Physical Activity- and Alcohol-dependent Association Between Air Pollution Exposure and Elevated Liver Enzyme Levels: An Elderly Panel Study

Objectives:

The deleterious effects of air pollution on various health outcomes have been demonstrated. However, few studies have examined the effects of air pollution on liver enzyme levels.

Methods:

Blood samples were drawn up to three times between 2008 and 2010 from 545 elderly individuals who regularly visited a community welfare center in Seoul, Korea. Data regarding ambient air pollutants (particulate matter ≤2.5 μm PM_2.5], nitrogen dioxide NO₂], ozone O₃], carbon monoxide, and sulfur dioxide) from monitoring stations were used to estimate air pollution exposure. The effects of the air pollutants on the concentrations of three liver enzymes (aspartate aminotransferase AST], alanine aminotransferase ALT], and γ-glutamyltranspeptidase γ-GTP)]) were evaluated using generalized additive and linear mixed models.

Results:

Interquartile range increases in the concentrations of the pollutants showed significant associations of PM_2.5 with AST (3.0% increase, p=0.0052), ALT (3.2% increase, p=0.0313), and γ-GTP (5.0% increase, p=0.0051) levels; NO₂ with AST (3.5% increase, p=0.0060) and ALT (3.8% increase, p=0.0179) levels; and O₃ with γ-GTP (5.3% increase, p=0.0324) levels. Significant modification of these effects by exercise and alcohol consumption was found (p for interaction <0.05). The effects of air pollutants were greater in non-exercisers and heavy drinkers.

Conclusions:

Short-term exposure to air pollutants such as PM_2.5, NO₂, and O₃ is associated with increased liver enzyme levels in the elderly. These adverse effects can be reduced by exercising regularly and abstinence from alcohol.