Type 2 diabetes in migrant south Asians: mechanisms, mitigation, and management

South Asians, particularly when living in high-income countries, are at a substantially elevated risk of type 2 diabetes compared with white Europeans, and typically develop the disease 5–10 years earlier and at a lower BMI. Migrant south Asians seem to be more insulin resistant than white Europeans across the life course and potentially experience β-cell exhaustion at a younger age. Differences in adiposity (high percentage of body fat and high proportion of deep subcutaneous and visceral fat) and skeletal muscle (low percentage of lean mass and low cardiorespiratory fitness) are likely to contribute these factors. No clear evidence is available suggesting genetic factors make a major contribution to the increased risk of diabetes in south Asians, but epigenetic factors might have a role. Irrespective of future mechanistic discoveries, south Asians need to be encouraged and helped—by various culturally appropriate methods—to maintain a high physical activity level and low bodyweight across the life course to prevent diabetes. In clinical terms, cardiovascular risks have attenuated over time in migrant south Asians with diabetes but retinopathy and renal complication risks remain high because of the high levels of glycaemia and rapid glycaemic deterioration noted in this population. We review these aspects and suggest areas for future research

Linking volume and intensity of physical activity to mortality

No abstract available

Authors' reply to Colquhoun and Buchinsky

No abstract available

Effects of breaking up sedentary time with "chair squats" on postprandial metabolism

Prolonged sitting induces adverse metabolic changes. We aimed to determine whether breaking up prolonged sedentary time with short periods of repeated sit-to-stand transitions (“chair squats”) every 20 minutes influences postprandial metabolic responses. Fourteen participants (11 men, 3 women), age 37 ± 16 years, BMI 30.5 ± 3.8 kg.m−2 (mean ± SD) each participated in two experimental trials in random order, in which they arrived fasted, then consumed a test breakfast (8 kcal.kg−1 body weight, 37% energy from fat, 49% carbohydrates, 14% protein) and, 3.5 hours later, an identical test lunch. Expired air and blood samples were taken fasted and for 6.5 hours postprandially. In one trial (SIT) participants sat continuously throughout the observation period; in the “Chair squat” trial (SIT/STAND), participants performed “chair squats” (10 × standing and sitting over 30 seconds, every 20 minutes). Compared to SIT, energy expenditure was 409.7 ± 41.6 kJ (16.6 ± 1.7%) higher in SIT/STAND (p < 0.0001). Postprandial insulin concentrations over the post-breakfast period were 10.9 ± 8.4% lower in SIT/STAND than SIT (p = 0.047), but did not differ between trials in the post-lunch period. Glucose and triglyceride concentrations did not differ significantly between trials. These data demonstrate that a simple, unobtrusive intervention to break up sedentary time can induce some favourable metabolic changes

Moderate exercise increases affinity of large very low density lipoproteins for hydrolysis by lipoprotein lipase

Context: Postprandial triglyceride (TG) concentration is independently associated with cardiovascular disease risk. Exercise reduces postprandial TG concentrations but the mechanisms responsible are unclear. Objective: To determine the effects of exercise on affinity of chylomicrons, large very low density lipoproteins (VLDL1) and smaller VLDL (VLDL2) for lipoprotein lipase (LPL) mediated TG hydrolysis. Design: Within-participant cross-over study. Setting: A University metabolic investigation unit. Participants: Ten overweight/obese men. Interventions: Participants undertook two oral fat tolerance tests, separated by 7–14 days, in which they had blood taken fasting and for 4 hours after a high-fat mixed meal. On the afternoon before one test, they performed a 90-minute treadmill walk at 50% maximal oxygen uptake (EX); no exercise was performed before the control test (CON). Main outcome measures: Circulating TG-rich lipoprotein concentrations; affinity of chylomicrons, VLDL1, VLDL2 for LPL-mediated TG hydrolysis. Results: Exercise significantly reduced fasting VLDL1-TG concentration (CON: 0.49(0.33–0.72) mmol.l−1, EX: 0.36(0.22–0.59) mmol.l−1, [geometric means (95% confidence interval)]; p=0.04). Time-averaged postprandial chylomicron-TG (CON: 0.55±0.10 mmol.l−1, EX: 0.39±0.08 mmol.l−1, [mean±SEM], p=0.03) and VLDL1-TG (CON: 0.85±0.13 mmol.l−1, EX: 0.66±0.10 mmol.l−1, p=0.01) concentrations were both lower in EX than CON. Affinity of VLDL1 for LPL-mediated TG hydrolysis increased by 2.2(1.3–3.7) fold (geometric mean (95% confidence interval)) (p=0.02) in the fasted state and 2.6(1.8–2.6) fold (p=0.001) postprandially. Affinity of chylomicrons and VLDL2 was not significantly different between trials. Conclusions: Exercise increases affinity of VLDL1 for LPL-mediated TG hydrolysis both fasting and postprandially. This mechanism is likely to contribute to exercise's TG-lowering effect

Plasma cholesteryl ester fatty acids do not mediate the association of ethnicity with type 2 diabetes: results from the HELIUS study

Scope: Ethnic minority groups have a higher risk of type 2 diabetes (T2D) than the host population. Our aim was to identify whether plasma cholesteryl ester fatty acids (CEFA) mediate the ethnic differences in type 2 diabetes. Methods and results: We included 202 Dutch, 206 South-Asian Surinamese, 205 African Surinamese, 215 Turkish and 213 Moroccan origin participants of the HELIUS study (Amsterdam, the Netherlands). Logistic regression was used to determine the associations between plasma CEFA and T2D. Mediation analysis was used to identify whether CEFA contributed to the association between ethnicity and T2D. We adjusted for ethnicity, age, sex, smoking, physical activity and BMI. Associations between plasma CEFA and T2D were similar across all ethnic groups. Although differences in plasma CEFA across ethnic groups were observed, CEFA did not mediate the differences in T2D prevalence between ethnic groups. Conclusion: Although ethnic differences in plasma CEFA were found and CEFA were associated with T2D, CEFA did not contribute to the difference in T2D prevalence between ethnic groups. If confirmed, this implies that maintenance of the more beneficial CEFA profiles in the non-Dutch ethnic groups may be encouraged to prevent an even higher prevalence of T2D in these groups

