David B. Dunger

Association between postnatal catch-up growth and obesity in childhood: prospective cohort study

Abstract Objective: To identify predictors of postnatal catch-up growth from birth to two years and its relation to size and obesity at five years. Design: Regional prospective cohort study. Setting: Avon longitudinal study of pregnancy and childhood, United Kingdom. Subjects: 848 full term singletons from a 10% random sample of the Avon longitudinal study of pregnancy and childhood. Main outcome measures: Maternal birth weight, prepregnancy weight, pregnancy weight gain, height, smoking, and parity, and paternal height. Weight and length of infants at birth, two years, and five years expressed as standard deviation (SD) scores from the UK reference scores for 1990. Percentage fat mass and total fat mass (estimated from skinfolds) and waist circumference at five years. Results: Size at birth was representative of the national reference. Overall, 30.7% (260 of 848) of infants showed a gain in SD score for weight greater than 0.67 SD scores between zero and two years, indicating clinically significant catch-up growth. These children had lower weight, length, and ponderal index at birth than other children, and were more often from primiparous pregnancies. They also had taller fathers than other children, and their mothers had lower birth weights and were more likely to smoke during pregnancy. Children who showed catch-up growth between zero and two years were heavier, taller, and fatter (body mass index, percentage body fat, and waist circumference) at five years than other children. Conclusions: In this contemporary well nourished cohort, catch-up growth was predicted by factors relating to intrauterine restraint of fetal growth. Children who showed catch-up growth between zero and two years were fatter and had more central fat distribution at five years than other children. Mechanisms that signal and regulate early catch-up growth in the postnatal period may influence associations between small size at birth and risks for disease in adulthood.

Robust associations of four new chromosome regions from genome-wide analyses of type 1 diabetes

The Wellcome Trust Case Control Consortium (WTCCC) primary genome-wide association (GWA) scan on seven diseases, including the multifactorial autoimmune disease type 1 diabetes (T1D), shows associations at P < 5 × 10−7 between T1D and six chromosome regions: 12q24, 12q13, 16p13, 18p11, 12p13 and 4q27. Here, we attempted to validate these and six other top findings in 4,000 individuals with T1D, 5,000 controls and 2,997 family trios independent of the WTCCC study. We confirmed unequivocally the associations of 12q24, 12q13, 16p13 and 18p11 (Pfollow-up ≤ 1.35 × 10−9; Poverall ≤ 1.15 × 10−14), leaving eight regions with small effects or false-positive associations. We also obtained evidence for chromosome 18q22 (Poverall = 1.38 × 10−8) from a GWA study of nonsynonymous SNPs. Several regions, including 18q22 and 18p11, showed association with autoimmune thyroid disease. This study increases the number of T1D loci with compelling evidence from six to at least ten.

A genome-wide association study of nonsynonymous SNPs identifies a type 1 diabetes locus in the interferon-induced helicase (IFIH1) region.

In this study we report convincing statistical support for a sixth type 1 diabetes (T1D) locus in the innate immunity viral RNA receptor gene region IFIH1 (also known as mda-5 or Helicard) on chromosome 2q24.3. We found the association in an interim analysis of a genome-wide nonsynonymous SNP (nsSNP) scan, and we validated it in a case-control collection and replicated it in an independent family collection. In 4,253 cases, 5,842 controls and 2,134 parent-child trio genotypes, the risk ratio for the minor allele of the nsSNP rs1990760 A → G (A946T) was 0.86 (95% confidence interval = 0.82–0.90) at P = 1.42 × 10−10.

Circulating concentrations of insulin-like growth factor-I and development of glucose intolerance: A prospective observational study

BACKGROUND Results of experimental and clinical studies suggest that insulin-like growth factor-I (IGF-I) and IGF binding protein-1 (IGFBP-1) could be important determinants of glucose homoeostasis. However, experimental models might also reflect compensatory and adaptive metabolic processes. We therefore prospectively examined the associations between circulating concentrations of IGF-I and IGFBP-1 and development of glucose tolerance. METHODS Participants in this cohort study were a random sample of 615 normoglycaemic men and women aged 45-65 years. Participants underwent oral glucose tolerance testing based on WHO definitions and criteria in 1990-92 and 1994-96. At the baseline visit, we measured serum concentrations of IGF-I and IGFBP-1, and assessed the relation between these peptides and subsequent glucose intolerance. FINDINGS At 4.5 years of follow-up, 51 (8%) of 615 participants developed impaired glucose tolerance or type-2 diabetes. After adjustment for correlates of IGF-I and risk factors for glucose intolerance, the odds ratio for risk of impaired glucose tolerance or type-2 diabetes for participants with IGF-I concentrations above the median (> or = 152 microg/L) compared with those with concentrations below the median (<152 microg/L) was 0.50 (0.26-0.95). Consistent with this finding, IGF-I also showed a significant inverse association with subsequent 2-h glucose concentrations, which was independent of correlates of IGF-I and risk factors for glucose tolerance (p for linear trend=0.026). We also found that this inverse association was independently modified by IGFBP-1 (p for interaction=0.011). INTERPRETATION These data show that circulating IGF-I and its interaction with IGFBP-1 could be important determinants of glucose homoeostasis and provide further evidence for the possible protective role of IGF-I against development of glucose intolerance.

