Insulin resistance in short children with intrauterine growth retardation

Diabetes mellitus and its correlates in an Iranian adult population

The rising epidemic of diabetes imposes a substantial economic burden on the Middle East. Using baseline data from a population based cohort study, we aimed to identify the correlates of diabetes mellitus (DM) in a mainly rural population from Iran. Between 2004 and 2007, 50044 adults between 30 and 87 years old from Golestan Province located in Northeast Iran were enrolled in the Golestan Cohort Study. Demographic and health-related information was collected using questionnaires. Individuals' body sizes at ages 15 and 30 were assessed by validated pictograms ranging from 1 (very lean) to 7 in men and 9 in women. DM diagnosis was based on the self-report of a physician's diagnosis. The accuracy of self-reported DM was evaluated in a subcohort of 3811 individuals using fasting plasma glucose level and medical records. Poisson regression with robust variance estimator was used to estimate prevalence ratios (PR's). The prevalence of self-reported DM standardized to the national and world population was 5.7% and 6.2%, respectively. Self-reported DM had 61.5% sensitivity and 97.6% specificity. Socioeconomic status was inversely associated with DM prevalence. Green tea and opium consumption increased the prevalence of DM. Obesity at all ages and extreme leanness in childhood increased diabetes prevalence. Being obese throughout life doubled DM prevalence in women (PR: 2.1; 95% CI: 1.8, 2.4). These findings emphasize the importance of improving DM awareness, improving general living conditions, and early lifestyle modifications in diabetes prevention.

Maternal protein restriction elevates cholesterol in adult rat offspring due to repressive changes in histone modifications at the cholesterol 7alpha-hydroxylase promoter

Adverse events in utero, such as intrauterine growth restriction (IUGR), can permanently alter epigenetic mechanisms leading to the metabolic syndrome, which encompasses a variety of symptoms including augmented cholesterol. The major site for cholesterol homeostasis occurs via the actions of hepatic cholesterol 7α-hydroxylase (Cyp7a1), which catabolizes cholesterol to bile acids. To determine whether posttranslational histone modifications influence the long-term expression of Cyp7a1 in IUGR, we used a protein restriction model in rats. This diet during pregnancy and lactation led to IUGR offspring with decreased liver to body weight ratios, followed by increased circulating and hepatic cholesterol levels in both sexes at d 21 and exclusively in the male offspring at d 130. The augmented cholesterol was associated with decreases in the expression of Cyp7a1. Chromatin immunoprecipitation revealed that this was concomitant with diminished acetylation and enhanced methylation of histone H3 lysine 9 [K9,14], markers of chromatin silencing, surrounding the promoter region of Cyp7a1. These epigenetic modifications originate in part due to dietary-induced decreases in fetal hepatic Jmjd2a expression, a histone H3 [K9] demethylase. Collectively, these findings suggest that the augmented cholesterol observed in low-protein diet-derived offspring is due to permanent repressive posttranslational histone modifications at the promoter of Cyp7a1. Moreover, this is the first study to demonstrate that maternal undernutrition leads to long-term cholesterol dysregulation in the offspring via epigenetic mechanisms.

Evaluation of the auxological and metabolic status in prepubertal children born small for gestational age

BACKGROUND

Low birth weight (BW) (<2,500 g) is associated with a high risk of impaired postnatal growth and late metabolic consequences. The aim of this study is to describe the postnatal growth pattern and the metabolic status of children born small for gestational age (SGA) and compare them with premature children born with low (1,500-2,500 g) and very low (<1,500 g) BW.

CHILDREN AND METHODS

104 prepubertal children (47 males and 57 females) aged 3.0 to 8.9 years were divided into four groups according to their birth weight adjusted for gestational age (GA): SGA-premature (SGApr): BW < -2 SD, GA <37 wk (n = 17); SGA-full-term (SGAt): BW < -2 SD, GA >37 wk (n = 29); low birth weight (LBW): BW = 1,500-2,500 g, GA <37 wk (n = 35); very low birth weight (VLBW): BW <1,500 g, GA <37 wk (n = 23). The control group consisted of 27 full-term appropriate for gestational age, prepubertal children matched for age. All children had anthropometric and laboratory measurements. The HOMA model was used to estimate insulin resistance (IR).

