Dattatray S. Bhat

Fetal Growth and Glucose and Insulin Metabolism in Four‐year‐old Indian Children

Studies in Britain have shown that adults who had a low birthweight have high plasma glucose concentrations 30 and 120 min after an oral glucose load, and an increased risk of Type 2 diabetes and impaired glucose tolerance. Both Type 2 diabetes and low birthweight are common in India. To determine whether low birthweight is associated with reduced glucose tolerance in Indian children, glucose tolerance tests were carried out on 379 4‐year‐old children, whose birthweights were recorded, in Pune, India. Among 201 children who had been looked after on the routine postnatal wards at birth, those with lower birthweights had higher plasma glucose and insulin concentrations 30 min after an oral glucose load, independently of their current size (p = 0.01 and 0.04, respectively). Mean glucose and insulin concentrations were 8.1 mmol I−1 and 321 pmol I−1 in children whose birthweight had been 2.4 kg or less, compared with 7.5 mmol I−1 and 289 pmol I−1 in those who weighed more than 3.0 kg. Among 178 children who had been looked after in the Special Care Baby Unit, those with lower birthweights also had higher plasma insulin concentrations at 30 min but there were no trends with plasma glucose. Our findings suggest that Indian children with reduced intra‐uterine growth have reduced glucose homeostasis after a glucose challenge. This is consistent with the hypothesis that Type 2 diabetes mellitus in India may be programmed in fetal life.

Vitamin B12 status of pregnant Indian women and cognitive function in their 9-year-old children

Background Recent research has highlighted the influence of maternal factors on the health of the offspring. Intrauterine experiences may program metabolic, cardiovascular, and psychiatric disorders. We have shown that maternal vitamin B12 status affects adiposity and insulin resistance in the child. Vitamin B12 is important for brain development and function. Objective We investigated the relationship between maternal plasma vitamin B12 status during pregnancy and the childs cognitive function at 9 years of age. Methods We studied children born in the Pune Maternal Nutrition Study. Two groups of children were selected on the basis of maternal plasma vitamin B12 concentration at 28 weeks of gestation: group 1 (n = 49) included children of mothers with low plasma vitamin B12 (lowest decile, < 77 pM) and group 2 (n = 59) children of mothers with high plasma vitamin B12 (highest decile, > 224 pM). Results Children from group 1 performed more slowly than those from group 2 on the Color Trail A test (sustained attention, 182 vs. 159 seconds; p < .05) and the Digit Span Backward test (short-term memory, p <.05), after appropriate adjustment for confounders. There were no differences between group 1 and group 2 on other tests of cognitive function (intelligence, visual agnosia). Conclusions Maternal vitamin B12 status in pregnancy influences cognitive function in offspring.

Spuriously High Prevalence of Prediabetes Diagnosed by HbA1c in Young Indians Partly Explained by Hematological Factors and Iron Deficiency Anemia

OBJECTIVE To examine the influence of glycemic and nonglycemic parameters on HbA1c concentrations in young adults, the majority of whom had normal glucose tolerance. RESEARCH DESIGN AND METHODS We compared the diagnosis of normal glucose tolerance, prediabetes, and diabetes between a standard oral glucose tolerance test (OGTT; World Health Organization 2006 criteria) and HbA1c concentrations (American Diabetes Association [ADA] 2009 criteria) in 116 young adults (average age 21.6 years) from the Pune Children’s Study. We also studied the contribution of glycemic and nonglycemic determinants to HbA1c concentrations. RESULTS The OGTT showed that 7.8% of participants were prediabetic and 2.6% were diabetic. By ADA HbA1c criteria, 23.3% were prediabetic and 2.6% were diabetic. The negative predictive value of HbA1c was 93% and the positive predictive value was 20% (only 20% had prediabetes or diabetes according to the OGTT; this figure was 7% in anemic participants). Of participants, 34% were anemic, 37% were iron deficient (ferritin <15 ng/mL), 40% were vitamin B12 deficient (<150 pmol/L), and 22% were folate deficient (<7 nmol/L). On multiple linear regression analysis, HbA1c was predicted by higher 2-h glucose (R2 = 25.6%) and lower hemoglobin (R2 = 7.7%). When hematological parameters were replaced by ferritin, vitamin B12, and folate, HbA1c was predicted by higher glycemia (R2 = 25.6%) and lower ferritin (R2 = 4.3%). CONCLUSIONS The use of HbA1c to diagnose prediabetes and diabetes in iron-deficient populations may lead to a spuriously exaggerated prevalence. Further investigation is required before using HbA1c as a screening tool in nutritionally compromised populations.

