Dual glucagon-like peptide-1 and glucagon receptor agonism reduces energy intake in type 2 diabetes with obesity

AIMS

To establish which components of energy balance mediate the clinically significant weight loss demonstrated with use of cotadutide, a glucagon-like peptide-1 (GLP-1)/glucagon receptor dual agonist, in early-phase studies.

MATERIALS AND METHODS

We conducted a phase 2a, single-centre, randomized, placebo-controlled trial in overweight and obese adults with type 2 diabetes. Following a 16-day single-blind placebo run-in, participants were randomized 2:1 to double-blind 42-day subcutaneous treatment with cotadutide (100-300 μg daily) or placebo. The primary outcome was percentage weight change. Secondary outcomes included change in energy intake (EI) and energy expenditure (EE).

RESULTS

A total of 12 participants (63%) in the cotadutide group and seven (78%) in the placebo group completed the study. The mean (90% confidence interval [CI]) weight change was -4.0% (-4.9%, -3.1%) and -1.4% (-2.7%, -0.1%) for the cotadutide and placebo groups, respectively (p = 0.011). EI was lower with cotadutide versus placebo (-41.3% [-66.7, -15.9]; p = 0.011). Difference in EE (per kJ/kg lean body mass) for cotadutide versus placebo was 1.0% (90% CI -8.4, 10.4; p = 0.784), assessed by doubly labelled water, and -6.5% (90% CI -9.3, -3.7; p < 0.001), assessed by indirect calorimetry.

CONCLUSION

Weight loss with cotadutide is primarily driven by reduced EI, with relatively small compensatory changes in EE.

A synthesis of pathways linking diet, metabolic risk and cardiovascular disease: a framework to guide further research and approaches to evidence-based practice

Cardiovascular disease (CVD) is the most common non-communicable disease occurring globally. Although previous literature has provided useful insights into the important role that diet plays in CVD prevention and treatment, understanding the causal role of diets is a difficult task considering inherent and introduced weaknesses of observational (e.g. not properly addressing confounders and mediators) and experimental research designs (e.g. not appropriate or well designed). In this narrative review, we organised current evidence linking diet, as well as conventional and emerging physiological risk factors, with CVD risk, incidence and mortality in a series of diagrams. The diagrams presented can aid causal inference studies as they provide a visual representation of the types of studies underlying the associations between potential risk markers/factors for CVD. This may facilitate the selection of variables to be considered and the creation of analytical models. Evidence depicted in the diagrams was systematically collected from studies included in the British Nutrition Task Force report on diet and CVD and database searches, including Medline and Embase. Although several markers and disorders linked to conventional and emerging risk factors for CVD were identified, the causal link between many remains unknown. There is a need to address the multifactorial nature of CVD and the complex interplay between conventional and emerging risk factors with natural and built environments, while bringing the life course into the spotlight.

Sumatriptan, a serotonin 5HT1B receptor agonist, acutely reduces insulin secretion and sensitivity and glucose effectiveness in overweight humans: A double-blinded placebo-controlled cross-over trial

AIM

Evidence from mouse models suggests that brain serotonergic pathways control blood glucose. We hypothesized that sumatriptan (5HT1B -receptor agonist) would alter glucose homeostasis in humans.

MATERIALS AND METHODS

We conducted a two-visit random-order double-blinded placebo-controlled cross-over trial in 10 overweight adults that were otherwise healthy. Participants received sumatriptan (single dose, 100 mg) or placebo before undergoing a 60-min intravenous glucose tolerance test, followed by a 120-min hyperinsulinaemic euglycaemic clamp.

RESULTS

Glucose excursion was greater during intravenous glucose tolerance test with sumatriptan compared with placebo [iAUC0-60 min 316 (268-333) vs. 251 (197-319) min/mmol/L p = .047]. This was probably explained by a combination of reduced circulating insulin levels [iAUC0-10 min 1626 (1103-2733) vs. 2336 (1702-3269) min/pmol/L, p = .005], reduced insulin sensitivity [M/I-value 2.11 (1.15, 4.05) vs. 3.03 (1.14, 4.90) mg/kg/min per pmol/L, p = .010] and glucose effectiveness [SG 0.17 (0.12, 0.21) vs. 0.22 (0.18, 0.65)/min, p = .027].

CONCLUSIONS

5HT1B receptors have a glucoregulatory role in humans, probably acting on insulin secretion, insulin sensitivity and glucose effectiveness.

Do markers of adiposity and glycaemia mediate the association between low carbohydrate diet and cardiovascular risk factors: findings from the UK National Diet and Nutrition Survey (NDNS) 2008-2016

Objectives

To examine the associations between low carbohydrate diet (LCD) and conventional cardiovascular risk factors and investigate whether these associations are mediated by body mass index (BMI), waist circumference (WC) and haemoglobin A1c (HbA1c) applying causal mediation analyses.

