Ambient air pollution and hospitalization for congestive heart failure among elderly people in seven large US cities

Objectives. Preexisting data sets were used to investigate the association between hospital admissions for congestive heart failure and air pollutants. Methods. Medicare hospital admissions data, ambient air pollution monitoring data, and meteorological data were used to create daily values of hospital admissions for congestive heart failure, maximum hourly temperature, and maximum hourly levels of carbon monoxide, nitrogen dioxide, sulfur dioxide, and ozone. Data were compiled for each of seven cities (Chicago, Detroit, Houston, Los Angeles, Milwaukee, New York, and Philadelphia) for 1986 through 1989. Single-pollutant and multipollutant models with adjustments for temperature, seasonal effects, and weekly cycles were used in conducting negative binomial regression analyses. Results. Ambient carbon monoxide levels were positively associated with hospital admissions for congestive heart failure in the single-pollutant and multipollutant models for each of the seven cities. The relative risk of hospital admission for congestive heart failure associated with an inerease of 10 ppm in carbon monoxide ranged from 1.10 in New York to 1.37 in Los Angeles. Conclusions. Hospital admissions for congestive heart failure exhibited a consistent association with daily variations in ambient carbon monoxide. This association was independent of season, temperature, and other major gaseous pollutants. (Am J Public Health. 1995;85:1361-1365)
Carbon monoxide concentration in the air appears to be associated with increased hospital admissions for congestive heart failure. Researchers correlated air pollution data between 1986 and 1989 with Medicare hospital admissions for congestive heart failure in Chicago, Detroit, Houston, Los Angeles, Milwaukee, New York, and Philadelphia. An increase in carbon monoxide levels was associated with an increase in hospital admissions in all seven cities. The increase persisted after taking into account the season, temperature, and the concentrations of the air pollutants nitrogen dioxide, sulfur dioxide, and ozone. Carbon monoxide was associated with 11% of admissions for congestive heart failure in Los Angeles, 4.5% in Chicago, 4% in Detroit and New York, 3.5% in Milwaukee, 3% in Philadelphia, and 2% in Houston. Carbon monoxide may cause heart failure in susceptible persons by directly poisoning the heart muscle or by placing additional demands on the heart to pump more blood to compensate for lower available oxygen levels.