Does Exposure to Indoor Allergens Contribute to the Development of Asthma and Allergy?

Common indoor allergens include house dust mite, cockroach, animal dander, and certain molds. In genetically susceptible children, exposure to these indoor allergens during the critical postnatal period may lead to sensitization in early childhood. Consistent evidence indicates that children sensitized to common indoor allergens are at several-fold higher risk of asthma and allergy. Due to conflicting evidence from prospective studies, some doubt remains regarding a direct and dose–response relationship between exposure and development of asthma. However, in recent years, evidence has accumulated that exposure to indoor allergen causes asthma and allergy, but this effect may depend on dose and type of allergen as well as the underlying genetic susceptibility of the child.     

Is the Mechanism of Supraventricular Tachycardia in Pediatrics Influenced by Age,Gender or Ethnicity?

Background. The mechanism of supraventricular tachycardia (SVT) in adults is influenced by age and gender. The purpose of this study was to determine whether age, gender, or ethnicity impact the mechanism of SVT in pediatric patients. Methods. A search of the Pediatric Electrophysiology Registry identified patients who had undergone a radiofrequency ablation for SVT from 1999 to 2004. Patients were grouped into categories based on the mechanism of tachycardia, age, gender, and ethnicity. US Census data from 2000 served as a benchmark for expected race and gender distributions. Results. The study looked at 3556 patients (≤7 years, n = 378; 7–12 years, n = 964; 12–21 years, n = 2214), with 1948 males, 2916 whites, 266 blacks, 248 Hispanics, 63 Asians, and 63 of another ethnicity. For accessory pathways (APs), there were 2418 patients (1405 male), and for atrioventricular node reentry tachycardia (AVNRT), there were 1138 patients (544 male). The APs decreased in proportion with increasing age; conversely, AVNRT increased with increasing age (P < .001). Significant differences were found in gender distribution between APs and AVNRT in the 12–21 years age group, with females more likely to have AVNRT than AP (P < .0001). No significant gender differences were present at younger ages. With respect to ethnicity, APs were more common than AVNRT in the white, black, and Hispanic ethnic groups (P < .02). When comparisons were made between ethnic groups from our registry and US Census data, whites had a much higher frequency of SVT than their representation in the US population (85% vs. 68.7%), while blacks (8.7% vs. 15%) and Hispanics (5.6% vs. 17.0%) had a lower frequency of SVT than their representation in the US population (P < .0001). Conclusion. The mechanism of SVT in pediatric patients is associated with age, gender, and ethnicity. The proportion of SVT due to APs decreases as age increases. Among children older than 12 years, females are more likely than males to have AVNRT as the mechanism of tachycardia. The racial distribution of patients in the registry differs from that of the US population, with a greater proportion of whites seen in the registry.     

Does the metabolic syndrome add to the diagnosis and treatment of cardiovascular disease?

Much controversy has surrounded both the pathological basis and the clinical utility of the metabolic syndrome. Key questions still revolve around the definition of this syndrome, its utility as a predictor of cardiovascular risk, and the treatment implications of diagnosis. The metabolic syndrome is associated with increased cardiovascular risk. However, the metabolic syndrome clearly underperforms compared with other, established prediction equations, such as the Framingham Risk Score and SCORE (Systemic COronary Risk Evaluation). Differences arise because the components are highly correlated (whereas other tools specifically include independent predictors) and because diagnosis is based on dichotomized variables. These facts, together with uncertain pathophysiology, mean that the metabolic syndrome in its current manifestation has limited utility for the diagnosis and treatment of cardiovascular disease. The syndrome has, however, served and continues to serve a useful purpose in raising awareness of the metabolic consequences of obesity, and as a spur for research into metabolic risk factor interactions.     

Vitamin D, UV, and skin cancer in the elderly: to expose or not to expose?

There is mounting concern about vitamin D insufficiency, especially in the ageing population. Increases in indoor lifestyle, obesity, car travel, clothing habits, the use of photo-protective makeup, and campaigns driven by dermatologists, governments, and the cosmetic industry to avoid or protect against the sun as much as possible are contributing to this trend. In a recent article in Gerontology, Barysch et al. [1] recommend that the ageing population avoid any 'intentional' UV radiation as well as 'minimize sun exposure' based on known dangers of developing skin cancer. They warn that 'studies with vitamin D supplements reported increased risks of prostate and esophagus cancer as well as atopy in childhood' and concluded that 'adequate levels of vitamin D are essential for the elderly', but do not suggest which level is optimal. I will argue that the ageing population should keep their serum 25-(OH)-vitamin D(3) (25-(OH)-D) levels in the 75-100 nmol/l range. An oral cholecalciferol intake of ～2,000 IU/day is recommended as a supplement throughout the year for those who cannot enjoy the sun in summer or only during 'vitamin D winter' for the others.