The influence of sensitisation to pollens and moulds on seasonal variations in asthma attacks.

No large study has described the seasonal variation in asthma attacks in population-based asthmatics in whom sensitisation to allergen has been measured. 2,637 young adults with asthma living in 15 countries reported the months in which they usually had attacks of asthma and had skin-prick tests performed. Differences in seasonal patterns by sensitisation status were assessed using generalised estimating equations.

A population-based study of tuberculosis epidemiology and innovative service delivery in Canada.

Objective: To compare and interpret tuberculosis (TB) incidence rates in a Canadian population across two decennials (1989-1998 and 1999-2008) as a benchmark for World Health Organization targets and the long-term goal of TB elimination. The population under study was served by two urban clinics in the first decennial and two urban and one provincial clinic in the second.

Methods: TB rates among Status Indians, Canadian-born 'others' and the foreign-born were estimated using provincial and national databases.

CO(2) inhalation as a treatment for apnea of prematurity: a randomized double-blind controlled trial.

Objective: To compare the effect of prolonged inhalation of a low concentration of CO(2) with theophylline for the treatment of apnea of prematurity.

Study Design: Prospective, randomized, double-blind controlled trial of 87 preterm infants with apnea of prematurity (27-32 weeks' gestational age) assigned to either theophylline plus 0.5 L/min of room air via nasal prongs or placebo plus 0.

The tuberculin skin test is unreliable in school children BCG-vaccinated in infancy and at low risk of tuberculosis infection.

Background: The tuberculin skin test (TST) is often used to screen for latent tuberculosis infection (LTBI) in school children, many of whom were bacille Calmette-Guérin (BCG)-vaccinated in infancy. The reliability of the TST in such children is unknown.

Methods: TSTs performed in low-risk BCG-vaccinated and -nonvaccinated grade 1 and grade 6 First Nations (North American Indian) school children in the province of Alberta, Canada, were evaluated retrospectively.

Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country.

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data.