Lakshmy Ramakrishnan

The Effect of Rural-to-Urban Migration on Obesity and Diabetes in India: A Cross-Sectional Study

Shah Ebrahim and colleagues examine the distribution of obesity, diabetes, and other cardiovascular risk factors among urban migrant factory workers in India, together with their rural siblings. The investigators identify patterns of change of cardiovascular risk factors associated with urban migration.

Methods for establishing a surveillance system for cardiovascular diseases in Indian industrial populations

OBJECTIVE To establish a surveillance network for cardiovascular diseases (CVD) risk factors in industrial settings and estimate the risk factor burden using standardized tools. METHODS We conducted a baseline cross-sectional survey (as part of a CVD surveillance programme) of industrial populations from 10 companies across India, situated in close proximity to medical colleges that served as study centres. The study subjects were employees (selected by age and sex stratified random sampling) and their family members. Information on behavioural, clinical and biochemical determinants was obtained through standardized methods (questionnaires, clinical measurements and biochemical analysis). Data collation and analyses were done at the national coordinating centre. FINDINGS We report the prevalence of CVD risk factors among individuals aged 20-69 years (n = 19 973 for the questionnaire survey, n = 10 442 for biochemical investigations); mean age was 40 years. The overall prevalence of most risk factors was high, with 50.9% of men and 51.9% of women being overweight, central obesity was observed among 30.9% of men and 32.8% of women, and 40.2% of men and 14.9% of women reported current tobacco use. Self-reported prevalence of diabetes (5.3%) and hypertension (10.9%) was lower than when measured clinically and biochemically (10.1% and 27.7%, respectively). There was marked heterogeneity in the prevalence of risk factors among the study centres. CONCLUSION There is a high burden of CVD risk factors among industrial populations across India. The surveillance system can be used as a model for replication in India as well as other developing countries.

Detection of altered global DNA methylation in coronary artery disease patients.

Epigenetic modifications, especially alteration in DNA methylation, are increasingly being recognized as a key factor in the pathogenesis of complex disorders, including atherosclerosis. However, there are limited data on the epigenetic changes in the coronary artery disease (CAD) patients. In the present study we evaluated the methylation status of genomic DNA from peripheral lymphocytes in a cohort of 287 individuals: 137 angiographically confirmed CAD patients and 150 controls. The differential susceptibility of genomic DNA to methylation-sensitive restriction enzymes was utilized to assess the methylation status of the genome. We observed that the genomic DNA methylation in CAD patients is significantly higher than in controls (p < 0.05). Since elevated homocysteine levels are known to be an independent risk factor for CAD and a key modulator of macromolecular methylation, we investigated the probable correlation between plasma homocysteine levels and global DNA methylation. We observed a significant positive correlation of global DNA methylation with plasma homocysteine levels in CAD patients (p = 0.001). Further, within a higher range of serum homocysteine levels (>/=12-50 muM), global DNA methylation was significantly higher in CAD patients than in controls. The alteration in genomic DNA methylation associated with cardiovascular disease per se appears to be further accentuated by higher homocysteine levels.

Educational status and cardiovascular risk profile in Indians

The inverse graded relationship of education and risk factors of coronary heart disease (CHD) has been reported from Western populations. To examine whether risk factors of CHD are predicted by level of education and influenced by the level of urbanization in Indian industrial populations, a cross-sectional survey (n = 19,973; response rate, 87.6%) was carried out among employees and their family members in 10 medium-to-large industries in highly urban, urban, and periurban regions of India. Information on behavioral, clinical, and biochemical risk factors of CHD was obtained through standardized instruments, and educational status was assessed in terms of the highest educational level attained. Data from 19,969 individuals were used for analysis. Tobacco use and hypertension were significantly more prevalent in the low- (56.6% and 33.8%, respectively) compared with the high-education group (12.5% and 22.7%, respectively; P < 0.001). However, dyslipidemia prevalence was significantly higher in the high-education group (27.1% as compared with 16.9% in the lowest-education group; P < 0.01). When stratified by the level of urbanization, industrial populations located in highly urbanized centers were observed to have an inverse graded relationship (i.e., higher-education groups had lower prevalence) for tobacco use, hypertension, diabetes, and overweight, whereas in less-urbanized locations, we found such a relationship only for tobacco use and hypertension. This study indicates the growing vulnerability of lower socioeconomic groups to CHD. Preventive strategies to reduce major CHD risk factors should focus on effectively addressing these social disparities.

Sociodemographic patterning of non-communicable disease risk factors in rural India: a cross sectional study.

