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.

Carbohydrate quantity is more closely associated with glycaemic control than weight in pregnant women with type 1 diabetes: Insights from the Diabetes and Pre-eclampsia Intervention Trial (DAPIT)

BACKGROUND

The present study aimed to explore the relationships between carbohydrate intake, body mass index (BMI) and glycaemic control (HbA1c) in pregnant women with type 1 diabetes mellitus (T1DM) METHODS: Secondary analysis of data was undertaken to assess dietary intake in a cohort of women who participated in a randomised controlled trial (RCT) of antioxidant supplementation to prevent preeclampsia (DAPIT¹⁰ ). Study-specific peripheral venous blood samples were obtained for HbA1c at 26 and 34 weeks. Diet was collected using a validated semiquantitative food frequency questionnaire at 26-28 weeks of gestation which assessed dietary intake over 2 weeks. Mean daily average nutrient intakes were analysed using Q Builder nutritional software and SPSS, version 25.

RESULTS

Dietary data were available for 547 pregnant women (72% of cohort) aged 29 years (95% confidence interval [CI] = 28.9-29.9) with average diabetes duration 11.8 years (95% confidence interval = 11.1-12.6). Average body mass index (BMI) (<16 weeks of gestation) was 26.7 kg/m² (95% CI = 26.3 -27, range 18.8-45.6 kg/m² ); 43% (n = 234) were overweight (BMI = 25.0-29.9 kg/m² ) and 20% (n = 112) were obese (BMI ≥ 30 kg/m² ). Differences in HbA1c and carbohydrate quantity and quality were found when adjusted for age and insulin dose. No differences between BMI group were observed for total carbohydrate and glycaemic control; however, differences were noted in fibre and glycaemic index.

CONCLUSIONS

Average quantity of dietary carbohydrate influenced HbA1c when adjusted for insulin dose however, BMI had less impact. More research is required on the relationship between carbohydrate consumption and glycaemic control in pregnancy.

Clinical utility of ultrasonography-measured visceral adipose tissue depth as a tool in early pregnancy screening for gestational diabetes: a proof-of-concept study

AIM

To examine, in a proof-of-concept study, the ability of visceral adipose tissue depth and subcutaneous fat depth measured in early pregnancy to predict subsequent gestational diabetes, and to assess the performance of these measures as screening tests for gestational diabetes compared with use of the current UK criteria.

METHODS

A total of 100 women in early pregnancy were recruited from a maternity hospital in Belfast, UK. Visceral adipose tissue depth and subcutaneous fat depth were measured, and each participant underwent a 75-g oral glucose tolerance test at 28 weeks' gestation for the diagnosis of gestational diabetes using WHO 2013 criteria.

RESULTS

Eighty women completed the study, of whom 15 (19%) developed gestational diabetes. Increasing visceral adipose tissue depth, but not subcutaneous fat depth, was associated with greater gestational diabetes risk after adjusting for confounding factors (odds ratio for a 1-sd rise 2.09, 95% CI 1.06-4.12; P=0.03). Visceral adipose tissue depth ≥4.27 cm had greater sensitivity compared with current National Institute of Health and Care Excellence criteria (87% vs 40%, respectively; P=0.02) and similar specificity (62% vs 74%, respectively; P=0.15) for identifying gestational diabetes.

CONCLUSIONS

Ultrasonography-measured visceral adipose tissue in early pregnancy is a potential clinical tool for improving sensitivity of selective screening for gestational diabetes, which, compared with universal oral glucose tolerance testing, is likely to reduce by half the numbers requiring this test. Further larger studies are now required for confirmation, including investigation into impact on clinical outcomes.

Maternal vitamin D and markers of glycaemia during pregnancy in the Belfast centre of the Hyperglycaemia and Adverse Pregnancy Outcome study

AIMS

To measure total 25-hydroxyvitamin D levels in women in mid-pregnancy who participated in the Belfast centre of the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) observational study, and to investigate the associations between levels of 25-hydroxyvitamin D and markers of gestational diabetes mellitus and lipid biomarkers.

METHODS

A total of 1585 pregnant women had serum samples available for measurement. Participants were recruited from the Royal Jubilee Maternity Hospital, Belfast, Northern Ireland, at 24-32 weeks' gestation, as part of the HAPO study. 25-hydroxyvitamin D concentrations were measured using liquid chromatography tandem mass spectrometry. Glucose, C-peptide and lipid levels were previously analysed in a central laboratory. Statistical analysis was performed.

RESULTS

The median (interquartile range) 25-hydroxyvitamin D concentration during pregnancy was 38.6 (24.1-60.7) nmol/l, with 65.8% of women being vitamin D-deficient (≤50 nmol/l). In regression analysis, the association between maternal 25-hydroxyvitamin D and fasting plasma glucose levels approached significance [regression coefficient -0.017 (95% CI -0.034 to 0.001); P=0.06], and a significant positive association was observed between maternal 25-hydroxyvitamin D and β-cell function [1.013 (95% CI 1.001 to 1.024); P=0.031]. Maternal 25-hydroxyvitamin D level was positively associated with HDL [0.047 (95% CI 0.021 to 0.073) P≤ 0.001] and total cholesterol [0.085 (95% CI 0.002 to 0.167); P=0.044] in regression analysis.

CONCLUSIONS

These results indicate a high prevalence of vitamin D deficiency during pregnancy, which requires identification and treatment; however, only weak associations were observed between 25-hydroxyvitamin D level and markers of glucose and insulin metabolism. This would suggest that these are of doubtful clinical significance.

A Role for Behavior in the Relationships Between Depression and Hostility and Cardiovascular Disease Incidence, Mortality, and All-Cause Mortality: the Prime Study

Background

Behavioral factors are important in disease incidence and mortality and may explain associations between mortality and various psychological traits.

Purpose

These analyses investigated the impact of behavioral factors on the associations between depression, hostility and cardiovascular disease(CVD) incidence, CVD mortality, and all-cause mortality.

Methods

Data from the PRIME Study (N = 6953 men) were analyzed using Cox proportional hazards models, following adjustment for demographic and biological CVD risk factors, and other psychological traits, including social support.

Results

Following initial adjustment, both depression and hostility were significantly associated with both mortality outcomes (smallest SHR = 1.24, p < 0.001). Following adjustment for behavioral factors, all relationships were attenuated both when accounting for and not accounting for other psychological variables. Associations with all-cause mortality remained significant (smallest SHR = 1.14, p = 0.04). Of the behaviors included, the most significant contribution to outcomes was found for smoking, but a role was also found for fruit and vegetable intakes and high alcohol consumption.

Conclusions

These findings demonstrate well-known associations between depression, hostility, and mortality and suggest the potential importance of behaviors in explaining these relationships.

Barriers to adopting a Mediterranean diet in Northern European adults at high risk of developing cardiovascular disease

BACKGROUND

Strong evidence links the consumption of a Mediterranean diet (MD) with a reduced cardiovascular disease (CVD) risk; however, there is uncertainty as to whether non-Mediterranean regions will adopt this diet. The present qualitative research aimed to investigate attitudes towards a MD in individuals at high CVD risk in a Northern European population. This information is needed to inform development of MD interventions in non-Mediterranean high-risk populations.

METHODS

Focus groups (n = 12) were held with individuals at high CVD risk from Northern Europe (≥2 CVD risk factors, aged ≥50 years, no established CVD/type 2 diabetes). Attitudes to dietary change towards a MD were explored. Data were analysed using inductive thematic analysis.

