Open-label randomized non-inferiority trial of a fixed-dose combination of glimepiride and atorvastatin for the treatment of people whose Type 2 diabetes is uncontrolled on metformin

AIMS

To evaluate, in a randomized, open-label study, the non-inferiority of a bioequivalent fixed-dose combination of glimepiride and atorvastatin vs. separately co-administered tablets in people with Type 2 diabetes mellitus.

METHODS

Participants with HbA1c ≥ 53 to < 80 mmol/mol (≥ 7.0 to < 9.5%), average fasting blood glucose > 7.0 mmol/l, who were on metformin for ≥ 3 months, were randomized to combination (n = 215) or co-administered glimepiride and atorvastatin (n = 212) once daily for 20 weeks. Up-titration of glimepiride (1-4 mg) and atorvastatin (10-20 mg) were based on average fasting blood glucose and LDL cholesterol, respectively. Co-primary endpoints were change from baseline to week 20 in HbA1c and LDL cholesterol.

RESULTS

Non-inferiority was demonstrated for both co-primary endpoints: the upper limits of 95% CIs for differences (combination-reference) were less than the prespecified margins of 3.3 mmol/mol (0.3%) for change from baseline in HbA1c [difference 0.1 mmol/mol (95% CI -1.6, 1.9); 0.01% (95% CI -0.15, 0.17)] and 6% for percentage change from baseline in LDL cholesterol [difference 0.87% (95% CI -2.47, 4.21)]. Similar proportions of participants on combination and reference had treatment-emergent adverse events (64 vs. 61%). More participants on combination had hypoglycaemia (21 vs. 13%); most events were considered by the treating physician to be unrelated to study drug.

CONCLUSIONS

The combination was non-inferior to separately co-administered tablets and the safety profile was consistent with the known profiles of glimepiride and atorvastatin. The observed increase in hypoglycaemia on the combination cannot be explained, but may be attributable to non-systematic collectiof glucose readings and may have been influenced by reporting bias in this open-label trial.

Predicting future weight status from measurements made in early childhood: a novel longitudinal approach applied to Millennium Cohort Study data

BACKGROUND/OBJECTIVE

There are reports that childhood obesity tracks into later life. Nevertheless, some tracking statistics such as correlations do not quantify individual agreement, whereas others such as diagnostic test statistics can be difficult to translate into practice. We aimed to employ a novel analytic approach, based on ordinal logistic regression, to predict weight status of 11-year-old children from measurements at age 5 years.

SUBJECTS/METHODS

The UK 1990 growth references were used to generate clinical weight status categories of 12 076 children enrolled in the Millennium Cohort Study. Using ordinal regression, we derived the predicted probability (percent chances) of 11-year-old children becoming underweight, normal weight, overweight, obese and severely obese from their weight status category at age 5 years.

RESULTS

The chances of becoming obese (including severely obese) at age 11 years were 5.7% (95% confidence interval: 5.2 to 6.2%) for a normal-weight 5-year-old child and 32.3% (29.8 to 34.8%) for an overweight 5-year-old child. An obese 5-year-old child had a 68.1% (63.8 to 72.5%) chance of remaining obese at 11 years. Severely obese 5-year-old children had a 50.3% (43.1 to 57.4%) chance of remaining severely obese. There were no substantial differences between sexes. Nondeprived obese 5-year-old boys had a lower probability of remaining obese than deprived obese boys: -21.8% (-40.4 to -3.2%). This association was not observed in obese 5-year-old girls, in whom the nondeprived group had a probability of remaining obese 7% higher (-15.2 to 29.2%). The sex difference in this interaction of deprivation and baseline weight status was therefore -28.8% (-59.3 to 1.6%).

CONCLUSIONS

We have demonstrated that ordinal logistic regression can be an informative approach to predict the chances of a child changing to, or from, an unhealthy weight status. This approach is easy to interpret and could be applied to any longitudinal data set with an ordinal outcome.

