Delaying diabetes through diet, exercise for 4 years reduces risk for death

Key takeaways:

• Delaying diabetes for 4 years reduced the risk for all-cause mortality and delaying it for 6 years halved the risk for CVD death.
• The findings may be due to the “legacy” effect phenomenon, researchers said.

People who delayed diabetes through diet and exercise for at least 4 years after their prediabetes diagnosis had a lower risk for death and other adverse outcomes vs. those who were diagnosed with diabetes during that time, a study showed.

Previous research has suggested that lifestyle changes and healthy diets, like those with low amounts of carbohydrates, can help improve glycemic control and prevent the development of diabetes in people with prediabetes.

However, Xin Qian, from the Chinese Academy of Medical Sciences and Peking Union Medical College in China, and colleagues noted that clinical recommendations “do not specify the target number of years for delaying the onset of diabetes through lifestyle interventions to prevent the associated comorbidities.”

In the post-hoc analysis, published in PLOS Medicine, the researchers examined data from 540 Chinese participants diagnosed with prediabetes included in the Da Qing Diabetes Prevention Study (DQDPS).

Between 1986 and 1992, participants were assigned to a control group or one of three lifestyle intervention groups — following a healthy diet, getting more exercise or both. Their diabetes status was assessed at 2, 4 and 6 years, and they were followed for more than 30 years.

The researchers found no significant differences in all-cause and CVD mortality between those who progressed to diabetes and those who did not after 2 years.

However, compared with the diabetes group, Qian and colleagues found that individuals who remained non-diabetic after 4 years had a significantly lower risk for:

• all-cause death (HR = 0.74; 95% CI, 0.57-0.97);
• cardiovascular events (HR = 0.63; 95% CI, 0.49-0.82);
• macrovascular complications (HR = 0.63; 95% CI, 0.49-82); and
• microvascular complications (HR = 0.62; 95% CI, 0.45-0.86).

A 50% risk reduction for CVD death (HR = 0.52; 95% CI, 0.33-0.80) was seen at 6 years in those who remained non-diabetic, and risk reductions in vascular complications and all-cause death persisted, according to Qian and colleagues.

These associations remained even after the researchers adjusted for factors like BMI, smoking and systolic BP.

Regarding possible mechanisms, Qian and colleagues wrote that prior studies on diabetes have shown “that strict, early, glycemic control can improve long-term adverse outcomes through a phenomenon called the ‘legacy’ effect.”

For example, in three previous trials on diabetes prevention, “the effect of a 3- to 6-year lifestyle intervention extended to a post-trial follow-up period of more than 10 years,” Qian and colleagues wrote.

“Our previous study reported that the median delay in diabetes duration in individuals who remained non-diabetes status for 6 years was 17 years,” they wrote. “Hence, it is easy to understand why time-limiting lifestyle interventions decrease the subsequent long-term risk of adverse clinical outcomes.”

Researchers noted limitations of the study included the findings may not be generalizable to other populations, and other unmeasured confounders that may have impacted the results could not be ruled out.

Qian and colleagues added that a study lasting more than 7 years is needed to confirm the effects of the interventions’ durations on death and vascular complications.

Ultimately, “taking action, including but not limited to lifestyle intervention, to prolong the diabetes-free time in people with prediabetes may be crucial,” they concluded.

References:

• Delaying diabetes with diet and exercise for 4 years results in better long-term health. https://www.eurekalert.org/news-releases/1050178. Published July 9, 2024. Accessed July 8, 2024.
• Qian X, et al. PLoS Med. 2024;doi:10.1371/journal. pmed.1004419.