RESULTS

Sixty-seven adults participated (60% female, mean age 64 years). There was some awareness of the term MD but limited knowledge of its composition. Barriers to general dietary change were evident, including perception of expense, concern over availability, expectation of time commitment, limited knowledge, lack of cooking skills, amount and conflicting nature of media information on diets, changing established eating habits and resistance to dietary change. Barriers specific to MD adoption were also identified, including perceived difficulty living in a colder climate, perceived impact on body weight, acceptability of a MD and cultural differences.

CONCLUSIONS

Knowledge of a MD was limited in this Northern European sample at high CVD risk. In addition to general barriers to dietary change, barriers specific to a MD were identified. These findings have implications for the development of interventions aiming to promote MD adoption in non-Mediterranean populations.

Effect of pregnancy planning on maternal and neonatal outcomes in women with Type 1 diabetes

AIMS

To assess the effect of pregnancy planning on maternal and neonatal outcomes in women with Type 1 diabetes.

METHODS

Pregnancy planning was assessed retrospectively in a cohort of women who participated in the Diabetes and Pre-eclampsia Intervention Trial (DAPIT). Pregnancy planning was determined based on self-report as to whether pregnancy was planned or unplanned. The effect of pregnancy planning on maternal and neonatal outcomes was examined, controlling for confounding variables.

RESULTS

A total of 747 women were included in the study, of whom 39% considered their pregnancy unplanned. Characteristics associated with unplanned pregnancy included being younger (P<0.001), being a current smoker (P<0.001), being from a lower social class (P<0.001) and having higher HbA_1c values prior to and throughout pregnancy (P≤0.005). Significantly fewer women with unplanned vs planned pregnancies received pre-pregnancy counselling (24% vs 64%; P<0.001). Infants of women with unplanned pregnancies were more likely to be small for gestational age (<5^th centile; P=0.004), to be admitted to the neonatal care unit (P=0.001) and to have a longer stay in hospital (P=0.01). Outcomes did not differ between the groups in relation to pre-eclampsia, congenital malformations or a composite adverse outcome.

CONCLUSIONS

Risks associated with diabetes in pregnancy need to be highlighted to all women, their partners and families, and healthcare professionals. Further research is required to determine if these groups are fully aware of the risks associated with diabetes in pregnancy.

Effect of implementation of a preconception counselling resource for women with diabetes: A population based study

AIM

To evaluate the effect of regional implementation of a preconception counselling resource into routine diabetes care on pregnancy planning indicators.

METHODS

A preconception counselling DVD was distributed to women by diabetes care teams and general practices. Subsequently, in a prospective population-based study, pregnancy planning indicators were evaluated. The post-DVD cohort (n=135), including a viewed-DVD subgroup (n=58), were compared with an historical cohort (pre-DVD, n=114). Primary outcome was HbA1c at first diabetes-antenatal visit. Secondary outcomes included preconception folic acid consumption, planned pregnancy and HbA1c recorded in the 6 months preconception.

RESULTS

Mean first visit HbA1c was lower post-DVD vs. pre-DVD: 7.5% vs. 7.8% [58.4 vs. 61.8mmol/mol]; p=0.12), although not statistically significant. 53% and 20% of women with type 1 and 2 diabetes, respectively, viewed the DVD. The viewed-DVD subgroup were significantly more likely to have lower first visit HbA1c: 6.9% vs. 7.8% [52.1 vs. 61.8mmol/mol], P<0.001; planned pregnancy (88% vs. 59%, P<0.001); taken folic acid preconception (81% vs. 43%, P=0.001); and had HbA1c recorded preconception (88% vs. 53%, P<0.001) than the pre-DVD cohort.

CONCLUSIONS

Implementation of a preconception counselling resource was associated with improved pregnancy planning indicators. Women with type 2 diabetes are difficult to reach. Greater awareness within primary care of the importance of preconception counselling among this population is needed.

Serum 25-hydroxyvitamin D and insulin resistance in people at high risk of cardiovascular disease: a euglycaemic hyperinsulinaemic clamp study

CONTEXT

In observational studies, low serum 25-hydroxyvitamin D (25-OHD) concentration is associated with an increased risk of type 2 diabetes mellitus (DM). Increasing serum 25-OHD may have beneficial effects on insulin resistance or beta-cell function. Cross-sectional studies utilizing suboptimal methods for assessment of insulin sensitivity and serum 25-OHD concentration provide conflicting results.

OBJECTIVE

This study examined the relationship between serum 25-OHD concentration and insulin resistance in healthy overweight individuals at increased risk of cardiovascular disease, using optimal assessment techniques.

METHODS

A total of 92 subjects (mean age 56·0, SD 6·0 years), who were healthy but overweight (mean body mass index 30·9, SD 2·3 kg/m(2) ), underwent assessments of insulin sensitivity (two-step euglycaemic hyperinsulinaemic clamp, HOMA2-IR), beta-cell function (HOMA2%B), serum 25-OHD concentration and body composition (DEXA).

RESULTS

Mean total 25-OHD concentration was 32·2, range 21·8-46·6 nmol/l. No association was demonstrated between serum 25-OHD concentration and insulin resistance.

CONCLUSIONS

In this study using optimal assessment techniques to measure 25-OHD concentration, insulin sensitivity and body composition, there was no association between serum 25-OHD concentration and insulin resistance in healthy, overweight individuals at high risk of developing cardiovascular disease. This study suggests the documented inverse association between serum 25-OHD concentration and risk of type 2 DM is not mediated by a relationship between serum 25-OHD concentration and insulin resistance.

Increasing fruit and vegetable intake has no effect on retinal vessel caliber in adults at high risk of developing cardiovascular disease

BACKGROUND AND AIM

Retinal vessel abnormalities are associated with cardiovascular disease (CVD) risk. To date, there are no trials investigating the effect of dietary factors on the retinal microvasculature. This study examined the dose response effect of fruit and vegetable (FV) intake on retinal vessel caliber in overweight adults at high CVD risk.

METHODS AND RESULTS

Following a 4 week washout period, participants were randomized to consume either 2 or 4 or 7 portions of FV daily for 12 weeks. Retinal vessel caliber was measured at baseline and post-intervention. A total of 62 participants completed the study. Self-reported FV intake indicated good compliance with the intervention, with serum concentrations of zeaxanthin and lutein increasing significantly across the groups in a dose-dependent manner (P for trend < 0.05). There were no significant changes in body composition, 24-h ambulatory blood pressure or fasting blood lipid profiles in response to the FV intervention. Increasing age was a significant determinant of wider retinal venules (P = 0.004) whereas baseline systolic blood pressure was a significant determinant of narrower retinal arterioles (P = 0.03). Overall, there was no evidence of any short-term dose-response effect of FV intake on retinal vessel caliber (CRAE (P = 0.92) or CRVE (P = 0.42)).

CONCLUSIONS

This study demonstrated no effect of increasing FV intake on retinal vessel caliber in overweight adults at high risk of developing primary CVD.

CLINICAL TRIAL REGISTRATION

NCT00874341.

Seasonal variation in month of diagnosis in children with type 1 diabetes registered in 23 European centers during 1989-2008: little short-term influence of sunshine hours or average temperature

BACKGROUND

The month of diagnosis in childhood type 1 diabetes shows seasonal variation.

OBJECTIVE

We describe the pattern and investigate if year-to-year irregularities are associated with meteorological factors using data from 50 000 children diagnosed under the age of 15 yr in 23 population-based European registries during 1989-2008.

