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Dive into the research topics where Alison Avenell is active.

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Featured researches published by Alison Avenell.


The Lancet | 2005

Oral vitamin D3 and calcium for secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled trial

Adrian Grant; Alison Avenell; Marion K Campbell; Alison McDonald; Graeme MacLennan; Gladys McPherson; F Anderson; C Cooper; Roger M. Francis; Cam Donaldson; W.J. Gillespie; C.M. Robinson; David Torgerson; W.A. Wallace

BACKGROUND Elderly people who have a fracture are at high risk of another. Vitamin D and calcium supplements are often recommended for fracture prevention. We aimed to assess whether vitamin D3 and calcium, either alone or in combination, were effective in prevention of secondary fractures. METHODS In a factorial-design trial, 5292 people aged 70 years or older (4481 [85%] of whom were women) who were mobile before developing a low-trauma fracture were randomly assigned 800 IU daily oral vitamin D3, 1000 mg calcium, oral vitamin D3 (800 IU per day) combined with calcium (1000 mg per day), or placebo. Participants who were recruited in 21 UK hospitals were followed up for between 24 months and 62 months. Analysis was by intention-to-treat and the primary outcome was new low-energy fractures. FINDINGS 698 (13%) of 5292 participants had a new low-trauma fracture, 183 (26%) of which were of the hip. The incidence of new, low-trauma fractures did not differ significantly between participants allocated calcium and those who were not (331 [12.6%] of 2617 vs 367 [13.7%] of 2675; hazard ratio (HR) 0.94 [95% CI 0.81-1.09]); between participants allocated vitamin D3 and those who were not (353 [13.3%] of 2649 vs 345 [13.1%] of 2643; 1.02 [0.88-1.19]); or between those allocated combination treatment and those assigned placebo (165 [12.6%] of 1306 vs 179 [13.4%] of 1332; HR for interaction term 1.01 [0.75-1.36]). The groups did not differ in the incidence of all-new fractures, fractures confirmed by radiography, hip fractures, death, number of falls, or quality of life. By 24 months, 2886 (54.5%) of 5292 were still taking tablets, 451 (8.5%) had died, 58 (1.1%) had withdrawn, and 1897 (35.8%) had stopped taking tablets but were still providing data for at least the main outcomes. Compliance with tablets containing calcium was significantly lower (difference: 9.4% [95% CI 6.6-12.2]), partly because of gastrointestinal symptoms. However, potentially serious adverse events were rare and did not differ between groups. INTERPRETATION The findings do not support routine oral supplementation with calcium and vitamin D3, either alone or in combination, for the prevention of further fractures in previously mobile elderly people.


BMJ | 2010

Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis

Mark J Bolland; Alison Avenell; John A. Baron; Andrew Grey; Graeme MacLennan; Greg Gamble; Ian R. Reid

Objective To investigate whether calcium supplements increase the risk of cardiovascular events. Design Patient level and trial level meta-analyses. Data sources Medline, Embase, and Cochrane Central Register of Controlled Trials (1966-March 2010), reference lists of meta-analyses of calcium supplements, and two clinical trial registries. Initial searches were carried out in November 2007, with electronic database searches repeated in March 2010. Study selection Eligible studies were randomised, placebo controlled trials of calcium supplements (≥500 mg/day), with 100 or more participants of mean age more than 40 years and study duration more than one year. The lead authors of eligible trials supplied data. Cardiovascular outcomes were obtained from self reports, hospital admissions, and death certificates. Results 15 trials were eligible for inclusion, five with patient level data (8151 participants, median follow-up 3.6 years, interquartile range 2.7-4.3 years) and 11 with trial level data (11 921 participants, mean duration 4.0 years). In the five studies contributing patient level data, 143 people allocated to calcium had a myocardial infarction compared with 111 allocated to placebo (hazard ratio 1.31, 95% confidence interval 1.02 to 1.67, P=0.035). Non-significant increases occurred in the incidence of stroke (1.20, 0.96 to 1.50, P=0.11), the composite end point of myocardial infarction, stroke, or sudden death (1.18, 1.00 to 1.39, P=0.057), and death (1.09, 0.96 to 1.23, P=0.18). The meta-analysis of trial level data showed similar results: 296 people had a myocardial infarction (166 allocated to calcium, 130 to placebo), with an increased incidence of myocardial infarction in those allocated to calcium (pooled relative risk 1.27, 95% confidence interval 1.01 to 1.59, P=0.038). Conclusions Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.


