Objective and subjective sleep measures are associated with HbA1c and insulin sensitivity in the general population: Findings from the ORISCAV-LUX-2 study.

AIM: To analyze the association of objective and subjective sleep measures with HbA1c and insulin sensitivity in the general population. METHODS: Using a cross-sectional design, data from 1028 participants in the ORISCAV-LUX-2 study from the general population in Luxembourg were analyzed. Objective sleep measures were assessed using accelerometers whereas subjective measures were assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Sleep measures were defined as predictors, while HbA1c and quantitative insulin sensitivity check index (QUICKI) scores were considered outcomes. Linear and spline regression models were fitted by progressively adjusting for demographic and lifestyle variables in the total sample population as well as by stratified analyses using gender, obesity status, depressive symptoms and diabetes status. RESULTS: In fully adjusted models, total and deep sleep durations were associated with lower HbA1c (mmol/mol) levels, whereas sleep coefficients of variation (%) and poor sleep efficiency, as measured by PSQI scores (units), were associated with higher HbA1c levels. In stratified models, such associations were observed mainly in men, and in subjects who had depressive symptoms, were overweight and no diabetes. In addition, total sleep, deep sleep, coefficients of variation and poor sleep efficiency as measured by PSQI revealed non-linear associations. Similarly, greater insulin sensitivity was associated with longer total sleep time and with PSQI-6 (use of sleep medication). CONCLUSION: Associations were more frequently observed between sleep characteristics and glycaemic control with the use of objective sleep measures. Also, such associations varied within subgroups of the population. Our results highlight the relevance of measuring sleep patterns as key factors in the prevention of diabetes.

Patient-reported outcomes after 10-year follow-up of intensive, multifactorial treatment in individuals with screen-detected type 2 diabetes: the ADDITION-Europe trial.

AIMS: To present the longer-term impact of multifactorial treatment of type 2 diabetes on self-reported health status, diabetes-specific quality of life, and diabetes treatment satisfaction at 10-year follow up of the ADDITION-Europe trial. METHODS: The ADDITION-Europe trial enrolled 3057 individuals with screen-detected type 2 diabetes from four centres [Denmark, the UK (Cambridge and Leicester) and the Netherlands], between 2001 and 2006. Participants were randomized at general practice level to intensive treatment or to routine care . The trial ended in 2009 and a 10-year follow-up was performed at the end of 2014. We measured self-reported health status (36-item Short-Form Health Survey and EQ-5D), diabetes-specific quality of life (Audit of Diabetes-Dependent Quality of Life questionnaire), and diabetes treatment satisfaction (Diabetes Treatment Satisfaction Questionnaire) at different time points during the study period. A mixed-effects model was applied to estimate the effect of intensive treatment (intention-to-treat analyses) on patient-reported outcome measures for each centre. Centre-specific estimates were pooled using a fixed effects meta-analysis. RESULTS: There was no difference in patient-reported outcome measures between the routine care and intensive treatment arms in this 10-year follow-up study [EQ-5D: -0.01 (95% CI -0.03, 0.01); Physical Composite Score (36-item Short-Form Health Survey): -0.27 (95% CI -1.11, 0.57), Audit of Diabetes-Dependent Quality of Life questionnaire: -0.01 (95% CI -0.11, 0.10); and Diabetes Treatment Satisfaction Questionnaire: -0.20 (95% CI -0.70, 0.29)]. CONCLUSIONS: Intensive, multifactorial treatment of individuals with screen-detected type 2 diabetes did not affect self-reported health status, diabetes-specific quality of life, or diabetes treatment satisfaction at 10-year follow-up compared to routine care.

Prospective association between late evening food consumption and risk of prediabetes and diabetes: the Whitehall II cohort study.