METHODS

Tests for seasonal variation in monthly counts aggregated over the 20 yr period were performed. Time series regression was used to investigate if sunshine hour and average temperature data were predictive of the 240 monthly diagnosis counts after taking account of seasonality and long term trends.

RESULTS

Significant sinusoidal pattern was evident in all but two small centers with peaks in November to February and relative amplitudes ranging from ± 11 to ± 38% (median ± 17%). However, most centers showed significant departures from a sinusoidal pattern. Pooling results over centers, there was significant seasonal variation in each age-group at diagnosis, with least seasonal variation in those under 5 yr. Boys showed greater seasonal variation than girls, particularly those aged 10-14 yr. There were no differences in seasonal pattern between four 5-yr sub-periods. Departures from the sinusoidal trend in monthly diagnoses in the period were significantly associated with deviations from the norm in average temperature (0.8% reduction in diagnoses per 1 °C excess) but not with sunshine hours.

CONCLUSIONS

Seasonality was consistently apparent throughout the period in all age-groups and both sexes, but girls and the under 5 s showed less marked variation. Neither sunshine hour nor average temperature data contributed in any substantial way to explaining departures from the sinusoidal pattern.

Chronic kidney disease and diabetes in the national health service: a cross-sectional survey of the U.K. national diabetes audit

AIMS

We investigated the prevalence of chronic kidney disease and attainment of therapeutic targets for HbA1c and blood pressure in a large U.K.-based diabetes population.

METHODS

The U.K. National Diabetes Audit provided data from 1 January 2007 to 31 March 2008. Inclusion criteria were a documented urinary albumin:creatinine ratio and serum creatinine. Patients were stratified according to chronic kidney disease stage and albuminuria status. Chronic kidney disease was defined as an estimated glomerular filtration rate < 60 ml min(-1) 1.73 m(-2) , albuminuria or both. The proportions of patients achieving nationally defined glycaemic and systolic blood pressure targets were determined.

RESULTS

The cohort comprised 1,423,669 patients, of whom 868,616 (61%) met inclusion criteria. Of the patients analysed, 92.2% had Type 2 diabetes. A higher proportion of people with Type 2 diabetes (42.3%) had renal dysfunction compared with those with Type 1 diabetes (32.4%). Achievement of systolic blood pressure and HbA1c targets was poor. Among people with Type 1 diabetes, 67.8% failed to achieve an HbA1c < 58 mmol/mol (7.5%). Of all people with diabetes, 37.8% failed to achieve a systolic blood pressure < 140 mmHg. Blood pressure control was poor in advanced chronic kidney disease. For example, mean (standard deviation) systolic blood pressure rose from 128.6 (15.4) mmHg among people with Type 1 diabetes and normal renal function to 141.0 (23.6) mmHg in those with chronic kidney disease stage 5 and macroalbuminuria.

CONCLUSIONS

The high prevalence of chronic kidney disease and poor attainment of treatment targets highlights a large subset of the diabetes population at increased risk of cardiovascular mortality or progressive kidney disease.

General practice-recorded depression and antidepressant use in young people with newly diagnosed Type 1 diabetes: a cohort study using the Clinical Practice Research Datalink

AIMS

To investigate whether young people with Type 1 diabetes have an increased rate of depression and antidepressant use and whether their risk varies by age group, time from diabetes diagnosis, calendar period of diagnosis or complications status.

METHODS

A cohort of incident cases of patients with Type 1 diabetes diagnosed before 35 years of age (n = 5548) was identified within the Clinical Practice Research Datalink and individually age and sex matched with up to two control subjects without diabetes (n = 10 657). Patients with depression were identified through general practice-recorded depression codes and antidepressant prescriptions. Cox regression models gave hazard ratios for depression in people with Type 1 diabetes compared with control subjects.

RESULTS

People with Type 1 diabetes were twice as likely to have a record of antidepressant use and general practice-diagnosed depression as their matched control subjects (hazard ratio 2.08, 95% CI 1.73-2.50, P < 0.001). These associations varied by time from diagnosis, with marked increases observed within the first 5 years of diagnosis (hazard ratio 2.14, 95% CI 1.51-3.03, P < 0.001), and by age at diabetes diagnosis, with excesses noted even in the 10- to 19-year age group (hazard ratio 1.45, 95% CI 1.06-1.98, P = 0.02).

CONCLUSIONS

This population-based study shows that people with Type 1 diabetes have higher rates of general practice-recorded depression and antidepressant use. The excess is present within 5 years of diabetes diagnosis, suggesting psychological input for patients is warranted in the early years of their condition.

Depression and mortality: artifact of measurement and analysis?

BACKGROUND

Previous research demonstrates various associations between depression, cardiovascular disease (CVD) incidence and mortality, possibly as a result of the different methodologies used to measure depression and analyse relationships. This analysis investigated the association between depression, CVD incidence (CVDI) and mortality from CVD (MCVD), smoking related conditions (MSRC), and all causes (MALL), in a sample data set, where depression was measured using items from a validated questionnaire and using items derived from the factor analysis of a larger questionnaire, and analyses were conducted based on continuous data and grouped data.

METHODS

Data from the PRIME Study (N=9798 men) on depression and 10-year CVD incidence and mortality were analysed using Cox proportional hazards models.

RESULTS

Using continuous data, both measures of depression resulted in the emergence of positive associations between depression and mortality (MCVD, MSRC, MALL). Using grouped data, however, associations between a validated measure of depression and MCVD, and between a measure of depression derived from factor analysis and all measures of mortality were lost.

LIMITATIONS

Low levels of depression, low numbers of individuals with high depression and low numbers of outcome events may limit these analyses, but levels are usual for the population studied.

CONCLUSIONS

These data demonstrate a possible association between depression and mortality but detecting this association is dependent on the measurement used and method of analysis. Different findings based on methodology present clear problems for the elucidation and determination of relationships. The differences here argue for the use of validated scales where possible and suggest against over-reduction via factor analysis and grouping.

Haptoglobin phenotype, pre-eclampsia, and response to supplementation with vitamins C and E in pregnant women with type-1 diabetes

OBJECTIVE

The phenotype of the antioxidant and pro-angiogenic protein haptoglobin (Hp) predicts cardiovascular disease risk and treatment response to antioxidant vitamins in individuals with diabetes. Our objective was to determine whether Hp phenotype influences pre-eclampsia risk, or the efficacy of vitamins C and E in preventing pre-eclampsia, in women with type-1 diabetes.

DESIGN

This is a secondary analysis of a randomised controlled trial in which women with diabetes received daily vitamins C and E, or placebo, from 8 to 22 weeks of gestation until delivery.

SETTING

Twenty-five antenatal metabolic clinics across the UK (in north-west England, Scotland, and Northern Ireland).

POPULATION

Pregnant women with type-1 diabetes.

METHODS

Hp phenotype was determined in white women who completed the study and had plasma samples available (n = 685).

MAIN OUTCOME MEASURE

Pre-eclampsia.

RESULTS

Compared with Hp 2-1, Hp 1-1 (OR 0.59, 95% CI 0.30-1.16) and Hp 2-2 (OR 0.93, 95% CI 0.60-1.45) were not associated with significantly decreased pre-eclampsia risk after adjusting for treatment group and HbA1c at randomisation. Our study was not powered to detect an interaction between Hp phenotype and treatment response; however, our preliminary analysis suggests that vitamins C and E did not prevent pre-eclampsia in women of any Hp phenotype (Hp 1-1, OR 0.77, 95% CI 0.22-2.71; Hp 2-1, OR 0.81, 95% CI 0.46-1.43; Hp 2-2, 0.67, 95% CI 0.34-1.33), after adjusting for HbA1c at randomisation.

