medwireNews: Individuals who maintain a blood glucose level below the diabetes threshold during middle age have a lower risk for cardiovascular disease (CVD) than those who convert to diabetes during this time, observational study data show.
Michael Bancks (Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA) and colleagues say their findings “strongly support the monitoring of glucose levels during middle age and the importance of public health and clinical strategies that target prevention of incident diabetes by midlife.”
The study included data for 19,630 individuals (56.1% women, 31.6% Black, 68.4% non-Hispanic White) with no history of a CVD event (coronary heart disease [CHD] or stroke) at age 55 years who were enrolled in seven observational cohorts with follow-up from 1960 to 2015.
When the participants were stratified according to fasting glucose level (<5.0, 5.0–5.5, 5.6–6.2, 6.3–6.9, ≥7.0 mmol/L) at age 55 years, the team found that the 30-year absolute risk for CVD ranged from 15.3 to 15.9% for women with glucose levels up to 6.2 mmol/L, then increased to 18.6% for those with a glucose level of 6.3–6.9 mmol/L, and to 38.6% for those with diabetes (fasting glucose ≥7.0 mmol/L).
For men, the corresponding values were 21.5–23.5%, 31.0%, and 47.7%.
After accounting for the competing risk for non-CVD death, Black and White patients had a similar 30-year CVD risk, whereas the risk was higher in men than women, the researchers note.
However, when the competing risk of death was not taken into account, Black men had higher CVD risk than their White counterparts, which was most pronounced in the diabetes category, at 53.5% versus 67.8%.
“This methodological consideration is important in this analysis given that black men have significantly higher risk for death due to diseases of non-cardiovascular origin relative to white men; notably, some of these are directly attributable to diabetes (i.e., diseases of the kidneys),” Bancks and co-authors remark.
In a subset of 16,070 individuals with repeated fasting glucose measurements over an average of 4 years, 20-year CVD risk was lowest among those who had normal levels (<5.6 mmol/L) at both examinations for both women (14.2%) and men (23.4%).
In contrast to the researchers’ hypothesis, the 20-year risk for CVD was not substantially higher for women and men who developed impaired fasting glucose (5.6–6.9 mmol/L) during the 4-year period (16.9% and 29.3%, respectively) or for those who had impaired levels at both time points (16.1% and 29.8%, respectively).
On the other hand, the CVD risk was significantly higher for both women and men who transitioned from normal fasting glucose to diabetes (25.5% and 42.8%, respectively) and from impaired fasting glucose to diabetes (35.7% and 38.0%), as well as for those with diabetes at both time points (57.2% and 55.5%, respectively), when compared with patients who maintained normal fasting glucose levels.
Writing in Diabetes Care, Bancks et al conclude that their “results suggest a threshold effect in glucose level for the long-term absolute risk for CVD, including both CHD and stroke,” which “strongly supports current diabetes diagnostic thresholds and an emphasis for diabetes prevention among individuals with prediabetes.”
By Laura Cowen
medwireNews is an independent medical news service provided by Springer Healthcare. © 2019 Springer Healthcare part of the Springer Nature group
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