According to the authors of recent research published in the journal Environmental Health, 'Longitudinal time-activity data are important for exposure modeling, since the extent to which short-term time-activity data represent long-term activity patterns is not well understood. This study was designed to evaluate longitudinal variations in human time-activity patterns.'
'We report on 24-hour recall diaries and questionnaires collected via the internet from 151 parents of young children (mostly under age 55), and from 55 older adults of ages 55 and older, for both a weekday and a weekend day every three months over an 18-month period. Parents also provided data for their children. The self-administrated diary and questionnaire distinguished similar to 30 frequently visited microenvironments and similar to 20 activities which we selected to represent opportunities for exposure to toxic environmental compounds. Due to the non-normal distribution of time-location/activity data, we employed generalized linear mixed-distribution mixed-effect models to examine intra-and inter-individual variations. Here we describe variation in the likelihood of and time spent engaging in an activity or being in a microenvironment by age group, day-type (weekday/weekend), season (warm/cool), sex, employment status, and over the follow-up period. As expected, day-type and season influence time spent in many location and activity categories. Longitudinal changes were also observed, e.g., young children slept less with increasing follow-up, transit time increased, and time spent on working and shopping decreased during the study, possibly related to human physiological changes with age and changes in macro-economic factors such as gas prices and the economic recession. This study provides valuable new information about time-activity assessed longitudinally in three major age groups and greatly expands our knowledge about intra-and inter-individual variations in time-location/activity patterns,' wrote X.M. Wu and colleagues, University of California (see also Environmental Health).
The researchers concluded: 'Longitudinal variations beyond weekly and seasonal patterns should be taken into account in simulating long-term time-activity patterns in exposure modeling.'
Wu and colleagues published their study in Environmental Health (Longitudinal variability of time-location/activity patterns of population at different ages: a longitudinal study in California. Environmental Health, 2011;10():1-15).
For additional information, contact X.M. Wu, University of California, Dept. of Public Health Science, Los Angeles, CA, United States.
The publisher's contact information for the journal Environmental Health is: Biomedical Central Ltd, 236 Grays Inn Rd., Floor 6, London WC1X 8HL, England.
Keywords: City:Los Angeles, State:California, Country:United States, Region:North and Central America
This article was prepared by Health & Medicine Week editors from staff and other reports. Copyright 2011, Health & Medicine Week via NewsRx.com.