Methods

We included 3640 adults aged 45-80 years from the UK National Diet and Nutrition Survey programme (2008-2016) with data on dietary intake, anthropometric and biochemical parameters. Four hypothetical interventions were examined: (1) LCD, (2) Low carbohydrate (LC) and high fibre diet (LCHF), (3) LC and high saturated fat diet (LCHS) and (4) LC and high unsaturated fat diet (LCHU). BMI and WC were used as markers of obesity. Biochemical markers included HbA1c, total cholesterol, high-density lipoprotein and low-density lipoprotein (LDL) cholesterol, triglycerides, systolic and diastolic blood pressure and C reactive protein (CRP). BMI, WC and HbA1c were used as a mediator of the effects. The analysis was adjusted for sociodemographic characteristic, smoking, estimated total energy intake, alcohol consumption and antihypertensive medication. To identify a potential causal effect of LCD on cardiovascular disease (CVD) risk, we estimated the average treatment effect, and corresponding p values and CI for the total, indirect and direct effect of the treatment on the outcome.

Results

BMI, WC and HbA1c fully mediated the association between LCD and triglycerides and fully mediated the effects of LCHF on LDL, although BMI and WC were not sufficient to fully mediate the effects of LCHF on triglycerides and CRP. BMI alone fully mediated the effects of LCHS on HbA1c, triglycerides, LDL and CRP. None of these mediators explained the effect of LCHU on CVD risk markers.

Conclusion

The causal hypotheses tested in this study demonstrate that individuals on LCD with high fibre intakes improved their CVD markers as expected, but those on LCD who increase fat intake had no effects on CVD markers mediated by obesity and diabetes.

Non-occupational physical activity and risk of cardiovascular disease, cancer and mortality outcomes: a dose-response meta-analysis of large prospective studies

OBJECTIVE

To estimate the dose-response associations between non-occupational physical activity and several chronic disease and mortality outcomes in the general adult population.

DESIGN

Systematic review and cohort-level dose-response meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science and reference lists of published studies.

ELIGIBILITY CRITERIA

Prospective cohort studies with (1) general population samples >10 000 adults, (2) ≥3 physical activity categories, and (3) risk measures and CIs for all-cause mortality or incident total cardiovascular disease, coronary heart disease, stroke, heart failure, total cancer and site-specific cancers (head and neck, myeloid leukaemia, myeloma, gastric cardia, lung, liver, endometrium, colon, breast, bladder, rectum, oesophagus, prostate, kidney).

RESULTS

196 articles were included, covering 94 cohorts with >30 million participants. The evidence base was largest for all-cause mortality (50 separate results; 163 415 543 person-years, 811 616 events), and incidence of cardiovascular disease (37 results; 28 884 209 person-years, 74 757 events) and cancer (31 results; 35 500 867 person-years, 185 870 events). In general, higher activity levels were associated with lower risk of all outcomes. Differences in risk were greater between 0 and 8.75 marginal metabolic equivalent of task-hours per week (mMET-hours/week) (equivalent to the recommended 150 min/week of moderate-to-vigorous aerobic physical activity), with smaller marginal differences in risk above this level to 17.5 mMET-hours/week, beyond which additional differences were small and uncertain. Associations were stronger for all-cause (relative risk (RR) at 8.75 mMET-hours/week: 0.69, 95% CI 0.65 to 0.73) and cardiovascular disease (RR at 8.75 mMET-hours/week: 0.71, 95% CI 0.66 to 0.77) mortality than for cancer mortality (RR at 8.75 mMET-hours/week: 0.85, 95% CI 0.81 to 0.89). If all insufficiently active individuals had achieved 8.75 mMET-hours/week, 15.7% (95% CI 13.1 to 18.2) of all premature deaths would have been averted.

CONCLUSIONS

Inverse non-linear dose-response associations suggest substantial protection against a range of chronic disease outcomes from small increases in non-occupational physical activity in inactive adults. PROSPERO registration number CRD42018095481.

Association Between Physical Activity and Risk of Depression: A Systematic Review and Meta-analysis

Importance

Depression is the leading cause of mental health-related disease burden and may be reduced by physical activity, but the dose-response relationship between activity and depression is uncertain.

Objective

To systematically review and meta-analyze the dose-response association between physical activity and incident depression from published prospective studies of adults.

Data Sources

PubMed, SCOPUS, Web of Science, PsycINFO, and the reference lists of systematic reviews retrieved by a systematic search up to December 11, 2020, with no language limits. The date of the search was November 12, 2020.

Study Selection

We included prospective cohort studies reporting physical activity at 3 or more exposure levels and risk estimates for depression with 3000 or more adults and 3 years or longer of follow-up.

Data Extraction and Synthesis

Data extraction was completed independently by 2 extractors and cross-checked for errors. A 2-stage random-effects dose-response meta-analysis was used to synthesize data. Study-specific associations were estimated using generalized least-squares regression and the pooled association was estimated by combining the study-specific coefficients using restricted maximum likelihood.

Main Outcomes and Measures

The outcome of interest was depression, including (1) presence of major depressive disorder indicated by self-report of physician diagnosis, registry data, or diagnostic interviews and (2) elevated depressive symptoms established using validated cutoffs for a depressive screening instrument.