The effects of evening bright light exposure on subsequent morning exercise performance

We investigated the effects of evening bright light on the circadian timing of core temperature and morning exercise performance under conditions of high thermal stress. At 20:00 h, 8 males were exposed to a standardised light protocol and thereafter to either polychromatic bright light (2,500 lux at 50 cm, BL) or no light (0 lux, NL) for 30 min. The following morning, intermittent cycling exercise was undertaken followed by a 10 km time-trial in an environmental chamber set to 35°C and 60% relative humidity. Core body temperature was measured throughout. Data were analysed using a within-subjects model and presented as mean±SD. Time of the sleep-trough in core temperature occurred ~1.75 h later following BL (P=0.07). Prior to time-trial, core temperature was 0.27±0.42°C lower in BL (95%CI: -0.02 to 0.57, P=0.07). The time-trial was completed 1.43±0.63 min (0.98-1.87) faster in BL (P=0.001). Post time-trial, intestinal temperature was 38.21±0.56°C (37.84-38.57) in BL compared to 38.64±0.42°C (38.34-38.93) in NL (P=0.10). These data provide the first evidence that a 30-min exposure to bright light prior to sleep can influence exercise performance under hot conditions during the subsequent early morning.

Influence of nocturnal and daytime sleep on initial orthostatic hypotension

PURPOSE

The incidence of vasovagal syncope is more common in the morning. Previous researchers have reported negligible diurnal variation in the physiological responses associated with initial orthostatic hypotension (IOH). Nevertheless, physical activity and sleep prior to morning and afternoon test times have not been controlled and may influence the findings. We designed a semi-constant routine protocol to examine diurnal variation in cardiorespiratory and cerebrovascular responses to active standing.

METHODS

At 06:00 and 16:00 hours, nine males (27 ± 9 years) completed an upright-stand protocol. Altimetry-measured sleep durations were 3.3 ± 0.4 and 3.2 ± 0.6 h immediately prior to the morning and afternoon test times. Continuous beat-to-beat measurements of middle cerebral artery velocity (MCAv), mean arterial blood pressure (MAP), heart rate (HR), and end-tidal carbon dioxide were obtained. Intestinal body temperature and salivary melatonin concentrations were also measured.

RESULTS

Compared with the afternoon, resting HR and body temperature were 4 ± 2 beats min(-1) and 0.45 ± 0.2 °C lower, respectively, whereas melatonin concentration was 28.7 ± 3.2 pg ml(-1) higher in the morning (P ≤ 0.02). Although all individuals experienced IOH at both times of the day, the initial decline in MAP during standing was 13 ± 4 mmHg greater in the afternoon (P = 0.01). Nevertheless, the decline in MCAv was comparable at both times of day (mean difference: 2 ± 3 cm s(-1); P = 0.5).

CONCLUSION

These findings indicate that a bout of sleep in the afternoon in healthy young individuals results in greater IOH that is compensated for by effective cerebral blood flow regulation.

Accounting for the impact of conservation on human well-being

Conservationists are increasingly engaging with the concept of human well-being to improve the design and evaluation of their interventions. Since the convening of the influential Sarkozy Commission in 2009, development researchers have been refining conceptualizations and frameworks to understand and measure human well-being and are starting to converge on a common understanding of how best to do this. In conservation, the term human well-being is in widespread use, but there is a need for guidance on operationalizing it to measure the impacts of conservation interventions on people. We present a framework for understanding human well-being, which could be particularly useful in conservation. The framework includes 3 conditions; meeting needs, pursuing goals, and experiencing a satisfactory quality of life. We outline some of the complexities involved in evaluating the well-being effects of conservation interventions, with the understanding that well-being varies between people and over time and with the priorities of the evaluator. Key challenges for research into the well-being impacts of conservation interventions include the need to build up a collection of case studies so as to draw out generalizable lessons; harness the potential of modern technology to support well-being research; and contextualize evaluations of conservation impacts on well-being spatially and temporally within the wider landscape of social change. Pathways through the smog of confusion around the term well-being exist, and existing frameworks such as the Well-being in Developing Countries approach can help conservationists negotiate the challenges of operationalizing the concept. Conservationists have the opportunity to benefit from the recent flurry of research in the development field so as to carry out more nuanced and locally relevant evaluations of the effects of their interventions on human well-being.