Increasing physical activity in older adults using STARFISH, an interactive smartphone application (app); a pilot study

Background:Increasing physical activity in older adults has preventative and therapeutic health benefits. We have developed STARFISH, a smartphone application, to increase physical activity. This paper describes the features of STARFISH, presents the views of older users on the acceptability and usability of the app and reports the results of a six week pilot study of the STARFISH app in older adults. Methods:The operationalisation of the behaviour change techniques (BCTs) within the STARFISH app was mapped against the BCT Taxonomy of Michie et al. Sixteen healthy older adults (eight women and eight men; age 71.1 ± 5.2 years) used the app, in groups of four, for six weeks. Focus groups explored the user experience and objective measure of steps per day recorded. Results:Participants were very positive about using the STARFISH app, in particular the embedded BCTs of self-monitoring, feedback and social support (in the form of group rewards). Objective step data, available for eight participants, showed that step counts increased by an average of 14% (p = 0.077, d = 0.56). Conclusion:The STARFISH app was acceptable and straightforward to use for older adults. STARFISH has potential to increase physical activity in older adults; however, a fully powered randomised controlled trial is required

Shorter sleep: a new potential target to address cardiovascular and metabolic risk?

No abstract available

Non-exercise equations to estimate fitness in white European and South Asian men

Cardiorespiratory fitness is a strong, independent predictor of health, whether it is measured in an exercise test or estimated in an equation. The purpose of this study was to develop and validate equations to estimate fitness in middle-aged white European and South Asian men.Multiple linear regression models (n=168, including 83 white European and 85 South Asian men) were created using variables that are thought to be important in predicting fitness (VO2 max, mL⋅kg⋅min): age (years); BMI (kg·m); resting heart rate (beats⋅min); smoking status (0=never smoked, 1=ex or current smoker); physical activity expressed as quintiles (0=quintile 1, 1=quintile 2, 2=quintile 3, 3=quintile 4, 4=quintile 5), categories of moderate- to vigorous-intensity physical activity (0=<75 min⋅wk, 1=75-150 min⋅wk, 2=>150-225 min⋅wk, 3=>225-300 min⋅wk, 4=>300 min⋅wk), or minutes of moderate- to vigorous-intensity physical activity (min⋅wk); and, ethnicity (0=South Asian, 1=white). The leave-one-out-cross-validation procedure was used to assess the generalizability and the bootstrap and jackknife resampling techniques were used to estimate the variance and bias of the models.Around 70% of the variance in fitness was explained in models with an ethnicity variable, such as: VO2 max = 77.409 - (age*0.374) - (BMI*0.906) - (ex or current smoker*1.976) + (physical activity quintile coefficient) - (resting heart rate*0.066) + (white ethnicity*8.032), where physical activity quintile 1 is 1, 2 is 1.127, 3 is 1.869, 4 is 3.793, and 5 is 3.029. Only around 50% of the variance was explained in models without an ethnicity variable. All models with an ethnicity variable were generalizable and had low variance and bias.These data demonstrate the importance of incorporating ethnicity in non-exercise equations to estimate cardiorespiratory fitness in multi-ethnic populations

Association between active commuting and incident cardiovascular disease, cancer, and mortality: prospective cohort study

Objective: To investigate the association between active commuting and incident cardiovascular disease (CVD), cancer, and all cause mortality. Design: Prospective population based study. Setting: UK Biobank. Participants: 263 450 participants (106 674 (52%) women; mean age 52.6), recruited from 22 sites across the UK. The exposure variable was the mode of transport used (walking, cycling, mixed mode v non-active (car or public transport)) to commute to and from work on a typical day. Main outcome measures: Incident (fatal and non-fatal) CVD and cancer, and deaths from CVD, cancer, or any causes. Results: 2430 participants died (496 were related to CVD and 1126 to cancer) over a median of 5.0 years (interquartile range 4.3-5.5) follow-up. There were 3748 cancer and 1110 CVD events. In maximally adjusted models, commuting by cycle and by mixed mode including cycling were associated with lower risk of all cause mortality (cycling hazard ratio 0.59, 95% confidence interval 0.42 to 0.83, P=0.002; mixed mode cycling 0.76, 0.58 to 1.00, P<0.05), cancer incidence (cycling 0.55, 0.44 to 0.69, P<0.001; mixed mode cycling 0.64, 0.45 to 0.91, P=0.01), and cancer mortality (cycling 0.60, 0.40 to 0.90, P=0.01; mixed mode cycling 0.68, 0.57 to 0.81, P<0.001). Commuting by cycling and walking were associated with a lower risk of CVD incidence (cycling 0.54, 0.33 to 0.88, P=0.01; walking 0.73, 0.54 to 0.99, P=0.04) and CVD mortality (cycling 0.48, 0.25 to 0.92, P=0.03; walking 0.64, 0.45 to 0.91, P=0.01). No statistically significant associations were observed for walking commuting and all cause mortality or cancer outcomes. Mixed mode commuting including walking was not noticeably associated with any of the measured outcomes. Conclusions: Cycle commuting was associated with a lower risk of CVD, cancer, and all cause mortality. Walking commuting was associated with a lower risk of CVD independent of major measured confounding factors. Initiatives to encourage and support active commuting could reduce risk of death and the burden of important chronic conditions