Maternal Lipids Are as Important as Glucose for Fetal Growth: Findings from the Pune Maternal Nutrition Study

OBJECTIVE To study the relationship between maternal circulating fuels and neonatal size and compare the relative effects of glucose and lipids. RESEARCH DESIGN AND METHODS The Pune Maternal Nutrition Study (1993–1996) investigated the influence of maternal nutrition on fetal growth. We measured maternal body size and glucose and lipid concentrations during pregnancy and examined their relationship with birth size in full-term babies using correlation and regression techniques. RESULTS The mothers (n = 631) were young (mean age 21 years), short (mean height 151.9 cm), and thin (BMI 18.0 kg/m2) but were relatively more adipose (body fat 21.1%). Their diet was mostly vegetarian. Between 18 and 28 weeks’ gestation, fasting glucose concentrations remained stable, whereas total cholesterol and triglyceride concentrations increased and HDL-cholesterol concentrations decreased. The mean birth weight of the offspring was 2666 g. Total cholesterol and triglycerides at both 18 and 28 weeks and plasma glucose only at 28 weeks were associated directly with birth size. One SD higher maternal fasting glucose, cholesterol, and triglyceride concentrations at 28 weeks were associated with 37, 54, and 36 g higher birth weights, respectively (P < 0.05 for all). HDL-cholesterol concentrations were unrelated to newborn measurements. The results were similar if preterm deliveries also were included in the analysis (total n = 700). CONCLUSIONS Our results suggest an influence of maternal lipids on neonatal size in addition to the well-established effect of glucose. Further research should be directed at defining the clinical relevance of these findings.

Multigenerational Undernutrition Increases Susceptibility to Obesity and Diabetes that Is Not Reversed after Dietary Recuperation

People in developing countries have faced multigenerational undernutrition and are currently undergoing major lifestyle changes, contributing to an epidemic of metabolic diseases, though the underlying mechanisms remain unclear. Using a Wistar rat model of undernutrition over 50 generations, we show that Undernourished rats exhibit low birth-weight, high visceral adiposity (DXA/MRI), and insulin resistance (hyperinsulinemic-euglycemic clamps), compared to age-/gender-matched control rats. Undernourished rats also have higher circulating insulin, homocysteine, endotoxin and leptin levels, lower adiponectin, vitamin B12 and folate levels, and an 8-fold increased susceptibility to Streptozotocin-induced diabetes compared to control rats. Importantly, these metabolic abnormalities are not reversed after two generations of unrestricted access to commercial chow (nutrient recuperation). Altered epigenetic signatures in insulin-2 gene promoter region of Undernourished rats are not reversed by nutrient recuperation, and may contribute to the persistent detrimental metabolic profiles in similar multigenerational undernourished human populations.

Maternal homocysteine in pregnancy and offspring birthweight: epidemiological associations and Mendelian randomization analysis

