.5) for cases vs. COMB controls. CONCLUSION: These findings suggest that long-term exposure to wood smoke from cooking may contribute to the development of lung cancer.

Transmission of tuberculosis from smear negative patients: a molecular epidemiology study.

BACKGROUND: While smear positive patients with tuberculosis (TB) are considered more infectious than smear negative patients, the latter can also transmit TB. METHODS: In a molecular epidemiology study of 791 patients in the Greater Vancouver regional district, the number of episodes of TB transmission from two groups of smear negative clustered patients by RFLP (assumed to be involved in recent transmission) was estimated after assessing for potential bias. Group 1 (n = 79) included patients with pulmonary TB or pulmonary + extrapulmonary disease (PTB or PTB+EPTB); group 2 (n = 129) included all patients in group 1 + extrapulmonary cases alone. RESULTS: In the total sample the mean (SD) age was 51 (21) years, 54.3% were male, and 17.0% of patients were clustered. Compared with smear negative patients, smear positive patients were more likely to be in a cluster (OR = 2.0, 95% CI 1.1 to 3.6) and to have had a history of ethanol abuse (OR = 2.7, 95% CI 1.0 to 6.7), diabetes mellitus (OR = 2.8, 95% CI 1.1 to 7.0), injection drug use (OR = 3.1, 95% CI 1.1 to 8.3), and to have had a previous hospital admission (OR = 8.5, 95% CI 5.1 to 14.0). The proportion of episodes of transmission from smear negative clustered patients ranged from 17.3% to 22.2% in group 1 and from 25% to 41% in group 2. CONCLUSION: In Greater Vancouver, smear negative cases appear responsible for at least one sixth of culture positive episodes of TB transmission.

Air pollution and respiratory health in Mexico City.

To determine the effect of air pollution in Mexico City on respiratory health, patient visits for upper respiratory tract infections were monitored in five clinics. Levels of ozone, nitrogen dioxide, carbon monoxide, and sulfur dioxide, and climatological variables were collected. Correlations of filtered data revealed an association between NO2 and O3 with an increase in visits to clinics because of respiratory problems. Autoregressive analysis indicated that pollutant levels/respiratory visits associations remained significant even after simultaneous inclusion of temperature, suggesting that air pollution was associated with 10 to 16% of the clinic visits. The relative risk indicated that high levels of O3 and NO2 could increase the total number of clinic visits to between 19 and 43% above average. The other pollutants and the control group did not demonstrate significant associations.