How does Asian ancestry affect heart disease risk?
January 19, 2016
The world is picking up the bad habits of Western culture when it comes to health. Lifestyle – especially what you eat and how much you exercise – has a big impact on heart disease. Unfortunately, many people are consuming too many calories and getting too little exercise. Across the globe, people are abandoning their traditional diets and lifestyles and are suffering the consequences.
For reasons that are unclear, Asians and Asian Americans tend to develop diabetes at a lower body mass index (BMI)than Caucasians. People of Asian descent who carry 20 extra pounds are at risk of developing diabetes, whereas Caucasians usually need to carry 40 or more extra pounds before they are at risk. This is true for people of Asian descent regardless of where in the world they live.
The literature indicates that an astonishing 11 percent of Chinese have diabetes. Perhaps even more amazing, 50 percent of Chinese have prediabetes, a condition that typically emerges into diabetes. Out of 1.3 billion human beings, that’s 143 million people with diabetes and 650 million with prediabetes!
Those are troublesome numbers for a cardiologist to hear because diabetes is one of the leading risk factors for heart attack.
Diabetes, sedentary lifestyle, environmental deterioration, and smoking trends in men are conspiring to have dramatic effects on the health of these people.
It’s not just in China that we’re seeing increasing rates of excess weight and diabetes. The same is true in Japan and South Asia. People from the Indian subcontinent seem particularly prone to coronary artery disease, and we don’t know why.
A knowledge gap
Much of our knowledge about the risk factors for heart disease grew out of the Framingham Heart Study, which began in 1948 in Framingham, Mass. The study followed thousands of people over decades to identify common characteristics that contribute to cardiovascular disease.
This study taught us that smoking, high cholesterol, and high blood pressure are harmful, notions which are bedrock to modern medicine. While an enormous body of knowledge came out of the study, it had some drawbacks – one being that it did not follow diverse populations.
More recent studies, including the Dallas Heart Study conducted here by several of my colleagues, have included large numbers of African-Americans and Hispanics, increasing our understanding of heart disease risk factors in those populations. The Dallas Heart Study included cardiovascular disease risk factors such as level of physical activity, access to health care, blood pressure measurements, and family history.
The next wave of studies needs to take a deeper look at heart disease risk factors among Asians. Government regulations in both China and India prohibit sending DNA samples out of the country, making it difficult to conduct epidemiological studies on these populations. Researchers doing genetic studies on populations in China or India must physically do the work in that country.
The MASALA study is a step in the right direction. This research program includes participants of Indian, Pakistani, Bangladeshi, Nepali, and Sri Lankan ethnicity, all of whom live in the Greater Chicago or San Francisco Bay area. Researchers are measuring the traditional, behavioral, cultural, and social risk factors of the participants in an effort to determine the reasons why people of South Asian ethnicity have a high cardiovascular risk.
During my most recent trip to China, I spoke to researchers about the possibility of a study to follow the health of a large group of individuals there. This project is only in the discussion phase now, but I hope it will happen.
There is much to be learned about why individuals of Asian descent, whether they live in Asia or in America, are at substantially higher risk for heart disease than others. We hope that with additional time and research we’ll have the information we need to help people of Asian descent be more proactive in their heart disease prevention.
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