Our individual fixed effect estimation strategy using the longitudinal data attempts to remove individual level time-invariant preference and health endowment that may affect the decision to donate and the health impact.
How well the unweighted average approximates the average of the individual-level time- and location-weighted ambient air pollutant concentrations is difficult to evaluate because the spatial distribution of monitoring stations differed by pollutant.
With these individual-level data, we can adjust for individual-level time-varying and non-time-varying confounding factors.
HEALS is a population-based prospective cohort study in Araihazar, Bangladesh, using individual-level time-weighted measures of arsenic exposure via drinking water.
This birth cohort study had daily air pollutant data for 5 months each year, respiratory outcomes over a 10-year calendar period, and individual-level time-varying home environmental factors on > 1,000 children.
Among the major strengths of the present study are use of individual-level, time-weighted water arsenic measures, micronutrient measure from a validated instrument, and the large size of the study population.
We performed a cross-sectional study using baseline data from the Health Effects of Arsenic Longitudinal Study (HEALS), 2000 2002, with individual-level, time-weighted measures of arsenic exposure from drinking water.
Detailed information about water consumption in the preceding years from questionnaires was used to construct the individual-level, time-weighted arsenic (TWA) exposure measure, taking into account both arsenic concentration and duration of water drinking from the index tube well (Ahsan et al. 2006a).
An additional 570 (4.8%) subjects were excluded either because there was not enough information in the questionnaire about their water-drinking habits to permit estimation of individual-level, time-weighted arsenic measures or because they did not undergo a physical examination for skin lesions status.
On the individual level, total time for PA in the four PA domains and total time for walking, moderate PA and vigorous PA, all expressed in minutes/week, were computed http://www.ipaq.ki.se at follow-up.
