Inborn errors of metabolism (IEM) are a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, more than 1000 different IEM have been identified. While individually rare, the cumulative incidence has been shown to be upwards of 1 in 800. Clinical presentations are protean, complicating diagnostic pathways. IEM are present in all ethnic groups and across every age. Some IEM are amenable to treatment, with promising outcomes. However, high clinical suspicion alone is not sufficient to reduce morbidities and mortalities. In the last decade, due to the advent of tandem mass spectrometry, expanded newborn screening (NBS) has become a mandatory public health strategy in most developed and developing countries. The technology allows inexpensive simultaneous detection of more than 30 different metabolic disorders in one single blood spot specimen at a cost of about USD 10 per baby, with commendable analytical accuracy and precision. The sensitivity and specificity of this method can be up to 99% and 99.995%, respectively, for most amino acid disorders, organic acidemias, and fatty acid oxidation defects. Cost-effectiveness studies have confirmed that the savings achieved through the use of expanded NBS programs are significantly greater than the costs of implementation. The adverse effects of false positive results are negligible in view of the economic health benefits generated by expanded NBS and these could be minimized through increased education, better communication, and improved technologies. Local screening agencies should be given the autonomy to develop their screening programs in order to keep pace with international advancements. The development of biochemical genetics is closely linked with expanded NBS. With ongoing advancements in nanotechnology and molecular genomics, the field of biochemical genetics is still expanding rapidly. The potential of tandem mass spectrometry is extending to cover more disorders. Indeed, the use of genetic markers in T-cell receptor excision circles for severe combined immunodeficiency is one promising example. NBS represents the highest volume of genetic testing. It is more than a test and it warrants systematic healthcare service delivery across the pre-analytical, analytical, and post-analytical phases. There should be a comprehensive reporting system entailing genetic counselling as well as short-term and long-term follow-up. It is essential to integrate existing clinical IEM services with the expanded NBS program to enable close communication between the laboratory, clinicians, and allied health parties. In this review, we will discuss the history of IEM, its clinical presentations in children and adult patients, and its incidence among different ethnicities; the history and recent expansion of NBS, its cost-effectiveness, associated pros and cons, and the ethical issues that can arise; the analytical aspects of tandem...

This article examines the impact of distance on global tourist flows through an analysis of departing visitor share from 41 major source markets to 146 destinations. The study concludes that 80% of all international travel occurs to countries within 1,000 kilometers of the source market and that, with few exceptions, distant destinations have great difficulty attracting more than a 1% or 2% share of departures. However, high volatility in share within each distance cohort was also noted. Regression analysis of variation in share by distance suggests that market access and the level of tourism development within a destination distort movement patterns regardless of distance. Relationship variables played an important role in short-haul travel; a mix of source, destination, and relationship characteristics influence travel to medium haul destinations; and destination attributes influence share at long-haul destinations.

Objective: To study the inter-relationships between sleeping hours, working hours and obesity in subjects from a working population.Research design: A cross-sectional observation study under the 'Better Health for Better Hong Kong' Campaign, which is a territory-wide health awareness and promotion program. Subjects: 4793 subjects (2353 (49.1%) men and 2440 (50.9%) women). Their mean age (7s.d.) was 42.478.9 years (range 17-83 years, median 43.0 years). Subjects were randomly selected using computer-generated codes in accordance to the distribution of occupational groups in Hong Kong. Results: The mean daily sleeping time was 7.0671.03 h (women vs men: 7.1471.08 h vs 6.9870.96 h, Po0.001). Increasing body mass index (BMI) was associated with reducing number of sleeping hours and increasing number of working hours reaching significance in the whole group as well as among male subjects. Those with short sleeping hour (6 h or less) and long working hours (49 h) had the highest BMI and waist in both men and women. Based on multiple regression analysis with age, smoking, alcohol drinking, systolic and diastolic blood pressure, mean daily sleeping hours and working hours as independent variables, BMI was independently associated with age, systolic and diastolic blood pressure in women, whereas waist was associated with age, smoking and blood pressure. In men, blood pressure, sleeping hours and working hours were independently associated with BMI, whereas waist was independently associated with age, smoking, blood pressure, sleeping hours and working hours in men. Conclusion: Obesity is associated with reduced sleeping hours and long working hours in men among Hong Kong Chinese working population. Further studies are needed to investigate the underlying mechanisms of this relationship and its potential implication on prevention and management of obesity.

Much of the research documenting the size and importance of special interest (SI) tourism is based on secondary analysis of visitor survey data. Segments are defined by analyzing responses to activity questions, with the assumption being that activities are a valid proxy for motives to travel or trip purpose. The soundness of this approach is based on two suppositions that do not appear to have been questioned. The first is that visitor surveys are constructed in such a way that valid SI trip-purpose segments can be defined. The second is the existence of a direct correlation between actions and motivations. This article illustrates that both suppositions are unfounded, resulting in the production of figures that overstate the true importance of SI tourism as a trip generator by as much as 20 times. The authors call for the discontinuation of the method.

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