Hip protectors to prevent hip fractures - a waste of time and money?

Abstract:
Background: An estimated 30-60% of older
adults fall every year and about 1% of falls result in a hip fracture. Hip fracture is a serious and growing problem, with a 3-10 fold rise in worldwide incidence predicted by 2050 (Gullberg, et al 1997). Hip protectors are underwear with built in protection for the greater trochanter. They are designed to prevent hip fractures by dispersing or absorbing the force of a fall. Trials
published to 2001 were broadly supportive of
the effectiveness of hip protectors, and this
was reflected in a Cochrane review in 2000.
However, earlier trials were methodologically
flawed and subsequent trials have not demonstrated effectiveness. The most recent Cochrane review describes only a marginal benefit (Parker et al, 2005).
Review and Discussion: This presentation
evaluates the current evidence for the use
of hip protectors and discusses the use of
that evidence by manufacturers, suppliers,
professional groups and guideline developers.
Interestingly, despite the limitations of the
evidence base, most advice has been broadly
supportive. Reasons for this are proposed
and discussed in the context of a critique of
evidence-based healthcare. protectors. However, the available evidence can be used in different ways and for different purposes by those with an interest in promoting
the use of hip protectors. A conservative
approach is warranted, where, if we cannot
demonstrate that hip protectors work, we
presume that they do not. This presentation will be of use to practitioners wanting to evaluate the evidence base for hip protectors (and other recommended interventions) on behalf of clients. It will also be of interest to policy makers who must assess the claims made for health care technologies as part of the decisionmaking process.
Recommended reading:
Gullberg B, Johnell O, Kanis JA (1997) Worldwide
projections for hip fracture. Osteoporos
Int. 7(5):407-13 .
Parker MJ, Gillespie WJ, Gillespie LD (2005) Hip
protectors for preventing hip fractures in older
people. The Cochrane Database of Systematic
Reviews Issue 3. Art. No.: CD001255.pub3. DOI:
10.1002/14651858.CD001255.pub3.

Rigorous Specification and Low-Latency Implementation of Technical Market Indicators

Technical market indicators are tools used by technical an- alysts to understand trends in trading markets. Technical (market) indicators are often calculated in real-time, as trading progresses. This paper presents a mathematically- founded framework for calculating technical indicators. Our framework consists of a domain specific language for the un- ambiguous specification of technical indicators, and a run- time system based on Click, for computing the indicators. We argue that our solution enhances the ease of program- ming due to aligning our domain-specific language to the mathematical description of technical indicators, and that it enables executing programs in kernel space for decreased latency, without exposing the system to users’ programming errors.

Mutual Funds and Mispriced Stocks

We find a strong negative predictive relation between the propensity of active mutual funds to hold overpriced stocks and their subsequent performance. High-propensity funds, or overpriced funds, display poor stock picking skills as they further purchase overpriced stocks during episodes of fund inflows. Interestingly, overpriced funds attract considerable capital inflows during high sentiment episodes, after controlling for the effects of past fund performance. The overall evidence is consistent with the notion that overpriced funds, unable to improve their stock picking skills through time, target optimistic investors by engaging in marketing activities and catering to preferences for skewed returns.

The influence of market deregulation on fast food consumption and body mass index:A cross-national time series analysis

Objective
To investigate the effect of fast food consumption on mean population body mass index (BMI) and explore the possible influence of market deregulation on fast food consumption and BMI.

Methods
The within-country association between fast food consumption and BMI in 25 high-income member countries of the Organisation for Economic Co-operation and Development between 1999 and 2008 was explored through multivariate panel regression models, after adjustment for per capita gross domestic product, urbanization, trade openness, lifestyle indicators and other covariates. The possible mediating effect of annual per capita intake of soft drinks, animal fats and total calories on the association between fast food consumption and BMI was also analysed. Two-stage least squares regression models were conducted, using economic freedom as an instrumental variable, to study the causal effect of fast food consumption on BMI.

Findings
After adjustment for covariates, each 1-unit increase in annual fast food transactions per capita was associated with an increase of 0.033 kg/m2 in age-standardized BMI (95% confidence interval, CI: 0.013–0.052). Only the intake of soft drinks – not animal fat or total calories – mediated the observed association (β: 0.030; 95% CI: 0.010–0.050). Economic freedom was an independent predictor of fast food consumption (β: 0.27; 95% CI: 0.16–0.37). When economic freedom was used as an instrumental variable, the association between fast food and BMI weakened but remained significant (β: 0.023; 95% CI: 0.001–0.045).

