The Obesity Problem:
Overweight and obesity are labels for ranges of weight that are greater than what is generally considered healthy for a given height (CDC). Overweight and obesity are considered one of the leading health indicators reflecting major public health concerns by Healthy People 2010 due to their associations with increased risk for hypertension, dyslipidemia (elevation of total cholesterol, elevation of “bad” LDL cholesterol and decrease in “good” HDL cholesterol), type 2 diabetes, coronary heart disease, stroke, several types of cancers (colon, postmenopausal breast, endometrial, kidney and esophagus), pregnancy complications, menstrual irregularities, gallbladder disease, osteoarthritis, sleep apnea, asthma, mental health and a decrease in life expectancy.
In adults, overweight and obesity ranges are determined by using weight and height to calculate the “body mass index” (BMI) (weight [kg]/height [m2]). BMI is the most utilized method for estimating body fat and body fat distribution, however, there are other measurements such as skin-fold thickness and waist circumference, calculation of waist-to-hip circumference ratios, and techniques such as ultrasound, computed tomography, and magnetic resonance imaging (MRI). Adults with a BMI between 25 and 29.9 are considered overweight, while those with a BMI of 30 or higher are considered obese. The age-adjusted prevalence of adult overweight and obesity (BMI >/ 25) is 66.3%. The prevalence of obesity (BMI >/ 30) is 32.2%, and the prevalence of extreme obesity (BMI >/ 40) is 4.8% (NHANES 2003-2004, NCHS).
For U.S. children and adolescents overweight and obesity are determined by being within the 95th percentile or higher of BMI values in a CDC growth chart that takes into account normal differences in body fat between boys and girls at various ages. More than 9 million children and adolescents between the ages of 6 and 19 years are considered overweight. The prevalence of overweight in children between 6 and 11 years increased from 4.0% in 1971-1974 to 17.5 in 2001-2004. The prevalence of overweight in teens between ages 12 and 19 increased from 6.1% to 17.0% (Health United States, 2006). 14% of preschool children between 2 and 5 years were overweight in 2003-2004.
Intersectionality and Obesity:
Obesity rates vary by race/ethnicity and by socioeconomic status.
Robert (2004), and Kumanyika (2006) on obesity in 2000, US:
- 30% of white women 13% white girls 14-15% white boys
- 40% of Hispanic women 17-20% Hispanic girls 27-25% Hispanic boys
- 50% of black women 23-24% black girls 17-19% black boys
(about 28% of men across races)
Asian groups typically have lower BMIs, but the standard BMI based groups may not be appropriate since they have elevated risk starting at lower BMIs. Data on Native American kids suggest obesity prevalences are increasing, currently around 27% for girls and 31% for boys.
Mujahid2005, using ARIC data (agreeing with previous studies) reported
- High income/education associated with low BMI among white women
- High education associated with high BMI among black women
- Weaker associations among men, same trends by race
Relationships between socioeconomic status and obesity seem to differ by country. Some work by Popkin and Kim (e.g. Kim 2004) has posited that before the “nutritional transition” some countries, such as China, have a positive association between BMI and SES, but more developed countries such as the US have an inverse relationship between BMI and SES.
A controversial US paper by Flegal using NHANES data suggested that the mortality risk for BMI based groups has been attenuating over time, possibly due to better pharmaceutical control of related risk factors. Internationally, obesity (BMI) has been increasing in most countries, while smoking, blood pressure and cholesterol have decreased – WHO MONICA.
The Obesity Solution?
Risk factors include race/ethnicity, gender, age (incidence doubles between 20 and 55), genetics, prevalence of chronic diseases (endocrine disorders such as Cushing’s disease, polycystic ovary syndrome, and thyroid deficiency), drugs that treat other chronic diseases such as steroids and some antidepressants, culture, behavior and the environment. Behavioral risk factors affecting obesity include tobacco smoking, physical inactivity (a sedentary lifestyle), and diet (an over-consumption of high caloric and high fat food). Environmental influences on population eating behaviors include: food supply trends (availability of fruits and vegetables, increase in soft drink consumption), increasing trends in eating out (larger portion sizes), and television advertising (encouragement of food consumption). Environmental influences on population physical inactivity patterns include: increased time devoted to television viewing, automobile use for transportation, decreased occupational physical activity, increased computer use, neighborhoods with limited park and recreation space, neighborhoods with decreased walkability (e.x. high crime areas, areas with no sidewalks), lack of access to affordable health clubs, and labor-saving products (ex. elevators/escalators vs. stairs). In addition to neighborhoods, schools and workplaces may shape physical activity and diet.
Adult obesity is associated with pediatric obesity, where there is a 70% chance that a child will become obese if both parents are obese, a 50% chance a child will be obese if one parent is obese, and only a 10% chance that a child will become obese if neither parent is obese. Childhood obesity is also associated with gestational diabetes in the mother, macrosomia (being born high birth weight > 4000g), and formula feeding (rather than breastfeeding) (CME Recommendations for family physicians, 2006).
Questions:
- What is driving the obesity epidemic – the steady increase in obesity over the past decades?
- How should we judge the success in our obesity interventions? Are we to stop the epidemic and reverse the rates in obesity? Should we decrease obesity within the overall population? Should we focus on eliminating disparities in obesity? Should we change the risk factor profiles or concentrate on the consequences of obesity? If more than one of these is important, how should we prioritize them?
- How do we prevent obesity interventions from stigmatizing those who are overweight or obese?
- Should we be concerned about the medicalization of obesity, e.x., bariatric surgery?
Brainstorming session on day 1:
- What interventions might you favor to reverse the increasing trend in obesity in adults?
- For different age, racial/ethnic, gender, and class groupings?