Results

Fifteen studies comprising 191 130 participants and 2 110 588 person-years were included. An inverse curvilinear dose-response association between physical activity and depression was observed, with steeper association gradients at lower activity volumes; heterogeneity was large and significant (I2 = 74%; P < .001). Relative to adults not reporting any activity, those accumulating half the recommended volume of physical activity (4.4 marginal metabolic equivalent task hours per week [mMET-h/wk]) had 18% (95% CI, 13%-23%) lower risk of depression. Adults accumulating the recommended volume of 8.8 mMET hours per week had 25% (95% CI, 18%-32%) lower risk with diminishing potential benefits and higher uncertainty observed beyond that exposure level. There were diminishing additional potential benefits and greater uncertainty at higher volumes of physical activity. Based on an estimate of exposure prevalences among included cohorts, if less active adults had achieved the current physical activity recommendations, 11.5% (95% CI, 7.7%-15.4%) of depression cases could have been prevented.

Conclusions and Relevance

This systematic review and meta-analysis of associations between physical activity and depression suggests significant mental health benefits from being physically active, even at levels below the public health recommendations. Health practitioners should therefore encourage any increase in physical activity to improve mental health.

Insights from a general practice service evaluation supporting a lower carbohydrate diet in patients with type 2 diabetes mellitus and prediabetes: a secondary analysis of routine clinic data including HbA1c, weight and prescribing over 6 years

Background

In a single general practice (GP) surgery in England, there was an eightfold increase in the prevalence of type 2 diabetes (T2D) in three decades with 57 cases and 472 cases recorded in 1987 and 2018, respectively. This mirrors the growing burden of T2D on the health of populations round the world along with healthcare funding and provision more broadly. Emerging evidence suggests beneficial effects of carbohydrate-restricted diets on glycaemic control in T2D, but its impact in a ‘real-world’ primary care setting has not been fully evaluated.

Methods

Advice on a lower carbohydrate diet was offered routinely to patients with newly diagnosed and pre-existing T2D or prediabetes between 2013 and 2019, in the Norwood GP practice with 9800 patients. Conventional ‘one-to-one’ GP consultations were used, supplemented by group consultations, to help patients better understand the glycaemic consequences of their dietary choices with a particular focus on sugar, carbohydrates and foods with a higher Glycaemic Index. Those interested were computer coded for ongoing audit to compare ‘baseline’ with ‘latest follow-up’ for relevant parameters.

Results

By 2019, 128 (27%) of the practice population with T2D and 71 people with prediabetes had opted to follow a lower carbohydrate diet for a mean duration of 23 months. For patients with T2D, the median (IQR) weight dropped from of 99.7 (86.2, 109.3) kg to 91.4 (79, 101.1) kg, p<0.001, while the median (IQR) HbA1c dropped from 65.5 (55, 82) mmol/mol to 48 (43, 55) mmol/mol, p<0.001. For patients with prediabetes, the median (IQR) HbA1c dropped from 44 (43, 45) mmol/mol to 39 (38, 41) mmol/mol, p<0.001. Drug-free T2D remission occurred in 46% of participants. In patients with prediabetes, 93% attained a normal HbA1c. Since 2015, there has been a relative reduction in practice prescribing of drugs for diabetes leading to a T2D prescribing budget £50 885 per year less than average for the area.

Conclusions

This approach to lower carbohydrate dietary advice for patients with T2D and prediabetes was incorporated successfully into routine primary care over 6 years. There were statistically significant improvements in both groups for weight, HbA1c, lipid profiles and blood pressure as well as significant drug budget savings. These results suggest a need for more empirical research on the effects of lower carbohydrate diet and long-term glycaemic control while recording collateral impacts to other metabolic health outcomes.

Time for nutrition in medical education

Aim

To synthesise a selection of UK medical students' and doctors' views surrounding nutrition in medical education and practice.

Methods

Information was gathered from surveys of medical students and doctors identified between 2015 and 2018 and an evaluation of nutrition teaching in a single UK medical school. Comparative analysis of the findings was undertaken to answer three questions: the perceived importance of nutrition in medical education and practice, adequacy of nutrition training, and confidence in current nutrition knowledge and skills.

Results

We pooled five heterogeneous sources of information, representing 853 participants. Most agreed on the importance of nutrition in health (>90%) and in a doctor's role in nutritional care (>95%). However, there was less desire for more nutrition education in doctors (85%) and in medical students (68%). Most felt their nutrition training was inadequate, with >70% reporting less than 2 hours. There was a preference for face-to-face rather than online training. At one medical school, nutrition was included in only one module, but this increased to eight modules following an increased nutrition focus. When medical students were asked about confidence in their nutrition knowledge and on advising patients, there was an even split between agree and disagree (p=0.869 and p=0.167, respectively), yet few were confident in the UK dietary guidelines. Only 26% of doctors were confident in their nutrition knowledge and 74% gave nutritional advice less than once a month, citing lack of knowledge (75%), time (64%) and confidence (62%) as the main barriers. There was some recognition of the importance of a collaborative approach, yet 28% of doctors preferred to get specialist advice rather than address nutrition themselves.