AIMS: We examined whether late evening food consumption was prospectively associated with the risk of developing prediabetes or diabetes in a large observational study of individuals with normoglycaemia. METHODS: Participants were 2642 men and women with normoglycaemia (HbA1c < 39 mmol/mol; < 5.7%) from the Whitehall II study. Time of last eating episode (TLEE) before the examination day was assessed at baseline. We studied the associations of TLEE with 5-year changes in HbA1c and risk of developing prediabetes or diabetes (HbA1c ≥ 39 mmol/mol; ≥ 5.7%). Potential heterogeneity in the association between TLEE and prediabetes or diabetes was examined using recursive partitioning modelling for time-to-event outcomes. RESULTS: There was a tendency of an overall association of TLEE with change in HbA1c but with little effect size [ß per 1-h increase in TLEE = 0.2 mmol/mol, 95% CI -0.0 to 0.3 (0.01%, -0.00 to 0.03); P = 0.055] and no association with the risk of developing prediabetes/diabetes (risk ratio per 1-h increase in TLEE = 1.03, 95% CI 0.94 to 1.13; P = 0.511). According to the recursive partitioning modelling, women with HbA1c ≤ 36 mmol/mol and TLEE after 21:00 had a 1.51 times (95% CI 1.16 to 1.93) higher 5-year risk of developing prediabetes or diabetes than those having their TLEE between 16:00 and 21:00 (35.4% vs. 23.5%; P = 0.003). CONCLUSIONS: There was no overall association of TLEE with the development of prediabetes or diabetes in the Whitehall II population. However, explorative analyses suggested that eating late in the evening was associated with increased risk of developing prediabetes/diabetes among women with good glycaemic control. Whether restricting late evening food consumption is effective and feasible for the prevention of Type 2 diabetes needs testing in randomized controlled trials.

Trajectories of obesity by spousal diabetes status in the English Longitudinal Study of Ageing.

AIMS: To examine whether the development of obesity with age was different for individuals with and without a spouse with diabetes. METHODS: We analysed data from the English Longitudinal Study of Ageing [n= 7123, median (interquartile range) age 59 (53-67) years, 51% men], which included four clinical examination waves between 1998 and 2012. The main exposure was having a spouse with diabetes. Outcomes of interest were BMI and waist circumference. We fitted quadratic age-related trajectories using mixed-effect models stratified by sex and adjusted for education, smoking and the corresponding interaction terms between age and spousal diabetes status. RESULTS: The baseline spousal diabetes prevalence was 4.4%. Men with a wife with diabetes experienced a steeper increase in BMI (1.6 kg/m2 ) between ages 50 to 65 years than men with a wife without diabetes (0.9 kg/m2 ). Women with a husband with diabetes had a similarly shaped BMI trajectory to women with a husband without diabetes, but their average BMI levels were higher between ages 55 and 65 years. Waist circumference trajectories showed a similar shape by spousal diabetes status for men and women, although individuals with a spouse with diabetes had higher waist circumference values throughout follow-up. CONCLUSIONS: We found a positive association between spousal diabetes status and obesity development, which differed by sex among middle-aged individuals. Evidence from couple-based interventions is needed to test whether the latter could improve the current individual-focused public health strategies for obesity prevention.

Methylglyoxal is associated with changes in kidney function among individuals with screen-detected Type 2 diabetes mellitus.

AIMS: The glycolysis-derived metabolite methylglyoxal has been linked to clinical microvascular complications, including diabetic nephropathy. We aimed to further investigate the hypothesis that methylglyoxal is involved in decline in renal function by assessing the associations between measures of renal function during a 6-year follow-up in 1481 people with screen-detected Type 2 diabetes, as part of the Danish arm of the ADDITION-Europe trial (ADDITION-DK). METHODS: Biobank serum samples collected at ADDITION-DK baseline (2001-2006) and follow-up (2009-2010) were used in the current analysis of methylglyoxal. We assessed cross-sectional baseline and longitudinal associations between methylglyoxal and urinary albumin-to-creatinine ratio (ACR) or estimated GFR (eGFR), and between methylglyoxal and categories of albuminuria or reduced eGFR. RESULTS: Baseline methylglyoxal was positively associated with ACR at baseline (12% higher ACR per doubling in methylglyoxal levels), and change in methylglyoxal during 6 years of follow-up was inversely associated with change in eGFR (-1.6 ml/min/1.73 m2 per doubling in methylglyoxal change), in models adjusted for age, sex, HbA1c , systolic blood pressure, anti-hypertensive treatment, LDL-cholesterol, lipid-lowering treatment, C-reactive protein and smoking. CONCLUSIONS: In a population of people with screen-detected Type 2 diabetes, we observed associations between methylglyoxal and markers of renal function: 6-year change in methylglyoxal was inversely associated with 6-year change in eGFR. Also, methylglyoxal at baseline was positively associated with ACR at baseline. Our study lends further support to a role for methylglyoxal in the pathogenesis of diabetic nephropathy.