BACKGROUND Disturbed one-carbon (1-C) metabolism in the mother is associated with poor fetal growth but causality of this relationship has not been established. METHODS We studied the association between maternal total homocysteine and offspring birthweight in the Pune Maternal Nutrition Study (PMNS, Pune, India) and Parthenon Cohort Study (Mysore, India). We tested for evidence of causality within a Mendelian randomization framework, using a methylenetetrahydrofolatereductase (MTHFR) gene variant rs1801133 (earlier known as 677C→T) by instrumental variable and triangulation analysis, separately and using meta-analysis. RESULTS Median (IQR) homocysteine concentration and mean (SD) birthweight were 8.6 µmol/l (6.7,10.8) and 2642 g (379) in the PMNS and 6.0 µmol/l (5.1,7.1) and 2871 g (443) in the Parthenon study. Offspring birthweight was inversely related to maternal homocysteine concentration-PMNS: -22 g/SD [95% confidence interval (CI): (-50, 5), adjusted for gestational age and offspring gender]; Parthenon: -57 g (-92, -21); meta-analysis: -40 g (-62, -17)]. Maternal risk genotype at rs1801133 predicted higher homocysteine concentration [PMNS: 0.30 SD/allele (0.14, 0.46); Parthenon: 0.21 SD (0.02, 0.40); meta-analysis: 0.26 SD (0.14, 0.39)]; and lower birthweight [PMNS: -46 g (-102, 11, adjusted for gestational age, offspring gender and rs1801133 genotype); Parthenon: -78 g (-170, 15); meta-analysis: -61 g (-111, -10)]. Instrumental variable and triangulation analysis supported a causal association between maternal homocysteine concentration and offspring birthweight. CONCLUSIONS Our findings suggest a causal role for maternal homocysteine (1-C metabolism) in fetal growth. Reducing maternal homocysteine concentrations may improve fetal growth.

Effect of physiological doses of oral vitamin B12 on plasma homocysteine – A randomized, placebo-controlled, double-blind trial in India

Background/Objectives:Vitamin B12 (B12) deficiency is common in Indians and a major contributor to hyperhomocysteinemia, which may influence fetal growth, risk of type II diabetes and cardiovascular disease. The purpose of this paper was to study the effect of physiological doses of B12 and folic acid on plasma total homocysteine (tHcy) concentration.Subjects/Methods:A cluster randomized, placebo-controlled, double-blind, 2 × 3 factorial trial, using the family as the randomization unit. B12 was given as 2 or 10 μg capsules, with or without 200 μg folic acid, forming six groups (B0F0, B2F0, B10F0, B0F200, B2F200 and B10F200). Plasma tHcy concentration was measured before and after 4 and 12 months of supplementation.Results:From 119 families in the Pune Maternal Nutrition Study, 300 individuals were randomized. There was no interaction between B12 and folic acid (P=0.14) in relation to tHcy concentration change and their effects were analyzed separately: B0 vs. B2 vs. B10; and F0 vs. F200. At 12 months, tHcy concentration reduced by a mean 5.9 (95% CI: −7.8, −4.1) μmol/l in B2, and by 7.1 (95% CI: −8.9, −5.4) μmol/l in B10, compared to nonsignificant rise of 1.2 (95% CI: −0.5, 2.9) μmol/l in B0. B2 and B10 did not differ significantly. In F200, tHcy concentration decreased by 4.8 (95% CI: −6.3, −3.3) μmol/l compared to 2.8 (95% CI: −4.3, −1.2) μmol/l in F0.Conclusion:Daily oral supplementation with physiological doses of B12 is an effective community intervention to reduce tHcy. Folic acid (200 μg per day) showed no additional benefit, neither had any unfavorable effects.

Lower Circulating B12 Is Associated with Higher Obesity and Insulin Resistance during Pregnancy in a Non-Diabetic White British Population

Objective Vitamin B12 and folate are critical micronutrients needed to support the increased metabolic demands of pregnancy. Recent studies from India have suggested that low vitamin B12 and folate concentrations in pregnancy are associated with increased obesity; however differences in diet, antenatal vitamin supplementation, and socioeconomic status may limit the generalisability of these findings. We aimed to explore the cross-sectional relationship of circulating serum vitamin B12 and folate at 28 weeks’ gestation with maternal adiposity and related biochemical markers in a white non diabetic UK obstetric cohort. Methods Anthropometry and biochemistry data was available on 995 women recruited at 28 weeks gestation to the Exeter Family Study of Childhood Health. Associations between B12 and folate with maternal BMI and other obesity-related biochemical factors (HOMA-R, fasting glucose, triglycerides, HDL and AST) were explored using regression analysis, adjusting for potential confounders (socioeconomic status, vegetarian diet, vitamin supplementation, parity, haemodilution (haematocrit)). Results Higher 28 week BMI was associated with lower circulating vitamin B12 (r = -0.25; P<0.001) and folate (r = -0.15; P<0.001). In multiple regression analysis higher 28 week BMI remained an independent predictor of lower circulating B12 (β (95% CI) = -0.59 (-0.74, -0.44) i.e. for every 1% increase in BMI there was a 0.6% decrease in circulating B12). Other markers of adiposity/body fat metabolism (HOMA-R, triglycerides and AST) were also independently associated with circulating B12. In a similar multiple regression AST was the only independent obesity-related marker associated with serum folate (β (95% CI) = 0.16 (0.21, 0.51)) Conclusion In conclusion, our study has replicated the previous Indian findings of associations between lower serum B12 and higher obesity and insulin resistance during pregnancy in a non-diabetic White British population. These findings may have important implications for fetal and maternal health in obese pregnancies.

