Effect of metformin on plasma metabolite profile in the Copenhagen Insulin and Metformin Therapy (CIMT) trial.

AIM: Metformin is the first-line treatment for Type 2 diabetes. However, not all people benefit from this drug. Our aim was to investigate the effects of metformin on the plasma metabolome and whether the pretreatment metabolite profile can predict HbA1c outcome. METHODS: Post hoc analysis of the Copenhagen Insulin and Metformin Therapy (CIMT) trial, a multicentre study from May 2008 to December 2012, was carried out. We used a non-target method to analyse 87 plasma metabolites in participants with Type 2 diabetes (n = 370) who were randomized in a 1 : 1 ratio to 18 months of metformin or placebo treatment. Metabolites were measured by liquid chromatography-mass spectrometry at baseline and at 18-month follow-up and the data were analysed using a linear mixed-effect model. RESULTS: At baseline, participants who were on metformin before the trial (n = 312) had higher levels of leucine/isoleucine and five lysophosphatidylethanolamines (LPEs), and lower levels of carnitine and valine compared with metformin-naïve participants (n = 58). At follow-up, participants randomized to metformin (n = 188) had elevated levels of leucine/isoleucine and reduced carnitine, tyrosine and valine compared with placebo (n = 182). At baseline, participants on metformin treatment with the highest levels of carnitine C10:1 and leucine/isoleucine had the lowest HbA1c (P-interaction = 0.02 and 0.03, respectively). This association was not significant with HbA1c at follow-up. CONCLUSIONS: Metformin treatment is associated with decreased levels of valine, tyrosine and carnitine, and increased levels of leucine/isoleucine. None of the identified metabolites can predict the HbA1c -lowering effect of metformin. Further studies of the association between metformin, carnitine and leucine/isoleucine are warranted.

Age-period-cohort modelling of type 1 diabetes incidence rates among children included in the EURODIAB 25-year follow-up study.

AIMS: Specific patterns in incidence may reveal environmental explanations for type 1 diabetes incidence. We aimed to study type 1 diabetes incidence in European childhood populations to assess whether an increase could be attributed to either period or cohort effects. METHODS: Nineteen EURODIAB centres provided single year incidence data for ages 0-14 in the 25-year period 1989-2013. Case counts and person years were classified by age, period and cohort (APC) in 1-year classes. APC Poisson regression models of rates were fitted using restricted cubic splines for age, period and cohort per centre and sex. Joint models were fitted for all centres and sexes, to find a parsimonious model. RESULTS: A total of 57,487 cases were included. In ten and seven of the 19 centres the APC models showed evidence of nonlinear cohort effects or period effects, respectively, in one or both sexes and indications of sex-specific age effects. Models showed a positive linear increase ranging from approximately 0.6 to 6.6%/year. Centres with low incidence rates showed the highest overall increase. A final joint model showed incidence peak at age 11.6 and 12.6 for girls and boys, respectively, and the rate-ratio was according to sex below 1 in ages 5-12. CONCLUSION: There was reasonable evidence for similar age-specific type 1 diabetes incidence rates across the EURODIAB population and peaks at a younger age for girls than boys. Cohort effects showed nonlinearity but varied between centres and the model did not contribute convincingly to identification of environmental causes of the increase.

Causes of death among diabetic patients in Denmark.