CONCLUSIONS

The Hp phenotype did not significantly affect pre-eclampsia risk in women with type-1 diabetes.

Trends in childhood type 1 diabetes incidence in Europe during 1989-2008: evidence of non-uniformity over time in rates of increase

AIMS/HYPOTHESIS

The aim of the study was to describe 20-year incidence trends for childhood type 1 diabetes in 23 EURODIAB centres and compare rates of increase in the first (1989-1998) and second (1999-2008) halves of the period.

METHODS

All registers operate in geographically defined regions and are based on a clinical diagnosis. Completeness of registration is assessed by capture-recapture methodology. Twenty-three centres in 19 countries registered 49,969 new cases of type 1 diabetes in individuals diagnosed before their 15th birthday during the period studied.

RESULTS

Ascertainment exceeded 90% in most registers. During the 20-year period, all but one register showed statistically significant changes in incidence, with rates universally increasing. When estimated separately for the first and second halves of the period, the median rates of increase were similar: 3.4% per annum and 3.3% per annum, respectively. However, rates of increase differed significantly between the first half and the second half for nine of the 21 registers with adequate coverage of both periods; five registers showed significantly higher rates of increase in the first half, and four significantly higher rates in the second half.

CONCLUSIONS/INTERPRETATION

The incidence rate of childhood type 1 diabetes continues to rise across Europe by an average of approximately 3-4% per annum, but the increase is not necessarily uniform, showing periods of less rapid and more rapid increase in incidence in some registers. This pattern of change suggests that important risk exposures differ over time in different European countries. Further time trend analysis and comparison of the patterns in defined regions is warranted.

Evaluation of a DVD for women with diabetes: impact on knowledge and attitudes to preconception care

AIMS

To determine if an educational DVD increases knowledge and changes attitudes of women with diabetes towards preconception care.

METHODS

Ninety-seven women with diabetes (Type 1, n = 89; Type 2, n = 8), aged 18-40 years, completed a pre-DVD and post-DVD intervention study by postal questionnaire. Beliefs and attitudes associated with preventing an unplanned pregnancy and seeking preconception care were assessed using a validated questionnaire; scales included benefits, barriers, personal attitudes and self-efficacy. Knowledge of pregnancy planning and pregnancy-related risks were assessed by a 22-item questionnaire.

RESULTS

After viewing the DVD there was significant positive change in women's perceived benefits of, and their personal attitudes to, receiving preconception care and using contraception: change in score post-DVD viewing 0.7 (95% confidence interval 0.3, 1.2), P = 0.003, and 0.8 (0.3, 1.2), P = 0.001, respectively. The DVD significantly improved self-efficacy, that is, self-confidence to use contraception for prevention of an unplanned pregnancy and to access preconception care [3.3 (1.9, 4.7), P < 0.001], and significantly reduced perceived barriers to preconception care [-0.7 (-1.2, -0.2), P = 0.01]. Knowledge of pregnancy planning and pregnancy-related risks increased significantly after viewing the DVD: mean increase was 37.6 ± 20.0%, P < 0.001, and 16.9 ± 21.2%, P < 0.001, respectively.

CONCLUSIONS

This study demonstrates the effectiveness of a DVD in increasing knowledge and enhancing attitudes of women with diabetes to preconception care. This DVD could be used as a prepregnancy counselling resource to prepare women with diabetes for pregnancy.

Do lifestyle behaviours explain socioeconomic differences in all-cause mortality, and fatal and non-fatal cardiovascular events? Evidence from middle aged men in France and Northern Ireland in the PRIME Study

OBJECTIVE

To examine the contribution of lifestyle behaviours to the socioeconomic gradient in all-cause mortality, and fatal and non-fatal cardiovascular events.

METHOD

10,600 men aged 50-59 years examined in 1991-1994 in Northern Ireland (NI) and France and followed annually for deaths and cardiovascular events for 10 years. Baseline smoking habit, physical activity, and fruit, vegetable, and alcohol consumption were assessed.

RESULTS

All lifestyle behaviours showed marked socioeconomic gradients for most indicators in NI and France, with the exception of percentage of alcohol consumers in NI and frequency of alcohol consumption in NI and France. At 10 years, there were 544 deaths from any cause and 440 fatal and non-fatal cardiovascular events. After adjustment for country and age, socioeconomic gradients were further adjusted for lifestyle behaviours. For total mortality, the median residual contribution of lifestyle behaviours was 28% and for cardiovascular incidence, 41%. When cardiovascular risk factors were considered in conjunction with lifestyle behaviours these percentages increased to 38% and 67% respectively.

CONCLUSION

Lifestyle behaviours contribute to the gradient in mortality and cardiovascular incidence between socioeconomic groups, particularly for cardiovascular incidence, but a substantial proportion of these differentials was not explained by lifestyle behaviours and cardiovascular risk factors.

A meta-analysis of the association between pre-eclampsia and childhood-onset Type 1 diabetes mellitus

AIMS

To review and synthesize the evidence for an increased risk of childhood Type 1 diabetes mellitus in children born to mothers diagnosed with pre-eclampsia during pregnancy.

METHODS

A comprehensive search of the published literature was performed in MEDLINE, Web of Science and EMBASE limited to studies published before August 2010. Crude odds ratios and 95% confidence intervals were calculated from the data reported in each study. Meta-analysis techniques were then used to derive a combined odds ratio and investigate heterogeneity. Sensitivity analyses were conducted by study design, ascertainment of pre-eclampsia and study quality.

RESULTS

Data were available from 16 studies including 8315 children with Type 1 diabetes. Overall, there was little evidence of an increase in the risk of Type 1 diabetes in children born to mothers who had pre-eclampsia during pregnancy (OR = 1.10, 95% CI 0.96-1.27; P = 0.17). This association did not vary much between studies (I(2) = 28%, P for heterogeneity =0.14). The association was similar in three cohort studies (OR = 1.05, 95% CI 0.77-1.44; P = 0.75) and in seven studies with a low risk of bias (OR = 1.13, 95% CI 0.91-1.40; P = 0.27), but was more marked in 13 studies which ascertained pre-eclampsia from obstetrical records or birth registry data (OR = 1.18, 95% CI 1.03-1.36; P = 0.02).

CONCLUSIONS

This analysis demonstrates little evidence of any substantial increase in childhood Type 1 diabetes risk after pregnancy complicated by pre-eclampsia.

Contribution of lifetime smoking habit in France and Northern Ireland to country and socioeconomic differentials in mortality and cardiovascular incidence: the PRIME Study

BACKGROUND

This study examines the contribution of lifetime smoking habit to the socioeconomic gradient in all-cause and smoking-related mortality and in cardiovascular incidence in two countries.

METHODS

10,600 men aged 50-59 years were examined in 1991-4 in centres in Northern Ireland and France and followed annually for 10 years. Deaths and cardiovascular events were documented. Current smoking habit, lifetime smoking (pack-years) and other health behaviours were evaluated at baseline. As socio-occupational coding schemes differ between the countries seven proxy socioeconomic indicators were used.

