Elevated blood sugar levels and diabetes are risk
factors for developing several types of cancer and
mortality, according to researchers at the Johns Hopkins
Bloomberg School of Public Health and Yonsei University in
Seoul, Korea. The researchers followed more than 1.2
million Koreans for 10 years, tracking new cancer cases and
deaths from cancer. Study participants with diabetes, as
well as those without diabetes and higher fasting blood
sugar levels, were more likely to develop cancer or to die
from cancer. For those without diabetes, cancer risk
increased with an increasing fasting blood sugar level. The
study is published in the Jan. 12 issue of the Journal of
the American Medical Association.
"Although past research has shown that having diabetes
or an elevated glucose level may increase cancer risk, the
evidence has been mixed, and many of the studies to date
were relatively small," said Jonathan M. Samet, a co-author
of the study and the Jacob I. and Irene B. Fabrikant
Professor of Health, Risk and Society and chair of the
Department of Epidemiology in the Bloomberg School.
The researchers carried out a 10-year study of
1,298,385 Korean men and women, ages 30 to 95. The study
participants were members of the National Health Insurance
Corp., which provides health insurance to government
employees, teachers and their dependents. The participants
provided information on their lifestyles and medical
histories. Fasting blood samples were taken at biennial
The risk of developing cancer was comparable to the
risk of dying from cancer. The group with the highest
fasting glucose levels (greater than 140 mg/dL) had higher
death rates from all cancers combined. In men, the
strongest associations were for pancreatic cancer;
significant associations were also found in men for cancers
of the esophagus, liver and colon/rectum. In women, the
strongest links were to cancers of the liver and cervix.
The authors noted that the study participants were
substantially leaner than the typical Western population.
They concluded that glucose intolerance may be one way that
obesity increases cancer risk and that the rising obesity
rates may increase future cancer rates.
"This study provides more information on glucose
intolerance, an emerging cause of cancer. It points to
increased cancer risk as another adverse consequence of
rising obesity around the world," concluded lead author Sun
Ha Jee, an adjunct assistant professor in the Bloomberg
School's Department of Epidemiology and an assistant
professor of epidemiology and disease control at Yonsei
The study authors were supported in part by grants
from the National Cancer Institute.
Additional co-authors of the study include Heechoul
Ohrr, Jae Woong Sull, Ji Eun Yun and Ji Min.