AIMS/HYPOTHESIS: To study the distribution of causes of death in the Danish population, and its variation by diabetes status, sex, age and calendar year as well as the years of life lost from the specific causes of death. METHODS: Persons aged 30-98 years were followed from 1995 to 2008 by linkage of Danish registers. Poisson regression was used to model cause-specific mortality rates by age and calendar time for each specific cause of death, according to sex and diabetes status. The mortality rates were also modelled as a function of age and birth cohort. We computed the distribution of causes of death and years of life lost from specific causes of death due to diabetes. RESULTS: During the 14-year study period, patients with diabetes contributed 2.3 million person-years of follow-up and 124,210 deaths, whereas persons without diabetes contributed 45.1 million person-years and 648,020 deaths. The mortality was higher among individuals with diabetes, and the mortality ratio (diabetes vs no diabetes) decreased with age and for all causes and cardiovascular diseases also by calendar time. The effect of sex on the association between diabetes and mortality varied with age and cause of death. About 9 years of life were lost to diabetes at age 30 years, and 3 years at age 70 years. CONCLUSIONS/INTERPRETATION: Age-specific mortality is higher among people with diabetes, and rate ratios vary with age, sex, calendar period and cause of death. The distribution of causes of death was similar for persons with and without diabetes.

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.

Diabetes and cancer (1): evaluating the temporal relationship between type 2 diabetes and cancer incidence.

Substantial evidence suggests that people with type 2 diabetes have an increased risk of developing several types of cancers. These associations may be due to a number of direct and indirect mechanisms. Observational studies of these associations, including the potential role for glucose-lowering therapy, are being increasingly reported, but face a number of methodological challenges. This paper is the first of two review papers addressing methodological aspects underpinning the interpretations of links between diabetes and cancer, and suggests potential approaches to study designs to be considered in observational studies. This paper reviews factors related to cancer incidence in the diabetic population; the second paper relates to studies of cancer mortality.

Increased incidence of genital warts among women and men with type 1 diabetes compared with the general population-results from a nationwide registry-based, cohort study.

AIMS: To estimate the incidence rates of genital warts (GWs) in women and men with type 1 diabetes compared to persons without diabetes. METHODS: In this nationwide registry-based cohort study, we included the entire population aged 15 to 49 years living in Denmark between 1996 and 2016. From national registries, we retrieved individual level information on diabetes status, diagnoses and treatment of GWs, and potential confounding variables. We used Poisson regression to model sex- and age-specific incidence rates of GWs in persons with type 1 diabetes and persons without diabetes. Based on the models, we computed sex-specific incidence rate ratios (IRRs) of GWs in persons with type 1 diabetes compared to persons without diabetes, overall and according to age. RESULTS: The analysis included 3,514,824 persons without type 2 diabetes and no GW diagnoses before baseline. The incidence rate of GWs in persons with type 1 diabetes was higher than in those without diabetes, both among women (IRR = 1.59; 95% CI, 1.42-1.78) and men (IRR = 1.36; 95% CI, 1.25-1.48). The pattern of increased incidence rates of GWs in persons with type 1 diabetes was seen at all ages. CONCLUSIONS: Persons with type 1 diabetes have higher incidence rates of GWs than persons without diabetes. This supports the importance of HPV vaccination of young girls and boys with type 1 diabetes.

HbA1(c) and mean blood glucose show stronger associations with cardiovascular disease risk factors than do postprandial glycaemia or glucose variability in persons with diabetes: the A1C-Derived Average Glucose (ADAG) study.

AIMS: Increased glucose excursions and postprandial hyperglycaemia have been suggested as unique risk factors for cardiovascular disease (CVD) and mortality in patients with diabetes mellitus. Much of the evidence is based on a single 2 h glucose value after oral glucose tolerance testing in epidemiological studies. We examined the association between various indices of glycaemia measured during everyday activities and metabolic CVD risk factors in the A1C-Derived Average Glucose (ADAG) study. METHODS: Participants (268 with type 1 diabetes, 159 with type 2 diabetes) completed 16 weeks of intensive continuous glucose monitoring (CGM) and self-monitoring of blood glucose (SMBG). From these data, common indices of postprandial glycaemia, overall hyperglycaemia, glucose variability and HbA1(c) were derived. The associations between glycaemic indices and known CVD risk factors (lipids, high-sensitivity C-reactive protein and blood pressure) were explored in linear regression models. RESULTS: For both diabetes types, the overall strongest associations with CVD risk factors were seen for the measures of average glycaemia (mean blood glucose and HbA1(c)). Associations between self-monitored postprandial and fasting glucose and CVD risk factors were weaker, but significant. Measurements of blood glucose variability showed non-significant associations. Overall, calculations based on CGM were not more informative than those based on frequent SMBG. CONCLUSIONS/INTERPRETATION: Mean glycaemia and HbA1(c) show consistent and stronger associations with CVD risk factors than fasting glucose or postprandial glucose levels or measures of glucose variability in patients with diabetes.