Long-term soccer-specific training enhances the rate of physical development of academy soccer players independent of maturation status

The aim of the study was to compare 3-year changes in physical performance between junior soccer players selected for an elite academy and age-matched controls. The 3-year changes in indicators of the physical performance were quantified in 12-16-year-old Premier League Academy (n=27) and non-academy soccer players (n=18). Data were analysed with an age-group×competitive level general linear model, covariate-adjusted for initial performance level and change in maturation. Covariate adjusted mean±SD changes were greater (standardised effect size>0.7) for the academy players in terms of countermovement jump (7.3±2.6 vs. 5.4±2.5 cm), 10 m sprint (- 0.15±0.05 vs. - 0.10±0.04 s), 20 m sprint (- 0.30±0.16 s vs. - 0.15±0.13 s), agility (- 0.19±0.01 s vs. - 0.08±0.08 s), repeated sprint (- 0.60±0.26 s vs. - 0.41±2.1 s) and intermittent endurance capacity (1 128±406 vs. 315±370 m). These data indicate that a 3-year programme of training in an elite soccer academy is associated with greater changes in physical performance indicators independently from the initial performance level of the child and change in maturation over the same period of time.

A meta-analytic approach to quantify the dose-response relationship between melatonin and core temperature

A melatonin-mediated reduction in body temperature could be useful as a "pre-cooling" intervention for athletes, as long as the melatonin dose is optimised so that substantial soporific effects are not induced. However, the melatonin-temperature dose-response relationship is unclear in humans. Individual studies have involved small samples of different sexes and temperature measurement sites. Therefore, we meta-analysed the effects of exogenous melatonin on body core temperature to quantify the dose-response relationship and to explore the influence of moderating variables such as sex and measurement site. Following a literature search, we meta-analysed 30 data-sets involving 193 participants and 405 ingestions of melatonin. The outcome was the mean difference (95 % confidence limits) in core temperature between the melatonin and placebo-controlled conditions in each study, weighted by the reciprocal of each standard error of the difference. The mean (95 % confidence interval) pooled reduction in core temperature was found to be 0.21 °C (0.18-0.24 °C). The dose-response relationship was found to be logarithmic (P < 0.0001). Doses of 0-5 mg reduced temperature by ~0.00-0.22 °C. Any further reductions in temperature were negligible with doses >5 mg. The pooled mean reduction was 0.13 °C (0.05-0.20 °C) for oral temperature vs 0.26 °C (0.20-0.32 °C) for tympanic and 0.22 °C (0.19-0.25 °C) for rectal temperature. In conclusion, our meta-regression revealed a logarithmic dose-response relationship between melatonin and its temperature lowering effects. A 5-mg dose of melatonin lowered core temperature by ~0.2 °C. Higher doses do not substantially increase this hypothermic effect and may induce greater soporific effects.

A meta-analytic approach to quantify the dose-response relationship between melatonin and core temperature

A melatonin-mediated reduction in body temperature could be useful as a "pre-cooling" intervention for athletes, as long as the melatonin dose is optimised so that substantial soporific effects are not induced. However, the melatonin-temperature dose-response relationship is unclear in humans. Individual studies have involved small samples of different sexes and temperature measurement sites. Therefore, we meta-analysed the effects of exogenous melatonin on body core temperature to quantify the dose-response relationship and to explore the influence of moderating variables such as sex and measurement site. Following a literature search, we meta-analysed 30 data-sets involving 193 participants and 405 ingestions of melatonin. The outcome was the mean difference (95 % confidence limits) in core temperature between the melatonin and placebo-controlled conditions in each study, weighted by the reciprocal of each standard error of the difference. The mean (95 % confidence interval) pooled reduction in core temperature was found to be 0.21 °C (0.18-0.24 °C). The dose-response relationship was found to be logarithmic (P < 0.0001). Doses of 0-5 mg reduced temperature by ~0.00-0.22 °C. Any further reductions in temperature were negligible with doses >5 mg. The pooled mean reduction was 0.13 °C (0.05-0.20 °C) for oral temperature vs 0.26 °C (0.20-0.32 °C) for tympanic and 0.22 °C (0.19-0.25 °C) for rectal temperature. In conclusion, our meta-regression revealed a logarithmic dose-response relationship between melatonin and its temperature lowering effects. A 5-mg dose of melatonin lowered core temperature by ~0.2 °C. Higher doses do not substantially increase this hypothermic effect and may induce greater soporific effects.

