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Responses of patients with persistent asthma to ambient air pollution may be different from those of general populations. For example, asthma medications may modify the effects of ambient air pollutants on peak expiratory flow (PEF). Few studies examined the association between air pollution and PEF in patients with persistent asthma on well-defined medication regimens using asthma clinical trial data. Airway obstruction effects of ambient air pollutants, using 14,919 person-days of daily self-measured peak expiratory flow (PEF), were assessed from 154 patients with persistent asthma during the 16 wk of active treatment in the Salmeterol Off Corticosteroids Study trial. The three therapies were an inhaled corticosteroid, an inhaled long-acting β-agonist, and placebo. The participants were nonsmokers aged 12 through 63 yr, recruited from 6 university-based ambulatory care centers from February 1997 to January 1999. Air pollution data were derived from the U.S. Environmental Protection Agency Aerometric Information Retrieval System. An increase of 10 ppb of ambient daily mean concentrations of NO2 was associated with a decrease in PEF of 1.53 L/min (95% confidence interval [CI] -2.93 to -0.14) in models adjusted for age, gender, race/ethnicity, asthma clinical center, season, week, daily average temperature, and daily average relative humidity. The strongest association between NO2 and PEF was observed among the patients treated with salmeterol. Negative associations were also found between PEF and SO2 and between PEF and PM10, respectively. The results show that the two medication regimens protected against the effects of PM10. However, salmeterol increased the sensitivity to NO2 and triamcinalone enhanced the sensitivity to SO2. [ABSTRACT FROM AUTHOR]

Concerns regarding human milk in our society are diverse, ranging from the presence of environmental chemicals to the health of breastfed infants and the economic value of breastfeeding to society. The panel convened for the Technical Workshop on Human Milk Surveillance and Biomonitoring for Environmental Chemicals in the United States, held at the Hershey Medical Center, Pennsylvania State College of Medicine, on 24–26 September 2004, considered how human milk research may contribute to environmental health initiatives to benefit society. The panel concluded that infant, maternal, and community health can benefit from studies using human milk biomonitoring. Unlike other biological specimens, human milk provides information regarding exposure of the mother and breastfed infant to environmental chemicals. Some of the health topics relevant to this field of research include disorders of growth and development in infants, cancer origins in women, and characterization of the trend of exposure to environmental chemicals in the community. The research focus will determine the design of the study and the need for the collection of alternative biological specimens and the long-term storage of these specimens. In order to strengthen the ability to interpret study results, it is important to identify reference ranges for the chemicals measured and to control for populations with high environmental chemical exposure, because the amount of data on environmental chemical levels in human milk that is available for comparison is extremely limited. In addition, it will be necessary to validate models used to assess infant exposure from breastfeeding because of the variable nature of current models. Information on differences between individual and population risk estimates for toxicity needs to be effectively communicated to the participant. Human milk research designed to answer questions regarding health will require additional resources to meet these objectives. [ABSTRACT FROM AUTHOR]

Human milk is a unique biological matrix that can be used to estimate exposures in both the mother and the breastfed infant. In addition, the presence of environmental chemicals in human milk may act as a sentinel for exposures to a broader population. Several factors play a role in determining the quantity of chemicals transferred to milk and, subsequently, to the breastfeeding infant, including maternal, infant, and chemical characteristics. Exposure to certain environmental chemicals during critical periods can disrupt normal infant development, yet few data exist to quantify the hazards posed by environmental chemicals in human milk. Chemicals measured in human milk may also provide insights to agents suspect in altering breast development and breast-related disease risk. Carefully designed exposure assessment and toxicokinetic studies are needed to elucidate mechanisms and establish relationships between human milk and other biologic matrices. Data from human milk biomonitoring studies can be used to inform and validate models that integrate information about chemical properties, human metabolism, and biomarker concentrations. Additional research is needed to determine the degree to which environmental chemicals enter, are present in, and are excreted from human milk, their impact on the host (mother), and the extent of their bioavailability to breastfeeding infants. This article describes how the collection and use of exposure data from human milk biomonitoring in the United States can be designed to inform future research and policy. [ABSTRACT FROM AUTHOR]