The incidence of obesity among US blacks is higher than among Hispanics and non-Hispanic whites, reports the Centers for Disease Control and
The report was prepared by Dr Liping Pan from the CDC's Division of Nutrition, Physical Activity, and Obesity, and colleagues and appears in the July 17 issue of the CDC's Morbidity and Mortality Weekly Report (MMWR).
The proportion of the American population that is now obese is twice what it was 30 years ago, said the CDC, and when you look inside that alarming trend you find that certain ethnic and racial groups have been disproportionately affected.
Using data from an ongoing telephone survey of US adults called the Behavioral Risk Factor Surveillance System (BRFSS), the CDC found that from 2006 to 2008, the rate of obesity among adult non-Hispanic blacks was 35.7 per cent. The next highest group was Hispanic adults, at 28.7 per cent, and non-Hispanic whites was 23.7 per cent.
The overall rate of obesity was estimated at 25.6 per cent and found to be consistently higher in women than in men.
These figures are somewhat under the prevalence rates showin in the 2003-2004 National Health and Nutrition Examination Survey (NHANES) which showed that among non-Hispanic blacks obesity prevalence was 45 per cent, followed by 36.8 per cent among Mexican-Americans and 30.6 per cent among non-Hispaic whites.
An editorial comment by the CDC on the new report suggests that the BRFSS derived figures are probably an under-estimate because they are based on self-reports done by phone, whereas the NHANES data comes from height and weight measurements taken by survey staff. However, while within the groups the prevalance rates may differ between the two data-sets, they point out the same disparity among the groups: non-Hispanic blacks have the greatest prevalence of obesity, followed by Hispanics and non-Hispanic whites.
The report also found large regional disparities. Among the four US census regions, the South had the greatest prevalence of obesity among non-Hispanic blacks (36.9 per cent), followed by the Midwest (36.3 per cent), the West (33.1 per cent) and the Northeast (31.7 per cent).
For whites, the greatest prevalence of obesity was in the Midwest (25.4 per cent), followed by the South (24.4 per cent), then the Northeast (22.6 per cent) and lastly the West (21.0 per cent).
For Hispanics, the highest prevalence was in the Midwest (29.6 per cent), followed by the South (29.2 per cent), then the West (29.0 per cent) and lastly the Northeast (26.6 per cent).
The state with the lowest obesity rate among non-Hispanic blacks was New Hampshire (23. 0 per cent). However, there were 5 states with 40 per cent or more obesity rates among non-Hispanic blacks: Alabama, Maine, Mississippi, Ohio, and Oregon.
The state with the lowest obesity rate among Hispanics was Maryland (21.0 per cent), while Tennessee had the highest (36.7 per cent).
And the state with the lowest obesity rate among non-Hispanic whites was DC (9.0 per cent), while the highest was West Virginia (30.2 per cent). However, there were also 5 states with obesity rates under 20 per cent for this group: California, Colorado, Connecticut, Hawaii, and New Mexico.
The CDC says that while the reasons for the diparity among the ethnic/racial groups are complex and unclear, it proposes, three, for which some research evidence exists:
- Firstly, racial/ethnic groups have different lifestyle behaviours that affect weight gain.
- For instance, blacks and Hispanics are less likely to exercise in their leisure time than Hispanics and non-Hispanic whites.
- Secondly, these groups also differ in their attitude to body weight: they have different cultural norms.
- For example, one study suggests that non-Hispanic black women and Hispanic women are happier with their body size than non-Hispanic white women (people who are less satisfied with their body size are more likely to try and lose weight).
- And thirdly, there are socio-economic disparities: for instance in terms of access to healthy food and safe places to exercise.
- There is evidence that neighbourhoods with large minority populations, and especially where these are on low income, have fewer shops where the healthy foods are the same price or cheaper than the energy dense foods.
- There is also evidence to support the idea that minority and low income groups live in neighbourhoods where there is less access to exercise locations, and where traffic and fear for personal safety stops also them taking up walking.
While citing a number of initiatives that are already in place, the CDC recommends that:
"To reduce disparities among populations in the prevalence of obesity, an effective public health response is needed that includes surveillance, policies, programs, and supportive environments achieved through the efforts of government, communities, workplaces, schools, families, and individuals."
"Differences in Prevalence of Obesity Among Black, White, and Hispanic Adults --- United States, 2006--2008."
L Pan, DA Galuska, B Sherry, AS Hunter, GE Rutledge, WH Dietz, Div of Nutrition, Physical Activity, and Obesity; LS Balluz, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.
MMWR, 58(27);740-744, 17 July 2009.
Written by: Catharine Paddock, PhD