The role of serum methylglyoxal on diabetic peripheral and cardiovascular autonomic neuropathy: the ADDITION Denmark study.

AIMS: Cardiovascular autonomic neuropathy and diabetic peripheral neuropathy are common diabetic complications and independent predictors of cardiovascular disease. The glucose metabolite methylglyoxal has been suggested to play a causal role in the pathogeneses of diabetic peripheral neuropathy and possibly diabetic cardiovascular autonomic neuropathy. The aim of this study was to investigate the cross-sectional association between serum methylglyoxal and diabetic peripheral neuropathy and cardiovascular autonomic neuropathy in a subset of patients in the ADDITION-Denmark study with short-term screen-detected Type 2 diabetes (duration ~ 5.8 years). METHODS: The patients were well controlled with regard to HbA(1c), lipids and blood pressure. Cardiovascular autonomic neuropathy was assessed by measures of resting heart rate variability and cardiovascular autonomic reflex tests. Diabetic peripheral neuropathy was assessed by vibration detection threshold (n = 319), 10 g monofilament (n = 543) and the Michigan Neuropathy Screening Instrument questionnaire (n = 966). Painful diabetic neuropathy was assessed using the Brief Pain Inventory short form (n = 882). RESULTS: No associations between methylglyoxal and cardiovascular autonomic reflex tests or any measures of diabetic peripheral neuropathy or painful diabetic neuropathy were observed. However, a positive association between methylglyoxal and several heart rate variability indices was observed, although these associations were not statistically significant when corrected for multiple testing. CONCLUSION: Serum methylglyoxal is not associated with cardiovascular autonomic neuropathy, diabetic peripheral neuropathy or painful diabetic neuropathy in this cohort of well-treated patients with short-term diabetes.

Sex-specific effects of naturally occurring variants in the dopamine receptor D2 locus on insulin secretion and type 2 diabetes susceptibility.

AIMS: Modulation of dopamine receptor D2 (DRD2) activity affects insulin secretion in both rodents and isolated pancreatic ß-cells. We hypothesized that single nucleotide polymorphisms in the DRD2/ANKK1 locus may affect susceptibility to type 2 diabetes in humans. METHODS: Four potentially functional variants in the coding region of the DRD2/ANKK1 locus (rs1079597, rs6275, rs6277, rs1800497) were genotyped and analysed for type 2 diabetes susceptibility in up to 25 000 people (8148 with type 2 diabetes and 17687 control subjects) from two large independent Dutch cohorts and one Danish cohort. In addition, 340 Dutch subjects underwent a 2-h hyperglycaemic clamp to investigate insulin secretion. Since sexual dimorphic associations related to DRD2 polymorphisms have been previously reported, we also performed a gender-stratified analysis. RESULTS: rs1800497 at the DRD2/ANKK1 locus was associated with a significantly increased risk for type 2 diabetes in women (odds ratio 1.14 (1.06-1.23); P = 4.1*104) but not in men (odds ratio 1.00 (95% CI 0.93-1.07); P = 0.92) or the combined group. Although rs1800497 was not associated with insulin secretion, we did find another single nucleotide polymorphism in this locus, rs6275, to be associated with increased first-phase glucose-stimulated insulin secretion in women (P = 5.5*104) but again not in men (P = 0.34). CONCLUSION: The present data identify DRD2/ANKK1 as a potential sex-specific type 2 diabetes susceptibility gene.

Glycaemic threshold for diabetes-specific retinopathy among individuals from Saudi Arabia, Algeria and Portugal.

We studied the glycaemic threshold and prevalence of diabetic retinopathy in screen-detected diabetes in Saudi Arabia, Algeria and Portugal. The prevalence of diabetes-specific retinopathy started to increase at an HbA1c level of 6-6.4% (42-47 mmol/mol) and in individuals with HbA(1c) >7.0% the prevalence was 6.0%.