BMJ | 2011

Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis

Mark J Bolland; Andrew Grey; Alison Avenell; Greg Gamble; Ian R. Reid

Objectives To investigate the effects of personal calcium supplement use on cardiovascular risk in the Women’s Health Initiative Calcium/Vitamin D Supplementation Study (WHI CaD Study), using the WHI dataset, and to update the recent meta-analysis of calcium supplements and cardiovascular risk. Design Reanalysis of WHI CaD Study limited access dataset and incorporation in meta-analysis with eight other studies. Data source WHI CaD Study, a seven year, randomised, placebo controlled trial of calcium and vitamin D (1g calcium and 400 IU vitamin D daily) in 36 282 community dwelling postmenopausal women. Main outcome measures Incidence of four cardiovascular events and their combinations (myocardial infarction, coronary revascularisation, death from coronary heart disease, and stroke) assessed with patient-level data and trial-level data. Results In the WHI CaD Study there was an interaction between personal use of calcium supplements and allocated calcium and vitamin D for cardiovascular events. In the 16 718 women (46%) who were not taking personal calcium supplements at randomisation the hazard ratios for cardiovascular events with calcium and vitamin D ranged from 1.13 to 1.22 (P=0.05 for clinical myocardial infarction or stroke, P=0.04 for clinical myocardial infarction or revascularisation), whereas in the women taking personal calcium supplements cardiovascular risk did not alter with allocation to calcium and vitamin D. In meta-analyses of three placebo controlled trials, calcium and vitamin D increased the risk of myocardial infarction (relative risk 1.21 (95% confidence interval 1.01 to 1.44), P=0.04), stroke (1.20 (1.00 to 1.43), P=0.05), and the composite of myocardial infarction or stroke (1.16 (1.02 to 1.32), P=0.02). In meta-analyses of placebo controlled trials of calcium or calcium and vitamin D, complete trial-level data were available for 28 072 participants from eight trials of calcium supplements and the WHI CaD participants not taking personal calcium supplements. In total 1384 individuals had an incident myocardial infarction or stroke. Calcium or calcium and vitamin D increased the risk of myocardial infarction (relative risk 1.24 (1.07 to 1.45), P=0.004) and the composite of myocardial infarction or stroke (1.15 (1.03 to 1.27), P=0.009). Conclusions Calcium supplements with or without vitamin D modestly increase the risk of cardiovascular events, especially myocardial infarction, a finding obscured in the WHI CaD Study by the widespread use of personal calcium supplements. A reassessment of the role of calcium supplements in osteoporosis management is warranted.


BMJ | 2010

Patient level pooled analysis of 68,500 patients from seven major vitamin D fracture trials in US and Europe

Bo Abrahamsen; Tahir Masud; Alison Avenell; F Anderson; Haakon E. Meyer; C Cooper; Helen Smith; Andrea Z. LaCroix; David Torgerson; A Johansen; Rebecca D. Jackson; Lars Rejnmark; Jean Wactawski-Wende; Kim Brixen; L. Mosekilde; John Robbins; Roger M. Francis

Objectives To identify participants’ characteristics that influence the anti-fracture efficacy of vitamin D or vitamin D plus calcium with respect to any fracture, hip fracture, and clinical vertebral fracture and to assess the influence of dosing regimens and co-administration of calcium. Design Individual patient data analysis using pooled data from randomised trials. Data sources Seven major randomised trials of vitamin D with calcium or vitamin D alone, yielding a total of 68 517 participants (mean age 69.9 years, range 47-107 years, 14.7% men). Study selection Studies included were randomised studies with at least one intervention arm in which vitamin D was given, fracture as an outcome, and at least 1000 participants. Data synthesis Logistic regression analysis was used to identify significant interaction terms, followed by Cox’s proportional hazards models incorporating age, sex, fracture history, and hormone therapy and bisphosphonate use. Results Trials using vitamin D with calcium showed a reduced overall risk of fracture (hazard ratio 0.92, 95% confidence interval 0.86 to 0.99, P=0.025) and hip fracture (all studies: 0.84, 0.70 to 1.01, P=0.07; studies using 10 μg of vitamin D given with calcium: 0.74, 0.60 to 0.91, P=0.005). For vitamin D alone in daily doses of 10 μg or 20 μg, no significant effects were found. No interaction was found between fracture history and treatment response, nor any interaction with age, sex, or hormone replacement therapy. Conclusion This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 μg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures.


