Shift workers are at a higher risk of moderate to severe asthma, suggests new research published in the journal Thorax. Given the prevalence of both shift work and asthma in industrialized nations, the public health implications of these findings are potentially "far-reaching," warn the researchers. Around 1 in 5 employees in the developed world works permanent or rotating night shifts. Shift work causes a person's internal body clock (circadian rhythm) to be out of step with the external light and dark cycle. This misalignment is associated with a heightened risk of various metabolic disorders, cardiovascular disease, and cancer. Get the full story at sciencedaily.com.