S. S. Naik

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.

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.

The spectrum of pancreatic exocrine and endocrine (Beta-cell) function in tropical calcific pancreatitis

SummaryExocrine pancreatic marker (immunoreactive-trypsin) and endocrine Beta-cell function (plasma insulin and C-peptide during an oral glucose tolerance test) were studied in 40 subjects with tropical-calcific-pancreatitis [seven non-diabetic, seven with impaired-glucose-tolerance and 26 diabetic (fibro-calculous-pancreatic-diabetes)]. In non-diabetic and impaired-glucose-tolerance subjects there was evidence of active pancreatitis in some and exocrine function was partially preserved. Fibro-calculous-pancreatic-diabetic subjects showed severely diminished exocrine pancreatic function; none showed ‘pancreatitic’ elevation of immunoreactive-trypsin. Beta-cell function was preserved in non-diabetic and impaired-glucose-tolerance subjects; diabetic subjects showed variable Beta-cell function but it was severely diminished in more than 75%. Immunoreactive-trypsin and C-peptide were directly correlated (rs=0.55, p<0.01). This cross sectional study demonstrates, for the first time, that the Beta-cell loss in tropical-calcific-pancreatitis is related to the exocrine loss. It suggests that diabetes in tropical-calcific-pancreatitis is either secondary to pancreatitis or that a common factor(s) acts simultaneously on both components.

The ketosis-resistance in fibro-calculous-pancreatic-diabetes. 1. Clinical observations and endocrine-metabolic measurements during oral glucose tolerance test.

We measured circulating levels of C-peptide, pancreatic glucagon, cortisol, growth hormone and metabolites (glucose, non-esterified fatty acids, glycerol and 3-hydroxybutyrate) in fibro-calculous-pancreatic diabetic (FCPD, n = 28), insulin-dependent diabetic (IDDM, n = 28) and non-diabetic control (n = 27) subjects during an oral glucose tolerance test. There was no difference in the two diabetic groups in age (FCPD 24 +/- 2, IDDM 21 +/- 2 years, mean +/- SEM), BMI (FCPD 16.0 +/- 0.6, IDDM 15.7 +/- 0.4 kg/m2), triceps skinfold thickness (FCPD 8 +/- 1, IDDM 7 +/- 1 mm), glycaemic status (fasting plasma glucose, FCPD 12.5 +/- 1.5, IDDM 14.5 +/- 1.2 mmol/l), fasting plasma C-peptide (FCPD 0.13 +/- 0.03, IDDM 0.08 +/- 0.01 nmol/l), peak plasma C-peptide during OGTT (FCPD 0.36 +/- 0.10, IDDM 0.08 +/- 0.03 nmol/l) and fasting plasma glucagon (FCPD 35 +/- 4, IDDM 37 +/- 4 ng/l). FCPD patients, however, showed lower circulating concentrations of non-esterified fatty acids (0.73 +/- 0.11 mmol/l), glycerol (0.11 +/- 0.02 mmol/l) and 3-hydroxybutyrate (0.15 +/- 0.03 mmol/l) compared to IDDM patients (1.13 +/- 0.14, 0.25 +/- 0.05 and 0.29 +/- 0.08 mmol/l, respectively). This could be due to enhanced sensitivity of adipose tissue lipolysis to the suppressive action of circulating insulin and possibly also to insensitivity of hepatic ketogenesis to glucagon. Our results also demonstrate preservation of alpha-cell function in FCPD patients when beta-cell function is severely diminished, suggesting a more selective beta-cell dysfunction or destruction than hitherto believed.

EXOCRINE PANCREATIC FUNCTION (SERUM IMMUNOREACTIVE TRYPSIN, FECAL CHYMOTRYPSIN, AND PANCREATIC ISOAMYLASE) IN INDIAN DIABETICS