BMJ | 2011

Randomised trial of glutamine, selenium, or both, to supplement parenteral nutrition for critically ill patients.

Peter Andrews; Alison Avenell; David W Noble; Marion K Campbell; Bernard L. Croal; William Simpson; Luke Vale; Claire G. Battison; David Jenkinson; Jonathan Cook

Objective To determine whether inclusion of glutamine, selenium, or both in a standard isonitrogenous, isocaloric preparation of parenteral nutrition influenced new infections and mortality among critically ill patients. Design Randomised, double blinded, factorial, controlled trial. Setting Level 2 and 3 (or combined) critical care units in Scotland. All 22 units were invited, and 10 participated. Participants 502 adults in intensive care units and high dependency units for ≥48 hours, with gastrointestinal failure and requiring parenteral nutrition. Interventions Parenteral glutamine (20.2 g/day) or selenium (500 μg/day), or both, for up to seven days. Main outcome measures Primary outcomes were participants with new infections in the first 14 days and mortality. An intention to treat analysis and a prespecified analysis of patients who received ≥5 days of the trial intervention are presented. Secondary outcomes included critical care unit and acute hospital lengths of stay, days of antibiotic use, and modified SOFA (Sepsis-related Organ Failure Assessment) score. Results Selenium supplementation did not significantly affect patients developing a new infection (126/251 v 139/251, odds ratio 0.81 (95% CI 0.57 to 1.15)), except for those who had received ≥5 days of supplementation (odds ratio 0.53 (0.30 to 0.93)). There was no overall effect of glutamine on new infections (134/250 v 131/252, odds ratio 1.07 (0.75 to 1.53)), even if patients received ≥5 days of supplementation (odds ratio 0.99 (0.56 to 1.75)). Six month mortality was not significantly different for selenium (107/251 v 114/251, odds ratio 0.89 (0.62 to 1.29)) or glutamine (115/250 v 106/252, 1.18 (0.82 to 1.70)). Length of stay, days of antibiotic use, and modified SOFA score were not significantly affected by selenium or glutamine supplementation. Conclusions The primary (intention to treat) analysis showed no effect on new infections or on mortality when parenteral nutrition was supplemented with glutamine or selenium. Patients who received parenteral nutrition supplemented with selenium for ≥5 days did show a reduction in new infections. This finding requires confirmation. Trial registration Current Controlled Trials ISRCTN87144826


Health Psychology Review | 2012

Identifying active ingredients in complex behavioural interventions for obese adults with obesity-related co-morbidities or additional risk factors for co-morbidities: a systematic review

Stephan U Dombrowski; Falko F. Sniehotta; Alison Avenell; Marie Johnston; Graeme MacLennan; Vera Araujo-Soares

Abstract Reducing obesity is an important preventive strategy for people who are at increased risk of major disabling or life-threatening conditions. Behavioural treatments for obesity are complex and involve several components aiming to facilitate behaviour change. Systematic reviews need to assess the components that moderate intervention effects. Electronic databases and journals were searched for randomised controlled trials of behavioural interventions targeting dietary and/or physical activity change for obese adults (mean BMI≥30, mean age≥40 years) with risk factors and follow-up data≥12 weeks. A reliable taxonomy of theory-congruent behaviour change techniques (BCTs; Abraham & Michie, 2008) was used to identify programme components. Meta-regression suggested that increasing numbers of identified BCTs are not necessarily associated with better outcomes. The BCTs provision of instructions (β =− 2.69, p=0.02), self-monitoring (β = − 3.37, p<0.001), relapse prevention (β = − 2.63, p=0.02) and prompting practice (β = − 3.63, p<0.001) could be linked to more successful interventions. Studies including more BCTs aimed at dietary change that are congruent with Control Theory were associated with greater weight loss (β = − 1.13, p=0.04). Post-hoc ratings of intervention components in published trials can lead to the identification of components and theories for behaviour change practice and research.


