Disease latency refers to the interval between an increment of exposure and a subsequent change in an individual’s risk. This implies that the risk from a certain exposure history does not depend on cumulative exposure alone, but on the timing of exposure. It can be expected that risk varies over time in a smooth way, and this variation can be described by a latency curve. We explain how to app...

In this paper we assume that the life time of a test unit follows a log-logistic distribution with known scale parameter. Tables of optimum times of changing stress level for simple step-stress plans under a cumulative exposure model are obtained by minimizing the asymptotic variance of the maximum likelihood estimator of the model parameters at the design stress with respect to the change time...

CONTENTS Chapter 1 General introduction 7 Chapter 2 Bone mineral density as a marker of cumulative endogenous estrogen 19 exposure: relationship to background genetic risk of psychotic disorder Chapter 3 Testing the estrogen hypothesis of schizophrenia: associations between 37 cumulative estrogen exposure and cerebral structural measures Chapter 4 Bone mineral density as a marker of cumulative ...

Occupational, environmental, and nutritional epidemiologists are often interested in estimating the prospective effect of time-varying exposure variables such as cumulative exposure or cumulative updated average exposure, in relation to chronic disease endpoints such as cancer incidence and mortality. From exposure validation studies, it is apparent that many of the variables of interest are me...

BACKGROUND Epidemiological evaluations of the risk of silicosis in relation to exposure to crystalline silica have raised the question of whether different types of silica dust exposures vary with respect to their ability to cause silicosis. The aim of this study is to compare the risk of silicosis among cohorts of silica dust-exposed Chinese tin miners, tungsten miners, and pottery workers and...

The spruce beetle, Dendroctonus rufipennis (Kirby), is an important mortality agent of native spruces throughout North America. The life-cycle duration of this species varies from 1 to 3 years depending temperature. The univoltine cycle (one generation per year) is thought to maximize outbreak risk and accelerate host mortality in established outbreaks. Prepupal diapause is associated with the ...

Previous research on the association between violence and biological stress regulation has been largely cross-sectional, and has also focused on childhood. Using longitudinal data from a low-income, high-risk, predominantly African-American sample (n = 266; 57 % female), we tested hypotheses about the influence of cumulative exposure to violence during adolescence and early adulthood on cortiso...

OBJECTIVES Cumulative radiation exposure is associated with increased risk of malignancy. This is important in cystic fibrosis (CF) as frequent imaging is required to monitor disease progression and diagnose complications. Previous estimates of cumulative radiation are outdated as the imaging was performed on older equipment likely to deliver higher radiation. Our objectives were to determine t...

Evidence from laboratory animals suggests that certain rates of deposition of dust can slow the normal clearance of the lungs by macrophages. If this occurs in humans, then estimates of exposure or dose for epidemiologic models may be improved by explicity incorporating this "overload" phenomenon into lung dose estimates. Using a model of dust overload, the authors estimated the lung dust dose ...