Forty-nine patients with tropical calcific pancreatitis (TCP), 51 insulin- dependent diabetics (IDDMs), 87 non-insulin-dependent diabetics (NIDDMs), and 66 nondiabetic controls were studied to evaluate their exocrine pancreatic function by measurement of serum immunoreactive trypsin (IRT, normal for white Caucasians from the U.K. of 140–414 μg/L), pancreatic isoamylase (PIA, normal of 35–125 U/L), and fecal chymotrypsin (FCT, normal of >6.6 u/g). The majority of patients were studied within 1 year of diagnosis. TCP subjects included 7 nondiabetics, 6 with impaired glucose tolerance (IGT-TCP), and 36 diabetics [fibrocalculous pancreatic diabetes (FCPD)]. There was evidence of active pancreatitis (IRT >800 μg/L) and partial preservation of function in nondiabetic TCP subjects [median IRT of 220 μg/L (range of 102–1,360 μg/L), FCT of 2.2 u/g (range 0.7–12.8 u/g)] and also in IGT-TCP subjects [IRT of 370 pg/L (range of 30–1,360 μg/L), FCT of 4.2 u/g (range of 1–38 u/g)]. FCPDs showed severely diminished exocrine function [IRT of 50 μg/L (range of CL184 μg/L), FCT of 0.23 u/g (range of 0–10.4 u/g)]; none showed IRT > 800 μg/L. IDDMs and NIDDMs also showed diminished exocrine pancreatic function in ∼30 and ∼10%, respectively. Controls showed a wide range of IRT and FCT concentrations; IRT concentrations tended to be higher than those reported in white Caucasians from the U.K. Three controls, one IDDM, and two NIDDMs showed “pancreatitic” IRT concentrations in the absence of symptoms. PIA concentrations were diminished in FCPD but were similar in IDDM and NIDDM subjects compared to controls. Simultaneous measurements showed that IRT concentrations were reduced when PIA concentrations were still normal. Our results suggest that TCP and FCPD (diagnosed by radiographically demonstrable pancreatic calculi) represent advanced disease and that a subclinical “pancreatopathy” appears to be common in tropical subjects (diabetic as well as nondiabetic). Endocrine impairment (hyperglycemia) in TCP parallels exocrine damage.

The Relationship Between Obesity, Plasma Immunoreactive Insulin Concentration and Blood Pressure in Newly Diagnosed Indian Type 2 Diabetic Patients

The association of blood pressure with clinical and biochemical measures was studied in 185 newly diagnosed Type 2 diabetic patients, 74 impaired‐glucose‐tolerant (IGT) and 128 non‐diabetic control subjects. Hyperglycaemic subjects were older than control subjects (controls 40 (24–59) years, IGT 48 (29–64) years, diabetic 43 (29–60) years, median (5th‐95th centile) both p < 0.05). They were also more obese (body mass index (BMI) controls 23.5 kg m−2 (17.2–29.9), IGT 26.0 kg m−2 (19.8–33.9), diabetic 24.2 kg m−2 (19.3–32.2)) and with a greater waist‐hip ratio (controls 0.83 (0.70–0.98), IGT 0.88 (0.75–0.98), diabetic 0.89 (0.75–1.00)). Blood pressure was significantly higher in both IGT (systolic 127mmHg (108–162), diastolic 80 mmHg (66–99)) and diabetic patients (systolic 130 mmHg (104–160), diastolic 84 mmHg (66–102)) compared to non‐diabetic controls (systolic 120 mmHg (100–151), diastolic 80 mmHg (60–94)). Univariate analysis showed that in diabetic patients systolic blood pressure was related to age (r = 0.17, p < 0.05), BMI (r= 0.23, p < 0.01) and plasma immunoreactive insulin (fasting and post glucose, r= ˜ 0.25, p<0.01) but not to C‐peptide concentrations; diastolic blood pressure to BMI (r= 0.35, p < 0.001), waist‐hip ratio (r = 0.23, p < 0.01) and plasma immunoreactive insulin (fasting r= 0.30, p < 0.001, post glucose r = ˜ 0.20, p < 0.05) but not to C‐peptide concentrations. Multivariate analysis revealed that systolic blood pressure in diabetic patients was related to BMI (p < 0.01) and fasting immunoreactive insulin (p < 0.05) while diastolic blood pressure was related to BMI (p < 0.001) and waist‐hip ratio (p < 0.01). Thus, blood pressure is associated with obesity even in our relatively non‐obese population and it is also associated with plasma immunoreactive insulin concentrations. The mechanism of these associations remains to be established.

Marked Gender Difference in Plasma Total Homocysteine Concentrations in Indian Adults with low Vitamin B12

CONTEXT Plasma total homocysteine (tHcy) is higher in men than women. OBJECTIVE To explore the gender differences in tHcy in relation to determinants of one-carbon metabolism in Indian people with low B₁₂ and adequate folate. SETTING The study took place in rural and urban areas of Pune, India. DESIGN AND PARTICIPANTS Participants were 441 men from the cross-sectional Coronary Risk of Insulin Sensitivity in Indian Subjects study (CRISIS) and premenopausal wives of 146 men (median ages 38 and 34 years, respectively). MAIN OUTCOME MEASURES Gender difference in fasting tHcy in relation to plasma albumin and creatinine concentrations, lifestyle factors, diet and lean mass, plasma B₁₂ and red cell folate (RCF) was assessed. RESULTS Prevalence of high tHcy (> 15 µmol/L, median 14.4 µM) was 40 %, low B12 (< 150 pmol/L, 114 pmol/L) 66 %, and low RCF (< 283 nmol/L, 525 nmol/L) 8 %. Men had higher (1.8x) plasma tHcy concentrations (16.2 µmol/L) than women (9.5 µmol/L). Only 50 % of the gender difference was explained by age, lean mass, B₁₂, and RCF. The difference remained after controlling for other explanatory variables. Women with a tHcy of 9.3 µM had the same B₁₂ concentration (129 pmol/L) as men with a tHcy of 15 µM; and for a tHcy of 10.0 µmol/L women had the same RCF concentration (533 nmol/L) as men with a tHcy of 15 µmol/L. CONCLUSIONS Adult Indian women have markedly lower tHcy concentrations compared to men. This suggests a lower threshold for supplementation to improve reproductive and cardiovascular outcomes.