Objectives To investigate the sociodemographic patterning of non-communicable disease risk factors in rural India. Design Cross sectional study. Setting About 1600 villages from 18 states in India. Most were from four large states due to a convenience sampling strategy. Participants 1983 (31% women) people aged 20–69 years (49% response rate). Main outcome measures Prevalence of tobacco use, alcohol use, low fruit and vegetable intake, low physical activity, obesity, central adiposity, hypertension, dyslipidaemia, diabetes, and underweight. Results Prevalence of most risk factors increased with age. Tobacco and alcohol use, low intake of fruit and vegetables, and underweight were more common in lower socioeconomic positions; whereas obesity, dyslipidaemia, and diabetes (men only) and hypertension (women only) were more prevalent in higher socioeconomic positions. For example, 37% (95% CI 30% to 44%) of men smoked tobacco in the lowest socioeconomic group compared with 15% (12% to 17%) in the highest, while 35% (30% to 40%) of women in the highest socioeconomic group were obese compared with 13% (7% to 19%) in the lowest. The age standardised prevalence of some risk factors was: tobacco use (40% (37% to 42%) men, 4% (3% to 6%) women); low fruit and vegetable intake (69% (66% to 71%) men, 75% (71% to 78%) women); obesity (19% (17% to 21%) men, 28% (24% to 31%) women); dyslipidaemia (33% (31% to 36%) men, 35% (31% to 38%) women); hypertension (20% (18% to 22%) men, 22% (19% to 25%) women); diabetes (6% (5% to 7%) men, 5% (4% to 7%) women); and underweight (21% (19% to 23%) men, 18% (15% to 21%) women). Risk factors were generally more prevalent in south Indians compared with north Indians. For example, the prevalence of dyslipidaemia was 21% (17% to 33%) in north Indian men compared with 33% (29% to 38%) in south Indian men, while the prevalence of obesity was 13% (9% to 17%) in north Indian women compared with 24% (19% to 30%) in south Indian women. Conclusions The prevalence of most risk factors was generally high across a range of sociodemographic groups in this sample of rural villagers in India; in particular, the prevalence of tobacco use in men and obesity in women was striking. However, given the limitations of the study (convenience sampling design and low response rate), cautious interpretation of the results is warranted. These data highlight the need for careful monitoring and control of non-communicable disease risk factors in rural areas of India.

Size at Birth, Weight Gain in Infancy and Childhood, and Adult Diabetes Risk in Five Low- or Middle-Income Country Birth Cohorts

OBJECTIVE We examined associations of birth weight and weight gain in infancy and early childhood with type 2 diabetes (DM) risk in five cohorts from low- and middle-income countries. RESEARCH DESIGN AND METHODS Participants were 6,511 young adults from Brazil, Guatemala, India, the Philippines, and South Africa. Exposures were weight at birth, at 24 and 48 months, and adult weight, and conditional weight gain (CWG, deviation from expected weight gain) between these ages. Outcomes were adult fasting glucose, impaired fasting glucose or DM (IFG/DM), and insulin resistance homeostasis model assessment (IR-HOMA, three cohorts). RESULTS Birth weight was inversely associated with adult glucose and risk of IFG/DM (odds ratio 0.91[95% CI 0.84–0.99] per SD). Weight at 24 and 48 months and CWG 0–24 and 24–48 months were unrelated to glucose and IFG/DM; however, CWG 48 months–adulthood was positively related to IFG/DM (1.32 [1.22–1.43] per SD). After adjusting for adult waist circumference, birth weight, weight at 24 and 48 months and CWG 0–24 months were inversely associated with glucose and IFG/DM. Birth weight was unrelated to IR-HOMA, whereas greater CWG at 0–24 and 24–48 months and 48 months–adulthood predicted higher IR-HOMA (all P < 0.001). After adjusting for adult waist circumference, birth weight was inversely related to IR-HOMA. CONCLUSIONS Lower birth weight and accelerated weight gain after 48 months are risk factors for adult glucose intolerance. Accelerated weight gain between 0 and 24 months did not predict glucose intolerance but did predict higher insulin resistance.

Homocysteine levels are associated with MTHFR A1298C polymorphism in Indian population.