Conclusion

There is a desire and a need for more nutrition within medical education, as well as a need for greater clarity of a doctor's role in nutritional care and when to refer for specialist advice. Despite potential selection bias and limitations in the sampling frame, this synthesis provides a multifaceted snapshot via a large number of insights from different levels of training through medical students to doctors from which further research can be developed.

Management of perioperative myocardial ischaemia after isolated coronary artery bypass graft surgery

Objectives

Updated knowledge about perioperative myocardial ischaemia (MI) after coronary artery bypass grafting (CABG) and treatment of acute graft failure is needed. We analysed main factors associated with perioperative MI and effects of immediate coronary angiography-based treatment strategy on patient outcome.

Methods

Among 1119 consecutive patients with coronary artery disease who underwent isolated CABG between January 2011 and December 2015, 43 (3.8%) patients underwent urgent coronary angiography due to suspected perioperative MI. All the data were prospectively collected and retrospectively analysed. The primary endpoint was 30-day mortality; postoperative left ventricular ejection fraction) and major adverse cardiac events were secondary endpoints.

Results

Overall, 30-day mortality in patients with CABG was 1.4% while in patients who developed perioperative MI was 9% (4 patients). Angiographic findings included incorrect graft anastomosis, graft spasm, dissection, acute coronary artery thrombotic occlusion and ischaemia due to incomplete revascularisation. Emergency reoperation (Redo) was performed in 14 (32%), acute percutaneous coronary intervention (PCI) in 15 (36%) and conservative treatment (Non-op) in 14 patients. Demographic and preoperative clinical characteristics between the groups were comparable. Postoperative LVEF was significantly reduced in the Redo group (45% post-op vs 53% pre-op) and did not change in groups PCI (56% post-op vs 57% pre-op) and Non-op (58% post-op vs 57% pre-op).

Conclusions

Urgent angiography allows identification of the various underlying causes of perioperative MI and urgent treatment when this is needed. Urgent PCI may be associated with improved clinical outcome in patients with early graft failure.

SUN-546 Coexistent Resistance to Thyroid Hormone Beta and Viral Thyroiditis

Background Resistance to thyroid hormone beta (RTHbeta) is a rare genetic disorder caused by a defective beta form of the thyroid hormone receptor and is characterized by elevated T3 and T4, non-suppressed TSH and variable tissue resistance to thyroid hormone (TH). In most cases a heterozygous mutation in THRB gene is identified. Clinical case A 32 year old adopted Caucasian woman presented with chest pain in the primary care setting in December 2016. Associated symptoms included palpitations, insomnia, poor concentration, restlessness, tremor, mood swings, headaches, irritability, increased appetite, dry scalp, cold extremities, weight gain and diarrhoea. She had no goitre. Based on thyroid function test (TFT) results, she was suspected to have hyperthyroidism and was commenced on antithyroid drugs for 13 months, but treatment was later stopped due to mouth ulcers. At this stage, further tests in our hospital showed elevated fT3 (8.4 pmol/L, RR 3.5-6.5 pmol/L) and fT4 (33.5 pmol/L, RR 10.0-19.8 pmol/L) and non-suppressed TSH (1.35 mU/L, RR 0.35-5.50 mU/L), without evidence of assay interference. SHBG and MRI pituitary were normal. THRB sequencing identified a heterozygous pathogenic mutation (R438H). She further reported that she struggled in school which prevented her from completing university education and remembered that her biological mother had learning disability. She was further assessed in our clinical research facility. Surprisingly, TFT results were very different: fT3 23.6 pmol/L, fT4 97.3 pmol/L and fully suppressed TSH (<0.03mU/L). Resting energy expenditure (REE) measured by indirect calorimetry was markedly raised [0.214 MJ/kg of lean body mass (LBM)]; compared to that seen in healthy controls (mean (SD): 0.148 (0.013) MJ/kg LBM). Given a recent coryzal illness and negative TRAB, thyrotoxicosis was deemed to be in keeping with thyroiditis. The TFT pattern evolved, without treatment, to mild hypothyroidism (fT3 6.8 pmol/L, fT4 16.2 pmol/L and TSH 21.54 mU/L), then returned to the pattern at presentation: elevated fT3 and fT4 and non-suppressed TSH (fT3 10.6 pmol/L, fT4 31.6 pmol/L, TSH 2.09 mU/L). Given ongoing thyrotoxic symptoms, identical to those present at time of referral, Tri-iodothyroacetic Acid (TRIAC) was commenced. Conclusion Coincident thyroid dysfunction can further complicate interpretation of TFTs in patients with RTHbeta. Notably, individuals with RTHbeta and coexistent thyrotoxicosis can exhibit a suppressed TSH, with underlying pituitary resistance to TH action only becoming evident once TH levels fall. Although thyroiditis rarely complicates RTHbeta, it has been reported that autoimmune thyroid disease occurs more commonly, so interpretation of such unusual TFT patterns may be required during the course of management of these individuals.