Determinants of Incident Hyperglycemia 6 Years After Delivery in Young Rural Indian Mothers The Pune Maternal Nutrition Study (PMNS)

OBJECTIVE—To study determinants of incident hyperglycemia in rural Indian mothers 6 years after delivery. RESEARCH DESIGN AND METHODS—The Pune Maternal Nutrition Study collected information in six villages near Pune on prepregnant characteristics and nutrition, physical activity, and glucose tolerance during pregnancy. An oral glucose tolerance test (OGTT) was repeated 6 years after delivery. RESULTS—A total of 597 mothers had an OGTT at 28 weeks’ gestation; 3 had gestational diabetes (by World Health Organization 1999 criteria). Six years later, 42 of 509 originally normal glucose-tolerant mothers were hyperglycemic (8 diabetic, 20 with impaired glucose tolerance, and 14 with impaired fasting glucose). The hyperglycemic women had shorter legs and thicker skinfolds before pregnancy (P < 0.01, both), were less active and more hyperglycemic (2-h plasma glucose 4.8 vs. 4.4 mmol/l, P < 0.001) during pregnancy, and gained more weight during follow-up (6.0 vs. 2.7 kg, P < 0.001). Multivariate analysis revealed that total leukocyte count and blood pressure during pregnancy were additional independent predictors of 2-h glucose concentration at follow-up. CONCLUSIONS—Our results suggest that compromised linear growth, adiposity, inflammation, and less physical activity predispose to hyperglycemia in young rural Indian women. International cut points of diabetes risk factors are largely irrelevant in these women.

Circulating lipids and cardiovascular risk in newly diagnosed non‐insulin‐dependent diabetic subjects in India

Circulating concentrations of total cholesterol, triglycerides, non‐esterified fatty acids (NEFA), glycerol, and 3‐hydroxybutyrate (3‐HB) were measured in 133 subjects with normal glucose tolerance (NGT), 78 with impaired‐glucose‐tolerance (IGT) and 189 non‐insulin dependent (Type 2) diabetic (NIDDM) patients. Plasma cholesterol concentration was similar in the three groups; NGT (4.2 (2.3–7.5) mmol l−1 , median (range)), IGT (4.7 (2.7–6.3)) and NIDDM (4.3 (2.3–6.9)). Plasma triglycerides (NGT 0.88 (0.37–2.80), IGT 1.26 (0.43–3.82) and NIDDM 1.38 (0.62–3.91) mmol l−1 ) and NEFA (NGT 0.81 (0.29–1.58), IGT 1.02 (0.33–1.87) and NIDDM 1.02 (0.48–2.77) mmol l−1 ) were higher in the two hyperglycaemic groups, but blood 3‐HB concentration was similar in the three groups. Plasma cholesterol concentration in these subjects is lower than that reported in white Caucasians in the UK and USA and migrant Indian NIDDM patients in the UK. In NIDDM patients plasma cholesterol concentration was related to age, body mass index (BMI), and plasma glucose concentration while plasma triglyceride concentration was related to plasma NEFA and insulin (IRI) concentration. Evidence of ischaemia on electrocardiography in patients with diabetes was associated with higher age, blood pressure, plasma triglyceride, glucose, and IRI concentrations. © 1997 by John Wiley & Sons, Ltd.

Serum Immunoreactive Trypsin in Tropical Pancreatic Diabetes Syndrome

Fifteen patients with tropical pancreatic diabetes syndrome (TPDS), 16 insulin-dependent diabetics (IDD), 27 non-insulin-dependent diabetics (NIDD) and 14 normal subjects, all from India, were investigated for markers of β-cell (C-peptide) and exocrine (immunoreactive trypsin; IRT) reserve. IRT and C-peptide concentrations were the lowest in TPDS, lower than normal in IDD, and not significantly different from normal in NIDDs. There was a highly significant correlation (r s = 0·;D93; P < 0·;00001) between IRT and C-peptide (measured in 50% of patients and controls) concentrations when all diabetic groups were combined. Such a correlation was absent when TPDS patients were considered in isolation, largely because of the markedly low IRT concentration. Fourteen of 15 patients (93%) with TPDS had subnormal IRT concentrations, of which 11 had IRT values of less than 50 μg/L. These IRT values are similar to those previously reported in cystic fibrosis. Only 6 of 16 IDDs (38%) had subnormal IRT concentrations, of which only one was below 50 μg/L. These data suggest that exocrine pancreatic reserve is markedly diminished in TPDS and that a subnormal IRT concentration may be a useful biochemical marker for this form of diabetes.