RESULTS

Lifetime smoking habit showed marked associations with most socioeconomic indicators in both countries, but lifetime smoking was more than 10 pack-years greater overall in Northern Ireland and smoking patterns differed. Total mortality was 49% higher in Northern Ireland than in France, and smoking-related mortality and cardiovascular incidence were 93% and 92% higher, respectively. Both lifetime smoking and fibrinogen contributed independently to these differentials, but together explained only 42% of the difference in total mortality between countries, adjusted for both biological and lifestyle confounders. Socioeconomic gradients were steeper for total and smoking-related mortality than for cardiovascular incidence. Residual contributions of lifetime smoking habit ranged from 6% to 34% for the seven proxy indicators of socioeconomic position for total and smoking-related mortality. Socioeconomic gradients in cardiovascular incidence were minimal following adjustment for confounders.

CONCLUSION

In Northern Ireland and France lifetime smoking appeared to explain a significant part of the gradients in total and smoking-related mortality between socioeconomic groups, but the contribution of smoking was generally small for cardiovascular incidence.

Association analysis of Notch pathway signalling genes in diabetic nephropathy

AIMS/HYPOTHESIS

Several studies have provided compelling evidence implicating the Notch signalling pathway in diabetic nephropathy. Co-regulation of Notch signalling pathway genes with GREM1 has recently been demonstrated and several genes involved in the Notch pathway are differentially expressed in kidney biopsies from individuals with diabetic nephropathy. We assessed single-nucleotide polymorphisms (SNPs; n = 42) in four of these key genes (JAG1, HES1, NOTCH3 and ADAM10) for association with diabetic nephropathy using a case-control design.

METHODS

Tag SNPs and potentially functional SNPs were genotyped using Sequenom or Taqman technologies in a total of 1371 individuals with type 1 diabetes (668 patients with nephropathy and 703 controls without nephropathy). Patients and controls were white and recruited from the UK and Ireland. Association analyses were performed using PLINK (http://pngu.mgh.harvard.edu/∼purcell/plink/) and haplotype frequencies in patients and controls were compared. Adjustment for multiple testing was performed by permutation testing.

RESULTS

In analyses stratified by centre, we identified six SNPs, rs8708 and rs11699674 (JAG1), rs10423702 and rs1548555 (NOTCH3), rs2054096 and rs8027998 (ADAM10) as being associated with diabetic nephropathy before, but not after, adjustment for multiple testing. Haplotype and subgroup analysis according to duration of diabetes also failed to find an association with diabetic nephropathy.

CONCLUSIONS/INTERPRETATION

Our results suggest that common variants in JAG1, HES1, NOTCH3 and ADAM10 are not strongly associated with diabetic nephropathy in type 1 diabetes among white individuals. Our findings, however, cannot entirely exclude these genes from involvement in the pathogenesis of diabetic nephropathy.

Investigation of ACE, ACE2 and AGTR1 genes for association with nephropathy in Type 1 diabetes mellitus

BACKGROUND

Polymorphisms in ACE and AGTR1 genes have been assessed in multiple studies for association with diabetic nephropathy; however, results are conflicting. The ACE2 gene has not been studied extensively for association with diabetic nephropathy.

METHODS

We investigated variants in ACE, ACE2 and AGTR1 for association with nephropathy in a case-control group (1467 participants with Type1 diabetes, case subjects n=718; control subjects n=749) of white descent with grandparents born in the British Isles. All recruited individuals were carefully phenotyped and genotyping was performed using Sequenom, Taqman and gel electrophoresis methods. The χ(2) -test for contingency tables was used to compare genotype and allele frequencies in case and control groups.

RESULTS

No departure from Hardy-Weinberg equilibrium was observed in cases or controls. Two variants within the ACE gene (rs4293, P(allelic) =0.02, P(genotypic) =0.008; rs4309, P(allelic) =0.02, P(genotypic) =0.01) were significantly associated with nephropathy at the 5% level. No variant remained statistically significant following adjustment for multiple comparisons. No single nucleotide polymorphisms in the ACE2 or AGTR1 genes were significantly associated with nephropathy when analysed either by genotype or allele frequencies.

CONCLUSIONS

Our independent case-control study provides no evidence that common variants in ACE, ACE2 and AGTR1 play a major role in genetic susceptibility to diabetic nephropathy in a white population with Type1 diabetes.

Greenland ice evidence of hemispheric lead pollution two millennia ago by greek and roman civilizations

Analysis of the Greenland ice core covering the period from 3000 to 500 years ago-the Greek, Roman, Medieval and Renaissance times-shows that lead is present at concentrations four times as great as natural values from about 2500 to 1700 years ago (500 B.C. to 300 A.D.). These results show that Greek and Roman lead and silver mining and smelting activities polluted the middle troposphere of the Northern Hemisphere on a hemispheric scale two millennia ago, long before the Industrial Revolution. Cumulative lead fallout to the Greenland Ice Sheet during these eight centuries was as high as 15 percent of that caused by the massive use of lead alkyl additives in gasoline since the 1930s. Pronounced lead pollution is also observed during Medieval and Renaissance times.

Investigation of the association of BMP gene variants with nephropathy in Type 1 diabetes mellitus

AIMS

Diabetic nephropathy is a leading cause of end-stage renal disease. The transforming growth factor beta-bone morphogenic protein (BMP) pathway is implicated in the pathogenesis of diabetic nephropathy. The BMP2, BMP4 and BMP7 genes are located near linkage peaks for renal dysfunction, and we hypothesize that genetic polymorphisms in these biological and positional candidate genes may be risk factors for diabetic kidney disease.

METHODS

The BMP7 gene was screened, variants identified and allele frequencies determined by bidirectionally sequencing 46 individuals to facilitate selection of tag SNPs (n = 4). For BMP2 and BMP4 genes, data were downloaded for 19 single nucleotide polymorphisms (SNPs) from the International HapMap project and six tag SNPs selected.

RESULTS

The BMP7 gene was screened for novel genetic polymorphisms, haplotypes were identified, an appropriate subset of variants selected for the investigation of common genetic risk factors, and BMP2, BMP4 and BMP7 genes assessed for association with diabetic nephropathy in 1808 individuals. Thirty-two SNPs were identified, of which 11 were novel, including an amino-acid changing SNP (+63639C>T). No significant differences (P > 0.2) were observed when comparing genotype or allele or haplotype frequencies between 864 individuals with Type 1 diabetes and nephropathy compared with 944 individuals with Type 1 diabetes without nephropathy, stratified by recruitment centre.

CONCLUSIONS

Common polymorphisms in these BMP genes do not strongly influence genetic susceptibility to diabetic nephropathy in White individuals with Type 1 diabetes mellitus.

Birthweight and the risk of childhood-onset type 1 diabetes: a meta-analysis of observational studies using individual patient data

AIMS/HYPOTHESIS

We investigated whether children who are heavier at birth have an increased risk of type 1 diabetes.

METHODS

Relevant studies published before February 2009 were identified from literature searches using MEDLINE, Web of Science and EMBASE. Authors of all studies containing relevant data were contacted and asked to provide individual patient data or conduct pre-specified analyses. Risk estimates of type 1 diabetes by category of birthweight were calculated for each study, before and after adjustment for potential confounders.Meta-analysis techniques were then used to derive combined ORs and investigate heterogeneity between studies.

RESULTS

Data were available for 29 predominantly European studies (five cohort, 24 case-control studies), including 12,807 cases of type 1 diabetes. Overall, studies consistently demonstrated that children with birthweight from 3.5 to 4 kg had an increased risk of diabetes of 6% (OR 1.06 [95% CI 1.01-1.11]; p=0.02) and children with birthweight over 4 kg had an increased risk of 10% (OR 1.10 [95% CI 1.04-1.19]; p=0.003), compared with children weighing 3.0 to 3.5 kg at birth. This corresponded to a linear increase in diabetes risk of 3% per 500 g increase in birthweight (OR 1.03 [95% CI 1.00-1.06]; p=0.03). Adjustments for potential confounders such as gestational age, maternal age, birth order, Caesarean section, breastfeeding and maternal diabetes had little effect on these findings.

