Cohort study designs have several advantages over case-control studies in terms of exposure measurement. If exposure measurement occurs before disease occurrence, cohort studies are much less prone to differential measurement error. Prospective data collection should also reduce measurement error due to poor recall of past exposures. The primary drawback of cohort studies is the large sample si...

BACKGROUND As part of a larger study of the role of close contacts in the transmission of M. leprae, we explored whether the proportion of newly detected cases with a family history of leprosy differs with different incidence rates of leprosy in a population. METHODS Retrospective analysis was performed of contacts of all new leprosy patients diagnosed during a 10-yr period in well-establishe...

The airship Italia, commanded by General Umberto Nobile, crashed during its return flight from the North Pole in 1928. The cause of the accident was never satisfactorily explained. We present evidence that the crash may have been fatigue-related. Nobile's memoirs indicate that at the time of the crash he had been awake for at least 72 h. Sleep deprivation impairs multiple aspects of cognitive f...

OBJECTIVE To analyze the cases of tuberculosis and the impact of direct follow-up on the assessment of treatment outcomes. METHODS This open prospective cohort study evaluated 504 cases of tuberculosis reported in the Sistema de Informação de Agravos de Notificação (SINAN - Notifiable Diseases Information System) in Juiz de Fora, MG, Southeastern Brazil, between 2008 and 2009. The incidence of ...

With increasing frequency, patients are being asked to make complex decisions about cancer screening, prevention, and treatment. These decisions are fraught with emotion and cognitive difficulty simultaneously. Many Americans have low numeracy skills making the cognitive demands even greater whenever, as is often the case, patients are presented with risk statistics and asked to make comparison...

OBJECTIVE To study whether formal education and occupational class are associated with incidence of rheumatoid arthritis overall and with the incidence of the two major subgroups of rheumatoid arthritis-seropositive (RF+) and seronegative (RF-) disease. METHODS 930 cases and 1126 controls participated in a population based case-control study using incident cases of rheumatoid arthritis, carri...

STUDY OBJECTIVE To examine the effect of a comprehensive prenatal and delivery programme administered by nurse-midwives on the risk of low weight births among indigent women. STUDY DESIGN Historical prospective study. Birth outcomes among the cohort were compared with all county births during the same period, adjusting for maternal age and race. Results are expressed as relative risks with 95...

Deltas are highly sensitive to increasing risks arising from local human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. We quantified changing flood risk due to extreme events using an integrated set of global environmental, geophysical, and social indicators. Although risks are distributed across all levels of economic development, wealthy ...

OBJECTIVE To identify the relative risk (RR) of mortality in bereaved parents compared with non-bereaved counterparts. DESIGN Retrospective data linkage study. SETTING United Kingdom, 1971-2006. PARTICIPANTS A random sample from death registrations (5%) of parents who had a live birth where the infant lived beyond its first year of life (non-bereaved parents) and parents who had experienc...