High Glycemic Index Foods May Increase Risk for Type 2 Diabetes in
Chinese Women CME

News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd

Complete author affiliations and disclosures, and other CME information,
are available at the end of this activity.

Release Date: December 4, 2007; Valid for credit through December 4, 2008
Credits Available
Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™ for physicians;
Family Physicians - up to 0.25 AAFP Prescribed credit(s) for physicians

All other healthcare professionals completing continuing education
credit for this activity will be issued a certificate of participation.
Physicians should only claim credit commensurate with the extent of
their participation in the activity.

December 4, 2007 — High intake of foods with a high glycemic index (GI),
especially rice, may increase the risk for type 2 diabetes mellitus in
middle-aged women of Chinese descent, according to the results of a
large prospective study in the November 26 issue of the Archives of
Internal Medicine.

"Much uncertainty exists about the role of dietary glycemic index and
glycemic load [GL] in the development of type 2 diabetes mellitus,
especially in populations that traditionally subsist on a diet high in
carbohydrates," write Raquel Villegas, PhD, from the Vanderbilt
University Medical Center in Nashville, Tennessee, and colleagues.
"Using data collected in the Shanghai Women's Health Study, we
prospectively examined the relationships between dietary carbohydrates,
GI, GL, and carbohydrate-rich foods with the risk of type 2 DM [diabetes
mellitus] in middle-aged Chinese women."

The investigators observed a cohort of 64,227 Chinese women free of
diabetes or other chronic disease at baseline for 4.6 years, using
in-person interviews and a validated questionnaire to collect data on
dietary habits, physical activity, and other pertinent information. Cox
proportional hazards models were used to determine associations between
dietary carbohydrate intake, GI, and GL and the incidence of diabetes.

During 297,755 person-years of follow-up, 1608 incident cases of type 2
diabetes mellitus were identified. Dietary carbohydrate and rice
consumption were each positively associated with the risk of developing
type 2 diabetes mellitus. For the highest vs the lowest quintiles of
intake, the multivariable-adjusted estimates of relative risk (RR) were
1.28 (95% confidence interval [CI], 1.09 - 1.50) for carbohydrates and
1.78 (95% CI, 1.48 - 2.15) for rice. For increasing quintiles of intake,
the RR was 1.00, 1.04, 1.02, 1.09, and 1.21 (95% CI, 1.03 - 1.43) for
dietary GI and 1.00, 1.06, 0.97, 1.23, and 1.34 (95% CI, 1.13 - 1.58)
for dietary GL.

"High intake of foods with a high glycemic index and glycemic load,
especially rice, the main carbohydrate-contributing food in this
population, may increase the risk of type 2 diabetes mellitus in Chinese
women," the study authors write.

Limitations of the study include limited follow-up and statistical
power, so that results of most of the tests for multiplicative
interaction were not significant.

"In this large population-based cohort study, we found that a diet high
in carbohydrates and with a high GI was associated with a higher risk of
type 2 DM, in particular in participants with high WHR [waist-hip ratio]
and BMI [body mass index]," the study authors conclude.

*****"Given that a large part of the world's population consumes rice
and carbohydrates as the mainstay of their diets, these prospective data
linking intake of refined carbohydrates to increased risk of type 2 DM
may have substantial implications for public health."*******

The US Public Health Service, National Institutes of Health, supported
this study. Two of the study authors have received funding. The
remaining study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2007;167:2310-2316.