CONCLUSIONS/INTERPRETATION

Children who are heavier at birth have a significant and consistent, but relatively small increase in risk of type 1 diabetes.

Polymorphisms of the macrophage migration inhibitory factor gene in a UK population with Type 1 diabetes mellitus

AIMS

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine whose production is transcriptionally regulated by glucose. Experimental data from both Type 1 diabetes mellitus (T1D) patients and animal models suggests a role for MIF in the development of T1D. The aim of this study was to employ gene resequencing to identify common DNA polymorphisms in the MIF gene and subsequently assess haplotype tagged single nucleotide polymorphisms (htSNPs) using a combination of case-control and family-based association analyses in order to assess the association of MIF htSNPs with the development of T1D in a white population.

METHODS

All exons, introns and approximately 3 kb upstream and downstream of the MIF gene were screened for DNA polymorphisms in 46 individuals using DNA sequencing. Genotyping of the htSNPs was performed in 432 cases, 407 control subjects and 290 T1D parent-offspring trios, using Taqman, Sequenom, Pyrosequencing and fluorescence-based microsatellite technologies.

RESULTS

Twenty-three polymorphisms (two novel) with a minor allele frequency > 10% were identified. Four MIF htSNPs (rs875643 G>A, rs7388067 C>T, rs5844572 -/CATT, rs6003941 T>G) were identified. Allele and haplotype frequencies were similar between case and control groups (P > 0.6 by permutation test) and assessment of allele transmission distortion from informative parents to affected offspring also failed to find an association. Stratification of these analyses for age-at-onset and human leukocyte antigen (HLA)-DR risk group (DR3/DR4) did not reveal any significant associations.

CONCLUSIONS

It is unlikely that common polymorphisms in the MIF gene strongly influence susceptibility to T1D in the UK population.

Genetic polymorphisms in nitric oxide synthase 3 gene and implications for kidney disease: a meta-analysis

BACKGROUND/AIMS

The NOS3 gene is a biological and positional candidate for diabetic nephropathy. However, the relationship between NOS3 polymorphisms and renal disease is inconclusive. This study aimed to clarify the association of NOS3 variants with nephropathy in individuals with type 1 diabetes.

METHODS

We conducted a case-control study examining all common SNPs in the NOS3 gene by a tag SNP approach. Individuals with type 1 diabetes and persistent proteinuria (cases, n = 718) were compared with individuals with type 1 diabetes but no evidence of renal disease (controls, n = 749). Our replication collection comprised 1,105 individuals with type 1 diabetes recruited to a nephropathy case group and 862 control individuals with normal urinary albumin excretion rates. Meta-analysis was conducted for SNPs where more than three genotype datasets were available.

RESULTS

A novel association was identified in the discovery collection (rs1800783, p(genotype) = 0.006, p(allele) = 0.002, OR = 1.26, 95% CI: 1.08-1.47) and supported by independent replication using a tag SNP (rs4496877, pairwise r² = 0.96 with rs1800783) in the replication collection (p(genotype) = 0.002, p(allele) = 0.0006, OR = 1.27, 95% CI: 1.10-1.45).

CONCLUSION

The A allele of rs1800783 is a significant risk factor for nephropathy in individuals with type 1 diabetes, and further comprehensive studies are warranted to confirm the definitive functional variant in the NOS3 gene.

An investigation of susceptibility loci in benign, aggressive and primary progressive multiple sclerosis in Northern Irish population

OBJECTIVE

To investigate the possibility that susceptibility loci in multiple sclerosis (MS) have a role in determining the disease outcome in Northern Ireland population.

BACKGROUND

The Genetic Analysis of Multiple Sclerosis in Europeans (GAMES) initiative and follow-up refined analysis identified 15 candidate susceptibility loci within the Northern Irish population for MS. We aimed to investigate the 12 most significant markers for their role in disease outcome.

METHODS

Cases with probable or definite MS (Poser criteria) were classified as benign onset (Kurtzke Expanded Disability Status Scale [EDSS]<or=3.0 at 10 years), aggressive (Kurtzke EDSS>or=6.0 by 10 years), or primary progressive MS. All cases were Caucasian of Northern Irish origin. DNA was extracted from venous blood, microsatellite markers were amplified using polymerase chain reaction and typed using fluorescent fragment analysis. Allele frequencies were compared statistically using a chi-squared test with allowance for multiple comparisons (critical P<0.0042); significant markers were further analyzed by CLUMP (critical P<0.0014).

RESULTS

Two microsatellite markers were significant: D3S1278 (Chr 3q13, P<0.001) and tumor necrosis factor (TNF)-alpha (Chr 6p21, P<0.001). A further three markers were significant in our preliminary analysis suggesting a trend toward impact on disease outcome; D4S432 (Chr 4p16, P=0.001), D2S347 (Chr 2q14, P=0.003), and D19S903 (Chr 19p13, P=0.003).

CONCLUSIONS

This is the first study to suggest a role for TNF-alpha in the disease outcome in MS. Larger replication studies need to be performed to assess the role of markers D4S432, D2S347, and D19S903.

Investigation of DNA polymorphisms in SMAD genes for genetic predisposition to diabetic nephropathy in patients with type 1 diabetes mellitus

AIMS/HYPOTHESIS

SMAD proteins are involved in multiple signalling pathways and are key modulators of gene expression. We hypothesised that genetic variation in selected SMAD genes contributes to susceptibility to diabetic nephropathy.

METHODS

We selected 13 haplotype tag (ht) single nucleotide polymorphisms (SNPs) from 67 variants identified by resequencing the SMAD2 and SMAD3 genes. For SMAD1, SMAD4 and SMAD5 genes, genotype data were downloaded for 217 SNPs from Phase II of the International HapMap project. Of these, 85 SNPs met our inclusion criteria, resulting in the selection of 13 tag SNPs for further investigation. A case-control approach was employed, using 267 nephropathic patients and 442 controls with type 1 diabetes from Ireland. Two further populations (totalling 1,407 patients, 2,238 controls) were genotyped to validate initial findings. Genotyping was conducted using iPLEX, TaqMan and gel electrophoresis.

RESULTS

The distribution of genotypes was in Hardy-Weinberg equilibrium. Analysis by the chi(2) test of genotype and allele frequencies in patients versus controls in the Irish population (n = 709) revealed evidence for the association of one allele at 5% level of significance (rs10515478, p(uncorrected) = 0.006; p(corrected) = 0.04). This finding represents a relatively small difference in allele frequency of 6.4% in the patient group compared with 10.7% in the control group; this difference was not supported in subsequent investigations using DNA from European individuals with similar phenotypic characteristics.

CONCLUSIONS/INTERPRETATION

We selected an appropriate subset of variants for the investigation of common genetic risk factors and assessed SMAD1 to SMAD5 genes for association with diabetic nephropathy. We conclude that common polymorphisms in these genes do not strongly influence genetic susceptibility to diabetic nephropathy in white individuals with type 1 diabetes mellitus.

