USA: Consuming a healthier diet may lower the risk of type 2 diabetes irrespective of genetic risk, a recent study in the journal PLOS One has concluded.
"Our data provide affirmation for the independent associations of genetic risk and diet quality with incident type 2 diabetes," Jordi Merino, Harvard Medical School, Boston, Massachusetts, USA, and colleagues wrote in their study. "Study findings might be a valuable piece of information for primary prevention of type 2 diabetes."

Both lifestyle and genetic factors contribute to type 2 diabetes risk, but there is no clarity on the the extent to which there is a synergistic effect of the 2 factors. The researchers' team therefore aimed to examine the joint associations of genetic risk and diet quality with incident type 2 diabetes.
For this purpose, the researchers analyzed data from 35,759 men and women in the United States who were participants in the Nurses' Health Study (NHS) I (1986 to 2016) and II (1991 to 2017) and the Health Professionals Follow-up Study (HPFS; 1986 to 2016) with available genetic data and who did not have diabetes, cardiovascular disease, or cancer at baseline.
Characterization of genetic risk was done using both a global polygenic score capturing overall genetic risk and pathway-specific polygenic scores denoting distinct pathophysiological mechanisms. The Alternate Healthy Eating Index (AHEI) was used for assessing diet quality. After adjusting for potential confounders, Cox models were used to calculate hazard ratios (HRs) for type 2 diabetes.
Based on the study, the researchers found the following:
With over 902,386 person-years of follow-up, 4,433 participants were diagnosed with type 2 diabetes.
The relative risk of type 2 diabetes was 1.29 per standard deviation (SD) increase in global polygenic score and 1.13 per 10-unit decrease in AHEI.
Irrespective of genetic risk, low diet quality, as compared to high diet quality, was associated with approximately 30% increased risk of type 2 diabetes.
The joint association of low diet quality and increased genetic risk was similar to the sum of the risk associated with each factor alone.
Limitations of this study include the self-report of diet information and possible bias resulting from inclusion of highly educated participants with available genetic data.
"Our results emphasizes the value of genetic risk assessment for identifying individuals at increased disease risk and their potential for risk stratification and surveillance," the authors wrote.
Reference:
Merino J, Guasch-Ferré M, Li J, Chung W, Hu Y, Ma B, et al. (2022) Polygenic scores, diet quality, and type 2 diabetes risk: An observational study among 35,759 adults from 3 US cohorts. PLoS Med 19(4): e1003972. https://doi.org/10.1371/journal.pmed.1003972