Reproducibility of ultrasonography for assessing abdominal fat distribution in a population at high risk of diabetes.

BACKGROUND: Visceral fat plays an important role in the development of metabolic disease independently of the effect of overall abdominal fat. Ultrasonography is an accessible method of accurately assessing abdominal fat distribution in epidemiological studies, but few details about the reproducibility of this method have been published. OBJECTIVE: The aim of this study was to investigate the reproducibility of ultrasonography in the assessment of abdominal fat distribution in a population at high risk of type 2 diabetes. DESIGN AND METHODS: Ultrasonography was used to estimate visceral and subcutaneous abdominal fat. Intra- and interobserver variation, short-term variation and variation between estimates in the fasting and non-fasting state were examined in three samples of 30, 33 and 23 participants from the ADDITION-PRO study. A variance components model was used to calculate intra- and interobserver variation, and Bland-Altman plots were drawn for all three substudies. RESULTS: Coefficients of variation for intra- and interobserver variation were in the range 3.4-6.1%, except for interobserver variation for subcutaneous fat (9.5%). Short-term variation over a median of 35 days had a coefficient of variation of 15%. The effect of a meal was primarily on the visceral estimates and did not extend beyond the first postprandial hour. Non-fasting visceral estimates were larger than fasting estimates. CONCLUSION: Both visceral and subcutaneous fat can be estimated with ultrasonography with adequate intra- and interobserver reproducibility by clinical researchers with limited training, making it a feasible method of assessing abdominal fat distribution in epidemiological studies.

The pro-inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) is associated with incident type 2 diabetes among overweight but not obese individuals with impaired glucose regulation: effect modification by smoking and body weight status.

AIMS/HYPOTHESIS: Recent evidence links the soluble urokinase plasminogen activator receptor (suPAR), a stable biomarker of systemic immune activation, to several chronic diseases, including type 2 diabetes. suPAR is also associated with adiposity and smoking. We hypothesised that this biomarker would be linked to incident type 2 diabetes in individuals with impaired glucose regulation and that this association would be modified by smoking and body weight status. METHODS: The study included 1,933 participants with impaired glucose regulation, who were drawn from the Danish arm of the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care (ADDITION) and for whom data on suPAR, BMI and smoking were available. Logistic regression analysis was used to estimate the odds for incident type 2 diabetes per twofold increase in suPAR levels. Interactions between both smoking and body weight status and suPAR were tested. RESULTS: During a 3-year follow-up (599 incident diabetes cases), there was a 48% overall increase in the odds of developing type 2 diabetes per twofold increase in suPAR (p = 0.006). This association was modified by body weight status in overweight, but not in obese individuals (OR 2.36, 95% CI 1.48, 3.76 in overweight group), and by smoking status (OR 2.05, 95% CI 1.20, 3.51 in non-smokers). After adjustment for other diabetes risk factors, the association between suPAR and type 2 diabetes was attenuated in the whole sample and among non-smokers, but remained robust among overweight participants. CONCLUSIONS/INTERPRETATION: suPAR may be a good novel biomarker for systemic sub-clinical inflammation and immune activation linked to incident type 2 diabetes risk in overweight individuals and non-smokers. The observed interactions with adiposity and smoking should be investigated further.

Risk scores for diabetes and impaired glycaemia in the Middle East and North Africa.

AIMS: To develop risk scores for diabetes and diabetes or impaired glycaemia for individuals living in the Middle East and North Africa region. In addition, to derive national risk scores for Algeria, Saudi Arabia and the United Arab Emirates and to compare the performance of the regional risk scores with the national risk scores. METHODS: An opportunistic sample of 6588 individuals aged 30-75 years was screened. Screening consisted of a questionnaire and a clinical examination including measurement of HbA(1c). Two regional risk scores and national risk scores for each of the three countries were derived separately by stepwise backwards multiple logistic regression with diabetes [HbA(1c) ≥ 48 mmol/mol (≥ 6.5%)] and diabetes or impaired glycaemia [HbA(1c) ≥ 42 mmol/mol (≥ 6.0%)] as outcome. The performance of the regional and national risk scores was compared in data from each country by receiver operating characteristic analysis. RESULTS: The eight risk scores all included age and BMI, while additional variables differed between the scores. The areas under the receiver operating characteristic curves were between 0.67 and 0.70, and for sensitivities approximately 75%; specificities varied between 50% and 57%. The regional and the national risk scores performed equally well in the three national samples. CONCLUSIONS: Two regional risk scores for diabetes and diabetes or impaired glycaemia applicable to the Middle East and North Africa region were identified. The regional risk scores performed as well as the national risk scores derived in the same manner.