The Cambridge Intensive Weight Management Programme Appears to Promote Weight Loss and Reduce the Need for Bariatric Surgery in Obese Adults

Objectives: To investigate the impact of the Cambridge Intensive Weight Management Programme (IWMP) on weight change, eligibility for bariatric surgery, HbA1c, and blood pressure. Design: Prospective non-randomized intervention. Setting: The IWMP is a multi-disciplinary weight loss intervention for severely obese patients to avoid or optimize their physiological state thus enabling bariatric surgery. It uses dietary interventions, pharmacotherapy, and physical activity along with behavior change counseling. Participants: Severely obese patients (Body Mass Index, BMI≥40 kg/m²). Interventions: IWMP is a prospective intervention conducted in a National Health Service Tier 3 obesity service. It includes 3 phases of 8 weeks each: weight loss, weight stabilization, and weight maintenance. In each phase, patients adhered to a prescribed dietary regime and attended regular clinic visits. Data included in this analysis are from those who enrolled in IWMP between 2009 and 2013. Primary and secondary measures: The primary outcome was weight change between baseline and completion of the programme. Secondary outcomes included changes in blood pressure, HbA1c and eligibility for bariatric surgery pre-assessment. Changes in outcomes were compared by age, sex, smoking status, and employment. Results: Of n = 222 eligible patients, complete data were available for n = 141 patients (63.5%). At baseline, the mean (SD) BMI was 49.7 (9.2) kg/m² for women, and 47.9 (7.2) kg/m² for men. Mean (SD) weight change for women was -18.64 (8.36) kg and -22.46 (10.98) kg for men. N = 97 (69%) of patients achieved ≥10% weight loss. Individuals aged ≤ 50 years lost significantly more weight than those aged >50 years [mean (SD) weight loss: 22.18 (10.9) kg vs. 18.32 (7.92) kg, p = 0.020]. Changes in weight were non-significant by smoking status or employment. Median (IQR) change in systolic and diastolic blood pressure was -6 (-14.6) mmHg and 0 (-8.6) mmHg (non-significant), respectively. There was ~50% reduction in the need for bariatric surgery. Conclusions: For the majority of the patients, IWMP is promoting weight loss and allowing for avoidance of, or optimization before, bariatric surgery.

Modeling Learning in Surgical Practice

OBJECTIVE

Methods that model surgical learning curves are frequently descriptive and lack the mathematical rigor required to extract robust, meaningful, and quantitative information. We aimed to formulate a method to model learning that is tailored to dealing with the high variability seen in surgical data and can readily extract important quantitative information such as learning rate, length of learning, and learnt level of performance.

METHODS

We developed a method where progressively more complex models are fitted to learning data. These include novel models that split the learning data into 2 linear phases and fit adjoining lines using least squares regression. The models were compared and the least complex model was selected unless a more complex one was significantly better. Significance was tested by Fischer tests. We applied this method to total hip and knee replacements using imageless navigation, analyzing the operative time for a surgeon's first 50 and 60 operations, respectively. This method was then tested against 4 sets of simulated learning data.

RESULTS

The proposed method of progressive model complexity successfully modeled the learning curve among real operative data. It was also effective in deducing the underlying trends in simulated scenarios, created to represent typical situations that can practically arise in any learning process.

CONCLUSIONS

The novel modeling method can be used to extract meaningful and quantitative information from learning data displaying high variability seen in surgical practice. By using simple and intuitive models, the method is accessible to researchers and educators without the need for specialist statistical knowledge.

Physical Activity Types and Coronary Heart Disease Risk in Middle-Aged and Elderly Persons: The Rotterdam Study

Physical activity is associated with decreased risk of coronary heart disease (CHD). The specific physical activity types that provide beneficial effects in an older population remain unclear. We assessed the association of total physical activity, walking, cycling, domestic work, sports, and gardening with CHD by using Cox proportional hazard models among 5,901 participants aged >55 (median age, 67) years from the prospective population-based Rotterdam Study, enrolled between 1997 and 2001. Activities were categorized into tertiles, and the lowest tertiles were used as reference. In the multivariable model, we adjusted for age, sex, smoking, alcohol consumption, education, diet, and other physical activity types. During 15 years of follow-up (median, 10.3 (interquartile range, 8.0-11.8) years), 642 participants (10.9%) experienced a CHD event. In the multivariable model, the respective hazard ratios for the medium and high categories compared with the low category were 0.79 (95% confidence interval CI): 0.66, 0.96) and 0.71 (95% CI: 0.58, 0.87) for total physical activity, 0.76 (95% CI: 0.63, 0.92) and 0.70 (95% CI: 0.57, 0.88) for cycling, and 0.81 (95% CI: 0.66, 0.98) and 0.71 (95% CI: 0.56, 0.90) for domestic work. Walking, sports, and gardening were not associated with CHD. In conclusion, in this long-term follow-up study of older adults, domestic work and cycling were associated with reduced CHD risk. Physical activity should be promoted in this population with the aim to prevent CHD.