AbstractAn elevated level of homocysteine is an independent risk factor for cardiovascular diseases and is associated with other complex disorders. Homocysteine levels can be elevated due to dietary and/or genetic factors. A majority of Indian population have a low level of vitamin B12 (presumably due to vegetarian diet)—a critical nutritional factor, deficiency of which results in hyperhomocysteinemia. Hence, polymorphisms in the genes responsible for homocysteine metabolism can be perceived to have a greater impact in relation to hyperhomocysteinemia in Indian population. For this reason, the effects of diet and/or methylenetetrahydrofolate reductase (MTHFR) polymorphism were assessed in 200 individuals having varying homocysteine levels. Homocysteine levels were significantly elevated in individuals adhering to a vegetarian diet (P=0.019) or having MTHFR A1298C polymorphism (P=0.006). The minor allele frequency (MAF) of MTHFR C677T and A1298C was 0.15 and 0.44 respectively in this cohort. Since the MAF of these polymorphisms differed considerably from Caucasian and other Asian populations, frequencies of these polymorphisms were also determined in more than 400 individuals from different ethnic populations, selected from the entire country based on their geographical location and linguistic lineage, and was found to be similar to that of our cohort. The fact that MTHFR A1298C polymorphism is significantly associated with homocysteine levels, and that the CC genotype is present at a higher frequency in the Indian population, makes it extremely relevant in terms of its potential impact on hyperhomocysteinemia.

Myocardial injury in coronary artery bypass grafting: On-pump versus off-pump comparison by measuring high-sensitivity C-reactive protein, cardiac troponin I, heart-type fatty acid-binding protein, creatine kinase- MB, and myoglobin release

OBJECTIVES We sought to investigate the release pattern of different cardiac biomarkers (high-sensitivity C-reactive protein, cardiac troponin I, heart-type fatty acid-binding protein, creatine kinase-MB, and myoglobin) and to establish the diagnostic discrimination limits of each marker protein to evaluate perioperative myocardial injury in patients undergoing coronary artery bypass grafting with or without cardiopulmonary bypass. METHODS Fifty patients were randomly assigned to on-pump or off-pump coronary artery bypass grafting. All cardiac biomarkers were measured in serial venous blood samples drawn before heparinization in both groups and after aortic unclamping at 1, 2, 4, 8, 24, 48, and 72 hours in the on-pump group. In the off-pump group samples were taken after the last distal anastomosis and at same time intervals as in the on-pump group. RESULTS The total amount of heart-type fatty acid-binding protein, cardiac troponin I, and high-sensitivity C-reactive protein released was significantly higher in the on-pump group than in the off-pump group. Receiver operating characteristic curve analysis of cardiac biomarkers indicated cardiac troponin I and heart-type fatty acid-binding protein as the superior diagnostic discriminators of myocardial injury, with an optimal cutoff value of greater than 0.92 ng/mL (area under the curve, 0.95 [95% CI, 0.88-1.00]; sensitivity, 92%; specificity, 92%; likelihood ratio [+], 11.50) and greater than 6.8 ng/mL (area under the curve, 0.94 [95% CI, 0.88-1.00]; sensitivity, 88%; specificity, 88%; likelihood ratio [+], 7.33), respectively. Logistic regression analysis revealed that patients with increased cardiac troponin I levels of greater than 0.92 ng/mL and heart-type fatty acid-binding protein levels of greater than 6.8 ng/mL were at 132.25 (95% confidence interval, 17.14-1020.49) times and 53.77 (95% confidence interval, 9.76-296.12) times higher risk of myocardial injury after on-pump coronary artery bypass grafting. CONCLUSIONS Off-pump coronary artery bypass grafting provides better myocardial protection than on-pump coronary artery bypass grafting. Cardiac troponin I and heart-type fatty acid-binding protein, but not high-sensitivity C-reactive protein, served as superior diagnostic discriminators of perioperative myocardial damage after on-pump coronary artery bypass grafting.

Prevalence and determinants of diabetes mellitus in the Indian industrial population

Aim   To highlight the regional difference in the prevalence of diabetes mellitus (DM) and to explore determinants in variability in the Indian industrial population.

Association Between Urban Life-Years and Cardiometabolic Risk The Indian Migration Study

Urban living is associated with an increase in cardiometabolic risks, but the speed at which these risks are accrued over time is unknown. Using a cross-sectional sibling-pair design, the authors surveyed migrant factory workers and their spouses from 4 cities in India together with their rural-dwelling siblings and examined the associations between urban life-years and cardiometabolic risk factors. Data on 4,221 participants (39% women; mean age = 41 years) were available (2005–2007). In regression models, a 2-slope pattern for body fat (with a marked shift at 10 years) was found, whereas a common slope could be accepted for other risk factors. In men, the regression coefficients (per decade of urban life) were 2.5% in the first decade and 0.1% thereafter for body fat; 1.4 mm Hg for systolic blood pressure; and 7% for fasting insulin. Age, gender, marital status, household structure, and occupation did not influence the patterns appreciably; however, stronger gradients for adiposity were noted in migrants from lower socioeconomic positions. The findings suggest that body fat increases rapidly when one first moves to an urban environment, whereas other cardiometabolic risk factors evolve gradually. Public health interventions focused on the control of obesity in newer migrants to urban areas, particularly those from lower socioeconomic positions, may be beneficial.