Researchers studied nearly 1,000 Iranian adults to understand how tiny differences in a gene called VDR (vitamin D receptor) might affect diabetes risk. They found that people with a specific genetic variation called the ApaI polymorphism had a higher chance of developing prediabetes or type 2 diabetes. This discovery suggests that our genes play a role in diabetes risk, and someday doctors might use genetic testing to identify who needs extra help preventing diabetes. However, this finding only applies to this specific population, and more research is needed before doctors can use this information in everyday medical care.

The Quick Take

  • What they studied: Whether specific variations in the VDR gene (which helps your body use vitamin D) are connected to the risk of developing prediabetes or type 2 diabetes
  • Who participated: 976 adults from Iran, divided into three groups: people with type 2 diabetes, people with prediabetes (blood sugar higher than normal but not yet diabetic), and healthy people without diabetes
  • Key finding: People who carry a specific genetic variation called the CC genotype of the ApaI polymorphism were 66% more likely to have prediabetes or diabetes compared to those with the AA genotype. People with at least one A version of this gene were 35% less likely to develop these conditions
  • What it means for you: Your genes may influence your diabetes risk, but genes are just one piece of the puzzle. Lifestyle choices like diet and exercise still matter greatly. This research is early-stage and mainly applies to Iranian populations—more studies are needed before genetic testing becomes a standard diabetes prevention tool

The Research Details

Scientists looked at information from 976 adults who were part of a larger Iranian health study. They divided participants into three groups: those with type 2 diabetes, those with prediabetes, and those who were healthy. The researchers examined five different spots in the VDR gene where people commonly have variations (called polymorphisms). They tested each person’s DNA to see which genetic variations they carried, then compared these genetic patterns between the three groups to see if any variations were more common in people with diabetes or prediabetes.

The researchers used statistical methods to account for other factors that affect diabetes risk, such as age, weight, gender, and vitamin D levels in the blood. This helps them figure out whether the gene variations themselves were connected to diabetes risk, or whether other factors were responsible. They focused especially on one variation called ApaI because it showed the strongest connection to diabetes risk.

Understanding the genetic factors behind diabetes is important because it could help doctors identify people at highest risk before they develop the disease. If we know which genes increase diabetes risk, we might be able to develop better prevention strategies tailored to each person’s genetics. This approach, called personalized medicine, could make diabetes prevention more effective than one-size-fits-all advice.

This study has several strengths: it included a reasonably large number of participants (976 people), it compared three different groups (healthy, prediabetic, and diabetic), and it accounted for other important factors that affect diabetes risk. However, the study was conducted only in Iran, so the results may not apply equally to other ethnic groups. The researchers only found a strong connection with one of the five gene variations they tested, which suggests the other variations may not be important for diabetes risk in this population. The study is observational, meaning it shows an association but cannot prove that the gene variation directly causes diabetes.

What the Results Show

The most important finding was about the ApaI gene variation. People with the CC genotype (meaning they inherited the C version from both parents) had a 66% higher risk of developing prediabetes or type 2 diabetes compared to people with the AA genotype (who inherited the A version from both parents). To put this in perspective, if 10 people with the AA genotype developed diabetes, about 16-17 people with the CC genotype would be expected to develop it.

When researchers looked at it another way, they found that people who had at least one A version of the gene (either AA or AC genotypes) were 35% less likely to develop prediabetes or diabetes compared to those with the CC genotype. This suggests that having the A version of this gene may be protective against diabetes risk.

The other four gene variations the researchers tested (TaqI, EcoRV, FokI, and BsmI) did not show a clear connection to diabetes or prediabetes risk in this Iranian population. This means that among these five variations, only the ApaI polymorphism appeared to be meaningfully related to diabetes risk.

The study confirmed that other known risk factors for diabetes were still important, including higher body weight (BMI), older age, and lower vitamin D levels. These factors remained connected to diabetes risk even after accounting for the genetic variations. This shows that genes are not the only thing that matters—lifestyle and environmental factors continue to play major roles in diabetes development.

Previous research on VDR gene variations and diabetes has produced mixed results, with some studies finding connections and others not finding them. This study adds to that body of research by focusing specifically on an Iranian population. The finding that ApaI polymorphism is connected to diabetes risk in Iranians is consistent with some previous studies but contradicts others, suggesting that genetic risk factors may differ between different ethnic groups. This highlights why it’s important to study diverse populations rather than assuming findings from one group apply to everyone.

The biggest limitation is that this study only included people from Iran, so we don’t know if these findings apply to people from other ethnic backgrounds or countries. The study is observational, meaning researchers simply observed which genetic variations people had and whether they had diabetes—they didn’t randomly assign people to different groups, so we can’t be completely certain the gene variation causes the increased risk. The study only looked at five specific gene variations, so there may be other variations in the VDR gene that also affect diabetes risk. Finally, the study was conducted at one point in time, so researchers couldn’t follow people over years to see who actually developed diabetes.

The Bottom Line

Based on this research, genetic testing for the ApaI polymorphism is not yet recommended as a standard tool for diabetes prevention (low confidence level for clinical use). However, this research suggests that if you have a family history of diabetes, it’s even more important to focus on proven prevention strategies: maintain a healthy weight, exercise regularly, eat a balanced diet, and get your vitamin D levels checked. If you’re interested in genetic testing for diabetes risk, discuss it with your doctor, but understand that genes are only part of the picture.

This research is most relevant to people of Iranian descent or those with similar genetic backgrounds. It’s particularly important for people who have family members with type 2 diabetes, as they may have inherited similar genetic variations. However, everyone should care about diabetes prevention regardless of genetics, since lifestyle factors remain the most changeable and impactful risk factors. People with prediabetes should especially focus on lifestyle changes, which can often prevent or delay type 2 diabetes development.

If you make lifestyle changes based on this research (like improving diet and exercise), you might see improvements in blood sugar levels within weeks to months. However, preventing the progression from prediabetes to type 2 diabetes typically takes months to years of consistent effort. Genetic factors don’t change, but their impact can be reduced through healthy lifestyle choices.

Want to Apply This Research?

  • If you have a family history of diabetes or prediabetes, track your fasting blood sugar levels monthly (if you have access to testing) or track your weight weekly and waist circumference monthly, as these are early warning signs of diabetes risk
  • Set a specific goal to increase physical activity to at least 150 minutes per week and reduce refined carbohydrates in your diet. Log these activities in your app to maintain accountability and see patterns over time
  • Create a long-term tracking dashboard that monitors weight, exercise frequency, diet quality (especially carbohydrate intake), and any available blood sugar measurements. Review trends quarterly to assess whether lifestyle changes are working and adjust strategies as needed

This research describes an association between a specific gene variation and diabetes risk in an Iranian population and should not be used for self-diagnosis or to replace medical advice. Genetic factors are only one piece of diabetes risk—lifestyle, diet, exercise, and other health factors play equally or more important roles. If you’re concerned about your diabetes risk, especially if you have a family history of diabetes or have been told you have prediabetes, consult with your healthcare provider. This study does not currently support routine genetic testing for this variation in clinical practice. Always discuss any genetic testing or major health decisions with a qualified healthcare professional.