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

Obesity

Environment Genes

• Differences by

country

• Diet
• Physical Activity
• Family Studies
• Genome Wide

Association

• Underlying risk

Obesity Rates in People of African Descent

BRFSS 2011-2013

United States Africa

Primary Drivers of Obesity

• Diet
• Physical Activity

Energy In = Energy Out Energy In > Energy Out

   

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

Source: http://demographics.coopercenter.org/DotMap/index.html

Racial Dot Map (green Black, blue White)

Physical Activity Guidelines

Physically Active

• 2 ½ hours

moderate intensity per week

• Muscle

strengthening 2x week

It’s Not All Environment: The Role

• f 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
• besity
• 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
• f 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
• besity 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
• besity 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