Sib-recruitment for studying migration and its impact on obesity and diabetes

Sex Differences in Bone Health Among Indian Older Adults with Obesity, Sarcopenia, and Sarcopenic Obesity

Age-related changes in fat and lean mass contribute to bone health, but these associations may be influenced by sex and ethnicity. This study investigated sex-specific associations of obesity and sarcopenia with bone mineral density (BMD) and bone mineral apparent density (BMAD) among Indian older adults. 1057 adults aged ≥ 50 years were included. Dual-energy X-ray absorptiometry (DXA) measured BMD at the hip, spine and whole-body, and BMAD was calculated as BMD/√bone area. Obesity was defined by body fat percentage (cut points; > 25% for men and > 35% for women), and sarcopenia was defined using the revised Asian Working Group for Sarcopenia classification with low hand grip strength (< 28 kg for men and < 18 kg for women) and appendicular lean mass index (< 7.0 kg/m² for men and < 5.4 kg/m² for women). Participants were classified into four groups: controls (no obesity or sarcopenia), obesity, sarcopenia, or sarcopenic obesity. Linear regression (β-coefficients and 95%CI) analyses were performed with adjustments for age, smoking status, protein intake, and socioeconomic status. Prevalence of sarcopenia (37%) and sarcopenic obesity (6%) were higher in men than women (17% and 4%, respectively). Compared with controls, men with obesity had lower whole-body BMD and BMAD, but women with obesity had higher hip and spine BMD and BMAD (all p < 0.05). Men, but not women, with sarcopenic obesity, had lower hip and whole-body BMD and BMAD (all p < 0.05) than controls. Men with sarcopenia had lower BMD and BMAD at the hip only, whereas women had lower BMD at all three sites and had lower BMAD at the hip and spine (all p < 0.05), compared with controls. Obesity, sarcopenia, and sarcopenic obesity have sex-specific associations with BMD and BMAD in Indian older adults. With the aging population in India, it is important to understand how body composition contributes to poor bone health among older adults.

Prevalence of Sarcopenia and Relationships Between Muscle and Bone in Indian Men and Women

Both ethnicity and age are important determinants of musculoskeletal health. We aimed to determine the prevalence of sarcopenia, assess the suitability of current diagnostic guidelines, and explore muscle-bone relationships in adults from India. A total of 1009 young (20-35 years) and 1755 older (> 40 years) men and women from existing studies were collated and pooled for the analysis. Dual-energy x-ray absorptiometry measured areal bone mineral density (aBMD) at the hip and spine, and fat and lean mass; hand dynamometer measured hand grip strength (HGS). Indian-specific cut-points for appendicular lean mass (ALM), ALM index (ALMI) and HGS were calculated from young Indian (-2SD mean) populations. Sarcopenia was defined using cut-points from The Foundations for the National Institutes of Health (FNIH), revised European Working Group on Sarcopenia in Older People (EWGSOP2), Asian Working Group for Sarcopenia (AWGS), and Indian-specific cut-points. Low lean mass cut-points were then compared for their predictive ability in identifying low HGS. The relationship between muscle variables (ALM, ALMI, HGS) and aBMD was explored, and sex differences were tested. Indian-specific cut-points (men-HGS:22.93 kg, ALM:15.41 kg, ALMI:6.03 kg/m²; women-HGS:10.76 kg, ALM:9.95 kg, ALMI:4.64 kg/m²) were lower than existing definitions. The Indian-specific definition had the lowest, while EWGSOP2 ALMI had the highest predictive ability in detecting low HGS (men:AUC = 0.686, women:AUC = 0.641). There were sex differences in associations between aBMD and all muscle variables, with greater positive associations in women than in men. The use of appropriate cut-points for diagnosing low lean mass and physical function is necessary in ethnic populations for accurate sarcopenia assessment. Muscle-bone relationships are more tightly coupled during ageing in Indian women than men.

Relative contribution of diet and physical activity to increased adiposity among rural to urban migrants in India: A cross-sectional study

BACKGROUND

In common with many other low- and middle-income countries (LMICs), rural to urban migrants in India are at increased risk of obesity, but it is unclear whether this is due to increased energy intake, reduced energy expenditure, or both. Knowing this and the relative contribution of specific dietary and physical activity behaviours to greater adiposity among urban migrants could inform policies for control of the obesity epidemic in India and other urbanising LMICs. In the Indian Migration Study, we previously found that urban migrants had greater prevalence of obesity and diabetes compared with their nonmigrant rural-dwelling siblings. In this study, we investigated the relative contribution of energy intake and expenditure and specific diet and activity behaviours to greater adiposity among urban migrants in India.

METHODS AND FINDINGS

The Indian Migration Study was conducted between 2005 and 2007. Factory workers and their spouses from four cities in north, central, and south of India, together with their rural-dwelling siblings, were surveyed. Self-reported data on diet and physical activity was collected using validated questionnaires, and adiposity was estimated from thickness of skinfolds. The association of differences in dietary intake, physical activity, and adiposity between siblings was examined using multivariable linear regression. Data on 2,464 participants (median age 43 years) comprised of 1,232 sibling pairs (urban migrant and their rural-dwelling sibling) of the same sex (31% female) were analysed. Compared with the rural siblings, urban migrants had 18% greater adiposity, 12% (360 calories/day) more energy intake, and 18% (11 kilojoules/kg/day) less energy expenditure (P < 0.001 for all). Energy intake and expenditure were independently associated with increased adiposity of urban siblings, accounting for 4% and 6.5% of adiposity difference between siblings, respectively. Difference in dietary fat/oil (10 g/day), time spent engaged in moderate or vigorous activity (69 minutes/day), and watching television (30 minutes/day) were associated with difference in adiposity between siblings, but no clear association was observed for intake of fruits and vegetables, sugary foods and sweets, cereals, animal and dairy products, and sedentary time. The limitations of this study include a cross-sectional design, systematic differences in premigration characteristics of migrants and nonmigrants, low response rate, and measurement error in estimating diet and activity from questionnaires.

CONCLUSIONS

We found that increased energy intake and reduced energy expenditure contributed equally to greater adiposity among urban migrants in India. Policies aimed at controlling the rising prevalence of obesity in India and potentially other urbanising LMICs need to be multicomponent, target both energy intake and expenditure, and focus particularly on behaviours such as dietary fat/oil intake, time spent on watching television, and time spent engaged in moderate or vigorous intensity physical activity.

Investigating associations between rural-to-urban migration and cardiometabolic disease in Malawi: a population-level study

Background

The extent to which rural-to-urban migration affects risk for cardiometabolic diseases (CMD) in Africa is not well understood. We investigated prevalence and risk for obesity, diabetes, hypertension and precursor conditions by migration status.

Methods

In a cross-sectional survey in Malawi (February 2013–March 2017), 13 903 rural, 9929 rural-to-urban migrant and 6741 urban residents (≥18 years old) participated. We interviewed participants, measured blood pressure and collected anthropometric data and fasting blood samples to estimate population prevalences and odds ratios, using negative binomial regression, for CMD, by migration status. In a sub-cohort of 131 rural–urban siblings-sets, migration-associated CMD risk was explored using conditional Poisson regression.

Results

In rural, rural-to-urban migrant and urban residents, prevalence estimates were; 8.9, 20.9 and 15.2% in men and 25.4, 43.9 and 39.3% in women for overweight/obesity; 1.4, 2.9 and 1.9% in men and 1.5, 2.8 and 1.7% in women for diabetes; and 13.4, 18.8 and 12.2% in men and 13.7, 15.8 and 10.2% in women for hypertension. Rural-to-urban migrants had the greatest risk for hypertension (adjusted relative risk for men 1.18; 95% confidence interval 1.04–1.34 and women 1.17: 95% confidence interval 1.05–1.29) and were the most screened, diagnosed and treated for CMD, compared with urban residents. Within sibling sets, rural-to-urban migrant siblings had a higher risk for overweight and pre-hypertension, with no evidence for differences by duration of stay.

Conclusions

Rural-to-urban migration is associated with increased CMD risk in Malawi. In a poor country experiencing rapid urbanization, interventions for the prevention and management of CMD, which reach migrant populations, are needed.

Causal relationships between lipid and glycemic levels in an Indian population: A bidirectional Mendelian randomization approach

BACKGROUND

Dyslipidemia and abnormal glycemic traits are leading causes of morbidity and mortality. Although the association between the two traits is well established, there still exists a gap in the evidence for the direction of causality.

OBJECTIVE

This study aimed to examine the direction of the causal relationship between lipids and glycemic traits in an Indian population using bidirectional Mendelian randomization (BMR).

METHODS

The BMR analysis was conducted on 4900 individuals (2450 sib-pairs) from the Indian Migration Study. Instrument variables were generated for each lipid and glycemic trait (fasting insulin, fasting glucose, HOMA-IR, HOMA-β, LDL-cholesterol, HDL-cholesterol, total cholesterol and triglycerides) to examine the causal relationship by applying two-stage least squares (2SLS) regression in both directions.

RESULTS

Lipid and glycemic traits were found to be associated observationally, however, results from 2SLS showed that only triglycerides, defined by weighted genetic risk score (wGRS) of 3 SNPs (rs662799 at APOAV, rs780094 at GCKR and rs4420638 at APOE/C1/C4), were observed to be causally effecting 1.15% variation in HOMA-IR (SE = 0.22, P = 0.010), 1.53% in HOMA- β (SE = 0.21, P = 0.001) and 1.18% in fasting insulin (SE = 0.23, P = 0.009). No evidence for a causal effect was observed in the reverse direction or between any other lipid and glycemic traits.

