Emma G. Wilmot

Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis

Aims/hypothesisSedentary (sitting) behaviours are ubiquitous in modern society. We conducted a systematic review and meta-analysis to examine the association of sedentary time with diabetes, cardiovascular disease and cardiovascular and all-cause mortality.MethodsMedline, Embase and the Cochrane Library databases were searched for terms related to sedentary time and health outcomes. Cross-sectional and prospective studies were included. RR/HR and 95% CIs were extracted by two independent reviewers. Data were adjusted for baseline event rate and pooled using a random-effects model. Bayesian predictive effects and intervals were calculated to indicate the variance in outcomes that would be expected if new studies were conducted in the future.ResultsEighteen studies (16 prospective, two cross-sectional) were included, with 794,577 participants. Fifteen of these studies were moderate to high quality. The greatest sedentary time compared with the lowest was associated with a 112% increase in the RR of diabetes (RR 2.12; 95% credible interval [CrI] 1.61, 2.78), a 147% increase in the RR of cardiovascular events (RR 2.47; 95% CI 1.44, 4.24), a 90% increase in the risk of cardiovascular mortality (HR 1.90; 95% CrI 1.36, 2.66) and a 49% increase in the risk of all-cause mortality (HR 1.49; 95% CrI 1.14, 2.03). The predictive effects and intervals were only significant for diabetes.Conclusions/interpretationSedentary time is associated with an increased risk of diabetes, cardiovascular disease and cardiovascular and all-cause mortality; the strength of the association is most consistent for diabetes.

Association of Sedentary Behaviour with Metabolic Syndrome: A Meta-Analysis

Background In recent years there has been a growing interest in the relationship between sedentary behaviour (sitting) and health outcomes. Only recently have there been studies assessing the association between time spent in sedentary behaviour and the metabolic syndrome. The aim of this study is to quantify the association between sedentary behaviour and the metabolic syndrome in adults using meta-analysis. Methodology/Principal Findings Medline, Embase and the Cochrane Library were searched using medical subject headings and key words related to sedentary behaviours and the metabolic syndrome. Reference lists of relevant articles and personal databases were hand searched. Inclusion criteria were: (1) cross sectional or prospective design; (2) include adults ≥18 years of age; (3) self-reported or objectively measured sedentary time; and (4) an outcome measure of metabolic syndrome. Odds Ratio (OR) and 95% confidence intervals for metabolic syndrome comparing the highest level of sedentary behaviour to the lowest were extracted for each study. Data were pooled using random effects models to take into account heterogeneity between studies. Ten cross-sectional studies (n = 21393 participants), one high, four moderate and five poor quality, were identified. Greater time spent sedentary increased the odds of metabolic syndrome by 73% (OR 1.73, 95% CI 1.55–1.94, p<0.0001). There were no differences for subgroups of sex, sedentary behaviour measure, metabolic syndrome definition, study quality or country income. There was no evidence of statistical heterogeneity (I2 = 0.0%, p = 0.61) or publication bias (Eggers test t = 1.05, p = 0.32). Conclusions People who spend higher amounts of time in sedentary behaviours have greater odds of having metabolic syndrome. Reducing sedentary behaviours is potentially important for the prevention of metabolic syndrome.

Self-Reported Sitting Time and Markers of Inflammation, Insulin Resistance, and Adiposity

BACKGROUND Sedentary behavior is emerging as an independent risk factor for chronic disease; however, potential mechanisms underpinning these observations are not well understood. PURPOSE This study aimed to investigate the association of self-reported weekday sitting time with biomarkers linked to chronic low-grade inflammation, insulin resistance, and adiposity. METHODS This study reports data from individuals attending a diabetes screening program, United Kingdom, 2004-2007; analysis was conducted in 2010. Sitting time and physical activity were measured using the International Physical Activity Questionnaire; biochemical outcomes included fasting and 2-hour postchallenge glucose, fasting insulin, C-reactive protein (CRP), leptin, adiponectin, and interleukin-6 (IL-6). RESULTS This study included 505 (female=46%; South-Asian ethnicity=19%, aged 59±10 years, BMI=29.5±4.7) individuals with valid sitting data. Increased sitting time was positively associated with fasting insulin, leptin, leptin/adiponectin ratio, CRP, and IL-6 in women, but not men, after adjustment for age, ethnicity, social deprivation, and smoking and medication status; interaction analysis revealed that the gender-specific differences were significant. The associations for women remained significant after additional adjustment for total moderate- to vigorous-intensity physical activity; however all associations were attenuated when further adjusted for BMI. There was no association between sitting time and glycemic status. CONCLUSIONS Total self-reported weekday sitting time was associated with biomarkers linked to chronic low-grade inflammation and poor metabolic health in women, but not men, independent of physical activity.