Levels of physical activity among a nationally representative sample of people in early old age: results of objective and self-reported assessments

BACKGROUND

Detailed assessment of physical activity (PA) in older adults is required to comprehensively describe habitual PA-levels in this growing population segment. Current evidence of population PA-levels is predominantly based on self-report.

METHODS

We examined PA and sedentary behaviour in a nationally representative sample of British people aged 60-64, using individually-calibrated combined heart-rate and movement sensing and a validated questionnaire (EPAQ2), and the socio-demographic and behavioural factors that may explain between-individual variation in PA.

RESULTS

Between 2006-2010, 2224 participants completed EPAQ2 capturing the past year's activity in four domains (leisure, work, transportation and domestic life) and 1787 participants provided 2-5 days of combined-sensing data. According to objective estimates, median(IQR) physical activity energy expenditure (PAEE) was 33.5 (25.3-42.2) and 35.5 (26.6- 47.3) kJ/kg/day for women and men, respectively. Median (IQR) time spent in moderate-to-vigorous PA (MVPA; >3MET), light-intensity PA (1.5-3 MET) and sedentary (<1.5 MET) was 26.0 (12.3-48.1) min/day, 5.4 (4.2-6.7) h/day and 18.0 (16.6-19.4) h/day, respectively, in women; and 41.0 (18.8-73.0) min/day, 5.2 (4.0-6.5) h/day and 17.9 (16.3-19.4) h/day in men. PAEE and time spent in MVPA were lower and sedentary time was greater in obese individuals, those with poor health, and those with lower educational attainment (women only). Questionnaire-derived PAEE and MVPA tended to have similar patterns of variation across socio-demographic strata. In the whole sample, domestic PA had the greatest relative contribution to total questionnaire-derived PAEE (58%), whereas occupational PA was the main driver among employed participants (54%). Only 2.2% of participants achieved an average of >30 min MVPA per day combined with >60 min strength-training per week.

CONCLUSIONS

The use of both self-report and objective monitoring to assess PA in early old age provides important information on the domains of PA, PAEE and time spent at different intensity levels. Our findings suggest PA levels are generally low and observed patterns of variation indicate specific subgroups who might benefit from targeted interventions to increase PA.

Validity of electronically administered Recent Physical Activity Questionnaire (RPAQ) in ten European countries

OBJECTIVE

To examine the validity of the Recent Physical Activity Questionnaire (RPAQ) which assesses physical activity (PA) in 4 domains (leisure, work, commuting, home) during past month.

METHODS

580 men and 1343 women from 10 European countries attended 2 visits at which PA energy expenditure (PAEE), time at moderate-to-vigorous PA (MVPA) and sedentary time were measured using individually-calibrated combined heart-rate and movement sensing. At the second visit, RPAQ was administered electronically. Validity was assessed using agreement analysis.

RESULTS

RPAQ significantly underestimated PAEE in women [median(IQR): 34.9 (22.3, 52.8) vs. 40.6 (32.4, 50.9) kJ/kg/day, 95%LoA: -44.4, 66.1 kJ/kg/day) and overestimated PAEE in men [45.9 (30.6, 71.1) vs. 45.5 (34.1, 57.6) kJ/kg/day, 95%LoA: -44.8, 102.6 kJ/kg/day]. Using individualised definition of 1MET, RPAQ significantly underestimated MVPA in women [median(IQR): 63.7 (30.5, 126.9) vs. 73.6 (47.8, 107.2) min/day, 95%LoA: -127.4, 311.9 min/day] and overestimated MVPA in men [90.0 (42.3, 188.6) vs. 83.3 (55.1, 125.0) min/day, 95%LoA: -134.8, 427.3 min/day]. Correlations (95%CI) between subjective and objective estimates were statistically significant [PAEE: women, rho = 0.20 (0.15-0.26); men, rho = 0.37 (0.30-0.44); MVPA: women, rho = 0.18 (0.13-0.24); men, rho = 0.31 (0.24-0.38)]. When using non-individualised definition of 1MET (3.5 mlO2/kg/min), MVPA was substantially overestimated (16 min/day, and 32 min/day in women and men, respectively). Revisiting occupational intensity assumptions in questionnaire estimation algorithms with occupational group-level empirical distributions reduced median PAEE-bias in manual (38.8 kJ/kg/day vs. 6.8 kJ/kg/day, p<0.001) and heavy manual workers (63.6 vs. -2.8 kJ/kg/day, p<0.001) in an independent hold-out sample [corrected].

CONCLUSION

Relative validity of RPAQ-derived PAEE and MVPA is comparable to previous studies but underestimation of PAEE is smaller. Electronic RPAQ may be used in large-scale epidemiological studies including surveys, providing information on all domains of PA.

Comparison of the EPIC Physical Activity Questionnaire with combined heart rate and movement sensing in a nationally representative sample of older British adults

Objectives

To compare physical activity (PA) subcomponents from EPIC Physical Activity Questionnaire (EPAQ2) and combined heart rate and movement sensing in older adults.