Impact of early detection and treatment of diabetes on the 6-year prevalence of cardiac autonomic neuropathy in people with screen-detected diabetes: ADDITION-Denmark, a cluster-randomised study.

AIMS/HYPOTHESIS: There is limited evidence on how multifactorial treatment improves outcomes of diabetes when initiated in the lead time between detection by screening and diagnosis in routine clinical practice. Cardiac autonomic neuropathy (CAN) in people with diabetes indicates widespread damage to the autonomic nervous system, which may severely affect health and quality of life. We examined effects of early detection and subsequent intensive treatment of type 2 diabetes in primary care on the prevalence of CAN at the 6-year follow-up examination in a pragmatic cluster-randomised parallel group trial. METHODS: One hundred and ninety general practices were randomised to deliver either intensive multifactorial treatment (IT) or routine care (RC) as recommended by national guidelines to patients with type 2 diabetes, identified through a stepwise screening programme in the primary care setting. 1533 people (IT, n = 910; RC, n = 623) were identified and included. At the 6-year follow-up examination, measures of CAN were applied in an unselected subsample of 777 participants using heart rate variability analysis and standard tests of CAN. RESULTS: At the 6-year follow-up examination, the prevalence of early CAN was 15.1% in the RC group and 15.5% in the IT group, while manifest CAN was present in 7.1% and 7.3%, respectively. We found no statistically significant effect of intensive treatment on the prevalence of CAN compared with routine care. CONCLUSIONS/INTERPRETATION: In the Danish arm of the ADDITION Study, signs of CAN were highly prevalent 6 years after a screening-based diagnosis of type 2 diabetes. Intensive multifactorial treatment did not significantly affect the prevalence of CAN compared with routine care. However, at follow-up the level of medication was also high in the RC group.

Dairy product intake in relation to glucose regulation indices and risk of type 2 diabetes.

BACKGROUND AND AIM: A high intake of dairy has been linked to lower risk of type 2 diabetes (T2D). The relationship between dairy intake and glucose metabolism is still not well understood. The aim of this study was to investigate the relation between the intake of total dairy and dairy subgroups and T2D and measures of glucose metabolism. METHODS AND RESULTS: A total of 5953 Danish men and women aged 30-60 years without baseline diabetes or cardiovascular diseases were included in this prospective analysis. The dairy intake at baseline was categorised into low-fat dairy, full-fat dairy, milk and milk products, cheese and fermented dairy. Fasting plasma glucose (FPG), 2-h plasma glucose (2hPG), HbA1c, insulin resistance (HOMA2-IR) and beta-cell function (HOMA2-B) were considered at 5-year follow-up. In the maximally-adjusted model (demographics, lifestyle factors, dietary factors and waist), cheese intake was inversely associated with 2hPG (ß = -0.048, 95% CI -0.095; -0.001). Fermented dairy intake was inversely associated with FPG (ß = -0.028, 95% CI -0.048; -0.008) and HbA1c (ß = -0.016, 95% CI -0.030; -0.001). Total dairy intake and the dairy subgroups were not related to HOMA-IR and HOMA-B in the maximally-adjusted model. Furthermore, there was no significant association between intake of total dairy or any of the dairy subgroups and incidence of T2D. CONCLUSION: Our data suggest a modest beneficial effect of cheese and fermented dairy on glucose regulation measures; however, this did not translate into a significant association with incident T2D.

Effect of time of day and fasting duration on measures of glycaemia: analysis from the Whitehall II Study.