RESULTS

Weight, height and body mass index (BMI) were significantly lower in the SGA groups -- both term and premature -- (p <0.05) and particularly lower in the VLBW children (p <0.01). At the age of 36 months, 99.6% of SGAt and a smaller percentage of SGApr (88.2%) children achieved catch-up growth. IGF-I and IGFBP-3 levels were lower in the children born SGA, both term and premature, compared to the controls (p <0.05) and especially in those who had catch-up after the age of 6 months (p <0.002). VLBW children aged 6-8.9 years had significantly higher HOMA compared to controls of the same age group (p = 0.005), whereas no evidence of IR was found in the SGA children. None of the children had developed premature adrenarche by the day of examination.

CONCLUSIONS

Prepubertal children born SGA and VLBW are thinner and shorter than their age-matched controls. A larger percentage of SGA full-term children achieve catch-up growth than SGA premature children by 3 years of age. SGA children and especially those with late catch-up growth have lower IGF-I levels. Children with VLBW show evidence of IR at age 6-8.9 years. None of the girls showed precocious sexual development by the day of examination.

Insulin sensitization early after menarche prevents progression from precocious pubarche to polycystic ovary syndrome

OBJECTIVE

Girls with low birth weight (LBW) and with a history of precocious pubarche in childhood (PP) are at high risk of polycystic ovary syndrome (PCOS) in adolescence. In formerly LBW-PP girls, we examined whether initiation of insulin sensitization therapy early after menarche could prevent progression of PCOS features. Study design Twenty-four girls, small at term birth (mean weight, 2.4 kg), who presented with PP (at mean age 6.7 years) and were currently (mean age, 12.4 years) postmenarcheal, with hyperinsulinemic hyperandrogenemia but nonobese, were randomly assigned to receive metformin (850 mg/d) or no treatment for 12 months. Six-month fasting blood samples were collected, and body composition was assessed by dual-energy x-ray absorptiometry. In addition, overnight growth hormone (GH) and gonadotropin secretion was analyzed in 10 girls (6 treated; 4 untreated) at 0 and 6 months.

RESULTS

At baseline, compared with healthy control subjects, LBW-PP girls had dyslipidemia, excess truncal fat, reduced lean body mass, and increased insulin-like growth factor-I and GH levels. In untreated girls, insulin sensitivity, serum androgens, lipids, total and truncal fat mass, and lean body mass significantly diverged further from normal over 12 months. In metformin-treated girls, all these abnormalities significantly reversed within 6 months, and body composition continued to improve between 6 and 12 months.

CONCLUSIONS

Early metformin therapy prevents progression from PP to PCOS in a high-risk group of formerly LBW girls. This confirms the key role of hyperinsulinemic insulin resistance in the ontogeny of PCOS. Furthermore, normalization of body composition, lipid profiles, and GH secretion could reduce long-term cardiovascular risk.