Factors influencing total cholesterol and high-density lipoprotein cholesterol concentrations in a population at high coronary risk

Serum total cholesterol and high-density lipoprotein (HDL) cholesterol concentrations were measured in 1122 men and 1147 women aged between 25 and 64 years during the first Belfast MONICA survey, and the results subjected to multiple regression analysis. In both men and women, total cholesterol increased with age. Although HDL-cholesterol showed little variation with age, the values were considerably higher in women than men. Total cholesterol increased with body mass index while HDL-cholesterol decreased, and these findings persisted after adjustment for age. Regular exercise was associated with higher HDL-cholesterol values, even after adjustment for age and body mass index. Among men and women who abstained from alcohol, lower values of HDL-cholesterol were observed. In both sexes, cigarette smoking was associated with significant increases in total cholesterol values and decreases in HDL-cholesterol values, though some of these findings became apparent only after adjustment for other relevant factors. Perhaps surprisingly, a measure of health knowledge showed no association with blood lipid concentrations.

Genetic polymorphisms in platelet-related proteins and coronary artery disease: investigation of candidate genes, including N-acetylgalactosaminyltransferase 4 (GALNT4) and sulphotransferase 1A1/2 (SULT1A1/2)

BACKGROUND

Both platelet function and heart disease show strong genetic components, many of which remain to be elucidated.

MATERIALS AND METHODS

The roles of candidate polymorphisms in ten platelet-associated genes were compared between 1,237 Acute Coronary Syndrome (ACS) cases (with myocardial infarction and unstable angina) and 386 controls, from an Irish Caucasian population. Additionally, 361 stable angina patients were investigated. Two genes of interest were followed up in a separate Irish study of 1,484 individuals (577 with IHD and 907 unaffected).

RESULTS

The GALNT4 (N-acetyl galactosaminyl transferase 4) 506I allele was significantly underrepresented in ACS (OR = 0.66, CI = 0.52-0.84; P = 0.001; P = 0.01 after correction for multiple testing), while the SULT1A1 (Sulphotransferase 1A1) 213H allele was associated with risk of ACS (OR = 1.37, CI = 1.08-1.74; P = 0.01; P = 0.1 after correction for multiple testing). Subsequent genotyping of further SNPs in GALNT4 in the family-based (IHD) group revealed that the 506I allele showed the same trend towards protecting against ACS but the haplotypic test over the four commonest haplotypes was not significant (P = 0.55). In contrast, the SULT1A1/SULT1A2 gene complex showed suggestive haplotypic association in the family-based study (P = 0.07), with the greatest increase in risk conferred by the SULT1A2 235T allele (P = 0.025).

CONCLUSION

We have identified two risk genes for cardiovascular disease, one of whose (GALNT4) effects may be on either platelet or endothelial function through modifications of PSGL1 or other important glycosylated proteins. The role of sulphotransferases (SULT1A1/2) in cardiovascular disease requires further exploration. Further validation of cardiovascular risks conferred by both genes in other populations (including gene copy number variation) is warranted.

Alcohol increases homocysteine and reduces B vitamin concentration in healthy male volunteers--a randomized, crossover intervention study

BACKGROUND

Few studies have examined the effect of alcohol consumption on total homocysteine (tHcy) concentrations.

AIM

To assess the effect of an 8-week intervention with vodka or red wine on plasma tHcy and B vitamin concentrations in healthy male volunteers. To assess the effect on tHcy according to methylenetetrahydrofolate reductase (MTHFR) 677C>T genotype.

DESIGN AND METHODS

A randomized controlled crossover intervention study measuring tHcy and serum folate and vitamin B(12) concentrations was conducted in 78 male subjects (21-70 years). Following a 2-week washout period during which no alcohol was consumed, all subjects consumed 24 g alcohol (either 240 ml red wine or 80 ml vodka)/day for a 2-week period. Following a further 2-week washout, participants consumed the alternate intervention for 2 weeks.

RESULTS

A significant increase in plasma tHcy was observed after the 2-week red wine intervention (5%, P = 0.03), and a non-significant increase in tHcy with vodka intervention (3%, P = 0.09). When the two interventions were compared, the change in tHcy did not differ between the vodka and red wine interventions (P = 0.57). There were significant decreases in serum vitamin B(12) and folate concentrations, and this decrease did not differ between interventions. The increase in tHcy observed in both interventions did not vary by MTHFR 677C>T genotype.

CONCLUSION

A 2-week alcohol intervention resulted in a decrease in folate and vitamin B(12) status and an increase in plasma tHcy. The effect of alcohol intervention on tHcy, folate and vitamin B(12) concentrations did not differ between the red wine and vodka intervention groups.

Genetic association analyses of non-synonymous single nucleotide polymorphisms in diabetic nephropathy

AIMS/HYPOTHESIS

Diabetic nephropathy, characterised by persistent proteinuria, hypertension and progressive kidney failure, affects a subset of susceptible individuals with diabetes. It is also a leading cause of end-stage renal disease (ESRD). Non-synonymous (ns) single nucleotide polymorphisms (SNPs) have been reported to contribute to genetic susceptibility in both monogenic disorders and common complex diseases. The objective of this study was to investigate whether nsSNPs are involved in susceptibility to diabetic nephropathy using a case-control design.

METHODS

White type 1 diabetic patients with (cases) and without (controls) nephropathy from eight centres in the UK and Ireland were genotyped for a selected subset of nsSNPs using Illumina's GoldenGate BeadArray assay. A chi (2) test for trend, stratified by centre, was used to assess differences in genotype distribution between cases and controls. Genomic control was used to adjust for possible inflation of test statistics, and the False Discovery Rate method was used to account for multiple testing.

RESULTS

We assessed 1,111 nsSNPs for association with diabetic nephropathy in 1,711 individuals with type 1 diabetes (894 cases, 817 controls). A number of SNPs demonstrated a significant difference in genotype distribution between groups before but not after correction for multiple testing. Furthermore, neither subgroup analysis (diabetic nephropathy with ESRD or diabetic nephropathy without ESRD) nor stratification by duration of diabetes revealed any significant differences between groups.

CONCLUSIONS/INTERPRETATION

The nsSNPs investigated in this study do not appear to contribute significantly to the development of diabetic nephropathy in patients with type 1 diabetes.

A rapid rise in circulating pancreastatin in response to somatostatin analogue therapy is associated with poor survival in patients with neuroendocrine tumours

Aim

To assess the value of pancreastatin as a predictive factor for identifying patients with neuroendocrine tumours (NETs) who respond poorly to somatostatin analogues.

Methods

A retrospective study of patients with NETs. Patient records from the Northern Ireland Neuroendocrine Tumour Register were interrogated. Those who had pancreastatin concentrations measured on two or more occasions, before and during somatostatin analogue therapy (within the set time-limits) were selected. Data relating to diagnosis, surgery, somatostatin analogue therapy and survival outcome were noted. Data were subjected to univariate and multivariate analysis using Cox proportional hazard model.

Results

Fifty-nine patients with gastroenteropancreatic NETs fulfilled the inclusion criteria. Factors associated with a poor survival outcome on univariate analysis were primary tumour site ( P = 0.006) and rapid rise in pancreastatin during somatostatin analogue treatment ( P < 0.001). In multivariate analysis, highly significant clinical prognostic indicators were: tumour location ( P < 0.001), pre-treatment pancreastatin ( P < 0.001) and pancreastatin change ( P < 0.001).

Conclusions

This study endorses the finding that pancreastatin is a useful prognostic indicator of neuroendocrine disease. On commencement of treatment, one-third of the subjects showed an immediate negative pancreastatin response to somatostatin analogues, which was associated with poor survival. This is the first study to document such an association. These findings have significant therapeutic consequences. In the presence of a rapidly rising pancreastatin alternative, treatment modalities should be sought.

