Patrice Carter

Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis

Objective To investigate the independent effects of intake of fruit and vegetables on incidence of type 2 diabetes. Design Systematic review and meta-analysis. Data sources Medline, Embase, CINAHL, British Nursing Index (BNI), and the Cochrane library were searched for medical subject headings and keywords on diabetes, prediabetes, fruit, and vegetables. Expert opinions were sought and reference lists of relevant articles checked. Study selection Prospective cohort studies with an independent measure of intake of fruit, vegetables, or fruit and vegetables and data on incidence of type 2 diabetes. Results Six studies met the inclusion criteria; four of these studies also provided separate information on the consumption of green leafy vegetables. Summary estimates showed that greater intake of green leafy vegetables was associated with a 14% (hazard ratio 0.86, 95% confidence interval 0.77 to 0.97) reduction in risk of type 2 diabetes (P=0.01). The summary estimates showed no significant benefits of increasing the consumption of vegetables, fruit, or fruit and vegetables combined. Conclusion Increasing daily intake of green leafy vegetables could significantly reduce the risk of type 2 diabetes and should be investigated further.

Sedentary Time and Markers of Chronic Low-Grade Inflammation in a High Risk Population

Background Sedentary behaviour has been identified as a distinct risk factor for several health outcomes. Nevertheless, little research has been conducted into the underlying mechanisms driving these observations. This study aimed to investigate the association of objectively measured sedentary time and breaks in sedentary time with markers of chronic low-grade inflammation and adiposity in a population at a high risk of type 2 diabetes mellitus. Methods This study reports data from an ongoing diabetes prevention programme conducted in Leicestershire, UK. High risk individuals were recruited from 10 primary care practices. Sedentary time (<25counts per 15s) was measured using Actigraph GT3X accelerometers (15s epochs). A break was considered as any interruption in sedentary time (≥25counts per 15s). Biochemical outcomes included interleukin-6 (IL-6), C-reactive protein (CRP), leptin, adiponectin and leptin:adiponectin ratio (LAR). A sensitivity analysis investigated whether results were affected by removing participants with a CRP level >10 mg/L, as this can be indicative of acute inflammation. Results 558 participants (age = 63.6±7.7years; male = 64.7%) had complete adipokine and accelerometer data. Following adjustment for various confounders, sedentary time was detrimentally associated with CRP (β = 0.176±0.057, p = 0.002), IL-6 (β = 0.242±0.056, p = <0.001), leptin (β = 0.146±0.043, p = <0.001) and LAR (β = 0.208±0.052, p = <0.001). Associations were attenuated after further adjustment for moderate-to-vigorous physical activity (MVPA) with only IL-6 (β = 0.231±0.073, p = 0.002) remaining significant; this result was unaffected after further adjustment for body mass index and glycosylated haemoglobin (HbA1c). Similarly, breaks in sedentary time were significantly inversely associated with IL-6 (β = −0.094±0.047, p = 0.045) and leptin (β = −0.075±0.037, p = 0.039); however, these associations were attenuated after adjustment for accelerometer derived variables. Excluding individuals with a CRP level >10 mg/L consistently attenuated the significant associations across all markers of inflammation. Conclusion These novel findings from a high risk population recruited through primary care suggest that sedentary behaviour may influence markers associated with inflammation, independent of MVPA, glycaemia and adiposity.

Fruit and vegetable intake and the association with glucose parameters: a cross-sectional analysis of the Let’s Prevent Diabetes Study

Background:Dietary recommendations for the prevention of type 2 diabetes mellitus include the message to consume 400 g fruit and vegetables per day. Measurement of habitual diet is inherently difficult, yet errors due to self-report can be eliminated by the use of nutritional biomarkers. The aim of this study was to determine plasma vitamin C concentrations as a biomarker for fruit and vegetable intake in individuals identified at high risk of diabetes. Fruit and vegetables may confer benefit via their antioxidant capacity, thus we also measured urinary F2-isoprostanes as a marker for oxidative stress.Subjects/Methods:Participants recruited from a high-risk population as part of a diabetes prevention trial provided fasting blood samples and a spot urine sample for the quantification of plasma vitamin C and F2-isoprostanes, respectively. We compared glycaemic parameters by the increments of the standard deviation of plasma vitamin C using multiple regression models.Results:Mean plasma vitamin C of participants was 39.3 μmol/l (s.d. 21.8). In the unadjusted model, 1 s.d. plasma vitamin C was significantly and inversely associated with HbA1c, fasting and 2 h blood glucose (P⩽0.0001). Relationships remained significant after adjustment for demographic variables and confounding factors. No significant association was observed between plasma vitamin C and urinary F2-isoprostanes.Conclusion:The data adds to the evidence that small lifestyle changes may influence glucose regulation. The role that fruit and vegetables independently have should be investigated further.

