Race: We cant live with it and we cant live without it: - PowerPoint PPT Presentation

Race: We can’t live with it and we can’t live without it: Researching the public health consequences of obesity Lisa J. Martin Professor Division of Human Genetics Cincinnati Children’s Hospital Medical Center

What is Obesity? • Excess accumulation of fat • Affects over one-third of the adult American population (~ 78 million). • Associated with increased healthcare costs and reduced life expectancy • Normal is a BMI less than 25 • Overweight is a BMI of 25 or more • Obesity is a BMI of 30 or more

Genes Environment • Differences by • Family Studies country • Genome Wide • Diet Association • Physical Activity • Underlying risk Obesity

Obesity Rates in People of African Descent United States Africa BRFSS 2011-2013

Primary Drivers of Obesity   Energy In = Energy Out   Energy In > Energy Out • Diet • Physical Activity Swinburn et al. AJCN 2009 90:1453-1456

Diet Varies Across the US Healthy People 2010 Goal – 3 servings of vegetables daily. Healthy People 2010 Goal – 3 servings of vegetables daily.

Access to Good Food Varies Bad Better Best Measure of the healthy (supermarket, large grocer, supercenter, produce stores) and less healthy (fast food, convenience, small grocers) food retailers

Poor Food Availability Associated with Black Neighborhoods Racial Dot Map (green Black, blue White) Source: http://demographics.coopercenter.org/DotMap/index.html

Physical Activity Guidelines Physically Active • 2 ½ hours moderate intensity per week • Muscle strengthening 2x week

It’s Not All Environment: The Role of Genetics in Obesity • Family Studies estimate 50% of variability in body weight due to genes – If you have an obese relative, you are at increased risk of obesity • Single gene effects lead to obesity – Both syndromic and non-syndromic • Population studies have identified risk variants – Modest increase in risk, OR = 1.2

Genetic Studies In Populations of African Descent • Most studies seek to replicate findings from European descent populations • The challenge is African Americans are admixed populations – Variants may be European derived and thus not as important in African populations – May miss variants playing a role solely in African descent populations.

Why Is a Bias Toward Europeans a Problem for Gene Discovery • Many pathways to obesity • Each pathway may have different consequences

Differences in Metabolic Obesity Co-Morbidities by Race ↑ In Blacks ↑ In Whites

What Does this Mean? • Genes associated with obesity may differ by ancestry • By screening primarily European descent populations, we may be missing important variants • These genes may have different effects on metabolic outcomes • May miss understanding about the impact of variants in specific populations – May not determine optimal treatment or prevention approaches

Ethical Issues • Obesity is considered a personal failure • Increased rates of obesity in African Americans likely due to both genes and environment • Clearly complex • Without recognition of factors that drive obesity in this subpopulation risk of failing to achieve improvement

Summary • Obesity is a complex trait influenced by both underlying genetic and environmental factors • In the US, African Americans have different underlying genes as well as environment • Thus, understanding the factors leading to obesity in African American populations is difficult. • This is a problem because cause of obesity may also determine consequences

Questions Acknowledgements: Dr. Jessica Woo Dr. Koffi Maglo