Prevalence of Diabetes in Chinese Adults

choi

Xu Y et al, Prevalence and Control of Diabetes in Chinese Adults. Journal of American Medical Association (JAMA), 310: 948-959 (Sept 4, 2013)
http://jama.jamanetwork.com/article.aspx?articleid=1734701
("The overall prevalence of diabetes was estimated to be 11.6% (95% CI, 11.3%-11.8%) in the Chinese adult population. * * * The prevalence of previously diagnosed diabetes was estimated to be 3.5% * * * in the Chinese [adult] population * * * The prevalence of undiagnosed diabetes was 8.1% * * * in the Chinese [adult] population")

Note:
(a) CI = confidence interval
http://en.wikipedia.org/wiki/Confidence_interval
("In applied practice, confidence intervals are typically stated at the 95% confidence level [approximately 2 standard deviations]. However, when presented graphically, confidence intervals can be shown at several confidence levels, for example 50%, 95% and 99%")
(b) In the US:
(i) 2011 National Diabetes Fact Sheet. US Center for Disease Control and Diabetes, 2011.
http://www.cdc.gov/diabetes/pubs/factsheet11.htm

In table of content:
(A) item 3 (titled "Diagnosed and undiagnosed diabetes among people aged 20 years or older, United States, 2010") states, "25.6 million, or 11.3% of all people in this age group, have diabetes"--without dividing into diagnosed and undiagnosed groups.
(B) However, item 1 (titled "Diagnosed and undiagnosed diabetes in the United States, all ages, 2010") does say:

"Total: 25.8 million people, or 8.3% of the U.S. population, have diabetes.

Diagnosed: 18.8 million people

Undiagnosed: 7.0 million people"

Perhaps Americans are more health-conscious (thus seeking medical advice frequently), or have more access to health care, numbers of Americans with undiagnosed diabetes are much smaller than those with diagnosed diabetes (the same may be said about ADULT Amerians)--something in contrast to the Chinese estimates reported in JAMA.

(ii) Number (in Millions) of Civilian, Noninstitutionalized Persons with Diagnosed Diabetes, United States, 1980–2011. CDC, undated.
http://www.cdc.gov/diabetes/stat ... onal/figpersons.htm
(A) I have read "Methods & Limitations" underneath teh table, which states that the number include people of all ages (adult and children), but exclude gestational diabetes (diabetes during pregnancy only).
(B) US Census Bureau reported American population in 1980 and 2010 226,5m and 308.7m, respectively. So the Proportion of Americans (all ages) with DIAGONOSED diabetes actually declined between 1980 and 2010/2011.