CONCLUSION

The study findings suggest that triglycerides may causally impact various glycemic traits. However, the findings need to be replicated in larger studies.

Association between migration and physical activity among medical students from a university located in Lima, Peru

Objective

To evaluate the association between migration and physical activity among medical students from a university located in Lima, Peru.

Methods

A cross-sectional study was conducted among second-year medical students from a Peruvian university. Data on moderate- to vigorous-intensity physical activity (MVPA) and migration features were obtained through a self-report questionnaire. To assess the associations of interest, prevalence ratios (PR) along with their 95% confidence intervals (95% CI) were calculated using Poisson regression with robust variances.

Results

We analyzed data from 312 students (54.5% were women, mean age: 19.0 years, standard deviation: 1.4 years), 90 (28.9%) students performed MVPA for ≥150 minutes/week, 118 (37.8%) performed MVPA for ≤30 minutes/week, and 114 (36.7%) were migrants. Being a migrant was not associated with performing MVPA for ≤30 nor ≥150 minutes/week. However, adjusted analysis showed that the frequency of performing MVPA for ≤30 minutes/week was greater among those who migrated less than five years ago (PR: 1.43; 95% CI: 1.05–1.93) and among those who migrated to continue their studies (PR: 1.44; 95% CI: 1.06–1.94), compared to non-migrants.

Conclusion

In our population, being a migrant was not associated with physical activity. However, low physical activity was more prevalent among recent migrants and among those who had migrated to study, compared to non-migrants.

Impact of rural-urban environment on metabolic profile and response to a 5-day high-fat diet

Epidemiological studies have indicated that rural living might be protective against type 2 diabetes development. We compared the metabolic profile and response to a short-term high-fat high-calorie diet (HFD) of men with the same genetic background living in an urban and rural area of Indonesia. First, we recruited 154 Floresian male subjects (18–65 years old), of whom 105 lived in a rural area (Flores) and 49 had migrated and lived in urban area (Jakarta) for more than 1 year. The urban group had significantly higher whole-body insulin resistance (IR), as assessed by homeostatic-model-assessment of IR (HOMA-IR), [mean difference (95% CI), p-value: 0.10 (0.02–0.17), p = 0.01]. Next, we recruited 17 urban and 17 rural age-and-BMI-matched healthy-young-male volunteers for a 5-day HFD challenge. The HOMA-IR increased in both groups similarly −0.77 (−2.03–0.49), p = 0.22]. Neither rural living nor factors associated with rural living, such as current helminth infection or total IgE, were associated with protection against acute induction of IR by HFD.

Association between empirically derived dietary patterns with blood lipids, fasting blood glucose and blood pressure in adults - the India migration study

BACKGROUND

Dietary patterns (DPs) in India are heterogenous. To date, data on association of indigenous DPs in India with risk factors of nutrition-related noncommunicable diseases (cardiovascular disease and diabetes), leading causes of premature death and disability, are limited. We aimed to evaluate the associations of empirically-derived DPs with blood lipids, fasting glucose and blood pressure levels in an adult Indian population recruited across four geographical regions of India.

METHODS

We used cross-sectional data from the Indian Migration Study (2005-2007). Study participants included urban migrants, their rural siblings and urban residents and their urban siblings from Lucknow, Nagpur, Hyderabad and Bangalore (n = 7067, mean age 40.8 yrs). Information on diet (validated interviewer-administered, 184-item semi-quantitative food frequency questionnaire), tobacco consumption, alcohol intake, physical activity, medical history, as well as anthropometric measurements were collected. Fasting-blood samples were collected for estimation of blood lipids and glucose. Principal component analysis (PCA) was used to identify major DPs based on eigenvalue> 1 and component interpretability. Robust standard error multivariable linear regression models were used to investigate the association of DPs (tertiles) with total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), triglycerides, fasting-blood glucose (FBG), systolic and diastolic blood pressure (SBP and DBP) levels.

RESULTS

Three major DPs were identified: 'cereal-savoury' (cooked grains, rice/rice-based dishes, snacks, condiments, soups, nuts), 'fruit-vegetable-sweets-snacks' (Western cereals, vegetables, fruit, fruit juices, cooked milk products, snacks, sugars, sweets) and 'animal food' (red meat, poultry, fish/seafood, eggs) patterns. High intake of the 'animal food' pattern was positively associated with levels of TC (β = 0.10 mmol/L; 95% CI: 0.02, 0.17 mmol/L; p-trend = 0.013); LDL-C (β = 0.07 mmol/L; 95% CI: 0.004, 0.14 mmol/L; p-trend = 0.041); HDL-C (β = 0.02 mmol/L; 95% CI: 0.004, 0.04 mmol/L; p-trend = 0.016), FBG: (β = 0.09 mmol/L; 95% CI: 0.01, 0.16 mmol/L; p-trend = 0.021) SBP (β = 1.2 mm/Hg; 95% CI: 0.1, 2.3 mm/Hg; p-trend = 0.032); DBP: (β = 0.9 mm/Hg; 95% CI: 0.2, 1.5 mm/Hg; p-trend = 0.013). The 'cereal-savoury' and 'fruit-vegetable-sweets-snacks' patterns showed no association with any parameter except for a positive association with diastolic blood pressure for high intake of 'fruits-vegetables-sweets-snacks' pattern.

CONCLUSION

Our results indicate positive associations of the 'animal food' pattern with cardio-metabolic risk factors in India. Further longitudinal assessments of dietary patterns in India are required to validate the findings.

Duration of US Residence and Obesity Risk in NYC Chinese Immigrants

We evaluated whether duration of time in the US is associated with obesity risk in NYC Chinese immigrants. We analyzed cross-sectional survey data on 2072 men and women. Duration of US residence was categorized into ≤5, 6-15, and 15 years and over. Obesity was defined using WHO Asian standards: BMI of 27.5 kg/m(2) or greater. Diet and physical activity (PA) were assessed as potential explanatory variables. After adjusting for covariates, increased time in the US was associated with an increased obesity risk (OR 1.49; 95 % CI 1.06, 2.08 for 15 years or more vs. ≤5 years); and in separate analysis, with having reported no work related PA (OR 0.76; 95 % CI 0.59, 0.99). Findings suggest that increased time living in the US is associated with an increased obesity risk, a finding possibly explained by a shift to more sedentary lifestyle characteristic of the transition of immigrants to the US.

Effect of marital distance on birth weight and length of offspring

Marital distance (MD), the geographical distance between birthplaces of spouses, is considered an agent favouring occurrence of heterosis and can be used as a measure of its level. Heterosis itself is a phenomenon of hybrid vigour and seems to be an important factor regulating human growth and development. The main aim of the study is to examine potential effects of MD on birth weight and length of offspring, controlling for socioeconomic status (SES), mother’s age and birth order. Birth weight (2562 boys and 2572 girls) and length (2526 boys, 2542 girls) of children born in Ostrowiec Swietokrzyski (Poland) in 1980, 1983, 1985 and 1988 were recorded during cross-sectional surveys carried out between 1994-1999. Data regarding the socio-demographic variables of families were provided by the parents. Analysis of covariance showed that MD significantly affected both birth weight and length, allowing for sex, birth order, mother’s age and SES of family. For both sexes, a greater marital distance was associated with a higher birth weight and a longer birth length. Our results support the hypothesis that a greater geographical distance between the birth places of parents may contribute to the heterosis effects in offspring. Better birth outcomes may be one of the manifestations of these effects.

The water use of Indian diets and socio-demographic factors related to dietary blue water footprint

Agriculture accounts for ~90% of India's fresh water use, and there are concerns that future food production will be threatened by insufficient water supply of adequate quality. This study aimed to quantify the water required in the production of diets in India using the water footprint (WF) assessment method. The socio-demographic associations of dietary WFs were explored using mixed effects regression models with a particular focus on blue (irrigation) WF given the importance for Indian agriculture. Dietary data from ~7000 adults living in India were matched to India-specific WF data for food groups to quantify the blue and green (rainfall) WF of typical diets. The mean blue and green WF of diets was 737l/capita/day and 2531l/capita/day, respectively. Vegetables had the lowest WFs per unit mass of product, while roots/tubers had the lowest WFs per unit dietary energy. Poultry products had the greatest blue WFs. Wheat and rice contributed 31% and 19% of the dietary blue WF respectively. Vegetable oils were the highest contributor to dietary green WF. Regional variation in dietary choices meant large differences in dietary blue WFs, whereby northern diets had nearly 1.5 times greater blue WFs than southern diets. Urban diets had a higher blue WF than rural diets, and a higher standard of living was associated with larger dietary blue WFs. This study provides a novel perspective on the WF of diets in India using individual-level dietary data, and demonstrates important variability in WFs due to different food consumption patterns and socio-demographic characteristics. Future dietary shifts towards patterns currently consumed by individuals in higher income groups, would likely increase irrigation requirements putting substantial pressure on India's water resources.