Size at birth and early childhood growth in relation to maternal smoking, parity and infant breast-feeding: longitudinal birth cohort study and analysis

There is remarkably wide variation in rates of infancy growth, however, its regulation is not well understood. We examined the relationship between maternal smoking, parity, and breast- or bottle-feeding to size at birth and childhood growth between 0 and 5 y in a large representative birth cohort. A total of 1335 normal infants had weight, length/height, and head circumference measured at birth and on up to 10 occasions to 5 y old. Multilevel modeling (MLwiN) was used to analyze longitudinal growth data. Infants of maternal smokers were symmetrically small at birth (p < 0.0005) compared with infants of nonsmokers, however, showed complete catch-up growth over the first 12 mo. In contrast, infants of primiparous pregnancies were thin at birth (p < 0.0005), showed dramatic catch-up growth, and were heavier and taller than infants of nonprimiparous pregnancies from 12 mo onwards. Breast-fed infants were similar in size at birth than bottle-fed infants, but grew more slowly during infancy. Among infants who showed catch-up growth, males caught up more rapidly than females (p = 0.002). In conclusion, early postnatal growth rates are strongly influenced by a drive to compensate for antenatal restraint or enhancement of fetal growth by maternal-uterine factors. The mechanisms that signal catch-up or catch-down growth are unknown but may involve programming of appetite. The importance of nutrition on early childhood growth is emphasized by the marked difference in growth rates between breast- and bottle-fed infants. The sequence of fetal growth restraint and postnatal catch-up growth may predispose to obesity risk in this contemporary population.

Polycystic ovaries and associated clinical and biochemical features in young women

To determine the prevalence of polycystic ovaries as identified by ultrasound in a group of young, postmenarcheal women in the normal population, and to investigate how polycystic ovaries are related to the spectrum of clinical and biochemical symptoms associated with the polycystic ovary syndrome (PCOS).

Quantification of islet-cell antibodies and prediction of insulin-dependent diabetes

The sensitivity and predictive value of islet-cell antibodies (ICA) for the future onset of insulin-dependent diabetes mellitus (IDDM) were determined in 719 first-degree relatives of IDDM patients. ICA were quantified in Juvenile Diabetes Foundation (JDF) units, by indirect immunofluorescence in serum samples taken during prospective follow-up of up to 10.5 years. The threshold of ICA detection was 4 JDF units. ICA were detected in the first sample of 26 (3.3%) of the relatives, compared with 12 (2.2%) of 540 controls (298 blood donors and 242 healthy children). ICA were detected in follow-up samples from a further 14 relatives. IDDM developed in 14 (35%) of the 40 relatives with detectable ICA at any time and in 2 (0.3%) relatives without detectable ICA. In all 5 relatives with peak ICA levels above 80 JDF units IDDM developed within follow-up of 7 years; survival without IDDM at 10 years was 27% among relatives with peak ICA levels of 20-80 JDF units and 82% for peak ICA levels of 4-20. The predictive value for IDDM development within 10 years ranged from 40% (threshold 4 JDF units) to 100% (80 JDF units) and the sensitivity from 31% (80 JDF units) to 88% (4 JDF units).

Localization of a type 1 diabetes locus in the IL2RA/CD25 region by use of tag single-nucleotide polymorphisms

As part of an ongoing search for genes associated with type 1 diabetes (T1D), a common autoimmune disease, we tested the biological candidate gene IL2RA (CD25), which encodes a subunit (IL-2R alpha) of the high-affinity interleukin-2 (IL-2) receptor complex. We employed a tag single-nucleotide polymorphism (tag SNP) approach in large T1D sample collections consisting of 7,457 cases and controls and 725 multiplex families. Tag SNPs were analyzed using a multilocus test to provide a regional test for association. We found strong statistical evidence in the case-control collection (P=6.5x10(-8)) for a T1D locus in the CD25 region of chromosome 10p15 and replicated the association in the family collection (P=7.3x10(-3); combined P=1.3x10(-10)). These results illustrate the utility of tag SNPs in a chromosome-regional test of disease association and justify future fine mapping of the causal variant in the region.

Current methods of transfer of young people with Type 1 diabetes to adult services

Aims To determine the efficacy and patient perception of various transfer procedures from paediatric to adult diabetes services.

Causes of death in children with insulin dependent diabetes 1990–96

BACKGROUND Mortality rates in children with insulin dependent diabetes (IDDM) in the UK are unknown and the causes of death not well documented. AIM To determine the mortality rate and causes of death in children with IDDM. METHODS The Office of National Statistics (England and Wales) and the General Register Office (Scotland) notified all deaths under 20 years of age from 1990 to 1996 with diabetes on the certificate. Further details were provided by coroners, pathologists, and clinicians. RESULTS 116 deaths were notified and 83 were caused by diabetes. The standardised mortality ratio was 2.3 (95% confidence interval (CI), 1.9 to 2.9), being highest in the age group 1–4 years, at 9.2 (95% CI, 5.4 to 14.7). Of the 83 diabetic deaths, hyperglycaemia/diabetic ketoacidosis (DKA) was implicated in 69 and hypoglycaemia in 7. Cerebral oedema was the most common cause of death in young children (25 of 36 diabetes related deaths in children under 12 years of age). 34 young people (10–19 years; 24 male) were either found dead at home (n = 26) or moribund on arrival at hospital (n = 8). In 24 of these, it appeared that DKA was the cause of death, in four hypoglycaemia was likely. Nine of these were found “dead in bed”. CONCLUSIONS Children with IDDM have a higher mortality than the general population. Cerebral oedema accounts for most hospital deaths in young children. There are a large number of young men dying at home from neglected IDDM. Early diagnosis of IDDM in children and closer supervision of young people might prevent some of these deaths. Key messages Children and young people with insulin dependent diabetes still have an increased mortality compared with the general population Diabetic ketoacidosis is the leading cause of death, particularly if it is complicated by cerebral oedema Hypoglycaemia is a rare cause of death even in those dying unexpectedly at home