Low birthweight and premature birth are both associated with type 2 diabetes in a random sample of middle-aged Danes.

AIMS/HYPOTHESIS: We studied the associations of size at birth and prematurity with type 2 diabetes, insulin sensitivity and beta cell function in the Danish population-based Inter99 study (ClinicalTrials.gov NCT00289237). METHODS: Information about size at birth and prematurity was identified from original midwife records in 4,744 middle-aged Danes. Type 2 diabetes status, insulin sensitivity (Matsuda index) and beta cell function (disposition index) were assessed using a 75 g oral glucose tolerance test. Participants born prematurely were compared with a group of at-term participants born small for gestational age. RESULTS: An increase in birthweight of 1 kg was associated with a 51% (OR 0.49, 95% CI 0.35-0.69) reduced risk of type 2 diabetes. Ponderal index, reflecting thinness at birth, was associated with type 2 diabetes to the same extent as birthweight. The prevalence of type 2 diabetes was increased to a similar degree in participants born prematurely and participants born small for gestational age, although the former had a higher ponderal index at birth. In addition, birthweight z-scores, reflecting fetal growth rate, were unrelated to the risk of type 2 diabetes and to other measures of glucose regulation in participants born prematurely. While low birthweight was inversely associated with insulin sensitivity and beta cell function, prematurity was associated solely with decreased insulin sensitivity. CONCLUSIONS/INTERPRETATION: While the association between birthweight and risk of type 2 diabetes is mediated via combined effects on beta cell function and insulin sensitivity, prematurity seems to influence risk of type 2 diabetes via attenuated insulin sensitivity only and independently of fetal growth rates.

Real-life glycaemic profiles in non-diabetic individuals with low fasting glucose and normal HbA1c: the A1C-Derived Average Glucose (ADAG) study.

AIMS/HYPOTHESIS: Real-life glycaemic profiles of healthy individuals are poorly studied. Our aim was to analyse to what extent individuals without diabetes exceed OGTT thresholds for impaired glucose tolerance (IGT) and diabetes. METHODS: In the A1C-Derived Average Glucose (ADAG) study, 80 participants without diabetes completed an intensive glucose monitoring period of 12 weeks. From these data, we calculated the average 24 h glucose exposure as time spent above different plasma glucose thresholds. We also derived indices of postprandial glucose levels, glucose variability and HbA(1c). RESULTS: We found that 93% of participants reached glucose concentrations above the IGT threshold of 7.8 mmol/l and spent a median of 26 min/day above this level during continuous glucose monitoring. Eight individuals (10%) spent more than 2 h in the IGT range. They had higher HbA(1c), fasting plasma glucose (FPG), age and BMI than those who did not. Seven participants (9%) reached glucose concentrations above 11.1 mmol/l during monitoring. CONCLUSIONS/INTERPRETATION: Even though the non-diabetic individuals monitored in the ADAG study were selected on the basis of a very low level of baseline FPG, 10% of these spent a considerable amount of time at glucose levels considered to be 'prediabetic' or indicating IGT. This highlights the fact that exposure to moderately elevated glucose levels remains under-appreciated when individuals are classified on the basis of isolated glucose measurements.

The Danish National Diabetes Register: trends in incidence, prevalence and mortality.

