EVALUATION OF REPEATED MEASURES OUTCOMES IN EPIDEMIOLOGY

Abstract

This thesis aims to evaluate repeated measures outcomes in epidemiology, assuming metabolic syndrome (MetS) as the main exposure of interest. The outcomes included all-cause and cause-specific mortality, age-related cataract and age-related macular degeneration (AMD). Advanced statistical methods were used to account for possible intra-subject correlation in measures which were repeatedly recorded at baseline, 5- and 10-year follow-up. Data from Blue Mountains Eye Study showed that the effect of MetS on all-cause and cause-specific death were time-dependent. Also, the pattern of the relationship between BMI and mortality depended on age. A 5-year reduction in BMI was associated with all-cause and cancer mortality. Changes in MetS predicted the 5-year incidence of cortical and posterior subcapcular cataract. Additionally, changes in MetS predicted the incidence of late AMD during the 10-year follow-up among subjects aged <=70 years. Full utilization of baseline and follow-up information provides a more precise estimate of exposure on outcomes.