Caesarean section is associated with an increased risk of childhood-onset type 1 diabetes mellitus: a meta-analysis of observational studies

AIMS/HYPOTHESIS

The aim of this study was to investigate the evidence of an increased risk of childhood-onset type 1 diabetes in children born by Caesarean section by systematically reviewing the published literature and performing a meta-analysis with adjustment for recognised confounders.

METHODS

After MEDLINE, Web of Science and EMBASE searches, crude ORs and 95% CIs for type 1 diabetes in children born by Caesarean section were calculated from the data reported in each study. Authors were contacted to facilitate adjustments for potential confounders, either by supplying raw data or calculating adjusted estimates. Meta-analysis techniques were then used to derive combined ORs and to investigate heterogeneity between studies.

RESULTS

Twenty studies were identified. Overall, there was a significant increase in the risk of type 1 diabetes in children born by Caesarean section (OR 1.23, 95% CI 1.15-1.32, p < 0.001). There was little evidence of heterogeneity between studies (p = 0.54). Seventeen authors provided raw data or adjusted estimates to facilitate adjustments for potential confounders. In these studies, there was evidence of an increase in diabetes risk with greater birthweight, shorter gestation and greater maternal age. The increased risk of type 1 diabetes after Caesarean section was little altered after adjustment for gestational age, birth weight, maternal age, birth order, breast-feeding and maternal diabetes (adjusted OR 1.19, 95% CI 1.04-1.36, p = 0.01).

CONCLUSIONS/INTERPRETATION

This analysis demonstrates a 20% increase in the risk of childhood-onset type 1 diabetes after Caesarean section delivery that cannot be explained by known confounders.

No association between routinely recorded infections in early life and subsequent risk of childhood-onset Type 1 diabetes: a matched case-control study using the UK General Practice Research Database

AIMS

To determine whether children with infections in early life (recorded routinely in general practice) have a reduced risk of Type 1 diabetes, as would be expected from the hygiene hypothesis.

METHODS

Children with Type 1 diabetes and up to 20 matched (on year of birth, sex and region) control subjects were selected from a cohort of children born in the UK at General Practice Research Database practices. For each child, the frequency of general practitioner consultations for infections and prescriptions for antibiotics in the first year of life were determined. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using conditional logistic regression.

RESULTS

The main analysis included 367 case and 4579 matched control subjects. There was no evidence of any reduction in the subsequent risk of Type 1 diabetes in children with at least one infection in the first year of life (OR = 1.03, 95%CI 0.79, 1.34) or in children prescribed antibiotics in the first year of life (OR = 1.03, 95%CI 0.82, 1.29). Further analyses also revealed little evidence of a difference in subsequent risk of Type 1 diabetes after different types of infection in the first year of life (including gastrointestinal, conjunctivitis, otitis media and upper and lower respiratory tract). Analyses of infections in the first 2 years of life reached similar conclusions.

CONCLUSIONS

This study provides no evidence of an association between infections in early life and subsequent risk of childhood-onset Type 1 diabetes and therefore does not support the hygiene hypothesis.

Early mortality in EURODIAB population-based cohorts of type 1 diabetes diagnosed in childhood since 1989

AIMS/HYPOTHESIS

The aims of this study were to provide a contemporary picture of mortality and causes of death in Europe following a diagnosis of type 1 diabetes made before the 15th birthday, and to examine excess mortality by country for possible links to incidence level or national prosperity.

METHODS

Thirteen population-based EURODIAB registers in 12 countries followed-up 28,887 children diagnosed since 1989, either by record linkage to population registers or through contact with doctors providing care.

RESULTS

There were 141 deaths in the cohort during 219,061 person-years of follow-up compared with 69.1 deaths expected from national mortality rates, a standardised mortality ratio (SMR) of 2.0 (95% CI 1.7-2.4). The SMR varied from 0 to 4.7 between countries, but showed little relationship with the country's incidence rate or gross domestic product (US$ per capita). The SMR did not change significantly with attained age, calendar period or time since diagnosis. The female SMR (2.7; 95% CI 2.0-3.5) was greater than the male SMR (1.8; 95% CI 1.4-2.2), although absolute numbers of excess deaths were similar in the two sexes. One-third of deaths were classified as directly attributable to diabetes (many with mention of ketoacidosis) and half were unrelated to diabetes. There was a non-significant excess of accidental/violent deaths (48 observed vs 40.7 expected; SMR 1.2; 95% CI 0.9-1.6) but little excess in suicides (11 observed, 10.2 expected; SMR 1.1; 95% CI 0.5-1.9).

CONCLUSIONS/INTERPRETATION

Before the onset of late complications, significant excess mortality existed following the diagnosis of type 1 diabetes in childhood, even in recent years. Variation between countries in this excess could not be explained.

Worldwide childhood type 1 diabetes incidence--what can we learn from epidemiology?

Type 1 diabetes is the most common form of diabetes in most part of the world, although reliable data are still unavailable in several countries. Wide variations exist between the incidence rates of different populations, incidence is lowest in China and Venezuela (0.1 per 100,000 per year) and highest in Finland and Sardinia (37 per 100,000 per year). In most populations girls and boys are equally affected. In general, the incidence increases with age, the incidence peak is at puberty. After the pubertal years, the incidence rate significantly drops in young women, but remains relatively high in young adult males up to the age 29-35 years. Prospective national and large international registries (DIAMOND and EURODIAB) demonstrated an increasing trend in incidence in most regions of the world over the last few decades and increases seem to be the highest in the youngest age group. Analytical epidemiological studies have identified environmental risk factors operating early in life which might have contributed to the increasing trend in incidence. These include enteroviral infections in pregnant women, older maternal age (39-42 years), preeclampsia, cesarean section delivery, increased birthweight, early introduction of cow's milk proteins and an increased rate of postnatal growth (weight and height). Optimal vitamin D supplementation during early life has been shown to be protective. Some of these environmental risk factors such as viruses may initiate autoimmunity toward the beta cell, other exposures may put on overload on the already affected beta cell and thus accelerate the disease process.

Paraoxonase activity and coronary heart disease risk in healthy middle-aged males: the PRIME study

OBJECTIVE

Classic coronary heart disease (CHD) risk factors fail to explain the large gradient in CHD incidence between Northern Ireland and France. The Prospective Epidemiological Study of Myocardial Infarction (PRIME) study, a multicentre prospective study of 10,593 middle-aged males, investigated novel risk factors in these populations. We tested the hypotheses that (1) higher paraoxonase activity is associated with decreased CHD risk and (2) PON55 LL genotype is associated with increased CHD risk.

METHODS

Paraoxonase activity was measured in 299 men who had developed CHD at 5-year follow-up and in 576 matched controls. DNA was available from 247 cases and 433 controls for genotyping for the PON55 polymorphism.

RESULTS

There was no significant difference in paraoxonase activity between cases and controls (geometric means 73.8 and 74.2U/l; p=0.81). There was no significant difference in CHD risk between fifths of paraoxonase activity either before (p=0.55) or after adjustment for classical risk factors (p=0.58). There was no significant association between genotype and CHD risk; relative to the LL genotype, the OR (95% CI) for the LM and MM genotypes were 0.92 (0.66-1.29) and 0.83 (0.50-1.36), respectively. The frequency of the L allele in cases (66.6%) and controls (64.5%) did not differ significantly, p=0.45.

CONCLUSIONS

These findings suggest that neither paraoxonase activity nor PON55 genotype is associated with CHD risk in males in the PRIME study.