Methods

Participants aged 60–64y from the MRC National Survey of Health and Development in Great Britain completed EPAQ2, which assesses self-report PA in 4 domains (leisure time, occupation, transportation and domestic life) during the past year and wore a combined sensor for 5 consecutive days. Estimates of PA energy expenditure (PAEE), sedentary behaviour, light (LPA) and moderate-to-vigorous PA (MVPA) were obtained from EPAQ2 and combined sensing and compared. Complete data were available in 1689 participants (52% women).

Results

EPAQ2 estimates of PAEE and MVPA were higher than objective estimates and sedentary time and LPA estimates were lower [bias (95% limits of agreement) in men and women were 32.3 (−61.5 to 122.6) and 29.0 (−39.2 to 94.6) kJ/kg/day for PAEE; −4.6 (−10.6 to 1.3) and −6.0 (−10.9 to −1.0) h/day for sedentary time; −171.8 (−454.5 to 110.8) and −60.4 (−367.5 to 246.6) min/day for LPA; 91.1 (−159.5 to 341.8) and 55.4 (−117.2 to 228.0) min/day for MVPA]. There were significant positive correlations between all self-reported and objectively assessed PA subcomponents (rho  = 0.12 to 0.36); the strongest were observed for MVPA (rho = 0.30 men; rho = 0.36 women) and PAEE (rho = 0.26 men; rho = 0.25 women).

Conclusion

EPAQ2 produces higher estimates of PAEE and MVPA and lower estimates of sedentary and LPA than objective assessment. However, both methodologies rank individuals similarly, suggesting that EPAQ2 may be used in etiological studies in this population.

Rate of weight gain predicts change in physical activity levels: a longitudinal analysis of the EPIC-Norfolk cohort

OBJECTIVE

To investigate the relationship of body weight and its changes over time with physical activity (PA).

DESIGN

Population-based prospective cohort study (Norfolk cohort of the European Prospective Investigation into Cancer and Nutrition, EPIC-Norfolk, United Kingdom).

SUBJECTS

A total of 25 639 men and women aged 39-79 years at baseline. PA was self-reported. Weight and height were measured by standard clinical procedures at baseline and self-reported at 18-month and 10-year follow-ups (calibrated against clinical measures). Main outcome measure was PA at the 10-year follow-up.

RESULTS

Body weight and PA were inversely associated in cross-sectional analyses. In longitudinal analyses, an increase in weight was associated with higher risk of being inactive 10 years later, after adjusting for baseline activity, 18-month activity, sex, baseline age, prevalent diseases, socioeconomic status, education, smoking, total daily energy intake and alcohol intake. Compared with stable weight, a gain in weight of >2 kg per year in the short-, medium- and long-term was consistently and significantly associated with greater likelihood of physical inactivity after 10 years, with the most pronounced effect for long-term weight gain, OR=1.89 (95% CI: 1.30-2.70) in fully adjusted analysis. Weight gain of 0.5-2 kg per year over long-term was substantially associated with physical inactivity after full adjustment, OR=1.26 (95% CI: 1.11-1.41).

CONCLUSION

Weight gain (during short-, medium- and long-term) is a significant determinant of future physical inactivity independent of baseline weight and activity. Compared with maintaining weight, moderate (0.5-2 kg per year) and large weight gain (>2 kg per year) significantly predict future inactivity; a potentially vicious cycle including further weight gain, obesity and complications associated with a sedentary lifestyle. On the basis of current predictions of obesity trends, we estimate that the prevalence of inactivity in England would exceed 60% in the year 2020.

Impact of study design on development and evaluation of an activity-type classifier

Methods to classify activity types are often evaluated with an experimental protocol involving prescribed physical activities under confined (laboratory) conditions, which may not reflect real-life conditions. The present study aims to evaluate how study design may impact on classifier performance in real life. Twenty-eight healthy participants (21-53 yr) were asked to wear nine triaxial accelerometers while performing 58 activity types selected to simulate activities in real life. For each sensor location, logistic classifiers were trained in subsets of up to 8 activities to distinguish between walking and nonwalking activities and were then evaluated in all 58 activities. Different weighting factors were used to convert the resulting confusion matrices into an estimation of the confusion matrix as would apply in the real-life setting by creating four different real-life scenarios, as well as one traditional laboratory scenario. The sensitivity of a classifier estimated with a traditional laboratory protocol is within the range of estimates derived from real-life scenarios for any body location. The specificity, however, was systematically overestimated by the traditional laboratory scenario. Walking time was systematically overestimated, except for lower back sensor data (range: 7-757%). In conclusion, classifier performance under confined conditions may not accurately reflect classifier performance in real life. Future studies that aim to evaluate activity classification methods are warranted to pay special attention to the representativeness of experimental conditions for real-life conditions.

Work ability as a major determinant of clinical nurses' quality of life

AIMS AND OBJECTIVES

To examine quality of life determinants among clinical nurses in Croatia with an emphasis on their work ability.

