Among patients with long QT syndrome (LQTS), disease severity and response to therapy vary according to the genetic mutation involved. Napolitano and colleaguesArticle performed genetic screening in 430 patients with LQTS and 1115 family members and describe the types and prevalence of mutations found. In addition, the authors confirmed their findings by testing for the identified mutations in a separate cohort of patients. Based on their results, the authors propose a strategy for genetic screening for LQTS. In an editorial, KaufmanArticle discusses the clinical importance of patient genotype in LQTS and the efficiency, affordability, accessibility, and accuracy of current genetic tests for LQTS.
Low cardiorespiratory fitness associated with physical inactivity is a risk factor for cardiovascular disease (CVD). To describe the prevalence of low fitness in the US population aged 12 through 49 years and to relate low fitness to CVD risk factors, Carnethon and colleagues reviewed results of submaximal graded exercise testing and maximal oxygen consumption from a nationally representative survey. They found low fitness in 33.6% of adolescents and 13.9% of adults. Among their findings were that body mass index and waist circumference were inversely associated with fitness and that persons with low fitness had higher total cholesterol levels and systolic blood pressure and lower high-density lipoprotein cholesterol levels compared with persons with high fitness.
An increasing occurrence and severity of Clostridium difficile–associated disease (CDAD) has been reported. Dial and colleagues conducted 2 population-based case-control studies to assess whether the use of gastric acid–suppressive agents is associated with increased risk of CDAD in the community. They found that prescribed use of a gastric acid–suppressive agent was significantly associated with risk of community-acquired CDAD. Proton pump inhibitors were associated with a higher risk than H2-receptor antagonists.
Erectile dysfunction and cardiovascular disease have similar risk factors, and it has been suggested that erectile dysfunction could be a marker for occult cardiovascular disease. To test this hypothesis, Thompson and colleagues examined the association of erectile dysfunction with subsequent cardiovascular disease in a prospective cohort study. The authors found that compared with men with no erectile dysfunction, men with erectile dysfunction had significantly increased risks of new cardiovascular events during the 7-year study.
Exposure to air pollution has been linked to an increased susceptibility to cardiovascular events, but the mechanism is not clear. In a mouse model, Sun and colleagues tested the hypothesis that long-term, low-level exposure to inhaled particulate matter has detrimental effects on the vasculature. Consistent with their hypothesis, they found that mice exposed to environmentally relevant concentrations of particulate matter had more atherosclerosis and vascular inflammation and a heightened vasoconstrictive response than mice exposed to filtered air. The effects were greater in mice fed a high-fat chow compared with mice fed normal chow.
Innovative animal studies are helping to show how stress and social factors cause changes in the brain that contribute to addiction.
Medical and legal issues in the preparticipation evaluation of competitive athletes.
The role of B-cell–related immunological memory in conferring long-term protection against invasive bacterial disease.
Health is subject to erosion from prenatal life onward, and early risk mediation is essential to preserve health.
Join Sandra Dial, MD, on January 18, 2006, to discuss new research on the use of gastric acid–suppressive agents and risk of community-acquired Clostridium difficile.
For more information and to register for “Author in the Room,” please visit http://www.ihi.org/authorintheroom.
For your patients: Information about fitness.
This Week in JAMA . JAMA. 2005;294(23):2943. doi:10.1001/jama.294.23.2943