Postural influences on the mechanical and neural components of the cardiovagal baroreflex

AIM

The ability to maintain arterial blood pressure when faced with a postural challenge has implications for the occurrence of syncope and falls. It has been suggested that posture-induced declines in the mechanical component of the baroreflex response drive reductions in cardiovagal baroreflex sensitivity associated with postural stress. However, these conclusions are largely based upon spontaneous methods of baroreflex assessment, the accuracy of which has been questioned. Therefore, the aim was to engage a partially open-loop approach to explore the influence of posture on the mechanical and neural components of the baroreflex.

METHODS

In nine healthy participants, we measured continuous blood pressure, heart rate, RR interval and carotid artery diameter during supine and standing postures. The modified Oxford method was used to quantify baroreflex sensitivity.

RESULTS

In response to falling pressures, baroreflex sensitivity was similar between postures (P = 0.798). In response to rising pressures, there was an attenuated (P = 0.042) baroreflex sensitivity (mean ± SE) in the standing position (-0.70 ± 0.11 beats min(-1) mmHg(-1)) compared with supine (-0.83 ± 0.06 beats min(-1) mmHg(-1)). This was explained by a diminished (P = 0.016) neural component whilst standing (-30.17 ± 4.16 beats min(-1) mm(-1)) compared with supine (-38.23 ± 3.31 beats min(-1) mm(-1)). These effects were consistent when baroreflex sensitivity was determined using RR interval.

CONCLUSION

Cardiovagal baroreflex sensitivity in response to rising pressures is reduced in young individuals during postural stress. Our data suggest that the mechanical component is unaffected by standing, and the reduction in baroreflex sensitivity is driven by the neural component.

Monitoring training in elite soccer players: systematic bias between running speed and metabolic power data

We compared measurements of high-intensity activity during field-based training sessions in elite soccer players of different playing positions. Agreement was appraised between measurements of running speed alone and predicted metabolic power derived from a combination of running speed and acceleration. Data was collected during a 10-week phase of the competitive season from 26 English Premier League outfield players using global positioning system technology. High-intensity activity was estimated using the total distance covered at speeds >14.4 km · h⁻¹ (TS) and the equivalent metabolic power threshold of >20 W · kg⁻¹ (TP), respectively. We selected 0.2 as the -minimally important standardised difference between methods. Mean training session TS was 478±300 m vs. 727±338 m for TP (p<0.001). This difference was greater for central defenders (~ 85%) vs. wide defenders and attackers (~ 60%) (p<0.05). The difference between methods also decreased as the proportion of high-intensity distance within a training session increased (R2=0.43; p<0.001). We conclude that the high-intensity demands of soccer training are underestimated by traditional measurements of running speed alone, especially in training sessions or playing positions associated with less high-intensity activity. Estimations of metabolic power better inform the coach as to the true demands of a training session.

Nitric oxide-mediated cutaneous microvascular function is impaired in polycystic ovary sydrome but can be improved by exercise training