BACKGROUND

An important personnel management challenge is to explore factors that stimulate or hinder the development of individual work ability and quality of life throughout a career.

DESIGN

A cross-sectional study.

METHODS

The study was performed during 2007-2008 in six randomly selected hospitals in Croatia. The self-administered questionnaires included the Work Ability Index (WAI) developed by the Finnish Institute of Occupational Health, the Quality of Life questionnaire (WHOQL-BREF) developed by the World Health Organization and additional socio-demographic questions. A total number of 1212 nurses completed the questionnaires, giving a response rate of 67(.) 3%. Binary logistic regression was performed to assess how socio-demographic characteristics and work ability groups predict each of the WHOQL-BREF domains.

RESULTS

Having a satisfactory WAI score (WAI ≥ 37) was significantly the most important predictor for all quality of life domains, with the odds ratios (OR) being as follows: OR = 6(.) 8 (95% CI: 4(.) 8-9(.) 6) for the physical domain, OR = 2(.) 3 (95% CI: 1(.) 7-3(.) 1) for the psychological domain, OR = 1(.) 7 (95% CI: 1(.) 3-2(.) 4) for the social relationship domain and OR = 1(.) 7 (95% CI: 1(.) 3-2(.) 3) for the environmental domain.

CONCLUSIONS

Satisfactory work ability was a major quality of life determinant in all WHOQL-BREF domains with the highest odds ratio for the physical domain. Maintaining clinical nurses' work ability is an important issue, because it is foundational for the quality of life of the workforce.

RELEVANCE TO CLINICAL PRACTICE

Our study provides quantified estimates of the extent to which a satisfactory WAI score predicts a better score in physical, psychosocial, social relationships and environmental domain of nurses' quality of life. Therefore, maintaining or improving nurses' work ability remains the essential aim of hospital managers.

Work-related stress, education and work ability among hospital nurses

AIM

This paper is a report of a study conducted to determine which occupational stressors are present in nurses' working environment; to describe and compare occupational stress between two educational groups of nurses; to estimate which stressors and to what extent predict nurses' work ability; and to determine if educational level predicts nurses' work ability.

BACKGROUND

Nurses' occupational stress adversely affects their health and nursing quality. Higher educational level has been shown to have positive effects on the preservation of good work ability.

METHOD

A cross-sectional study was conducted in 2006-2007. Questionnaires were distributed to a convenience sample of 1392 (59%) nurses employed at four university hospitals in Croatia (n = 2364). The response rate was 78% (n = 1086). Data were collected using the Occupational Stress Assessment Questionnaire and Work Ability Index Questionnaire.

FINDINGS

We identified six major groups of occupational stressors: 'Organization of work and financial issues', 'public criticism', 'hazards at workplace', 'interpersonal conflicts at workplace', 'shift work' and 'professional and intellectual demands'. Nurses with secondary school qualifications perceived Hazards at workplace and Shift work as statistically significantly more stressful than nurses a with college degree. Predictors statistically significantly related with low work ability were: Organization of work and financial issues (odds ratio = 1.69, 95% confidence interval 122-236), lower educational level (odds ratio = 1.69, 95% confidence interval 122-236) and older age (odds ratio = 1.07, 95% confidence interval 1.05-1.09).

CONCLUSION

Hospital managers should develop strategies to address and improve the quality of working conditions for nurses in Croatian hospitals. Providing educational and career prospects can contribute to decreasing nurses' occupational stress levels, thus maintaining their work ability.

Calculating impact factor: how bibliographical classification of journal items affects the impact factor of large and small journals

As bibliographical classification of published journal items affects the denominator in this equation, we investigated how the numerator and denominator of the impact factor (IF) equation were generated for representative journals in two categories of the Journal Citation Reports (JCR). We performed a full text search of the 1st-ranked journal in 2004 JCR category "Medicine, General and Internal" (New England Journal of Medicine, NEJM, IF = 38.570) and 61st-ranked journal (Croatian Medical Journal, CMJ, IF = 0.690), 1st-ranked journal in category "Multidisciplinary Sciences" (Nature, IF = 32.182) and journal with a relative rank of CMJ (Anais da Academia Brasileira de Ciencias, AABC, IF = 0.435). Large journals published more items categorized by Web of Science (WoS) as non-research items (editorial material, letters, news, book reviews, bibliographical items, or corrections): 63% out of total 5,193 items in Nature and 81% out of 3,540 items in NEJM, compared with 31% out of 283 items in CMJ and only 2 (2%) out of 126 items in AABC. Some items classified by WoS as non-original contained original research data (9.5% in Nature, 7.2% in NEJM, 13.7% in CMJ and none in AABC). These items received a significant number of citations: 6.9% of total citations in Nature, 14.7% in NEJM and 18.5% in CMJ. IF decreased for all journals when only items presenting original research and citations to them were used for IF calculation. Regardless of the journal's size or discipline, publication of non-original research and its classification by the bibliographical database have an effect on both numerator and denominator of the IF equation.