BMJ | 2014

Long term maintenance of weight loss with non-surgical interventions in obese adults: systematic review and meta-analyses of randomised controlled trials.

Stephan U Dombrowski; Keegan Knittle; Alison Avenell; Vera Araujo-Soares; Falko F. Sniehotta

Objective To systematically review and describe currently available approaches to supporting maintenance of weight loss in obese adults and to assess the evidence for the effectiveness of these interventions. Design Systematic review with meta-analysis. Data sources Medline, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials. Study selection Studies were identified through to January 2014. Randomised trials of interventions to maintain weight loss provided to initially obese adults (aged ≥18) after weight loss of ≥5% body weight with long term (≥12 months) follow-up of weight change (main outcome) were included. Study appraisal and synthesis Potential studies were screened independently and in duplicate; study characteristics and outcomes were extracted. Meta-analyses were conducted to estimate the effects of interventions on weight loss maintenance with the inverse variance method and a random effects model. Results are presented as mean differences in weight change, with 95% confidence intervals. Results 45 trials involving 7788 individuals were included. Behavioural interventions focusing on both food intake and physical activity resulted in an average difference of −1.56 kg (95% confidence interval −2.27 to −0.86 kg; 25 comparisons, 2949 participants) in weight regain compared with controls at 12 months. Orlistat combined with behavioural interventions resulted in a −1.80 kg (−2.54 to −1.06; eight comparisons, 1738 participants) difference compared with placebo at 12 months. All orlistat studies reported higher frequencies of adverse gastrointestinal events in the experimental compared with placebo control groups. A dose-response relation for orlistat treatment was found, with 120 mg doses three times a day leading to greater weight loss maintenance (−2.34 kg, −3.03 to −1.65) compared with 60 mg and 30 mg three times a day (−0.70 kg, 95% confidence interval −1.92 to 0.52), P=0.02. Conclusions Behavioural interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance.


The American Journal of Gastroenterology | 2007

Does enteral nutrition affect clinical outcome? A systematic review of the randomized trials.

Ronald L. Koretz; Alison Avenell; Timothy O. Lipman; Carol L. Braunschweig; Anne C. Milne

BACKGROUND:Both parenteral nutrition (PN) and enteral nutrition (EN) are widely advocated as adjunctive care in patients with various diseases. A systematic review of 82 randomized controlled trials (RCTs) of PN published in 2001 found little, if any, effect on mortality, morbidity, or duration of hospital stay; in some situations, PN increased infectious complication rates.OBJECTIVE:The objective was to assess the effect of EN or volitional nutrition support (VNS) in individual disease states from available RCTs.DESIGN:We conducted a systematic review. RCTs comparing EN or VNS with untreated controls, or comparing EN with PN, were identified and separated according to the underlying disease state. Meta-analysis was performed when at least three RCTs provided data. The evidence from the RCTs was summarized into one of five grades. A or B, respectively, indicated the presence of strong or weak (low-quality RCTs) evidence supporting the use of the intervention. C indicated a lack of adequate evidence to make any decision about efficacy. D indicated that limited data could not support the intervention. E indicated either that strong data found no effect, or that either strong or weak data suggested that the intervention caused harm.PATIENTS AND SETTINGS:RCTs could include either hospitalized or nonhospitalized patients. The EN or VNS had to be provided as part of a treatment plan for an underlying disease process.INTERVENTIONS:The RCT had to compare recipients of either EN or VNS with controls not receiving any type of artificial nutrition or had to compare recipients of EN with recipients of PN.OUTCOME MEASURES:These were mortality, morbidity (disease specific), duration of hospitalization, cost, or interventional complications.SUMMARY OF GRADING:A: No indication was identified. B: EN or VNS in the perioperative patient or in patients with chronic liver disease; EN in critically ill patients or low birth weight infants (trophic feeding); VNS in malnourished geriatric patients. (The low-quality trials found a significant difference in survival favoring the VNS recipients in the malnourished geriatric patient trials; two high-quality trials found nonsignificant differences that favored VNS as well.) C: EN or VNS in liver transplantation, cystic fibrosis, renal failure, pediatric conditions other than low birth weight infants, well-nourished geriatric patients, nonstroke neurologic conditions, AIDS; EN in acute pancreatitis, chronic obstructive pulmonary disease, nonmalnourished geriatric patients; VNS in inflammatory bowel disease, arthritis, cardiac disease, pregnancy, allergic patients, preoperative bowel preparation. D: EN or VNS in patients receiving nonsurgical cancer treatment or in patients with hip fractures; EN in patients with inflammatory bowel disease; VNS in patients with chronic obstructive pulmonary disease. EN in the first week in dysphagic, or VNS at any time in nondysphagic, stroke patients who are not malnourished; dysphagia persisting for weeks will presumably ultimately require EN.CONCLUSIONS:There is strong evidence for not using EN in the first week in dysphagic, and not using VNS at all in nondysphagic, stroke patients who are not malnourished. There is reasonable evidence for using VNS in malnourished geriatric patients. The recommendations to consider EN/VNS in perioperative/liver/critically ill/low birth weight patients are limited by the low quality of the RCTs. No evidence could be identified to justify the use of EN/VNS in other disease states.