Endocrine-Related Causes and Consequences of Intrauterine Growth Retardation

The term intrauterine growth retardation (IUGR) is assigned to newborns born with a birth weight and/or birth length below the tenth percentile for their gestational age. Intrauterine growth retardation is usually due to maternal, fetal factors, or placental insufficiency, while endocrine factors represent just a small minority in its etiology. Main endocrine-related causes of IUGR are disorders in insulin or insulin-like growth factor-I (IGF-I) secretion or action. Newborns with IUGR are at increased risk to develop a metabolic syndrome later in life, namely obesity, arterial hypertension, hypercholesterolemia, cardiovascular disease, impaired glucose tolerance, or diabetes mellitus type 2. This association is the result of the adaptational changes of the fetal endocrine-metabolic mechanisms to the impaired intrauterine milieu to assure survival in the short term. The persistence of these changes after birth can be detrimental in adult life. Furthermore, premature adrenarche, as well as ovarian hyperandrogenism, seem to be associated with IUGR in girls, demonstrating that IUGR may have long-lasting effects on both somatic health and reproductive function. Finally, the intrauterine exposure of the fetus to stressors may affect the individual's ability to face stress in postnatal life. Therefore, if optimization of somatic and psychosocial well-being of the individual is the golden goal of medicine, special attention should be paid to maintain an optimal intrauterine milieu devoid of any stressors with adequate nutrient supply and to reserve ideal psychosocial support to the pregnant woman.

Is birth weight related to later glucose and insulin metabolism?--A systematic review

AIM

To determine the relationship of birth weight to later glucose and insulin metabolism.

METHODS

Systematic review of the published literature. Data sources were Medline and Embase. Included studies were papers reporting the relationship of birth weight with a measure of glucose or insulin metabolism after 1 year of age, including the prevalence of Type 2 diabetes mellitus (DM). Three reviewers abstracted information from each paper according to specified criteria.

RESULTS

Forty-eight papers fulfilled the criteria for inclusion, mostly of adults in developed countries. Most studies reported an inverse relationship between birth weight and fasting plasma glucose concentrations (15 of 25 papers), fasting plasma insulin concentrations (20 of 26), plasma glucose concentrations 2 h after a glucose load (20 of 25), the prevalence of Type 2 DM (13 of 16), measures of insulin resistance (17 of 22), and measures of insulin secretion (16 of 24). The predominance of these inverse relationships and the demonstration in a minority of studies of other directions of the relationships could not generally be explained by differences between studies in the sex, age, or current size of the subjects. However, the relationship of birth weight with insulin secretion was inconsistent in studies of adults.

CONCLUSIONS

The published literature shows that, generally, people who were light at birth have an adverse profile of later glucose and insulin metabolism. This is related to higher insulin resistance, but the relationship to insulin secretion in adults is less clear.

Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome is a heterogeneous clinical syndrome, which has been defined as the association of hyperandrogenism with chronic anovulation in women without specific adrenal and pituitary gland disease. A family history of polycystic ovary syndrome may be present in a subset of patients; however, the genetic basis of the syndrome remains unclear. Most often, the age of onset is perimenarchal and it is characterized by the appearance of menstrual disturbances, hirsutism, acne, and more rarely, a male pattern of alopecia. In some cases, premature adrenarche may present as a precursor to the development of the syndrome. Polycystic ovary syndrome is also associated with metabolic disturbances, such as obesity and insulin resistance with hyperinsulinemia, for which the pathophysiological role in the development of the syndrome has been recognized. The therapeutic approaches to polycystic ovary syndrome include lifestyle modifications, dietary-induced weight loss, insulin-sensitizing agents, antiandrogens, and oral contraceptives. These treatments may improve the clinical manifestations of excess androgen production and normalize menses in many adolescents and young women with polycystic ovary syndrome. Early recognition of the syndrome and thus, early treatment, may prevent and possibly ameliorate all the symptoms and the potential later development of metabolic and cardiovascular complications.

Intrauterine growth restriction and postnatal steroid treatment effects on insulin sensitivity in preterm neonates

OBJECTIVES

To study whether intrauterine growth restriction (IUGR) is associated with decreased sensitivity to the main fetal growth factor, insulin, and the effect of glucocorticoid therapy on insulin sensitivity in preterm infants.

STUDY DESIGN

Newborn infants with a birth weight (BW) of< 1500 g were classified as appropriate for gestational age ([AGA], BW within +/- 1 SD, n = 10), or small for gestational age ([SGA], BW <-2 SD, n = 13); 5 AGA infants and 8 SGA infants received systemic steroids. An abbreviated modified minimal model test was performed, consisting of sequential blood samples for glucose and insulin assays, and intravenous infusions of 0.3 g/kg glucose and 0.02 U/kg regular human insulin. The insulin sensitivity index (S(I)) was calculated using a computer program.