Dietary patterns and non-communicable disease risk in Indian adults: secondary analysis of Indian Migration Study data

Objective

Undernutrition and non-communicable disease (NCD) are important public health issues in India, yet their relationship with dietary patterns is poorly understood. The current study identified distinct dietary patterns and their association with micronutrient undernutrition (Ca, Fe, Zn) and NCD risk factors (underweight, obesity, waist:hip ratio, hypertension, total:HDL cholesterol, diabetes).

Design

Data were from the cross-sectional Indian Migration Study, including semi-quantitative FFQ. Distinct dietary patterns were identified using finite mixture modelling; associations with NCD risk factors were assessed using mixed-effects logistic regression models.

Setting

India.

Subjects

Migrant factory workers, their rural-dwelling siblings and urban non-migrants. Participants (7067 adults) resided mainly in Karnataka, Andhra Pradesh, Maharashtra and Uttar Pradesh.

Results

Five distinct, regionally distributed, dietary patterns were identified, with rice-based patterns in the south and wheat-based patterns in the north-west. A rice-based pattern characterised by low energy consumption and dietary diversity (‘Rice & low diversity’) was consumed predominantly by adults with little formal education in rural settings, while a rice-based pattern with high fruit consumption (‘Rice & fruit’) was consumed by more educated adults in urban settings. Dietary patterns met WHO macronutrient recommendations, but some had low micronutrient contents. Dietary pattern membership was associated with several NCD risk factors.

Conclusions

Five distinct dietary patterns were identified, supporting sub-national assessments of the implications of dietary patterns for various health, food system or environment outcomes.

Prevalence and severity of depressive symptoms in relation to rural-to-urban migration in India: a cross-sectional study

Background

Migration is a major life event, which may also be a risk factor for depression. However, little is known regarding the relationship between these phenomena in low and middle income settings. This study explores the frequency and severity of depressive symptoms among rural-to-urban migrants compared to permanent rural and to urban residents in India.

Methods

We assessed 884 subjects; urban non-migrants (n = 159), urban migrants (n = 461) and rural non-migrants (n = 264) in Hyderabad, India, in 2009–2010. The frequency and severity of depressive symptoms was assessed with the validated Telugu version of the Brief Patient Health Questionnaire. Multivariable logistic regression was used to examine the association between the presence of depressive symptoms and migration status while adjusting for gender, age and several sociodemographic and health-related parameters using Stata v.12.

Results

The prevalence of mild to severe depressive symptoms was higher in women (11.3, 95 % confidence interval (CI) 8.3–14.3 %) compared to men (5.8 %, 95 % CI 3.7–7.9 %). Rural residents reported the highest prevalence of mild to severe depressive symptoms (women: 16.7 %, 95 % CI 9.8–23.5 %; men: 8.0 %, 95 % CI 3.7–12.3 %). Among women, the lowest prevalence was reported by migrants (8.2 %, 95 % CI 4.6–11.9 %). Among men, prevalence was similar in migrants (5.0 %, 95 % CI 2.2–7.7 %) and urban residents (3.9 %, 95 % CI 0–8.3 %). Multivariable logistic regression analyses showed no evidence for increased prevalence of mild to severe depressive symptoms among migrants compared to either rural or urban residents.

Conclusions

There was no evidence for an increased prevalence of mild to severe depressive symptoms among rural-urban migrants compared to rural or urban residents.

Legume consumption and its association with fasting glucose, insulin resistance and type 2 diabetes in the Indian Migration Study

Objective

Legume consumption is associated with lower fasting glucose (FG) and insulin levels in nutrition trials and lower CVD mortality in large-scale epidemiological studies. In India, legumes are widely consumed in various preparations, yet no epidemiological study has evaluated the association of legumes with FG levels, insulin resistance and diabetes risk. The present study aimed to fill this gap.

Design

Fasting blood samples, in-person interviews to obtain information on demographic/socio-economic factors, physical activity, alcohol and tobacco use, and anthropometric measurements were collected. Dietary intakes were assessed by an interviewer-administered, validated, semi-quantitative FFQ.

Setting

Lucknow, Nagpur, Hyderabad and Bangalore, India.

Subjects

Men and women (n 6367) aged 15–76 years – urban residents, urban migrants and their rural siblings.

Results

In multivariate random-effects models adjusted for age, BMI, total energy intake, macronutrients, physical activity and rural/migration status, daily legume consumption was not associated with FG (P-for-trend=0·78), insulin resistance (homeostasis model assessment score; P-for-trend=0·73) or the prevalence of type 2 diabetes mellitus (P-for-trend=0·41). Stratified analyses by vegetarian diet and migration status did not change the findings. Inverse associations between legumes and FG emerged for participants with lower BMI and higher carbohydrate, protein, fat and sugar intakes.

Conclusions

Although legumes are essential in traditional Indian diets, as well as in prudent and Mediterranean diets in the West, we did not find an association between legumes and markers of glycaemic control, insulin resistance or diabetes, except for subgroups based on BMI and macronutrient intake. The ubiquitous presence and complexity of legume preparations in Indian diets may contribute to these findings.

Hypertension and diabetes in Africa: design and implementation of a large population-based study of burden and risk factors in rural and urban Malawi

Background

The emerging burden of cardiovascular disease and diabetes in sub-Saharan Africa threatens the gains made in health by the major international effort to combat infectious diseases. There are few data on distribution of risk factors and outcomes in the region to inform an effective public health response. A comprehensive research programme is being developed aimed at accurately documenting the burden and drivers of NCDs in urban and rural Malawi; to design and test intervention strategies. The programme includes population surveys of all people aged 18 years and above, linking individuals with newly diagnosed hypertension and diabetes to healthcare and supporting clinical services. The successes, challenges and lessons learnt from the programme to date are discussed.

Results

Over 20,000 adults have been recruited in rural Karonga and urban Lilongwe. The urban population is significantly younger and wealthier than the rural population. Employed urban individuals, particularly males, give particular recruitment challenges; male participation rates were 80.3 % in the rural population and 43.6 % in urban, whilst female rates were 93.6 and 75.6 %, respectively. The study is generating high quality data on hypertension, diabetes, lipid abnormalities and risk factors.

Conclusions

It is feasible to develop large scale studies that can reliably inform the public health approach to diabetes, cardiovascular disease and other NCDs in Sub-Saharan Africa. It is essential for studies to capture both rural and urban populations to address disparities in risk factors, including age structure. Innovative approaches are needed to address the specific challenge of recruiting employed urban males.

Associations between diet, physical activity and body fat distribution: a cross sectional study in an Indian population

BACKGROUND

Obesity is a growing health problem in India and worldwide, due to changes in lifestyle. This study aimed to explore the independent associations between dietary and physical activity exposure variables and total body fat and distribution in an Indian setting.

METHODS

Individuals who had participated in the Indian Migration Study (IMS) or the Andhra Pradesh Children And Parents' Study (APCAPS), were invited to participate in the Hyderabad DXA Study. Total and abdominal body fat of study participants was measured using DXA scans. Diet and physical activity (PA) levels were measured using questionnaires.

RESULTS

Data on 2208 participants was available for analysis; mean age was 49 yrs in IMS, 21 yrs in APCAPS. Total energy intake was positively associated with total body fat in the APCAPS sample: a 100 kcal higher energy intake was associated with 45 g higher body fat (95% CI 22, 68). In the IMS sample no association was found with total energy intake, but there was a positive association with percent protein intake (1% higher proportion of energy from protein associated with 509 g (95% CI 138,880) higher total body fat). Broadly the same pattern of associations was found with proportion of fat in the abdominal region as the outcome. PA was inversely associated with total body fat in both populations (in APCAPS, one MET-hour higher activity was associated with 46 g (95% CI 12, 81) less body fat; in the IMS it was associated with 145 g less body fat (95% CI 73, 218)). An inverse association was observed between PA and percentage abdominal fat in the IMS but no association was seen in the APCAPS population.

CONCLUSIONS

In this Indian population, there was an inverse association between PA and body fat. Associations between body fat and dietary variables differed between the younger APCAPS population and older IMS population. Further longitudinal research is needed to elucidate causality and directions of these associations across the life course.

Dietary patterns in India and their association with obesity and central obesity

OBJECTIVE

Obesity is a growing problem in India, the dietary determinants of which have been studied using an 'individual food/nutrient' approach. Examining dietary patterns may provide more coherent findings, but few studies in developing countries have adopted this approach. The present study aimed to identify dietary patterns in an Indian population and assess their relationship with anthropometric risk factors.

DESIGN

FFQ data from the cross-sectional sib-pair Indian Migration Study (IMS; n 7067) were used to identify dietary patterns using principal component analysis. Mixed-effects logistic regression was used to examine associations with obesity and central obesity.

SETTING

The IMS was conducted at four factory locations across India: Lucknow, Nagpur, Hyderabad and Bangalore.

SUBJECTS

The participants were rural-to-urban migrant and urban non-migrant factory workers, their rural and urban resident siblings, and their co-resident spouses.

RESULTS

Three dietary patterns were identified: 'cereals-savoury foods' (cooked grains, rice/rice-based dishes, snacks, condiments, soups, nuts), 'fruit-veg-sweets-snacks' (Western cereals, vegetables, fruit, fruit juices, cooked milk products, snacks, sugars, sweets) and 'animal-food' (red meat, poultry, fish/seafood, eggs). In adjusted analysis, positive graded associations were found between the 'animal-food' pattern and both anthropometric risk factors. Moderate intake of the 'cereals-savoury foods' pattern was associated with reduced odds of obesity and central obesity.