AIMS/HYPOTHESIS: We aimed to study diurnal variation in glucose regulation by examining the effects of time of day and fasting duration on fasting plasma glucose (FPG), 2 h post-load plasma glucose (2hPG) and HbA(1c) levels. METHODS: We analysed data from 5,978 non-diabetic white men and women from the prospective Whitehall II Study. All studied participants fasted for at least 8 h before a clinical examination, which included an OGTT and anthropometric measurements. We fitted mixed-effects models for FPG, 2hPG and HbA(1c) as outcome variables, and time of day and/or fasting duration as explanatory variables. Models were adjusted for age, BMI and study phase. RESULTS: Time of day and fasting duration were associated inversely with FPG and positively with 2hPG. The mean difference between measures at 08:00 and 15:00 hours in men/women was -0.46 (95% CI -0.50, -0.42) mmol/l/-0.39 (95% CI -0.46, -0.31) mmol/l and 1.39 (95% CI 1.25, 1.52) mmol/l/1.19 (95% CI 0.96, 1.42) mmol/l for FPG and 2hPG, respectively. HbA(1c) levels were independent of either time. Time of day and fasting duration were independently associated with 2hPG. In contrast, the effect of fasting duration on FPG was markedly attenuated with adjustment for time of day. Ageing, but not obesity, was associated with increased diurnal variation in glucose tolerance. CONCLUSIONS/INTERPRETATION: Both time of day and fasting duration should be considered in clinical practice and epidemiological studies, since they have clinically relevant effects on FPG and 2hPG levels. As biochemically expected, HbA(1c) levels are independent of time of blood sampling and fasting duration.

The role of anthropometric and other predictors for diabetes among urban Tanzanians with tuberculosis.

BACKGROUND: As diabetes impairs tuberculosis (TB) treatment outcomes, it is essential to identify diabetes among TB patients. While little is known about predictors of diabetes among healthy individuals in Africa, predictors among TB patients are almost non-existent. OBJECTIVE: To assess potential predictors for diabetes among newly diagnosed pulmonary TB patients in Tanzania. METHODS: TB patients were tested for diabetes using an oral glucose tolerance test, demographic information was collected and anthropometric measurements taken. The association between diabetes and possible predictors were examined using logistic regression analyses. RESULTS: Of 1205 TB patients, 16.4% (n = 197) had diabetes, 9.0% (n = 108) were aged ≥55 years, 3.3% (n = 40) were overweight (body mass index [BMI] ≥ 25 kg/m(2)) and 12.7% (n = 152) severely underweight (BMI < 16 kg/m(2)). Diabetes was most prevalent in the 45-55 year age group, and increasing weight, BMI and waist circumference were associated with diabetes. Severe underweight (BMI < 16 kg/m(2)) among male TB patients (sex-BMI interaction, P = 0.02) was associated with diabetes (OR 2.52, P = 0.004). CONCLUSION: Diabetes is a common comorbidity among TB patients. Although diabetes was associated with obesity and was more prevalent among the middle-aged, the majority of TB patients with diabetes comorbidity were young and lean. With diabetes as a major risk factor for TB, and with the lack of strong predictors for diabetes, universal diabetes screening should be implemented in the TB programme.

Sleep duration and sleep quality are associated differently with alterations of glucose homeostasis.

AIMS: Studies suggest that inadequate sleep duration and poor sleep quality increase the risk of impaired glucose regulation and diabetes. However, associations with specific markers of glucose homeostasis are less well explained. The objective of this study was to explore possible associations of sleep duration and sleep quality with markers of glucose homeostasis and glucose tolerance status in a healthy population-based study sample. METHODS: The study comprised 771 participants from the Danish, population-based cross-sectional 'Health2008' study. Sleep duration and sleep quality were measured by self-report. Markers of glucose homeostasis were derived from a 3-point oral glucose tolerance test and included fasting plasma glucose, 2-h plasma glucose, HbA(1c), two measures of insulin sensitivity (the insulin sensitivity index(0,120) and homeostasis model assessment of insulin sensitivity), the homeostasis model assessment of ß-cell function and glucose tolerance status. Associations of sleep duration and sleep quality with markers of glucose homeostasis and tolerance were analysed by multiple linear and logistic regression. RESULTS: A 1-h increment in sleep duration was associated with a 0.3 mmol/mol (0.3%) decrement in HbA(1c) and a 25% reduction in the risk of having impaired glucose regulation. Further, a 1-point increment in sleep quality was associated with a 2% increase in both the insulin sensitivity index(0,120) and homeostasis model assessment of insulin sensitivity, as well as a 1% decrease in homeostasis model assessment of ß-cell function. CONCLUSIONS: In the present study, shorter sleep duration was mainly associated with later alterations in glucose homeostasis, whereas poorer sleep quality was mainly associated with earlier alterations in glucose homeostasis. Thus, adopting healthy sleep habits may benefit glucose metabolism in healthy populations.

