Environmental risk factors for reduced kidney function due to undetermined cause in India: an environmental epidemiologic analysis.

BACKGROUND: An epidemic of chronic kidney disease is occurring in rural communities in low-income and middle-income countries that do not share common kidney disease risk factors such as diabetes and hypertension. This chronic kidney disease of unknown etiology occurs primarily in agricultural communities in Central America and South Asia. Consequently, environmental risk factors including heat stress, heavy metals exposure, and low altitude have been hypothesized as risk factors. We conducted an environmental epidemiological analysis investigating these exposures in India which reports the disease. METHODS: We used a random sample population in rural and urban sites in Northern and Southern India in 2010, 2011, and 2014 (n = 11,119). We investigated associations of the heat index, altitude, and vicinity to cropland with estimated glomerular filtration rate (eGFR) using satellite-derived data assigned to residential coordinates. We modeled these exposures with eGFR using logistic regression to estimate the risk of low eGFR, and linear mixed models (LMMs) to analyze site-specific eGFR-environment associations. RESULTS: Being over 55 years of age, male, and living in proximity to cropland was associated with increased risk of low eGFR [odds ratio (OR) (95% confidence interval (CI) = 2.24 (1.43, 3.56), 2.32 (1.39, 3.88), and 1.47 (1.16, 2.36)], respectively. In LMMs, vicinity to cropland was associated with low eGFR [-0.80 (-0.44, -0.14)]. No associations were observed with temperature or altitude. CONCLUSIONS: Older age, being male, and living in proximity to cropland were negatively associated with eGFR. These analyses are important in identifying subcommunities at higher risk and can help direct future environmental investigations.

Genetic studies of type 2 diabetes in South Asians: a systematic overview.

Diabetes Mellitus, which affects 366 million people worldwide, is a leading cause of mortality, morbidity, and loss of quality of life. South Asians, comprising 24% of the world's population, suffer a large burden of type 2 diabetes. With intriguing risk phenotypes, unique environmental triggers, and potential genetic predisposition, South Asians offer a valuable resource for investigating the pathophysiology of type 2 diabetes. Genomics has proven its potential to underpin some of the etiology of type 2 diabetes by identifying a number of susceptibility genes, but such data are scarce and unclear in South Asians. We present a systematic review of studies on the genetic basis of type 2 diabetes or its complications in South Asians published between 1987-2012, and discuss the findings and limitations of the available data. Of the 91 eligible studies meeting our inclusion criteria, a vast majority included Indian populations, followed by a few in those of Pakistani origin, while other South Asian countries were generally under-represented. Though a large number of studies focused on the replication of findings from genome-wide association studies (GWAS) in European populations, a few studies explored new genes and pathways along with GWAS in South Asians and suggested the potential to unravel population- specific susceptibility genes in this population. We find encouraging improvements in study designs, sample sizes and the numbers of genetic variants investigated over the last five years, which reflect the existing capacity and scope for large-scale genetic studies in South Asians.

Lean people with dysglycemia have a worse metabolic profile than centrally obese people without dysglycemia.

AIM: This study compared metabolic profiles of Asian Indians with normal waist circumference (WC) and dysglycemia versus those with high WC without dysglycemia. SUBJECTS AND METHODS: In 2,350 subjects ≥20 years of age from the Chennai Urban Rural Epidemiology Study with full anthropometric and biochemical characterization, high WC was defined as ≥90 cm in males and ≥80 cm in females. Dysglycemia was defined as prediabetes (fasting plasma glucose ≥100 mg/dL and/or 2-h plasma glucose ≥140 mg/dL) or diabetes (fasting plasma glucose ≥126 mg/dL, 2-h plasma glucose ≥200 mg/dL, or treatment for diagnosed diabetes). Coronary artery disease (CAD) was defined as known myocardial infarction or Q waves on electrocardiography. Multivariable logistic regression models were used to explore factors associated with CAD. RESULTS: Of the subjects, 260 (11.1%) had dysglycemia with normal WC, and 679 (28.9%), had high WC without dysglycemia. Compared with subjects with high WC without dysglycemia, those with dysglycemia/normal WC, adjusted for age, were more likely to be males (P<0.001) and have higher systolic blood pressure (P<0.05), higher serum triglycerides (P<0.001), higher tumor necrosis factor-α (P<0.001), lower high-density lipoprotein cholesterol (P<0.05), and higher prevalence of CAD (6.3% vs. 2.0%; odds ratio 3.25 [95% confidence interval 1.52-6.94]; P=0.002). CONCLUSIONS: Dysglycemia is associated with a worse cardiometabolic profile than central obesity alone.

Clinical profile of diabetes in the young seen between 1992 and 2009 at a specialist diabetes centre in south India.

AIM: To describe the trends and clinical profile of young diabetic patients (YD) attending a tertiary diabetes centre in south India. METHODS: We reviewed medical records of 2630 YD patients (age at onset ≤25 years) registered between 1992 and 2009. Patients were classified as type 1 diabetes (T1DM), type 2 diabetes (T2DM) gestational diabetes mellitus (GDM) and other types. Retinopathy was assessed initially by direct and indirect ophthalmoscopy and later by retinal photography, nephropathy if urine protein excretion was >500 mg/day, neuropathy if vibration perception threshold on biothesiometry was ≥20 V. RESULTS: The percentage of YD patients rose from 0.55% in 1992 to 2.5% in 2009 (trend chi square, 15.1, p<0.001). Of the 2630 YD subjects registered, 1135 (43.2%) had T1DM, 1262 (48.0%) had T2DM, 118 (4.5%) had GDM and 115 (4.4%) other types. T1DM patients were younger, had lower body mass index, waist circumference, systolic and diastolic blood pressures, and less family history of diabetes compared to T2DM (p<0.001 for each). Retinopathy was seen in 71.9% and 77.3% nephropathy in 22.1% and 12.1% and neuropathy in 34.5% and 21.4% of T2DM and T1DM respectively in those with ≥15 years duration of diabetes. CONCLUSIONS: The percentage of YD in south India is increasing, predominantly due to early onset T2DM.