CONCLUSIONS

Distinct dietary patterns were identified in a large Indian sample, which were different from those identified in previous literature. A clear 'plant food-based/animal food-based pattern' dichotomy emerged, with the latter being associated with higher odds of anthropometric risk factors. Longitudinal studies are needed to further clarify this relationship in India.

Associations Between Sociodemographic Characteristics, Pre Migratory and Migratory Factors and Psychological Distress Just After Migration and After Resettlement: The Indian Migration Study

BACKGROUND/OBJECTIVES

Migration is suspected to increase the risk for psychological distress for those who enter a new cultural environment. We investigated the association between sociodemographic characteristics, premigratory and migratory factors and psychological distress in rural-to-urban migrants just after migration and after resettlement.

METHODS

Data from the cross-sectional sib-pair designed Indian Migration Study (IMS, 2005-2007) were used. The analysis focused on 2112 participants aged ≥18 years from the total IMS sample (n = 7067) who reported being migrant. Psychological distress was assessed based on the responses of the 7-questions in a five-point scale, where the respondents were asked to report about their feelings now and also asked to recall these feelings when they first migrated. The associations were analyzed using multiple logistic regression models.

RESULTS

High prevalence of psychological distress was found just after migration (7.3%; 95% confidence interval [CI]: 6.2-8.4) than after settlement (4.7%; 95% CI: 3.8-5.6). Push factors as a reason behind migration and not being able to adjust in the new environment were the main correlates of psychological distress among both the male and female migrants, just after migration.

CONCLUSIONS

Rural-urban migration is a major phenomenon in India and given the impact of premigratory and migratory related stressors on mental health, early intervention could prevent the development of psychological distress among the migrants.

The association between a vegetarian diet and cardiovascular disease (CVD) risk factors in India: the Indian Migration Study

Background

Studies in the West have shown lower cardiovascular disease (CVD) risk among people taking a vegetarian diet, but these findings may be confounded and only a minority selects these diets. We evaluated the association between vegetarian diets (chosen by 35%) and CVD risk factors across four regions of India.

Methods

Study participants included urban migrants, their rural siblings and urban residents, of the Indian Migration Study from Lucknow, Nagpur, Hyderabad and Bangalore (n = 6555, mean age-40.9 yrs). Information on diet (validated interviewer-administered semi-quantitative food frequency questionnaire), tobacco, alcohol, physical history, medical history, as well as blood pressure, fasting blood and anthropometric measurements were collected. Vegetarians ate no eggs, fish, poultry or meat. Using robust standard error multivariate linear regression models, we investigated the association of vegetarian diets with blood cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides, fasting blood glucose (FBG), systolic (SBP) and diastolic blood pressure (DBP).

Results

Vegetarians (32.8% of the study population) did not differ from non-vegetarians with respect to age, use of smokeless tobacco, body mass index, and prevalence of diabetes or hypertension. Vegetarians had a higher standard of living and were less likely to smoke, drink alcohol (p<0.0001) and were less physically active (p = 0.04). In multivariate analysis, vegetarians had lower levels of total cholesterol (β = −0.1 mmol/L (95% CI: −0.03 to −0.2), p = 0.006), triglycerides (β = −0.05 mmol/L (95% CI: −0.007 to −0.01), p = 0.02), LDL (β = −0.06 mmol/L (95% CI: −0.005 to −0.1), p = 0.03) and lower DBP (β = −0.7 mmHg (95% CI: −1.2 to −0.07), p = 0.02). Vegetarians also had decreases in SBP (β = −0.9 mmHg (95% CI: −1.9 to 0.08), p = 0.07) and FBG level (β = −0.07 mmol/L (95% CI: −0.2 to 0.01), p = 0.09) when compared to non-vegetarians.

Conclusion

We found beneficial association of vegetarian diet with cardiovascular risk factors compared to non-vegetarian diet.

Association of common genetic variants with lipid traits in the Indian population

Genome-wide association studies (GWAS) have been instrumental in identifying novel genetic variants associated with altered plasma lipid levels. However, these quantitative trait loci have not been tested in the Indian population, where there is a poorly understood and growing burden of cardiometabolic disorders. We present the association of six single nucleotide polymorphisms in 1671 sib pairs (3342 subjects) with four lipid traits: total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C). We also investigated the interaction effects of gender, location, fat intake and physical activity. Each copy of the risk allele of rs964184 at APOA1 was associated with 1.06 mmol/l increase in triglycerides (SE = 0.049; p = 0.006), rs3764261 at CETP with 1.02 mmol/l increase in both total cholesterol (SE = 0.042; p = 0.017) and HDL-C (SE = 0.041; p = 0.008), rs646776 at CELSR2-PSRC1-SORT1 with 0.96 mmol/l decrease in cholesterol (SE = 0.043; p = 0.0003) and 0.15 mmol/l decrease in LDL-C levels (SE = 0.043; p = 0.0003) and rs2954029 at TRIB1 with 1.02 mmol/l increase in HDL-C (SE = 0.039; p = 0.047). A combined risk score of APOA1 and CETP loci predicted an increase of 1.25 mmol/l in HDL-C level (SE = 0.312; p = 0.0007). Urban location and sex had strong interaction effects on the genetic association of most of the studied loci with lipid traits. To conclude, we validated four genetic variants (identified by GWAS in western populations) associated with lipid traits in the Indian population. The interaction effects found here may explain the sex-specific differences in lipid levels and their heritability. Urbanization appears to influence the nature of the association with GWAS lipid loci in this population. However, these findings will require replication in other Indian populations.

Immigrant generation and diabetes risk among Mexican Americans: the Sacramento area Latino study on aging

OBJECTIVES

We examined whether acculturation and immigrant generation, a marker for assimilation, are associated with diabetes risk in an aging Mexican-origin population.

METHODS

We analyzed data on 1789 adults aged 60 to 101 years from the Sacramento Area Latino Study on Aging. We ascertained type 2 diabetes on the basis of diabetic medication use, self-report of physician diagnosis, or a fasting glucose of 126 milligrams/deciliter or greater. Logistic regression modeled prevalent diabetes.

RESULTS

Adjusting for age and gender, we observed significant but divergent associations between immigrant generation, acculturation, and diabetes risk. Relative to first-generation adults, second-generation adults had an odds ratio (OR) of 1.8 (95% confidence interval [CI] = 1.4, 2.4) and third-generation adults had an OR of 2.1 (95% CI = 1.4, 3.1) of having diabetes. Greater US acculturation, however, was associated with a slightly decreased diabetes rate. In the full model adjusting for socioeconomic and lifestyle factors, the association between generation (but not acculturation) and diabetes remained significant.

CONCLUSIONS

Our study lends support to the previously contested notion that assimilation is associated with an increased diabetes risk in Mexican immigrants. Researchers should examine the presence of a causal link between assimilation and health more closely.

Nutritional profile of Indian vegetarian diets--the Indian Migration Study (IMS)

Background

The cardiovascular and other health benefits and potential harms of protein and micronutrient deficiency of vegetarian diets continue to be debated.

Methods

Study participants included urban migrants, their rural siblings and urban residents (n = 6555, mean age - 40.9 yrs) of the Indian Migration Study from Lucknow, Nagpur, Hyderabad and Bangalore. Information on diet (validated interviewer-administered semi-quantitative food frequency questionnaire), tobacco, alcohol, physical activity, medical histories, as well as blood pressure, fasting blood and anthropometric measurements were collected. Nutrient databases were used to calculate nutrient content of regional recipes. Vegetarians ate no eggs, fish, poultry and meat. Using multivariate linear regression with robust standard error model, we compared the macro- and micro-nutrient profile of vegetarian and non-vegetarian diets.

Results

Vegetarians, (32.8% of the population), consumed greater amounts of legumes, vegetables, roots and tubers, dairy and sugar, while non-vegetarians had a greater intake of cereals, fruits, spices, salt (p < 0.01), fats and oils. Vegetarians had a higher socioeconomic status, and were less likely to smoke, drink alcohol (p < 0.0001) and engage in less physical activity (p = 0.04). On multivariate analysis, vegetarians consumed more carbohydrates (β = 7.0 g/day (95% CI: 9.9 to 4.0), p < 0.0001), vitamin C (β = 8.7 mg/day (95% CI: 4.3 to13.0), p < 0.0001) and folate (β = 8.0 mcg/day (95% CI: 3.3 to 12.7), p = 0.001) and lower levels of fat (β = −1.6 g/day (95% CI: −0.62 to −2.7), p = 0.002), protein (β = −6.4 g/day (95% CI: −5.8 to −7.0), p < 0.0001), vitamin B12 (β = −1.4 mcg/day (95% CI: −1.2 to −1.5), p < 0.0001) and zinc (β = −0.6 mg/day (95% CI: −0.4 to −0.7), p < 0.0001).

Conclusion

Overall, Indian vegetarian diets were found to be adequate to sustain nutritional demands according to recommended dietary allowances with less fat. Lower vitamin B12 bio-availability remains a concern and requires exploration of acceptable dietary sources for vegetarians.