Conclusion
Fast food consumption is an independent predictor of mean BMI in high-income countries. Market deregulation policies may contribute to the obesity epidemic by facilitating the spread of fast food.

Offshore wind power forecasting error and electricity market implications

Wind energy has been identified as key to the European Union’s 2050 low carbon economy. However, as wind is a variable resource and stochastic by nature, it is difficult to plan and schedule the power system under varying wind power generation. This paper investigates the impacts of offshore wind power forecast error on the operation and management of a pool-based electricity market in 2050. The impact of the magnitude and variance of the offshore wind power forecast error on system generation costs, emission costs, dispatch-down of wind, number of start-ups and system marginal price is analysed. The main findings of this research are that the magnitude of the offshore wind power forecast error has the largest impact on system generation costs and dispatch-down of wind, but the variance of the offshore wind power forecast error has the biggest impact on emissions costs and system marginal price. Overall offshore wind power forecast error variance results in a system marginal price increase of 9.6% in 2050.

Disinflation with labor market frictions

This paper studies disinflationary shocks in a non-linear New Keynesian model with search and matching frictions and moral hazard in the labor markets. Our focus is on understanding the wage formation process as well as welfare costs of disinflations in the presence of such labor market frictions.

The presence of imperfect information in labor markets imposes a lower bound on worker surplus that varies endogenously. Consequently equilibrium can take two forms depending on whether the no shirking condition is binding or not. We also evaluate both regimes from a welfare perspective when the economy is subject to a perfectly credible disinflationary shock.

Impacts of compressed air energy storage plant on an electricity market with a large renewable energy portfolio

Renewable energy generation is expected to continue to increase globally due to renewable energy targets and obligations to reduce greenhouse gas emissions. Some renewable energy sources are variable power sources, for example wind, wave and solar. Energy storage technologies can manage the issues associated with variable renewable generation and align non-dispatchable renewable energy generation with load demands. Energy storage technologies can play different roles in each of the step of the electric power supply chain. Moreover, large scale energy storage systems can act as renewable energy integrators by smoothing the variability. Compressed air energy storage is one such technology. This paper examines the impacts of a compressed air energy storage facility in a pool based wholesale electricity market in a power system with a large renewable energy portfolio.

Impact of offshore wind power forecast error in a carbon constraint electricity market

This paper investigates the impacts of offshore wind power forecast error on the operation and management of a pool-based electricity market in 2050. The impact from offshore wind power forecast errors of up to 2000 MW on system generation costs, emission costs, dispatch-down of wind, number of start-ups and system marginal price are analysed. The main findings of this research are an increase in system marginal prices of approximately 1% for every percentage point rise in the offshore wind power forecast error regardless of the average forecast error sign. If offshore wind power generates less than forecasted (−13%) generation costs and system marginal prices increases by 10%. However, if offshore wind power generates more than forecasted (4%) the generation costs decrease yet the system marginal prices increase by 3%. The dispatch down of large quantities of wind power highlights the need for flexible interconnector capacity. From a system operator's perspective it is more beneficial when scheduling wind ahead of the trading period to forecast less wind than will be generated.

Lead in rice: Analysis of baseline lead levels in market and field collected rice grains

In a large scale survey of rice grains from markets (13 countries) and fields (6 countries), a total of 1578 rice grain samples were analysed for lead. From the market collected samples, only 0.6% of the samples exceeded the Chinese and EU limit of 0.2 μg g− 1 lead in rice (when excluding samples collected from known contaminated/mine impacted regions). When evaluating the rice grain samples against the Food and Drug Administration's (FDA) provisional total tolerable intake (PTTI) values for children and pregnant women, it was found that only people consuming large quantities of rice were at risk of exceeding the PTTI from rice alone. Furthermore, 6 field experiments were conducted to evaluate the proportion of the variation in lead concentration in rice grains due to genetics. A total of 4 of the 6 field experiments had significant differences between genotypes, but when the genotypes common across all six field sites were assessed, only 4% of the variation was explained by genotype, with 9.5% and 11% of the variation explained by the environment and genotype by environment interaction respectively. Further work is needed to identify the sources of lead contamination in rice, with detailed information obtained on the locations and environments where the rice is sampled, so that specific risk assessments can be performed.