Obesity Reviews | 2004

Effects of weight loss in overweight/obese individuals and long-term lipid outcomes--a systematic review.

Amudha S. Poobalan; Lorna Aucott; W. C. S. Smith; Alison Avenell; R. T. Jung; J. Broom; A. M. Grant

This paper aims to review the evidence for long‐term effectiveness of weight loss on cholesterol, high‐density lipoprotein (HDL), low‐density lipoprotein (LDL) and triglycerides in overweight/obese people. Current evidence is mostly based on short‐term studies. A systematic review of long‐term lipid outcomes of weight loss in studies published between 1966 and 2001, was conducted. Inclusion criteria included all cohort studies and trials carried out on participants with body mass index of greater than or equal to 28 kg m−2. Studies had at least two weight change measurements and follow‐up of more than 2 years. Thirteen long‐term studies with a follow‐up of more than 2 years were included. Cholesterol has a significant positive linear relationship with weight change (r = 0.89) where change in weight explains about 80% of the cholesterol difference variation (Adj R2 = 0.80). For every 10 kg weight loss a drop of 0.23 mmol L−1 in cholesterol may be expected for a person suffering from obesity or are grossly overweight. Weight loss has long‐term beneficial effects especially on LDL and cholesterol. Weight loss in obese patients should be encouraged and sustained.


Hypertension | 2005

Effects of Weight Loss in Overweight/Obese Individuals and Long-Term Hypertension Outcomes A Systematic Review

Lorna Aucott; Amudha S. Poobalan; W. Cairns S. Smith; Alison Avenell; R. T. Jung; J. Broom

Many studies have assessed short-term effects of weight loss on blood pressure, whereas little attention has been paid to long-term effects. We conducted a systematic review to evaluate the long-term effects of weight loss on hypertension outcome measures in adults using literature published from 1966 to 2001. All prospective studies and trials, performed on participants with body mass index of ≥28 kg/m2 with a follow-up of >2 years and weight changes recorded, were included. The data from these studies were used to model the long-term effects on blood pressure. Previous reviews on shorter-term studies indicate a 1:1 drop in blood pressure (mm Hg) with weight loss (kilograms). Our findings, based on studies with follow-up of ≥2 years, demonstrate blood pressure decreases less than this after weight loss. The surgical intervention studies exhibited huge weight losses with undramatic blood pressures changes. When surgical interventions are excluded, the models suggest that for 10 kg weight loss, decreases of 4.6 mm Hg and 6.0 mm Hg in diastolic and systolic blood pressure, respectively, may be expected, about half of that predicted from the short-term trials. Initial blood pressure, the length of follow-up, medication changes, and physiological restrictions may contribute to this reduced effect in the long-term studies. Extrapolation of short-term blood pressure changes with weight loss to the longer term is potentially misleading. The weight/hypertension relationship is complex and needs well-conducted studies with long-term follow-up to examine the effects of weight loss on hypertension outcomes.

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Andrew Grey

University of Auckland

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