Las generaciones de inmigrantes y sus descendientes y el riesgo de diabetes en la población de los Estados Unidos de origen o ascendencia mexicana: el Estudio sobre Envejecimiento en Latinos del Área de Sacramento (estudio SALSA)

Objetivo. Se investigó si la aculturación de los inmigrantes y sus descendientes y la generación a la que pertenecen, un marcador de la asimilación, se relacionan con el riesgo de diabetes en una población de adultos mayores de ascendencia u origen mexicano.

Métodos. Se analizaron los datos sobre 1 789 adultos de 60 a 101 años de edad del Estudio sobre Envejecimiento en Latinos del Área de Sacramento (estudio SALSA). Se determinó la presencia de diabetes tipo 2 con base en el uso de medicamentos antidiabéticos, la mención por el paciente del diagnóstico de un médico, o una glucosa en ayunas de 126 mg/dL o mayor. Se aplicó un modelo de regresión logística para la prevalencia de diabetes.

Resultados. Tras ajustar por edad y sexo, se observaron asociaciones significativas pero divergentes entre las generaciones de inmigrantes y sus descendientes, la aculturación y el riesgo de diabetes. En relación con los adultos de la primera generación, los de la segunda tuvieron una razón de posibilidades (odds ratio, OR) de padecer diabetes de 1,8 (intervalo de confianza [IC] de 95% = 1,4, 2,4) y los adultos de la tercera generación tuvieron una OR de 2,1 (IC de 95% = 1,4, 3,1). Sin embargo, una mayor aculturación a los Estados Unidos se relacionó con una tasa ligeramente menor de diabetes. En el modelo completo, tras la incorporación de ajustes para tener en cuenta los factores socioeconómicos y del modo de vida, la relación entre la generación y la diabetes seguía siendo significativa, no así la relación de esta última con la aculturación.

Conclusiones. El presente estudio respalda la idea, anteriormente cuestionada, de que la asimilación se relaciona con un mayor riesgo de diabetes entre los inmigrantes de origen mexicano. Los investigadores deben analizar más detalladamente la presencia de una relación causal entre la asimilación y la salud.

The effect of rural-to-urban migration on renal function in an Indian population: cross-sectional data from the Hyderabad arm of the Indian Migration Study

Background

Urban migration is associated with an increased risk of hypertension, obesity and diabetes in Indian migrants. This study assessed the relationship between internal migration and renal function in the Hyderabad arm of the Indian Migration Study.

Methods

We assessed 841 subjects; urban non-migrants (n = 158), urban migrants (n = 424) and rural non-migrants (n = 259). Muscle mass was ascertained from DXA scanning. We derived urban life years for urban migrants and rural non-migrants. Multivariable linear regression was used to examine the association between tertiles of urban life years and 4-variable MDRD eGFR using Stata 11.

Results

Mean eGFR was lower in urban non-migrants and urban migrants compared to rural non-migrants. The prevalence of CKD 3-5 was higher in the rural non-migrant population (5.0%) than in the urban non-migrant populations (2.5%) due to a negatively skewed distribution of eGFR in rural non-migrants. As urban life years increased, eGFR declined (p = 0.008) though there was no obvious dose response effect. After adjustment for muscle mass, the association was attenuated and the trend was consistent with chance (p = 0.08). Further adjustment for vascular risk factors weakened the association to a small degree (p = 0.11).

Conclusions

The high prevalence of reduced eGFR in rural areas requires further research. Urbanization was associated with reduced eGFR. This association appears mostly to be due to higher muscle mass with a small contribution from adverse vascular disease risk factors.

Burden of healthcare utilization and out-of-pocket costs among individuals with NCDs in an Indian setting

Non communicable diseases (NCDs) are now the major cause of death and disability worldwide. It increasingly affects people from developing as well as developed countries. Over the coming decades the burden from NCDs is projected to rise particularly fast in the developing world. There is a lack of optimal data collection about the burden of risk factors related to NCDs especially in the developing countries. To assess the burden of healthcare utilization and out-of-pocket costs associated with NCDs in an Indian setting. A cross sectional study was performed to enroll a convenient sample of 166 participants aged 18 years and above from a tertiary hospital in Punjab, a Northern state of India. The data was gathered during the period of Feb 2010-April 2010. A mixed methods approach was used to assess the burden of diabetes, hypertension, high cholesterol, and their associated risk factors. Further we evaluated the burden of healthcare utilization and out-of-pocket costs associated with these conditions using self-reported assessments. Results showed the average age of the participants was 50 years, 63 % (n = 104) were females, 32 % (n = 53) had education less than high school and 20 % (n = 33) had no formal education. About 96 % of the study participants were living with a partner. Majority of the study participants were non-smokers and 17 % (n = 27) of them reported to have history of alcohol consumption. The majority of the participants had access to cell phones (94 %; n = 156) and about 40 % (n = 66) had computers at home. About 33 % (n = 55) of the study participants had some form of previous knowledge of computers. Majority of the study participants went to the private hospital (47.5 %) for seeking healthcare. About 32 % (n = 53) also sought healthcare from some kind of healthcare professional including a primary care doctor or a nurse or even a pharmacist in a village setting. Doctor visits related to diabetes were higher as compared to the individuals either with hypertension or high cholesterol. However; the out-of-pocket costs of the visit to the healthcare professional were much higher for hypertension than for diabetes or high cholesterol. A strengthened surveillance system, effective inter-sectoral action, and improved access to basic healthcare are pivotal to prevent NCDs. A multifaceted NCDs surveillance system could help us measure the burden of risk factors, its associated health care utilization and out of pocket costs, and further facilitate interventions that can guide evidence based decision making.

[Immigrant generation and diabetes risk among Mexican Americans: the Sacramento Area Latino Study on Aging]

OBJECTIVES

We examined whether acculturation and immigrant generation, a marker for assimilation, are associated with diabetes risk in an aging Mexican-origin population.

METHODS

We analyzed data on 1789 adults aged 60 to 101 years from the Sacramento Area Latino Study on Aging. We ascertained type 2 diabetes on the basis of diabetic medication use, self-report of physician diagnosis, or a fasting glucose of 126 milligrams/deciliter or greater. Logistic regression modeled prevalent diabetes.

RESULTS

Adjusting for age and gender, we observed significant but divergent associations between immigrant generation, acculturation, and diabetes risk. Relative to first-generation adults, second-generation adults had an odds ratio (OR) of 1.8 (95% confidence interval [CI] = 1.4, 2.4) and third-generation adults had an OR of 2.1 (95% CI = 1.4, 3.1) of having diabetes. Greater US acculturation, however, was associated with a slightly decreased diabetes rate. In the full model adjusting for socioeconomic and lifestyle factors, the association between generation (but not acculturation) and diabetes remained significant.

CONCLUSIONS

Our study lends support to the previously contested notion that assimilation is associated with an increased diabetes risk in Mexican immigrants. Researchers should examine the presence of a causal link between assimilation and health more closely.

Associations between active travel to work and overweight, hypertension, and diabetes in India: a cross-sectional study

BACKGROUND

Increasing active travel (walking, bicycling, and public transport) is promoted as a key strategy to increase physical activity and reduce the growing burden of noncommunicable diseases (NCDs) globally. Little is known about patterns of active travel or associated cardiovascular health benefits in low- and middle-income countries. This study examines mode and duration of travel to work in rural and urban India and associations between active travel and overweight, hypertension, and diabetes.

METHODS AND FINDINGS

Cross-sectional study of 3,902 participants (1,366 rural, 2,536 urban) in the Indian Migration Study. Associations between mode and duration of active travel and cardiovascular risk factors were assessed using random-effect logistic regression models adjusting for age, sex, caste, standard of living, occupation, factory location, leisure time physical activity, daily fat intake, smoking status, and alcohol use. Rural dwellers were significantly more likely to bicycle (68.3% versus 15.9%; p<0.001) to work than urban dwellers. The prevalence of overweight or obesity was 50.0%, 37.6%, 24.2%, 24.9%; hypertension was 17.7%, 11.8%, 6.5%, 9.8%; and diabetes was 10.8%, 7.4%, 3.8%, 7.3% in participants who travelled to work by private transport, public transport, bicycling, and walking, respectively. In the adjusted analysis, those walking (adjusted risk ratio [ARR] 0.72; 95% CI 0.58-0.88) or bicycling to work (ARR 0.66; 95% CI 0.55-0.77) were significantly less likely to be overweight or obese than those travelling by private transport. Those bicycling to work were significantly less likely to have hypertension (ARR 0.51; 95% CI 0.36-0.71) or diabetes (ARR 0.65; 95% CI 0.44-0.95). There was evidence of a dose-response relationship between duration of bicycling to work and being overweight, having hypertension or diabetes. The main limitation of the study is the cross-sectional design, which limits causal inference for the associations found.

CONCLUSIONS

Walking and bicycling to work was associated with reduced cardiovascular risk in the Indian population. Efforts to increase active travel in urban areas and halt declines in rural areas should be integral to strategies to maintain healthy weight and prevent NCDs in India. Please see later in the article for the Editors' Summary.

Association between milk and milk product consumption and anthropometric measures in adult men and women in India: a cross-sectional study

BACKGROUND

The nutritional aetiology of obesity remains unclear, especially with regard to the role of dairy products in developing countries.

OBJECTIVE

To examine whether milk/milk product consumption is associated with obesity and high waist circumference among adult Indians.