A Mediterranean diet improves HbA1c but not fasting blood glucose compared to alternative dietary strategies: a network meta‐analysis

BACKGROUND Overweight or obese individuals with type 2 diabetes are encouraged to lose weight for optimal glucose management, yet many find this difficult. Determining whether alterations in dietary patterns irrespective of weight loss can aid glucose control has not been fully investigated. METHODS We conducted a systematic review and meta-analysis aiming to determine the effects of a Mediterranean diet compared to other dietary interventions on glycaemic control irrespective of weight loss. Electronic databases were searched for controlled trials that included a Mediterranean diet intervention. The interventions included all major components of the Mediterranean diet and were carried out in free-living individuals at high risk or diagnosed with type 2 diabetes. Network meta-analysis compared all interventions with one another at the same time as maintaining randomisation. Analyses were conducted within a Bayesian framework. RESULTS Eight studies met the inclusion criteria, seven examined fasting blood glucose (n = 972), six examined fasting insulin (n = 1330) and three examined HbA1c (n = 487). None of the interventions were significantly better than the others in lowering glucose parameters. The Mediterranean diet reduced HbA1c significantly compared to usual care but not compared to the Palaeolithic diet. CONCLUSIONS The effect of alterations in dietary practice irrespective of weight loss on glycaemic control cannot be concluded from the present review. The need for further research in this area is apparent because no firm conclusions about relative effectiveness of interventions could be drawn as a result of the paucity of the evidence.

Is the number of fast-food outlets in the neighbourhood related to screen-detected type 2 diabetes mellitus and associated risk factors?

OBJECTIVE We investigated whether a higher number of fast-food outlets in an individuals home neighbourhood is associated with increased prevalence of type 2 diabetes mellitus and related risk factors, including obesity. DESIGN Cross-sectional study. SETTING Three UK-based diabetes screening studies (one general population, two high-risk populations) conducted between 2004 and 2011. The primary outcome was screen-detected type 2 diabetes. Secondary outcomes were risk factors for type 2 diabetes. SUBJECTS In total 10 461 participants (mean age 59 years; 53% male; 21% non-White ethnicity). RESULTS There was a higher number of neighbourhood (500 m radius from home postcode) fast-food outlets among non-White ethnic groups (P<0.001) and in socially deprived areas (P<0.001). After adjustment (social deprivation, urban/rural, ethnicity, age, sex), more fast-food outlets was associated with significantly increased odds for diabetes (OR=1.02; 95% CI 1.00, 1.04) and obesity (OR=1.02; 95% CI 1.00, 1.03). This suggests that for every additional two outlets per neighbourhood, we would expect one additional diabetes case, assuming a causal relationship between the fast-food outlets and diabetes. CONCLUSIONS These results suggest that increased exposure to fast-food outlets is associated with increased risk of type 2 diabetes and obesity, which has implications for diabetes prevention at a public health level and for those granting planning permission to new fast-food outlets.

The effects of supervised exercise training 12–24 months after bariatric surgery on physical function and body composition: a randomised controlled trial

Background:Bariatric surgery is effective for the treatment of stage II and III obesity and its related diseases, although increasing evidence is showing weight regain ~12–24 months postsurgery. Weight regain increases the risk of physical function decline, which negatively affects an individuals ability to undertake activities of daily living. The study assessed the effects of a 12-week supervised exercise intervention on physical function and body composition in patients between 12 and 24 months post bariatric surgery.Methods:Twenty-four inactive adult bariatric surgery patients whose body mass index remained ⩾30 kg m2 12 to 24 months post surgery were randomised to an exercise intervention (n=12) or control group (n=12). Supervised exercise consisted of three 60-min gym sessions per week of moderate intensity aerobic and resistance training for 12 weeks. Control participants received usual care. The incremental shuttle walk test (ISWT) was used to assess functional walking performance after the 12-week exercise intervention, and at 24 weeks follow-up. Measures of anthropometric, physical activity, cardiovascular and psychological outcomes were also examined. Using an intention-to-treat protocol, independent t-tests were used to compare outcome measures between groups.Results:Significant improvements in the exercise group were observed for the ISWT, body composition, physical function, cardiovascular and self-efficacy measures from baseline to 12 weeks. A large baseline to 12-week change was observed for the ISWT (exercise: 325.00±117.28 m; control: 355.00±80.62 m, P<0.001). The exercise group at 24 weeks recorded an overall mean improvement of 143.3±86.6 m and the control group recorded a reduction of −32.50±75.93 m. Findings show a 5.6 kg difference between groups in body mass change from baseline to 24 weeks favouring the exercise group.Conclusions:A 12-week supervised exercise intervention led to significant improvements in body mass and functional walking ability post intervention, with further improvements at the 24-week follow-up.

