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Research Matters


A head "START" on solving a medical mystery

Why is it that South Asians originally from India, Pakistan, Sri Lanka and Bangladesh face an increased risk of Type 2 diabetes and early heart disease?
A head "START" on solving a medical mystery

Dr. Sonia Anand, Canada Research Chair in Ethnic Diversity and Cardiovascular Disease

Type 2 diabetes affects 80 million people in India. In Canada, diabetes and early heart disease are found among increasing numbers of South Asians who have migrated here.

Why South Asians originally from India, Pakistan, Sri Lanka and Bangladesh face this increased risk is a mystery being investigated by Dr. Sonia Anand, professor of medicine and epidemiology in the Michael G. DeGroote School of Medicine at McMaster University and Canada Research Chair in Ethnic Diversity and Cardiovascular Disease.

Anand and her colleague, cardiologist Dr. Milan Gupta, are working with collaborators in Canada and the St. John Research Institute in Bangalore, India in a novel research study which is designed to determine how maternal health behaviours, genetic and other in utero exposures in South Asians may contribute later in life to the development of Type 2 diabetes and heart disease.

The START (SouTh Asian birth cohoRT) study is funded by the Canadian Institute of Health Research (CIHR), the India Council of Medical Research and the Heart and Stroke Foundation of Ontario.

The study involves two birth cohorts - South Asians in Southern Ontario and another in urban and rural India. (Dr. Anand has applied for funding to create an additional cohort among Aboriginal mothers and newborns from the Six Nations reserve in Ontario).

For three years, 1,000 pregnant women of South Asian origin, 18 – 40 years of age, in Ontario will be followed, along with their newborns. During their pregnancy, the mothers will undergo extensive assessments, ranging from having their blood sugar tested, height and weight recorded to having their diets and physical activity evaluated. As soon as they deliver their baby, the infant will undergo extensive screening. Cord blood will be collected to test blood sugar, insulin and genetic factors, along with birth weight and fat.

Researchers, mothers and their babies will meet once a year. In between, they will be in contact by telephone or computer.

 “The study is designed to find out why central adiposity and diabetes are so prevalent among the South Asisan population,” said Anand. “If we can identify factors in utero, or during the early years, we will be in a better position to prevent diabetes in individuals as they age.”

Anand holds the Eli Lilly Canada-May Cohen Chair in Women’s Health and the Michael DeGroote Heart and Stroke Chair in Population Health and Epidemiology. She is a joint member of the department of clinical epidemiology and biostatistics where she directs the population genomics program and is a scientist at the Population Health Research Institute (PHRI).

As a research scientist, her focus is on understanding the environmental and genetic causes of early cardiovascular risk factors, including type 2 diabetes and cardiovascular disease among high risk, diverse ethnic groups.

Recently, in collaboration with researchers at McGill University, her research conducted at the PHRI received international attention with a study published in the journal PLoS Medicine which showed a diet high in fruits and vegetables appears to lessen the genetic risk of the 9p21 gene on heart disease.

The research, which represents one of the largest gene-diet interaction studies ever conducted on cardiovascular disease, involved the analysis of more than 8,000 individuals from five ethnicities – European, South Asian, Chinese, Latin American and Arab – and the effect that their diets had on the 9p21 gene.

The results suggested that individuals with the high risk genotype who consumed a prudent diet, composed mainly of raw vegetables, fruits and berries, had a similar risk of heart attack to those with the low risk genotype.

“We observed that the effect of a high risk genotype can be mitigated by consuming a diet high in fruits and vegetables,” said Anand, joint principal investigator of the study.

She added that this finding fits well with public health recommendations to eat five or more services of fruits and vegetables a day. “Genetic information may be a motivation to help people take the public health recommendation seriously.”

Experts, such as Dr. William O’Neill, cardiology professor and executive dean of clinical affairs at the University of Miami’s Miller School of Medicine, suggested this research points the way toward the future in terms of understanding the genetics of heart disease.

With this unique finding, Anand is now conducting the population-based SAHARA (South Asian Heart Risk Assessment) study to determine if knowing about this gene motivates individuals at risk of a heart attack to change their habits.

The study, funded by the Heart and Stroke Foundation of Ontario is the first in Canada designed to help South Asians lower their risk of heart disease. It will screen 1,000 South Asians in the Greater Toronto area to determine their risk for heart disease and diabetes.

Using e-mail and other multimedia devices, such as smartphones and cell phones, researchers will test the effectiveness of culturally tailored multi-media based intervention that provides health messages and feedback to help participants reduce their risk factors over a six month period. An assessment after six months will reveal if there have been any changes in an individual’s heart disease risk profile.

Participants receive a personal heart disease risk report and, if randomly selected, the opportunity to participate in an online goals setting program.