METHODS

Information on plain milk, tea, curd and buttermilk/lassi consumption assessed using a Food Frequency Questionnaire was obtained from the cross-sectional sib-pair designed Indian Migration Study (3698 men and 2659 women), conducted at four factory locations across north, central and south India. The anthropometric measures included were Body Mass Index (BMI) and Waist Circumference (WC). Mixed-effect logistic regression models were conducted to accommodate sib-pair design and adjust for potential confounders.

RESULTS

After controlling for potential confounders, the risk of being obese (BMI ≥ 25 kg/m(2)) was lower among women (OR = 0.57;95%CI:0.43-0.76;p ≤ 0.0001) and men (OR = 0.67;95%CI: 0.51-0.87;p = 0.005), and the risk of a high WC (men: >90 cm; women: >80 cm) was lower among men (OR = 0.71;95%CI:0.54-0.93;p = 0.005) and women (OR = 0.79;95%CI:0.59-1.05;p>0.05) who consume ≥1 portions of plain milk daily than those who do not consume any milk. The inverse association between daily plain milk consumption and obesity was also confirmed in sibling-pair analyses. Daily tea consumption of ≥ 1 portion was associated with obesity (OR = 1.51;95%CI:1.00-2.25;p>0.050) and high WC (OR = 1.65;95%CI:1.08-2.51;p>0.019) among men but not among women but there was no strong evidence of association of curd and buttermilk/lassi consumption with obesity and high waist circumference among both men and women.

CONCLUSIONS

The independent, inverse association of daily plain milk consumption with the risk of being obese suggests that high plain milk intake may lower the risk of obesity in adult Indians. However, this is an observational finding and uncontrolled confounding cannot be excluded as an explanation for the association. Therefore, confirmatory studies are needed to clarify this relationship.

Immigrant generation and diabetes risk among Mexican Americans: the Sacramento Area Latino Study on Aging

OBJECTIVES

We examined whether acculturation and immigrant generation, a marker for assimilation, are associated with diabetes risk in an aging Mexican-origin population.

METHODS

We analyzed data on 1789 adults aged 60 to 101 years from the Sacramento Area Latino Study on Aging. We ascertained type 2 diabetes on the basis of diabetic medication use, self-report of physician diagnosis, or a fasting glucose of 126 milligrams/deciliter or greater. Logistic regression modeled prevalent diabetes.

RESULTS

Adjusting for age and gender, we observed significant but divergent associations between immigrant generation, acculturation, and diabetes risk. Relative to first-generation adults, second-generation adults had an odds ratio (OR) of 1.8 (95% confidence interval [CI] = 1.4, 2.4) and third-generation adults had an OR of 2.1 (95% CI = 1.4, 3.1) of having diabetes. Greater US acculturation, however, was associated with a slightly decreased diabetes rate. In the full model adjusting for socioeconomic and lifestyle factors, the association between generation (but not acculturation) and diabetes remained significant.

CONCLUSIONS

Our study lends support to the previously contested notion that assimilation is associated with an increased diabetes risk in Mexican immigrants. Researchers should examine the presence of a causal link between assimilation and health more closely.

Migration and DNA methylation: a comparison of methylation patterns in type 2 diabetes susceptibility genes between indians and europeans

Background

Type 2 diabetes is a global problem that is increasingly prevalent in low and middle income countries including India, and is partly attributed to increased urbanisation. Genotype clearly plays a role in type 2 diabetes susceptibility. However, the role of DNA methylation and its interaction with genotype and metabolic measures is poorly understood. This study aimed to establish whether methylation patterns of type 2 diabetes genes differ between distinct Indian and European populations and/or change following rural to urban migration in India.

Methods

Quantitative DNA methylation analysis in Indians and Europeans using Sequenom^® EpiTYPER^® technology was undertaken in three genes: ADCY5, FTO and KCNJ11. Metabolic measures and genotype data were also analysed.

Results

Consistent differences in DNA methylation patterns were observed between Indian and European populations in ADCY5, FTO and KCNJ11. Associations were demonstrated between FTO rs9939609 and BMI and between ADCY5rs17295401 and HDL levels in Europeans. However, these observations were not linked to local variation in DNA methylation levels. No differences in methylation patterns were observed in urban-dwelling migrants compared to their non-migrant rural-dwelling siblings in India.

Conclusions

Analysis of DNA methylation at three type 2 diabetes susceptibility loci highlighted geographical and ethnic differences in methylation patterns. These differences may be attributed to genetic and/or region-specific environmental factors.

Differences in estimation of creatinine generation between renal function estimating equations in an Indian population: cross-sectional data from the Hyderabad arm of the Indian migration study

Background

Creatinine based formulae for estimating renal function developed in white populations may be less valid in other ethnic groups. We assessed the performance of various estimating formulae in an Indian population.

Methods

917 subjects were recruited from the Hyderabad arm of the Indian Migration Study. Data were collected on comorbidity, serum creatinine and body composition from DXA scans. Renal function was compared using the modified Cockcroft-Gault, MDRD and CKD-EPI formulae. 24-hour creatinine production was derived from each estimate and the agreement with measured muscle mass examined. 24-hour creatinine production estimates were compared to that derived from a formula by Rule incorporating DXA measured muscle mass. Potential systematic biases were examined by age and eGFR. We assessed the association of renal function by each formula with hypertension and self-reported measures of vascular disease.

Results

Mean modified Cockcroft-Gault eCCl was 98.8 ml/min/1.73 m², MDRD eGFR 91.2 ml/min/1.73 m² and CKD-EPI eGFR 96.3 ml/min/1.73 m². MDRD derived 24-hour creatinine production showed the least age-related underestimation compared to the Rule formula. CKD-EPI showed a marked bias at higher eGFRs. All formulae showed similar strength associations with vascular disease and hypertension.

Conclusions

Our analyses support the use of MDRD for estimating renal function in Indian populations. Further work is required to assess the predictive value of formulae for incident disease and complications of CKD.

Validation of dual energy X-ray absorptiometry measures of abdominal fat by comparison with magnetic resonance imaging in an Indian population

Objective

Abdominal adiposity is an important risk factor for diabetes and cardiovascular disease in Indians. Dual energy X-ray absorptiometry (DXA) can be used to determine abdominal fat depots, being more accessible and less costly than gold standard measures such as magnetic resonance imaging (MRI). DXA has not been fully validated for use in South Asians. Here, we determined the accuracy of DXA for measurement of abdominal fat in an Indian population by comparison with MRI.

Design

146 males and females (age range 18–74, BMI range 15–46 kg/m²) from Hyderabad, India underwent whole body DXA scans on a Hologic Discovery A scanner, from which fat mass in two abdominal regions was calculated, from the L1 to L4 vertebrae (L1L4) and from the L2 to L4 vertebrae (L2L4). Abdominal MRI scans (axial T1-weighted spin echo images) were taken, from which adipose tissue volumes were calculated for the same regions.

Results

Intra-class correlation coefficients between DXA and MRI measures of abdominal fat were high (0.98 for both regions). Although at the level of the individual, differences between DXA and MRI could be large (95% of DXA measures were between 0.8 and 1.4 times MRI measures), at the sample level, DXA only slightly overestimated MRI measures of abdominal fat mass (mean difference in L1L4 region: 2% (95% CI:0%, 5%), mean difference in L2L4 region:4% (95% CI: 1%, 7%)). There was evidence of a proportional bias in the association between DXA and MRI (correlation between difference and mean −0.3), with overestimation by DXA greater in individuals with less abdominal fat (mean bias in leaner half of sample was 6% for L1L4 (95%CI: 2, 11%) and 7% for L2L4 (95% CI:3,12%).

Conclusions

DXA measures of abdominal fat are suitable for use in Indian populations and provide a good indication of abdominal adiposity at the population level.

Evaluation of seven common lipid associated loci in a large Indian sib pair study

Background

Genome wide association studies (GWAS), mostly in Europeans have identified several common variants as associated with key lipid traits. Replication of these genetic effects in South Asian populations is important since it would suggest wider relevance for these findings. Given the rising prevalence of metabolic disorders and heart disease in the Indian sub-continent, these studies could be of future clinical relevance.

Methods

We studied seven common variants associated with a variety of lipid traits in previous GWASs. The study sample comprised of 3178 sib-pairs recruited as participants for the Indian Migration Study (IMS). Associations with various lipid parameters and quantitative traits were analyzed using the Fulker genetic association model.

Results

We replicated five of the 7 main effect associations with p-values ranging from 0.03 to 1.97x10^-7. We identified particularly strong association signals at rs662799 in APOA5 (beta=0.18 s.d, p=1.97 x 10^-7), rs10503669 in LPL (beta =−0.18 s.d, p=1.0 x 10^-4) and rs780094 in GCKR (beta=0.11 s.d, p=0.001) loci in relation to triglycerides. In addition, the GCKR variant was also associated with total cholesterol (beta=0.11 s.d, p=3.9x10^-4). We also replicated the association of rs562338 in APOB (p=0.03) and rs4775041 in LIPC (p=0.007) with LDL-cholesterol and HDL-cholesterol respectively.

Conclusions

We report associations of five loci with various lipid traits with the effect size consistent with the same reported in Europeans. These results indicate an overlap of genetic effects pertaining to lipid traits across the European and Indian populations.