AIMS/HYPOTHESIS: The aim of the study was to describe trends in the incidence rate, prevalence and mortality rate for diabetes in Denmark. METHODS: Healthcare registers at the National Board of Health were used to compile a register of diabetic patients in the Danish population (5.4 million people). Age- and sex-specific prevalence, incidence rates, mortality rates and standardised mortality ratios relative to the non-diabetic part of the population were calculated. RESULTS: The register contains records for about 360,000 persons with diabetes; 230,000 were alive at 1 January 2007, corresponding to an overall prevalence of 4.2%. The prevalence increased by 6% per year. In 2004 the incidence rates were 1.8 per 100,000 at age 40 years and 10.0 per 100,000 at age 70 years. The incidence rate increased 5% per year before 2004 and then stabilised. The mortality rate in the diabetic population decreased 4% per year, compared with 2% per year in the non-diabetic part of the population. The mortality rate decreased 40% during the first 3 years after inclusion in the register. The standardised mortality ratio decreased with age, from 4.0 at age 50 years to 2.5 at age 70 years and just under 2 at age 85 years, identically for men and women. The standardised mortality ratio decreased 1% per calendar year. The lifetime risk of diabetes was 30%. CONCLUSIONS/INTERPRETATION: The prevalence of diabetes in Denmark rose in 1995-2006, but the mortality rate in diabetic patients decreased faster than that of the non-diabetic population. The mortality rate decreased markedly just after inclusion in the register. Incidence rates have shown a tendency to decrease during the last few years, but this finding should be viewed with caution.

Diabetes-related tuberculosis in Denmark: effect of ethnicity, diabetes duration and year of diagnosis.

BACKGROUND: The association between diabetes mellitus (DM) and tuberculosis (TB) has been established on the basis of cross-sectional studies; however, only a few longitudinal studies have been conducted, with inconsistent results. OBJECTIVE: To study the effect of ethnicity and the presence and duration of DM on the risk of incident TB based on 15 years of follow-up of the entire Danish population. DESIGN AND METHODS: Using Poisson regression analysis, we estimated TB incidence in individuals with DM vs. those without DM by linking nationwide DM and TB registers to the National Civil Register at case level. RESULTS: The TB rate ratio was 1.9 in individuals with DM compared to non-DM individuals, regardless of country of birth, with the exception of African-born individuals (rate ratio 0.5). The risk decreased drastically within the first 2 years after the diagnosis of DM; no association was found with longer durations of DM. The risk also decreased the later the year of DM diagnosis. CONCLUSIONS: The study confirmed DM as a risk factor for TB, except in the case of African-born individuals. Other non-DM risk factors for TB could act as effect-modifiers on the DM-TB association. Implementing earlier DM diagnosis and improving metabolic control may reduce the risk of DM-related TB.

Accuracy of clinical diagnosis of cirrhosis among alcohol-abusing men.

There is a considerable variation among specialists in the use of liver biopsy for the diagnosis of alcoholic cirrhosis, which is often based solely on clinical findings, sometimes supplemented with blood tests. To assess the diagnostic accuracy that may be achieved by this approach, we related items of the history, symptoms and signs, and routine blood tests to the presence/absence of cirrhosis in a unique, previously established, consecutive series of 303 alcohol-abusing men, in whom liver biopsy was performed irrespective of the clinical and biochemical findings. Using logistic regression analyses, we created a clinical, a combined clinical and biochemical, and a pure biochemical diagnostic model. The probability of cirrhosis in patients with the specified characteristics was estimated, the diagnostic accuracy was assessed as functions of diagnostic thresholds for cirrhosis defined by the probability of cirrhosis varying between 0 and 1,and confidence intervals were estimated by bootstrap sampling. The clinical model, including facial teleangiectasia, vascular spiders, white nails, abdominal veins, fatness, and peripheral edema, could be used with high diagnostic accuracy and it was clearly superior to the biochemical model. Adding biochemical findings to the clinical model improved the accuracy of the clinical model only slightly. We conclude that cirrhosis may be diagnosed in alcohol-abusing men with a high accuracy using selected, properly weighted clinical observations only.

Leukemia and other related hematological disorders among Danish patients exposed to Thorotrast.