Prediction of body-fat percentage from skinfold and bio-impedance measurements in Indian school children

Background/Objectives:Few equations for calculating body-fat percentage (BF%) from field methods have been developed in South-Asian children. The objective of this study was to assess agreement between BF% derived from primary reference methods and that from skinfold equations and bio-impedance analysis (BIA) in Indian children.Subjects/Methods:We measured BF% in two groups of Indian children. In Pune, 570 rural children aged 6–8 years underwent dual-energy X-ray absorptiometry (DXA) scans. In Mysore 18O in doubly labeled water was administered to 59 urban children aged 7–9 years. We conducted BIA at 50 kHz and anthropometry, including sub-scapular and triceps skinfold thicknesses. We used the published equations of Wickramasinghe, Shaikh, Slaughter and Dezenburg to calculate BF% from anthropometric data and the manufacturers equation for BIA measurements. We assessed agreement with values derived from DXA and doubly labeled water using Bland–Altman analysis.Results:Children were light and thin on average compared with international standards. There was poor agreement between the reference BF% values and those from all equations. Assumptions for Bland–Altman analysis were not met for Wickramasinghe, Shaikh and Slaughter equations. The Dezenberg equations under-predicted BF% for most children (mean difference in Pune −13.4, LOA −22.7, −4.0 and in Mysore −7.9, LOA (−13.7 and −2.2). The mean bias for the BIA equation in Pune was +5.0% and in Mysore +1.95%, and the limits of agreement were wide; −5.0, 15.0 and –7.8, 11.7 respectively.Conclusions:Currently available skinfold equations do not accurately predict BF% in Indian children. We recommend development of BIA equations in this population using a four-compartment model.

Increases in Plasma Holotranscobalamin Can Be Used to Assess Vitamin B-12 Absorption in Individuals with Low Plasma Vitamin B-12

Low plasma concentrations of vitamin B-12 are common in Indians, possibly due to low dietary intakes of animal-source foods. Whether malabsorption of the vitamin contributes to this has not been investigated. A rise in the plasma holotranscobalamin (holo-TC) concentration after a standard dose of oral vitamin B-12 has been proposed as a measure of gastrointestinal absorption in people with normal plasma vitamin B-12 concentrations. We studied 313 individuals (children and parents, 109 families) in the Pune Maternal Nutrition Study. They received 3 doses of 10 microg (n = 191) or 2 microg (n = 122) of cyanocobalamin at 6-h intervals. A rise in plasma holo-TC of > or =15% and >15 pmol/L above baseline was considered normal vitamin B-12 absorption. The baseline plasma vitamin B-12 concentration was <150 pmol/L in 48% of participants; holo-TC was <35 pmol/L in 98% and total homocysteine was high in 50% of participants (>10 micromol/L in children and >15 micromol/L in adults). In the 10 microg group, the plasma holo-TC concentration increased by 4.8-fold from (mean +/- SD) 9.3 +/- 7.0 pmol/L to 53.8 +/- 25.9 pmol/L and in the 2 microg group by 2.2-fold from 11.1 +/- 8.5 pmol/L to 35.7 +/- 19.3 pmol/L. Only 10% of the participants, mostly fathers, had an increase less than the suggested cut-points. Our results suggest that an increase in plasma holo-TC may be used to assess vitamin B-12 absorption in individuals with low vitamin B-12 status. Because malabsorption is unlikely to be a major reason for the low plasma vitamin B-12 concentrations in this population, increasing dietary vitamin B-12 should improve their status.