Early and current socio-economic position and cardiometabolic risk factors in the Indian Migration Study

Aims:

The aim of this study is to estimate the associations of early and current socio-economic position (SEP) on adult cardiometabolic risk factors in the Indian Migration Study (N = 7,067).

Methods and Results:

Linear mixed models were used to estimate associations between early and current SEP and cardiometabolic risk factors: systolic blood pressure (SBP), body fat and Homeostasis Model Assessment (HOMA) score. In males, high current SEP was associated with higher SBP. In both genders, high early and current SEP were associated with higher body fat, current SEP dominating the associations. High early SEP was associated with higher HOMA score in males only, and the effect size halved after adjustment for current SEP. High current SEP was associated with higher HOMA score more strongly in males than in females.

Conclusion:

Higher SEP, more importantly in adulthood than childhood, was associated with cardiometabolic risk factors in an Indian population. The relationship between SEP over the life course and urbanization should be considered in the Indian context when public health interventions to prevent cardiovascular disease are planned.

North Korean refugee health in South Korea (NORNS) study: study design and methods

Background

Understanding the health status of North Korean refugees (NKRs), and changes in health during the resettlement process, is important from both the humanitarian standpoint and the scientific perspective. The NOrth Korean Refugee health iN South Korea (NORNS) study aims to document the health status and health determinants of North Korean refugees, to observe various health outcomes as they occur while adapting to the westernized lifestyle of South Korea, and to explain the mechanisms of how health of migrants and refugees changes in the context of new environmental risks and opportunities.

Methods

The NORNS study was composed of an initial survey and a follow-up survey 3.5 years apart. Participants were recruited voluntarily among those aged 30 or more living in Seoul. The survey consists of a health questionnaire and medical examination. The health questionnaire comprises the following six domains: 1) demographic and migration information 2) disease history, 3) mental health, 4) health-related lifestyle, 5) female reproductive health, and 6) sociocultural adaptation. The medical examination comprises anthropometric measurements, blood pressure and atherosclerosis, and various biochemical measurements. Prevalence of several diseases able to be diagnosed from the medical examination, the changes between the two surveys, and the association between the outcome and other measurements, such as length of stay and extent of adaptation in South Korea will be investigated. Furthermore, the outcome will be compared to a South Korean counterpart cohort to evaluate the relative health status of NKRs.

Discussion

The NORNS study targeting adult NKRs in South Korea is a valuable study because various scales and medical measurements are employed for the first time. The results obtained from this study are expected to be utilized for developing a health policy for NKRs and North Korean people after unification. Additionally, since NKRs are an immigrant group who are the same race and have the same genetic characteristics as South Koreans, this study has the characteristics of a unique type of migrant health study.

Evaluation of the Indian Migration Study Physical Activity Questionnaire (IMS-PAQ): a cross-sectional study

Background

Socio-cultural differences for country-specific activities are rarely addressed in physical activity questionnaires. We examined the reliability and validity of the Indian Migration Study Physical Activity Questionnaire (IMS-PAQ) in urban and rural groups in India.

Methods

A sub-sample of IMS participants (n = 479) was used to examine short term (≤1 month [n = 158]) and long term (> 1 month [n = 321]) IMS-PAQ reliability for levels of total, sedentary, light and moderate/vigorous activity (MVPA) intensity using intraclass correlation (ICC) and kappa coefficients (k). Criterion validity (n = 157) was examined by comparing the IMS-PAQ to a uniaxial accelerometer (ACC) worn ≥4 days, via Spearman's rank correlations (ρ) and k, using Bland-Altman plots to check for systematic bias. Construct validity (n = 7,000) was established using linear regression, comparing IMS-PAQ against theoretical constructs associated with physical activity (PA): BMI [kg/m²], percent body fat and pulse rate.

Results

IMS-PAQ reliability ranged from ICC 0.42-0.88 and k = 0.37-0.61 (≤1 month) and ICC 0.26 to 0.62; kappa 0.17 to 0.45 (> 1 month). Criterion validity was ρ = 0.18-0.48; k = 0.08-0.34. Light activity was underestimated and MVPA consistently and substantially overestimated for the IMS-PAQ vs. the accelerometer. Criterion validity was moderate for total activity and MVPA. Reliability and validity were comparable for urban and rural participants but lower in women than men. Increasing time spent in total activity or MVPA, and decreasing time in sedentary activity were associated with decreasing BMI, percent body fat and pulse rate, thereby demonstrating construct validity.

Conclusion

IMS-PAQ reliability and validity is similar to comparable self-reported instruments. It is an appropriate tool for ranking PA of individuals in India. Some refinements may be required for sedentary populations and women in India.

Socio-demographic patterning of physical activity across migrant groups in India: results from the Indian Migration Study

OBJECTIVE

To investigate the relationship between rural to urban migration and physical activity (PA) in India.

METHODS

6,447 (42% women) participants comprising 2077 rural, 2,094 migrants and 2,276 urban were recruited. Total activity (MET hr/day), activity intensity (min/day), PA Level (PAL) television viewing and sleeping (min/day) were estimated and associations with migrant status examined, adjusting for the sib-pair design, age, site, occupation, education, and socio-economic position (SEP).

RESULTS

Total activity was highest in rural men whereas migrant and urban men had broadly similar activity levels (p<0.001). Women showed similar patterns, but slightly lower levels of total activity. Sedentary behaviour and television viewing were lower in rural residents and similar in migrant and urban groups. Sleep duration was highest in the rural group and lowest in urban non-migrants. Migrant men had considerably lower odds of being in the highest quartile of total activity than rural men, a finding that persisted after adjustment for age, SEP and education (OR 0.53, 95% CI 0.37, 0.74). For women, odds ratios attenuated and associations were removed after adjusting for age, SEP and education.

CONCLUSION

Our findings suggest that migrants have already acquired PA levels that closely resemble long-term urban residents. Effective public health interventions to increase PA are needed.

Effect of rural-to-urban within-country migration on cardiovascular risk factors in low- and middle-income countries: a systematic review

CONTEXT

Limited information is available of effects of rural-to-urban within-country migration on cardiovascular (CV) risk factors in low- and middle- income countries (LMIC).

OBJECTIVE

A systematic review of studies evaluating these effects was performed with rural and/or urban control groups.

STUDY SELECTION

Two teams of investigators searched observational studies in Medline, Web of Science and Scopus until May 2011. Studies evaluating international migration were excluded.

DATA EXTRACTION

Three investigators extracted the information stratified by gender. Information on 17 known CV risk factors was obtained.

RESULTS

Eighteen studies (n=58,536) were included. Studies were highly heterogeneous with respect to study design, migrant sampling frame, migrant urban exposure and reported CV risk factors. In migrants, commonly reported CV risk factors-systolic and diastolic blood pressure, body mass index, obesity, total cholesterol and low-density lipoprotein-were usually higher or more common than in the rural group and usually lower or less common than in the urban group. This gradient was usually present in both genders. Anthropometric (waist-to-hip ratio, hip/waist circumference, triceps skinfolds) and metabolic (fasting glucose/insulin, insulin resistance) risk factors usually followed the same gradient, but conclusions were weak as information was insufficient. Hypertension, high-density lipoprotein, fibrinogen and C-reactive protein did not follow any pattern.

CONCLUSIONS

In LMIC, most but not all, CV risk factors are higher or more common in migrants than in rural groups but lower or less common than in urban groups. Such gradients may or may not be associated with differential CV events and long-term evaluations are necessary.

Associations of FTO and MC4R Variants with Obesity Traits in Indians and the Role of Rural/Urban Environment as a Possible Effect Modifier

Few studies have investigated the association between genetic variation and obesity traits in Indian populations or the role of environmental factors as modifiers of these relationships. In the context of rapid urbanisation, resulting in significant lifestyle changes, understanding the aetiology of obesity is important. We investigated associations of FTO and MC4R variants with obesity traits in 3390 sibling pairs from four Indian cities, most of whom were discordant for current dwelling (rural or urban). The FTO variant rs9939609 predicted increased weight (0.09 Z-scores, 95% CI: 0.03, 0.15) and BMI (0.08 Z-scores, 95% CI: 0.02, 0.14). The MC4R variant rs17782313 was weakly associated with weight and hip circumference (P < .05). There was some indication that the association between FTO and weight was stronger in urban than that in rural dwellers (P for interaction = .03), but no evidence for effect modification by diet or physical activity. Further studies are needed to investigate ways in which urban environment may modify genetic risk of obesity.

Pepsi and Coca Cola in Delhi, India: availability, price and sales

OBJECTIVE

India is experiencing increased consumption of sugar-sweetened carbonated drinks, consumption that may be associated with increased risk of type 2 diabetes and obesity. The aim of the study was to determine the availability, price and quantity sold of 'Pepsi' and 'Coca Cola' in their 'regular' and 'diet' forms in Delhi and London.

DESIGN

A questionnaire about the availability, price and quantity sold per day of both regular and diet Pepsi and Coca Cola was devised and piloted. Using this, a survey of food and drink outlets within a 100 m radius of randomly selected Metro stations was conducted in both cities.

SUBJECTS

Store vendors, owners and staff of food and drink outlets.

SETTING

Delhi, India; London, United Kingdom.