At least 60 case studies of leukemia among people exposed to chronic low-dose alpha-particle radiation from injections with the radiographic contrast medium Thorotrast and 115 cases from follow-up studies have been described in the literature. In the present study, malignant hematological diseases among 1003 Danish patients injected during 1935-1947 and followed to 1992 accruing 20,433 person-years were assessed and available histopathological specimens revised. The mean cumulative bone marrow alpha-particle radiation dose (1.34 Gy) was estimated from records of the amount of Thorotrast injected (mean 18.7 ml). Sixteen cases of acute myelogenous leukemia (AML) and seven cases of myelodysplastic syndrome (MDS) were diagnosed 8-40 years after injection, the cumulative frequency reaching 7.6%. No significant relationship was seen between the cumulative frequency of AML + MDS and the age at injection, gender, or amount of Thorotrast injected, but a multivariate analysis described data best by a model with the bone marrow dose and the power of the attained age. The risk estimate for AML + MDS was 173 cases/10(4) persons per Gy. If also considering cases of acute lymphocytic leukemia (1), chronic myelogenous leukemia (3), non-Hodgkins lymphoma (4), and multiple myeloma (2), the risk estimate became 248 cases/10(4) persons per Gy. It is suggested that RBE of alpha particles from thorium may be lower than 20.

Mortality and cancer incidence after cerebral arteriography with or without Thorotrast.

Mortality and cancer incidence among 999 neurological patients exposed to chronic alpha-particle irradiation from 232ThO2 (Thorotrast) administered for cerebral angiography in 1935-1947 was compared to that of 1480 similar patients examined with cerebral angiography without Thorotrast in 1946-1963 (controls). The ratio of standardized mortality/morbidity ratios (SMRs) for patients exposed to Thorotrast and controls was the relative risk, which was analyzed by multiplicative regression (RRREG). For mortality from all causes, RRREG was significantly increased mainly due to cancer, benign and unspecified tumors and benign liver conditions, while RRREG for all other causes combined was not significantly increased. The RRREG was significantly associated with the injected amount of Thorotrast for cancer and for benign liver conditions, while no other dependence on the amount of Thorotrast was seen. Cancer incidence was significantly increased, caused mostly by liver cancer, leukemia, metastases and cancer at unspecified sites. The risk for cancer other than liver, hematological, brain, metastases and cancer at unspecified sites combined was also significantly increased, but the temporal trend of RR for this category of sites did not indicate a radiation effect. A significant association between relative risk of cancer and injected amount of Thorotrast was largely accounted for by liver cancer. Thus increased mortality among patients exposed to Thorotrast is due mainly to cancer and benign liver diseases, and increased cancer incidence is caused by high risks of liver cancer, leukemia and ill-defined types (metastases, etc.). The time trend and dependence of the amount of Thorotrast injected do not support that cancer at most other sites is related to radiation from Thorotrast.

Primary liver tumors among Danish patients exposed to Thorotrast.

The potential carcinogenic effects of internally deposited alpha-particle-emitting nuclides, notably plutonium, in the liver in humans are unknown but are of concern in relation to exposures from the nuclear industry. However, patients injected with the radiographic contrast medium Thorotrast are chronically exposed to alpha-particle radiation from 232ThO2 in the liver. Among 1003 patients injected with Thorotrast, 584 of whom were alive 15 years after the injection and 40 at the end of follow-up, a total of 127 liver cancers were diagnosed, 45 of which were hepatocellular carcinomas, 41 cholangiocarcinomas and 33 hemangiosarcomas. The median time from injection to diagnosis was 35 years (range 18-48) and the cumulative frequency was 55.4% after 48 years. In univariate and multivariate analyses, the cumulative frequency of liver cancer was best described as a function of the estimated mean cumulative alpha-particle radiation dose to the liver 15 years ago, being independent of age, gender and volume of injected Thorotrast. This may be interpreted to mean that the liver cancer rate is not related to the dose rate and that the period from malignant transformation to diagnosis of cancer is 15 years. The risk of liver carcinogenesis induced by alpha-particle radiation, assuming 15 years from induction to diagnosis, was estimated to be 712 cases/10(4) persons per gray. This value is considerably higher than estimated earlier.

