1.
Vitamin D for secondary prevention of acute wheeze attacks in preschool and school-age children.
Stefanidis, C, Martineau, AR, Nwokoro, C, Griffiths, CJ, Bush, A
Thorax. 2019;(10):977-985
Abstract
INTRODUCTION Vitamin D is best known for its role in bone health; however, the discovery of the vitamin D receptor and the expression of the gene encoding the vitamin D 1α-hydroxylase (CYP27B1) enzyme in a wide variety of tissues including immune cells and respiratory epithelium has led to the discovery of potential roles for vitamin D in the prevention of acute wheeze. METHODS We review here the literature concerning the relationships between circulating 25-hydroxyvitamin D (25(OH)D) concentration and secondary prevention of acute wheeze attacks in preschool and school-age children. RESULTS Epidemiological data suggest that vitamin D insufficiency (25(OH)D <75 nmol/L) is highly prevalent in preschool and school-age children with wheeze. Preschool age children with a history of wheeze attacks and circulating 25(OH)D <75 nmol/L are at increased risk and frequency of future acute wheeze. However, no consistent association between low vitamin D status and risk of acute wheeze is reported in school-age children. Seven randomised controlled trials (RCTs) with relatively small sample sizes (30-430) and variable quality showed inconsistent results regarding the effect of oral vitamin D supplementation during childhood on the risk of asthma attacks, asthma symptom control, inhaled corticosteroid requirements, spirometry and unscheduled healthcare attendances for wheeze. A RCT showed that vitamin D supplementation had no effect on the frequency of unplanned healthcare attendances due to acute wheeze in 22 preschool children. DISCUSSION An evidence-based recommendation for the use of vitamin D as a preventive therapy for wheeze attacks cannot be made until results of further trials are available. The assessment of circulating 25(OH)D concentration and the optimisation of vitamin D status to prevent acute respiratory tract infections, and to maintain skeletal and general health in preschool and school-age children with acute wheeze is worthwhile in its own right, but whether this will reduce the risk of acute wheeze attacks is unclear.
2.
The AUStralian MEDiterranean Diet Heart Trial (AUSMED Heart Trial): A randomized clinical trial in secondary prevention of coronary heart disease in a multiethnic Australian population: Study protocol.
Itsiopoulos, C, Kucianski, T, Mayr, HL, van Gaal, WJ, Martinez-Gonzalez, MA, Vally, H, Kingsley, M, Kouris-Blazos, A, Radcliffe, J, Segal, L, et al
American heart journal. 2018;:4-11
Abstract
The Mediterranean diet was first characterized as a heart-protective diet in the 1960s. The significant cardioprotective effects of the Mediterranean diet in comparison to the standard-care low-fat diet have been established in the primary prevention of cardiovascular disease (CVD); however, there is insufficient evidence in secondary prevention research to influence the current standard of care. Opportunity exists to assess the Mediterranean diet as a therapeutic target for secondary CVD prevention within Australia's ethnoculturally diverse communities. The AUSMED Heart Trial is a multisite randomized controlled trial that will evaluate the efficacy of the Mediterranean diet for secondary prevention of CVD in the Australian health care setting. This trial aims to evaluate the effect of a 6-month Mediterranean diet intervention (delivered by dietitians) versus a "standard-care" low-fat diet in reducing the composite incidence of cardiovascular events at 12 months and at trial end in participants with documented evidence of a previous acute myocardial infarction at trial entry. The quality of the diet at baseline and follow-up will be assessed using comprehensive dietary questionnaires and diaries as well as relevant dietary biomarkers (such as urinary polyphenols and erythrocyte fatty acids). Cardiovascular risk markers, including novel measures of immune and inflammatory status, endothelial function, vascular compliance, platelet activity, and body composition, will be collected to explore possible mechanisms for treatment effect. Cost-effectiveness will also be estimated to support policy translation. We plan to recruit 1,032 participants (516 per arm) from cardiology clinics in major Australian hospitals in Melbourne, Adelaide, and Brisbane.