RESULTS

In Delhi, of the outlets stocking regular Pepsi and Coca Cola, only 34% sold diet versions and these were more readily available in the most affluent areas than in the poorest areas (34% v. 6%, Z=3.67, P<0.001). This social patterning was not observed in London. Little price differential between regular and diet versions of Pepsi and Coca Cola was observed in Delhi; however, profit margins were better for regular, relative to diet, Coca Cola. Sales of regular products were significantly greater than those of diet products (P<0.002).

CONCLUSIONS

Low availability of diet versions of Pepsi and Coca Cola in less affluent areas of Delhi is likely to exacerbate the obesity and diabetes trends. Price differentials to promote diet versions and other healthier or traditional low-energy drinks may be beneficial.

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.

Effects of migration on food consumption patterns in a sample of Indian factory workers and their families

OBJECTIVES

To study the impact of migration on food consumption among Indian factory workers and their siblings and spouses.

DESIGN

A cross-sectional study was conducted to assess diet using an interviewer-administered semi-quantitative FFQ from which intake of 184 commonly consumed food items was obtained.

SETTINGS

Participants recruited from factory sites in Bangalore, Lucknow, Nagpur and Hyderabad.

SUBJECTS

The sample comprised 7049 participants (41·6 % female), and included urban, migrant and rural groups.

RESULTS

Thirteen food items were eaten by the greatest proportion of individuals on a daily basis. These were all indigenous foods. The proportion of people consuming tandoori roti, dal with vegetables, potato and ghee on a daily basis was highest in the urban sample, intermediate in the migrant group and lowest in the rural group (P ≤ 0·01). The proportion of individuals consuming Western food on a weekly basis followed a similar trend.

CONCLUSIONS

The diet of this sample is predominantly indigenous in nature, irrespective of migration status, with the prevalence of daily Western food consumption being minimal.

The effect of rural-to-urban migration on obesity and diabetes in India: a cross-sectional study

BACKGROUND

Migration from rural areas of India contributes to urbanisation and may increase the risk of obesity and diabetes. We tested the hypotheses that rural-to-urban migrants have a higher prevalence of obesity and diabetes than rural nonmigrants, that migrants would have an intermediate prevalence of obesity and diabetes compared with life-long urban and rural dwellers, and that longer time since migration would be associated with a higher prevalence of obesity and of diabetes.

METHODS AND FINDINGS

The place of origin of people working in factories in north, central, and south India was identified. Migrants of rural origin, their rural dwelling sibs, and those of urban origin together with their urban dwelling sibs were assessed by interview, examination, and fasting blood samples. Obesity, diabetes, and other cardiovascular risk factors were compared. A total of 6,510 participants (42% women) were recruited. Among urban, migrant, and rural men the age- and factory-adjusted percentages classified as obese (body mass index [BMI] >25 kg/m(2)) were 41.9% (95% confidence interval [CI] 39.1-44.7), 37.8% (95% CI 35.0-40.6), and 19.0% (95% CI 17.0-21.0), respectively, and as diabetic were 13.5% (95% CI 11.6-15.4), 14.3% (95% CI 12.2-16.4), and 6.2% (95% CI 5.0-7.4), respectively. Findings for women showed similar patterns. Rural men had lower blood pressure, lipids, and fasting blood glucose than urban and migrant men, whereas no differences were seen in women. Among migrant men, but not women, there was weak evidence for a lower prevalence of both diabetes and obesity among more recent (

CONCLUSIONS

Migration into urban areas is associated with increases in obesity, which drive other risk factor changes. Migrants have adopted modes of life that put them at similar risk to the urban population. Gender differences in some risk factors by place of origin are unexpected and require further exploration. Please see later in the article for the Editors' Summary.

Collapse

Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Aged
• Cross-Sectional Studies
• Diabetes Mellitus/epidemiology
• Female
• Humans
• India/epidemiology
• Male
• Middle Aged
• Obesity/epidemiology
• Population Dynamics
• Risk Factors
• Socioeconomic Factors
• Young Adult

Collapse

Grants

• Wellcome Trust
• 084674 Wellcome Trust
• G0600705 Medical Research Council
• GR070797MF Wellcome Trust

Collapse

Affiliation(s)

Shah Ebrahim Department of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom.
Sanjay Kinra
Liza Bowen
Elizabeth Andersen
Yoav Ben-Shlomo
Tanica Lyngdoh
Lakshmy Ramakrishnan
R C Ahuja
Prashant Joshi
S Mohan Das
Murali Mohan
George Davey Smith
Dorairaj Prabhakaran
K Srinath Reddy

Collapse

Assessment of physical activity using accelerometry, an activity diary, the heart rate method and the Indian migration study questionnaire in south Indian adults

OBJECTIVE

To validate questionnaire-based physical activity level (PAL) against accelerometry and a 24 h physical activity diary (24 h AD) as reference methods (Protocol 2), after validating these reference methods against the heart rate-oxygen consumption (HRVO2) method (Protocol 1).

DESIGN

Cross-sectional study.

SETTING

Two villages in Andhra Pradesh state and Bangalore city, South India.

SUBJECTS

Ninety-four participants (fifty males, forty-four females) for Protocol 2; thirteen males for Protocol 1.

RESULTS

In Protocol 2, mean PAL derived from the questionnaire (1.72 (sd 0.20)) was comparable to that from the 24 h AD (1.78 (sd 0.20)) but significantly higher than the mean PAL derived from accelerometry (1.36 (sd 0.20); P < 0.001). Mean bias of PAL from the questionnaire was larger against the accelerometer (0.36) than against the 24 h AD (-0.06), but with large limits of agreement against both. Correlations of PAL from the questionnaire with that of the accelerometer (r = 0.28; P = 0.01) and the 24 h AD (r = 0.30; P = 0.006) were modest. In Protocol 1, mean PAL from the 24 h AD (1.65 (sd 0.18)) was comparable, while that from the accelerometer (1.51 (sd 0.23)) was significantly lower (P < 0.001), than mean PAL obtained from the HRVO2 method (1.69 (sd 0.21)).

CONCLUSIONS

The questionnaire showed acceptable validity with the reference methods in a group with a wide range of physical activity levels. The accelerometer underestimated PAL in comparison with the HRVO2 method.

The effect on cardiovascular risk factors of migration from rural to urban areas in Peru: PERU MIGRANT Study

BACKGROUND

Mass-migration observed in Peru from the 1970s occurred because of the need to escape from politically motivated violence and work related reasons. The majority of the migrant population, mostly Andean peasants from the mountainous areas, tends to settle in clusters in certain parts of the capital and their rural environment could not be more different than the urban one. Because the key driver for migration was not the usual economic and work-related reasons, the selection effects whereby migrants differ from non-migrants are likely to be less prominent in Peru. Thus the Peruvian context offers a unique opportunity to test the effects of migration.

METHODS/DESIGN

The PERU MIGRANT (PEru's Rural to Urban MIGRANTs) study was designed to investigate the magnitude of differences between rural-to-urban migrant and non-migrant groups in specific CVD risk factors. For this, three groups were selected: Rural, people who have always have lived in a rural environment; Rural-urban, people who migrated from rural to urban areas; and, Urban, people who have always lived in a urban environment.

DISCUSSION

Overall response rate at enrolment was 73.2% and overall response rate at completion of the study was 61.6%. A rejection form was obtained in 282/323 people who refused to take part in the study (87.3%). Refusals did not differ by sex in rural and migrant groups, but 70% of refusals in the urban group were males. In terms of age, most refusals were observed in the oldest age-group (>60 years old) in all study groups. The final total sample size achieved was 98.9% of the target sample size (989/1000). Of these, 52.8% (522/989) were females. Final size of the rural, migrant and urban study groups were 201, 589 and 199 urban people, respectively. Migrant's average age at first migration and years lived in an urban environment were 14.4 years (IQR 10-17) and 32 years (IQR 25-39), respectively. This paper describes the PERU MIGRANT study design together with a critical analysis of the potential for bias and confounding in migrant studies, and strategies for reducing these problems. A discussion of the potential advantages provided by the case of migration in Peru to the field of migration and health is also presented.

Estimation of additive genetic and environmental sources of quantitative trait variation using data on married couples and their siblings

Twin studies have been used to understand the sources of genetic and environmental variation in body height, body weight and other common human quantitative traits. However, it is rather unclear whether these two sources of variation could be really separated in practice. Here, we consider a special study design where phenotype data from married couples and their siblings have been collected. The marital status gives information about the shared environment, while siblings give information about both genetic and environmental variation. To dissect sources of variation and to allow some deviations and pedigree errors in the data, we model such data using a robust polygenic model with finite genome length assumption. As a summary, we provide the estimates for age-dependent proportions of total variation which are due to polygenic and environmental effects. Here, these estimates are provided for body height, weight, systolic blood pressure and total serum cholesterol measured from subjects of the Indian Migration Study.

Hypertension in the developing world: A consequence of progress

Hypertension is one of the leading causes of death and disability in developing countries. The increasing burden of hypertension in these countries has been attributed to several indicators of economic progress such as increased life expectancy, urbanization and its attendant lifestyle changes, and the overall epidemiologic transition these countries are experiencing currently. The public health response to this challenge must be to promote health among all sections of the populations of these countries, and a concerted effort to promote awareness about hypertension, its risk factors, and risk behaviors. The health policies of these countries need to be reoriented to include chronic diseases in their ambit. These efforts have the potential to reduce the emergence or lessen the toll of hypertension and its complication in many parts of the developing world.