Effect of tylosin used as a growth promoter on the occurrence of macrolide-resistant enterococci and staphylococci in pigs.

This study was conducted to investigate the effect of tylosin used as a growth promoter on the occurrence of macrolide-resistant enterococci and staphylococci in pigs. Two identical feeding experiments with 10 pigs each were conducted to evaluate the effect of tylosin on the occurrence of erythromycin resistance among enterococci sampled from feces and Staphylococcus hyicus sampled by skin swabs. Half of the pigs were fed antibiotic-free feed and the other half feed with tylosin (30 microg/g) added. For each pig, weekly fecal samples and skin swabs were collected and examined for erythromycin-susceptible and erythromycin-resistant enterococci and S. hyicus, respectively. There was an immediate effect of tylosin on the fraction of resistant enterococci recovered, increasing by a factor 2.4; the effect on S. hyicus was more gradual, increasing at a rate of about 8% per day and totaling a five-fold increase over 20 days. Thus, a clear effect on resistance occurrence was demonstrated, not only in intestinal bacteria, but also on bacteria sampled from the skin.

The importance of surgery and accurate axillary staging for survival in breast cancer.

AIMS: The purpose of this study was to investigate, within the context of the Danish Breast Cancer Cooperative Group (DBCG) programmes, whether a dedicated surgical approach had a significant bearing on the outcome of breast cancer treatment. METHODS: From 1 January 1980 to 31 December 1990, patients below 70 years of age with operable breast cancer from Odense University Hospital (n=743) were compared with those from the rest of Denmark (denoted rest-DK) (n=15,419). All patients were treated according to nationwide DBCG guidelines and reported to the DBCG Data Centre. The potential median observation time was 11.2 years (range 6.0-16.9). Patients underwent mastectomy or breast conserving therapy, and high risk lymph-node positive patients had adjuvant systemic therapy with or without radiotherapy. RESULTS: Comparing total patients series, overall survival (OS) was significantly superior in patients from Odense compared with rest-DK (P=0.02), with 10-year OSs of 62% (95% CI: 58-65%) and 56% (55-57%), respectively. In subgroups, the OS of low-risk node negative patients (protocol A) in Odense compared with rest-DK was significantly better (P=0.02); 10-year OS was 78% (73-84%) versus 72% (70-73%). Among the high-risk pre-menopausal patients (protocol B), the OS was significantly better in Odense (P=0.009); 10-year OS was 67% (60-75%) versus 53% (51-55%) in rest-DK. Post-menopausal high-risk patients (protocol C) did not differ significantly in OS between Odense and rest-DK (P=0.61). Locoregional control in the Odense series was superior compared with rest-DK. More lymph nodes were recovered and examined from the axilla in the Odense series than in rest-DK, a median of 10 vs. 6 nodes. In the Odense series, a significantly higher proportion of pre-menopausal patients had positive lymph nodes, predominantly one to three positive nodes, and subsequently a lower proportion of pre-menopausal patients had negative lymph nodes compared with rest-DK (P=0.02), indicating a more accurate staging in Odense vs. rest-DK. The survival benefit among the patients from Odense cannot be explained by stage migration alone, but seems to represent a true survival advantage. Overall mortality was significantly lower in the Odense series compared with rest-DK. Whether or not this difference could be explained by lower background mortality in the Odense series or was caused by superior treatment is discussed. CONCLUSIONS: The extent of surgery seems important for locoregional tumour control and accurate axillary lymph-node staging. In combination, these might lead to superior recurrence-free and overall survival, although differences in background mortality cannot be ignored. Surgery, therefore, might represent a risk factor by itself.