Type 2 diabetes in younger adults: the emerging UK epidemic

There is an emerging epidemic of type 2 diabetes (T2DM) in younger adults. They represent an extreme phenotype: likely to be obese, lead a sedentary lifestyle, have a strong family history of T2DM, be of black or minority ethnic origin, and come from less affluent socioeconomic groups. An accurate diagnosis of T2DM in younger adults, while essential to guide management, can be challenging even for the experienced diabetologist. Comorbidities such as hypertension, nephropathy and hyperlipidaemia are prevalent in this group, and, despite the lack of longitudinal data, they represent a very high risk group, with a need for aggressive management. This focused review of the epidemiology, aetiology, clinical outcomes, comorbidities and management of younger adults with T2DM will provide the non-specialist with up-to-date insight into the UKs emerging epidemic.

Subclinical diastolic dysfunction in young adults with Type 2 diabetes mellitus: a multiparametric contrast-enhanced cardiovascular magnetic resonance pilot study assessing potential mechanisms

AIMS To assess the cardiac, vascular, anthropometric, and biochemical determinants of subclinical diastolic dysfunction in younger adults with Type 2 diabetes mellitus (T2DM) using multiparametric contrast-enhanced cardiovascular magnetic resonance (CMR) imaging. METHODS AND RESULTS Twenty adults <40 years with T2DM [mean age 31.8(6.6) years, T2DM duration 4.7(4.0) years] and 20 age and sex-matched controls [10 obese non-diabetic controls and 10 lean controls (LC)] were studied. Cardiac volumes and function, circumferential strain and peak early diastolic strain rate (PEDSR), myocardial perfusion reserve, aortic stiffness (distensibility, pulse-wave velocity), focal fibrosis on late gadolinium enhancement, and pre- and post-contrast T1 mapping for contrast agent partition coefficient (subset, n = 26) were determined by CMR. In the T2DM cohort, mean aortic distensibility correlated with PEDSR (r = 0.564, P = 0.023) and diabetes duration correlated inversely with PEDSR (r = -0.534, P = 0.015) on univariate analysis. There was a close association between PEDSR and peak systolic strain (r = -0.580, P = 0.007). CONCLUSION In young adults with T2DM, diabetes duration and aortic distensibility were associated with diastolic dysfunction. Interventional studies are required to assess whether cardiac dysfunction can be reversed in this phenotype of patients.

Stand up for your health: Is it time to rethink the physical activity paradigm?

The area of physical activity and health research has been energised by the creation of a new paradigm: sedentary behaviour. Sedentary behaviour and physical activity are increasingly viewed as different constructs with independent effects on the disease process. The creation of the new sedentary behaviour paradigm is likely to have a significant impact on research and interventions aimed at the prevention and management of diabetes in the future. This article highlights the key concepts and implications of this new paradigm.

Characteristics, complications and management of a large multiethnic cohort of younger adults with type 2 diabetes

AIMS To describe the characteristics and management of a cohort with type 2 diabetes (T2DM) <40 years. METHODS Cross-sectional study of the last visit of 648 adults attending 2 specialist centres in the UK. Differences between the lowest (≤22) vs. highest quintile (≥33) of age of diagnosis were analysed. RESULTS 57.9% were female; 45.5% Black or Minority Ethnic origin (91.9% of South Asian origin); median age at diagnosis was 28 years (24-31); diabetes duration of 4.0 years (1.9-7.0); BMI of 33.0 kg/m(2) (28.3-38.7). HbA1c of 8.2% (6.8-9.9) with HbA1c >7% in 70%. 71.8% had cholesterol >4 mmol/l, 54.9% triglycerides >1.7 mmol/l, 45% had hypertension, 19.8% retinopathy, 16.9% microalbuminuria. Insulin was used in 43.3%. 27.7% received antihypertensives and 31.5% a statin. Compared to the highest quintile of age of diagnosis, the lowest quintile had more often retinopathy (22.1% vs. 16.9%, p=0.021), was less on insulin (45.6% vs. 46.4%, p=0.039) and often managed with diet only (9.6% vs. 6.2%, p=0.005). CONCLUSIONS These younger adults with T2DM often have inadequately treated risk factors. In particular, patients from the lowest quintile of age of diagnosis were less aggressively treated. There is a need for tailored strategies to manage this high-risk group.

