Increased consumption of red meat over a 4-year period was associated with higher risk that type 2 diabetes would develop during the next 4 years, according to a report published online June 17 in JAMA Internal Medicine.
This association was strong in both men and women in a large cohort study with 12-16 years of follow-up, regardless of the subjects’ baseline level of red meat intake, the overall quality of their diet, or their body weight, said An Pan, Ph.D., of the department of nutrition, Harvard School of Public Health, Boston, and his associates.
Previous studies, largely cross-sectional, have noted a correlation between the consumption of red meat and current diabetes risk but have had limited duration of follow-up. This is the first study to assess changes in the intake of red meat over time and subsequent diabetes risk, and it confirms the robustness of the association, the investigators said.
©Len Rizzi/National Cancer Institute
A new report suggests that read meat consumption may increase risk of developing type 2 diabetes.
However, because this was an observational study, it cannot determine causality, they noted.
Dr. Pan and his colleagues examined the issue using data from three large cohort studies: the Health Professionals Follow-Up Study (HPFS), the Nurses’ Health Study (NHS), and the Nurses’ Health Study II (NHS II). All of these collected measurements of red meat intake every 4 years, as well as other dietary, lifestyle, and medical factors.
For their investigation, Dr. Pan and his associates analyzed data for 26,357 male health care professionals aged 40-75 years at baseline in 1986 and 122,786 female nurses aged 25-55 years at baseline in either 1986 or 1991.
These subjects reported how often, on average, they consumed a standard portion size of red meat, which was defined as beef, pork, or lamb as a main dish; hamburger; beef, pork or lamb as a sandwich or mixed dish; as well as bacon, hot dogs, sausage, salami, bologna, and other processed red meats. The responses ranged from never or less than once per month to six or more times per day.
A total of 7,540 cases of incident type 2 diabetes developed during follow-up: 1,561 in the HPFS, 3,482 in the NHS, and 2,497 in the NHS II.
Compared with people whose intake of red meat was relatively stable during each 4-year period, those who increased their intake were at elevated risk for developing diabetes in all three cohorts, said Dr. Pan, who is also at the National University of Singapore, and his colleagues.
Raising consumption by more than 0.5 servings per day was associated with a 48% rise in diabetes risk during the next 4 years in the study population as a whole. And even among nonobese adults, increasing intake by 0.5 servings per day was associated with a 65% greater risk of diabetes, the investigators said (JAMA Intern. Med. 2013 June 17 [doi:10.1001/jamainternmed.2013.6633]).
Diabetes risk was "modestly" attenuated when the data were adjusted to account for the concurrent weight gain that often accompanied greater intake of red meat. This suggests that weight gain accounted for some, but not all, of the association between red meat intake and diabetes.
In addition, the association was stronger for processed than for nonprocessed red meats.
Unfortunately, study subjects who cut back on red meat did not show a significant reduction in diabetes risk during the ensuing 4 years. However, the highest reduction of red meat intake – decreasing consumption by more than 0.5 servings per day during the initial 4 years of follow-up – was associated with a 10% lower risk of diabetes by the end of the entire follow-up of 16 years after adjustment for BMI plus concurrent weight gain.
This study was limited in that the reasons why subjects increased or decreased their intake of red meat were unknown, and could not be accounted for in the data analysis. In addition, the study subjects were primarily white and well-educated adults, so the findings may not be generalizable to other populations, the researchers said.
This study was supported by the National Institutes of Health and the National Heart, Lung, and Blood Institute. No financial conflicts of interest were reported.