Cancer occurrence in Danish diabetic patients: duration and insulin effects.

AIMS/HYPOTHESIS: Cancer is more frequent among diabetes patients, but it is unknown how this excess varies with duration of diabetes and insulin use. The aim of this study was to analyse disease data to examine this issue further. METHODS: We linked the Danish National Diabetes Register and Cancer Registry and performed a cohort analysis of the entire Danish population by diabetes status, duration of diabetes and insulin use, comparing cancer incidence rates in diabetic patients with the non-diabetic population for the 15 year period 1995-2009, using Poisson regression with natural splines to describe the variation by duration. RESULTS: We found 20,032 cancer cases among patients not using insulin and 2,794 cancer cases among diabetic patients using insulin. The cancer incidence rate ratio among non-insulin users relative to the non-diabetic population decreased from over 2 at diagnosis to 1.15 after 2 years of diabetes duration. The cancer incidence rate ratio was higher among patients using insulin, decreasing from 5 at the start of insulin treatment to about 1.3 [corrected] after 5 years of insulin use. Among non-insulin users, cancers of the stomach, colorectum, liver, pancreas, lung, corpus uteri, kidney and brain, and lymphomas were elevated. Among insulin users the rate ratio of prostate cancer was decreasing by duration whereas we found higher risk of cancer of the stomach, lung, liver, pancreas and kidney. Breast cancer incidence rates were not affected by either diabetes or insulin use. CONCLUSIONS: The observed duration effects suggest that both increased surveillance for cancer in the first years after diagnosis of diabetes, and reverse causation, where undiagnosed cancers increase the likelihood of diabetes diagnosis, play a role. For longer durations, a combination of common causes for diabetes and cancer, as well as the effects of diabetes and insulin exposure per se, may play a role in the association between diabetes and some cancers.

Association studies of novel obesity-related gene variants with quantitative metabolic phenotypes in a population-based sample of 6,039 Danish individuals.

AIMS/HYPOTHESIS: Genome-wide association studies have identified novel WHR and BMI susceptibility loci. The aim of this study was to elucidate if any of these loci had an effect on quantitative measures of glucose homeostasis, including estimates of insulin release and insulin sensitivity in an epidemiological setting. METHODS: By applying an additive genetic model, 14 WHR-associated gene variants and 18 BMI-associated variants were investigated for their relationships with glucose-related metabolic traits in treatment-naive individuals from the population-based Inter99 study sample (n = 6,039). RESULTS: Of the variants associated with BMI, the QPCTL rs2287019 C allele was associated with an increased insulinogenic index of 7.4% per risk allele (p = 4.0 × 10⁻7) and increased disposition index of 5.6% (p = 6.4 × 10⁻5). The LRP1B rs2890652 C allele was associated with insulin resistance, showing a 3.3% increase (p = 0.0011) using the HOMA-insulin resistance (HOMA-IR) index and a 2.2% reduction (p = 0.0014) with the Matsuda index. Of the variants associated with WHR, LYPLAL1/SLC30A10 rs4846567 G allele carriers showed a 5.2% lower HOMA-IR (p = 0.00086) in women, indicating improved insulin sensitivity. Female carriers of the VEGFA rs6905288 A allele were insulin resistant, with a 3.7% increase in HOMA-IR (p = 0.00036) and 4.0% decrease in Matsuda index (p = 2 × 10⁻4). CONCLUSIONS: Our correlative findings from analysing single-locus data suggest that some variation in validated BMI and WHR loci are associated with either increased or decreased insulin sensitivity and thereby potentially with metabolically healthy or metabolically unhealthy subsets of obesity. The results call for testing in larger study samples and for further physiological exploration of the possible metabolic implications of these loci.