A Randomised Controlled Trial to Reduce Sedentary Time in Young Adults at Risk of Type 2 Diabetes Mellitus: Project STAND (Sedentary Time ANd Diabetes)

Aims Type 2 diabetes mellitus (T2DM), a serious and prevalent chronic disease, is traditionally associated with older age. However, due to the rising rates of obesity and sedentary lifestyles, it is increasingly being diagnosed in the younger population. Sedentary (sitting) behaviour has been shown to be associated with greater risk of cardio-metabolic health outcomes, including T2DM. Little is known about effective interventions to reduce sedentary behaviour in younger adults at risk of T2DM. We aimed to investigate, through a randomised controlled trial (RCT) design, whether a group-based structured education workshop focused on sitting reduction, with self-monitoring, reduced sitting time. Methods Adults aged 18–40 years who were either overweight (with an additional risk factor for T2DM) or obese were recruited for the Sedentary Time ANd Diabetes (STAND) RCT. The intervention programme comprised of a 3-hour group-based structured education workshop, use of a self-monitoring tool, and follow-up motivational phone call. Data were collected at three time points: baseline, 3 and 12 months after baseline. The primary outcome measure was accelerometer-assessed sedentary behaviour after 12 months. Secondary outcomes included other objective (activPAL) and self-reported measures of sedentary behaviour and physical activity, and biochemical, anthropometric, and psycho-social variables. Results 187 individuals (69% female; mean age 33 years; mean BMI 35 kg/m2) were randomised to intervention and control groups. 12 month data, when analysed using intention-to-treat analysis (ITT) and per-protocol analyses, showed no significant difference in the primary outcome variable, nor in the majority of the secondary outcome measures. Conclusions A structured education intervention designed to reduce sitting in young adults at risk of T2DM was not successful in changing behaviour at 12 months. Lack of change may be due to the brief nature of such an intervention and lack of focus on environmental change. Moreover, some participants reported a focus on physical activity rather than reductions in sitting per se. The habitual nature of sedentary behaviour means that behaviour change is challenging. Trial Registration Controlled-Trials.com ISRCTN08434554

Type 2 diabetes mellitus and obesity in young adults: the extreme phenotype with early cardiovascular dysfunction.

A pilot study to phenotype young adults (< 40 years) with Type 2 diabetes mellitus.

Type 2 diabetes in younger adults: Clinical characteristics, diabetes-related complications and management of risk factors

AIM To describe the clinical characteristics and risk factors of adults <35 years with type 2 diabetes (T2DM). METHODS Observational study of 185 younger adults attending a specialist diabetes clinic. RESULTS In this cohort 65% were female, 51% Caucasian, 43% South Asian. Characteristics at presentation: age 24 ± 5.5 years, BMI 33 ± 7.6 kg/m(2) and HbA1c 9.0% ± 2.3. Follow up of 3.2 ± 2.8 years with a diabetes duration of 4.5 ± 3.6 years. HbA1c had improved compared with diagnosis (8.3 ± 2.2% vs. 9.0% ± 2.3%, p<0.0001), but 63% still had an HbA1c>7%. Oral anti-diabetic drugs were used in 72%, insulin alone in 19% and both in 26%. 41% had a BP ≥ 140/80 mmHg, 78% total cholesterol >4 mmol/l, 63% LDL >2 mmol/l, 56% triglycerides >1.7 mmol/l. From diagnosis only the cholesterol and LDL improved significantly, with a modest increase in primary prevention therapy (statin 12-26%, p<0.0001, anti-hypertensives 16-29%, p<0.0001, aspirin 8-12%, p=0.18). 13% had retinopathy, 21% microalbuminuria. 46% had not been reviewed within the past year. CONCLUSIONS This group represents an extreme phenotype with a high prevalence of insufficiently treated metabolic risk factors. There is need for tailored management strategies to engage and aggressively manage this high-risk group.