Effects of air pollution on the respiratory health of asthmatic children living in Mexico City.

The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.

Effects of urban air pollutants on emergency visits for childhood asthma in Mexico City.

The metropolitan area of Mexico City, Mexico, has serious air pollution problems. Although air contaminants may contribute to clinical asthma, there are at present no data on the relation between air pollution exposure and childhood asthma in Mexico City. The authors reviewed data on emergency visits from January to June 1990 at one major pediatric hospital in Mexico City. They used a Poisson regression model to study the relation between the number of daily emergency visits for asthma and air pollutant levels. The levels of ozone and sulfur dioxide-exposure were significantly associated with the number of emergency visits for asthma. After adjustment for potential confounding factors, the multivariate regression model predicted that an increase of 50 ppb in the 1-hour maximum ozone level would lead to a 43% increase in the number of emergency visits for asthma on the following day. Exposure to high ozone levels (> 110 ppb) for 2 consecutive days increased the number of asthma-related emergency visits by 68 percent. The results of this study suggest that ozone exposure is positively associated with the number of children's emergency visits for asthma in Mexico City.

PIP: A retrospective analysis of records of emergency visits during January-June 1990 at the Hospital Infantil de Mexico Federico Gomez in the northern section of Mexico City was conducted to examine the association between the 395 children's (16 years) emergency visits for asthma (2.5% of all emergency visits) and daily levels of different air pollutants. Most emergency visits for asthma (67%) included children aged less than 5. The mean ozone daily one-hour maximum level was 90 ppb (range: 10-250 ppb). The ozone level exceeded the Mexican ozone standard (110 ppb) on 49 days (28%). Concentrations of ozone and sulfur dioxide exposure were linked to the number of emergency visits for asthma (p = 0.001 for 1-hour maximum with 1-day lag and p = 0.07 for 1-hour maximum on same day). When the researchers controlled for confounding factors, they found that a rise in the ozone level of 50 ppb was related to a 43% increase in the number of emergency visits for asthma with a one-day lag period. 133% of these visits were made after two consecutive days of ozone levels of at least 110 ppb. Exposure to such high ozone levels increased the number of emergency visits for asthma by 68%. These findings demonstrate a positive relationship between ozone exposure and the number of children living in Mexico City who were treated for asthma. In fact, they suggest that cumulative exposure to ozone strengthens this association.

Angina, functional impairment and physical inactivity among Mexican-American women with depressive symptoms.

There has been a long-standing interest in the relationship between cardiovascular disease (CVD) and psychiatric morbidity, specifically depressive symptoms. The aims of this study were to determine the following: 1. The relationship between the presence of angina and depressive symptoms; 2. The influences of sociodemographic covariates on this relationship; and 3. The effects of functional impairment or inactivity level in mediating the relationship between angina and depressive symptoms. The data utilized for this study was from the Hispanic Health and Nutrition Examination Survey (HHANES) on 1,558 Mexican American women. The survey was cross sectional, conducted in 1982-84. The dependent variable was depression as measured by the Center for Epidemiologic Depression Scale (CES-D). The independent variable was the presence of angina as measured by the Rose Questionnaire. Covariates included functional impairment, physical activity, age, education, acculturation, poverty level, marital status, and work status. The findings suggest that functional impairment has a stronger association with depressive symptoms than angina or physical inactivity. Significant sociodemographic variables include single marital status and poverty. Comorbidity has been a neglected area of research for Mexican American women, but this study suggests that functional impairment is a more important factor associated with depressive symptomatology than angina.