Diabetes in Greenland and its relationship with urbanization.

BACKGROUND AND AIM: Most studies show that diabetes increases with migration and urbanization. Previous studies from Greenland have shown inconsistent associations between cardiovascular risk and urbanization. Thus, the aim was to study the association between diabetes and urbanization among Greenland Inuit. METHODS: A total of 3089 adult Inuit aged 18 years and older participated in a geographically representative, population-based study 'Inuit Health in Transition Study'. The examination included a 75 g oral glucose tolerance test and anthropometric measurements. Information on socio-demographic characteristic and health behaviour was obtained by interview or questionnaire. The participants were categorized according to degree of urbanization into three groups based on current place of residence: (1) participants living in towns (> 2000 inhabitants), (2) participants living in small towns (< 2000 inhabitants) and (3) participants living in villages (< 500 inhabitants). RESULTS: The total prevalence of diabetes was 9% of which 79% were previously unknown. Nine per cent had impaired glucose tolerance and 19% had impaired fasting glycaemia (IFG). Compared with towns, odds rations (ORs) for diabetes and impaired fasting glycaemia were higher in small towns [OR(diabetes) = 1.5 (1.0-2.3), OR(IFG) = 1.9 (1.2-2.3)] and villages [OR(diabetes) = 1.2 (0.8-1.9), OR(IFG) = 1.3 (0.9-2.0)], whereas no association was seen for impaired glucose tolerance. The inverse association between urbanization and diabetes and impaired fasting glycaemia persisted after adjustment for relevant confounders. CONCLUSION: Diabetes and impaired fasting glycaemia decreased with urbanization contrary to the results of most studies. It appears that Greenland Inuit follow the pattern usually observed in industrialized countries with the highest risk of diabetes in the lower socio-economic groups.

Homozygous carriers of the G allele of rs4664447 of the glucagon gene (GCG) are characterised by decreased fasting and stimulated levels of insulin, glucagon and glucagon-like peptide (GLP)-1.

AIMS/HYPOTHESIS: The glucagon gene (GCG) encodes several hormones important for energy metabolism: glucagon, oxyntomodulin and glucagon-like peptide (GLP)-1 and -2. Variants in GCG may associate with type 2 diabetes, obesity and/or related metabolic traits. METHODS: GCG was re-sequenced as a candidate gene in 865 European individuals. Twenty-nine variants were identified. Four variants that were considered to have a likelihood for altered functionality: rs4664447, rs7581952, Ile158Val and Trp169Ter, were genotyped in 17,584 Danes. RESULTS: When examined in 5,760 treatment-naive individuals, homozygous carriers of the low frequency (minor allele frequency 2.3%) G allele of rs4664447, predicted to disrupt an essential splice enhancer binding site, had lower levels of fasting plasma glucose (mean ± SD, 4.8 ± 1.2 vs 5.5 ± 0.8 mmol/l, p = 0.004); fasting serum insulin (22 ± 14 vs 42 ± 27 pmol/l, p = 0.04); glucose-stimulated serum insulin (159 ± 83 vs 290 ± 183 pmol/l, p = 0.01) and adult height (165 ± 10 vs 172 ± 9 cm, p = 0.0009) compared with A allele carriers. During oral glucose tolerance and hyperglycaemic arginine stimulation tests, the plasma AUC for GLP-1 (730 ± 69 vs 1,334 ± 288 pmol/l × min, p = 0.0002) and basal and stimulated levels of serum insulin and plasma glucagon were ∼50% decreased (p < 0.001) among three homozygous carriers compared with nine matched wild-type carriers. rs7581952, Ile158Val and Trp169Ter (where 'Ter' indicates 'termination') variants of GCG did not significantly associate or co-segregate with the metabolic traits examined. CONCLUSIONS/INTERPRETATION: Re-sequencing of GCG revealed a low frequency intronic variant, rs4664447, and follow-up physiological studies suggest that this variant in homozygous form may cause decreased fasting and stimulated levels of insulin, glucagon and GLP-1. Overall, our findings suggest that variation in GCG has no major impact on carbohydrate metabolism in the study populations examined.