RESULTS

The basal insulin/glucose ratio (I/G) and S(I) did not differ between the AGA and SGA groups. Steroids did not influence the I/G nor the S(I) of AGA infants (10.2 +/- 6.7 vs 8.2 +/- 2.3), but decreased the S(I) in the SGA group (12.2 +/- 5.1 vs 5.3 +/- 2.7, P <.05).

CONCLUSIONS

Insulin sensitivity of neonates can be measured by the modified minimal model. IUGR is not associated with impaired fetal glucose tolerance. Early neonatal steroid treatment decreases insulin sensitivity in SGA infants, which may contribute to their risk of having hyperglycemia.

Hypersecretion of FSH in infant boys and girls born small for gestational age

Prenatal growth restraint, as reflected in a low birthweight for gestational age, is a risk factor for postpubertal FSH hypersecretion and for reduced gonadal size. The ontogeny of the low-birthweight effect on the FSH-inhibin B feedback loop is unknown. Infancy is an episode of choice to study the possibility of an early low-birthweight effect on the FSH-inhibin B loop because this phase is characterized by high activity within the gonadal axis. We assessed serum concentrations of FSH and inhibin B in 46 infants [26 girls and 20 boys; mean age, 4 months; range, 3-6 months; 17 appropriate for gestational age (AGA), 29 small for gestational age (SGA); mean birthweight, 3.2 kg for AGA vs. 2.3 kg for SGA], together with circulating levels of LH, E2, and free androgen index. In SGA girls and boys, serum FSH levels were 2- and 4-fold higher (P < 0.001), respectively, than in AGA controls of the same gender (7.3 +/- 0.9 vs. 3.8 +/- 0.4 IU/ml and 2.9 +/- 0.5 vs. 0.7 +/- 0.2 IU/ml). Serum LH, inhibin B, and free androgen index/E2 concentrations were similar in AGA and SGA infants. In conclusion, prenatal growth restraint was found to be followed by elevated serum FSH concentrations in infant girls and boys. SGA infants seem to need an augmented FSH drive to fulfill inhibin B requirements on the afferent side of the feedback loop. The late-endocrine correlates of early growth restraint are herewith extended to include the main axis of reproduction in both genders. It remains to be studied whether FSH hypersecretion in infancy is a marker of subsequent subfertility.

Polycystic ovary syndrome after precocious pubarche: ontogeny of the low-birthweight effect

OBJECTIVE

Young girls with precocious pubarche (PP) are at increased risk of developing polycystic ovary syndrome (PCOS), including hyperinsulinism, dyslipidaemia and ovarian hyperandrogenism, particularly if PP itself was preceded by a low birthweight. Resistance to insulin is thought to be a key factor in the pathogenesis of this sequence. We aimed to elucidate the peripubertal ontogeny of the low birthweight effect on hyperinsulinism, dyslipidaemia and ovarian dysfunction after PP.

PATIENTS AND DESIGN

We obtained fully longitudinal data from 51 girls with a history of PP and compared normal-birthweight (n = 26) with low-birthweight (n = 25) girls (birthweight SD score 0.0 +/- 0-2 vs. - 2.4 +/- 0.2) for measurements obtained at diagnosis of PP (mean age 7.0 years), in early puberty (10.4 years) and after menarche (14.3 years).

MEASUREMENTS

Fasting serum lipids and lipoproteins, together with insulin responses to an oral glucose load, were assessed at diagnosis of PP, in early puberty and after menarche; serum gonadotropins were measured in early puberty and after menarche; ovarian function was examined postmenarche.

