Meta-analysis of the life style factors relevant to environmental hazards for the aging population

The population of older adults in the United States is rapidly expanding and is expected to exceed 70 million people by 2030. Aging changes activity patterns, exposure, physiology, and susceptibility to environmental exposures. With aging, human body organ systems may become more vulnerable to environmental hazards accompanied by a reduced capacity to detoxify and eliminate toxicants. Health effects resulting from a lifetime of toxicant exposures may also become manifest with age.

The goal of this U.S. Environmental Protection Agency (EPA) study is to characterize activity patterns, physiological changes, and environmental exposures for the aging population. A related aspect is to identify data gaps that need to be addressed in order to adequately model health risks in the elderly population.

Over 2000 articles were reviewed to collect information on life-style factors, daily time/activity data, physical activity, physiological changes, dietary intakes, and chronic illness and disabilities in the aging population. Meta analysis was performed to evaluate the lifestyle factors most relevant to the aging population, and to develop statistical distributions of inputs to EPA's time series exposure models. These data will provide information to reduce uncertainties in conducting risk assessments for the aging population, especially in better characterizing intake dose rates in elderly people. This information will also be used to evaluate the differential susceptibility of this heterogeneous aging population as it relates to decisions affecting public health protection. In addition, these data should provide age-specific information for EPA's Exposure Factors Handbook.