Dietary Recommendations for the Prevention of Type 2 diabetes: What Are They Based on?

Introduction. Type 2 diabetes is increasing in all populations and all age groups across the world. Areas undergoing rapid westernisation and rapid nutrition transition are seeing the greatest increases in prevalence suggesting that environmental factors are important. Studies from around the world have shown that dietary modification for the prevention of T2DM can be successful; however which dietary factors are important remains to be fully elucidated. The WHO, ADA, and Diabetes UK have developed guidelines for the prevention of T2DM even though the WHO states that data from lifestyle modification programmes does not allow for the disentanglement of dietary factors. Aim of Review. The aim of this focused review is to evaluate the current dietary recommendations for the prevention of T2DM. In addition we aim to explore the available evidence from both observation studies and clinical trials to determine whether these recommendations are appropriate.

The effect of antiobesity drugs on waist circumference: a mixed treatment comparison.

To use meta‐analytic techniques to quantitatively evaluate the efficacy of orlistat and lorcaserin in the treatment of people who are overweight and obese.

Association between direct measurement of active serum calcium and risk of type 2 diabetes mellitus: A prospective study.

BACKGROUND AND AIMS Previous prospective studies showing a positive association between serum calcium and incidence of type 2 diabetes mellitus (T2DM) have relied on total calcium or an indirect estimate of active, ionized calcium (iCa). We aimed to assess this relationship using a direct measurement of iCa. METHODS AND RESULTS iCa and cardiometabolic risk factors were measured in a population-based sample of 2350 men without a known history of T2DM at baseline. Associations between iCa levels and incident cases of T2DM (self-reported, ascertained with a glucose tolerance test, or determined by record linkage to national registers) were estimated using Cox regression analyses adjusted for potential confounders. At baseline, mean (standard deviation) age was 53 (5) years and mean iCa 1.18 (0.05) mmol/L. During a median follow-up of 23.1 years, 140 new cases of T2DM were recorded. In a multivariable analysis adjusted for age, body mass index, systolic blood pressure, serum HDL-cholesterol, and family history of T2DM, there was no association comparing second (hazard ratio 0.84; 95% confidence interval 0.59-1.18), third (0.77; 0.52-1.14), or fourth (0.98; 0.69-1.39) vs first quartile of iCa (p for trend 0.538); further adjustment for C-reactive protein, physical activity level, and triglycerides did not change the estimates (p for trend 0.389). CONCLUSION In this study, we did not find evidence of an association between direct measurement of active calcium and risk of T2DM. Further studies are needed to confirm our findings and define the relationship between factors influencing indirect calcium estimation and incident T2DM.

South Asian individuals at high risk of type 2 diabetes have lower plasma vitamin C levels than white Europeans.

Individuals of South Asian origin are at high risk of developing type 2 diabetes; the relationship between this risk and diet remains to be investigated fully. Furthermore, fruit and vegetable intake remains low throughout the world and previous data suggest that intake is associated with risk of diabetes. The aim of this research study was to compare plasma vitamin C concentrations, measured as a biomarker for fruit and vegetable intake, in South Asian and white European individuals. Participants recruited as part of the Lets Prevent Diabetes Study provided samples for the quantification of plasma vitamin C. We compared vitamin C levels by ethnicity using multiple regression, both unadjusted and adjusted for confounders, including glycaemic status. Mean plasma vitamin C was significantly lower in the South Asian participants compared with white European participants (34.5 (sd 19·8) v. 39·9 (sd 22·1) µmol/l, respectively; P ≤ 0·0001). Significantly fewer South Asian individuals consumed five portions of fruit and vegetables per d, as determined by a plasma vitamin C concentration of ≥ 50 µmol/l (23·2 % (n 58) v. 31·4 % (n 558); P = 0·01). Vitamin C reflects habitual fruit and vegetable consumption; thus results suggest that South Asians have lower fruit and vegetable intake. However, it cannot be excluded that vitamin C is utilised differently. Dietary advice specifically targeting the South Asian population should be developed.