Polycystic ovary syndrome (PCOS) is associated with cardiovascular disease. The contribution of the nitric oxide (NO) dilator system to cutaneous endothelial dysfunction is currently unknown in PCOS. Our aim was to examine whether women with PCOS demonstrate impaired cutaneous microvascular NO function and whether exercise training can ameliorate any impairment. Eleven women with PCOS (age, 29 ± 7 years; body mass index, 34 ± 6 kg m(-2)) were compared with six healthy obese control women (age, 29 ± 7 years; body mass index, 34 ± 5 kg m(-2)). Six women with PCOS (30 ± 7 years; 31 ± 6 kg m(-2)) then completed 16 weeks of exercise training. Laser Doppler flowmetry, combined with intradermal microdialysis of l-N(G)-monomethyl-l-arginine, a nitric oxide antagonist, in response to incremental local heating of the forearm was assessed in women with PCOS and control women, and again in women with PCOS following exercise training. Cardiorespiratory fitness, homeostasis model assessment for insulin resistance, hormone and lipid profiles were also assessed. Differences between women with PCOS and control women and changes with exercise were analysed using Student's unpaired t tests. Differences in the contribution of NO to cutaneous blood flow [expressed as a percentage of maximal cutaneous vasodilatation (CVCmax)] were analysed using general linear models. At 42°C heating, cutaneous NO-mediated vasodilatation was attenuated by 17.5%CVCmax (95% confidence interval, 33.3, 1.7; P = 0.03) in women with PCOS vs. control women. Exercise training improved cardiorespiratory fitness by 5.0 ml kg(-1) min(-1) (95% confidence interval, 0.9, 9.2; P = 0.03) and NO-mediated cutaneous vasodilatation at 42°C heating by 19.6% CVCmax (95% confidence interval, 4.3, 34.9; P = 0.02). Cutaneous microvascular NO function is impaired in women with PCOS compared with obese matched control women but can be improved with exercise training.

The practicality and effectiveness of supplementary bright light for reducing jet-lag in elite female athletes

Although bright light can alter circadian timing, the practicality and effectiveness of supplementary bright light for reducing jet-lag symptoms in world-class athletes is unclear. Therefore, we randomised 22 world class female footballers to a bright light intervention or control group before a flight from USA to Europe. Intra-aural temperature, grip strength, sleep and various jet-lag symptoms were measured serially. For 4 days, the intervention participants were exposed, in pairs within their rooms, to 2 500 lux of bright light at ≈50 cm for 45-60 min at a time-of-day predicted to accelerate circadian adjustment. On post-flight day 1, indoor light transiently increased intra-aural temperature by 0.38°C (95%CI: 0.16 to 0.60, P=0.001) and increased overall jet-lag rating by ≈1 unit. Light had negligible effects on functioning, diet, bowel and sleep symptoms, which varied substantially between- and within-subjects. In conclusion, supplementary indoor light administered within the schedule of world-class athletes was not substantially effective for reducing jet-lag symptoms after a flight from the USA-Europe. Ours is the first study of the practical effectiveness of supplementary bright light in world class athletes, although sample size was naturally small, compromises were required to implement the intervention and there appears to be large inter-individual variation in the perception of what constitutes jet-lag.

Effects of exercise intensity on flow mediated dilation in healthy humans

Previous studies have demonstrated conflicting results on the effects of acute exercise on FMD. The aim of the study was to examine brachial artery FMD before and after 3 bouts of acute exercise performed at different intensities. 10 healthy males (mean±SD age: 22±1 years) completed 30 min of cycling at 50, 70 and 85% maximal heart rate (HRmax). Brachial artery FMD and the shear rate area-under-the-curve (cuff deflation to peak dilation; SRAUC) were assessed pre- and immediately post-exercise using high-resolution echo-Doppler. A generalized estimating equation (GEE) analysis was used to estimate the effect magnitudes of exercise intensity and time (pre/post) on FMD, whilst controlling for the influence of baseline diameter and SRAUC. Both baseline diameter and SRAUC were elevated by exercise. With covariate-control of these variables, the decrease in brachial artery FMD was negligible after exercise at 50% HRmax (6.3±2.6 vs. 5.9±2.5%; 95%CI for difference: - 0.59-1.34%) with larger decreases in FMD after exercise at 70% (6.1±1.8 vs. 4.7±1.9%; 95%CI for difference: 0.08-2.58%) and at 85% HRmax (6.6±1.6 vs. 3.6±2.2%; 95%CI: 0.41-5.42%). In conclusion, even after accounting for exercise-mediated changes in shear and baseline diameter, our data indicate that a negative relationship exists between exercise intensity and FMD.