RESULTS

Comparisons of endocrine-metabolic results between normal- and low-birthweight PP girls showed no detectable differences before puberty. The hypertriglyceridaemia and elevated LDL-cholesterol levels characterizing low-birthweight PP girls became detectable by early puberty; reduced insulin sensitivity was not evident until postmenarche, when the tendency to ovarian dysfunction also became obvious. Body mass indices of normal- and low-birthweight subgroups were identical in early puberty and postmenarche.

CONCLUSIONS

These longitudinal data show that, in PP girls, the endocrine-metabolic risk conferred by prenatal growth restraint is not readily detectable until puberty or postmenarche, and is not attributable to a higher body mass index.

Programming effects in sheep of prenatal growth restriction and glucocorticoid exposure

Our aim was to determine the postnatal effects of single and repeated glucocorticoid injections during late gestation. Repeated (104, 111, 118, 125 days) or single (104 days) injections of betamethasone or saline were given to the ewe or by ultrasound guided injection to the fetus (term 150 days). Lambs were born spontaneously and studied at 3 and 6 mo and 1 yr of age. Arterial pressure was measured at each age, and we performed intravenous glucose tolerance tests at 6 mo and 1 yr. Repeated maternal, but not single maternal or fetal, betamethasone injections prolonged gestation, reduced weight at birth and 3 mo, and was associated with low arterial pressure at 3 mo but not at 6 mo and 1 yr. Glucose metabolism was altered in all betamethasone treatment groups, regardless of the number or route of injections. Our data demonstrate that glucocorticoid-induced fetal growth restriction is associated with a transient reduction in postnatal arterial pressure, but glucocorticoid exposure with or without growth restriction alters glucose metabolism.

Tall or short? Twenty years after preeclampsia exposure in utero: comparisons of final height, body mass index, waist-to-hip ratio, and age at menarche among women, exposed and unexposed to preeclampsia during fetal life

Women exposed to preeclampsia during fetal life have lower risk of breast cancer, compared with unexposed women, possibly through fetal programming. Hypothetically, preeclampsia exposure could affect well-known risk factors for breast cancer, such as pubertal development or adult anthropometry. Women born in a defined geographic area of Sweden from 1973 through 1978, with verified preeclampsia exposure (n = 230) and nonexposure (n = 359) during fetal life, answered questions about anthropometric measures, smoking, parity, and age at menarche in a telephone interview in early adulthood. Compared with unexposed offspring, female offspring of women who had preeclampsia were lighter and shorter for gestational age, but in young adulthood there were no differences in height, body mass index, waist-to-hip ratio, or age at menarche. When analyzing the effects of other maternal and fetal characteristics, the results indicate that approximately 50% of the variance in final height was explained by parental heights and birth length for gestational age. Young-adult body mass index was weakly associated with maternal body mass index, maternal smoking, and birth weight for gestational age, which together explained 12% of the variance. Neither of the assessed maternal or fetal characteristics were significantly associated with age at menarche or waist-to-hip ratio. These data indicate that neither adult anthropometry nor age at menarche is in the causal pathway between intrauterine preeclampsia exposure and the reduced risk of breast cancer.

The thrifty phenotype hypothesis

The thrifty phenotype hypothesis proposes that the epidemiological associations between poor fetal and infant growth and the subsequent development of type 2 diabetes and the metabolic syndrome result from the effects of poor nutrition in early life, which produces permanent changes in glucose-insulin metabolism. These changes include reduced capacity for insulin secretion and insulin resistance which, combined with effects of obesity, ageing and physical inactivity, are the most important factors in determining type 2 diabetes. Since the hypothesis was proposed, many studies world-wide have confirmed the initial epidemiological evidence, although the strength of the relationships has varied from one study to another. The relationship with insulin resistance is clear at all ages studied. Less clear is the relationship with insulin secretion. The relative contribution of genes and environment to these relationships remains a matter of debate. The contributions of maternal hyperglycaemia and the trajectory of postnatal growth need to be clarified.