Researchers studied 200 adults between ages 35-45 to understand why some people have type 2 diabetes without knowing it. They found that about 1 in 7 people in this age group had undiagnosed diabetes. The study discovered that people who were overweight, didn’t exercise much, or smoked were more likely to have diabetes without realizing it. These findings suggest that doctors should pay special attention to these risk factors when deciding who needs diabetes screening, especially in middle-aged patients visiting clinics.

The Quick Take

  • What they studied: Why some middle-aged adults have type 2 diabetes but don’t know it, and what lifestyle habits are connected to undiagnosed diabetes
  • Who participated: 200 adults aged 35-45 years old who visited outpatient clinics (regular doctor’s offices) between January and June 2024
  • Key finding: About 14.5% (roughly 1 in 7) of the middle-aged adults studied had undiagnosed type 2 diabetes. People with undiagnosed diabetes were more likely to be overweight, exercise less, and smoke compared to those without diabetes.
  • What it means for you: If you’re in your late 30s or 40s and have extra weight, don’t exercise regularly, or smoke, you might benefit from getting your blood sugar checked even if you feel fine. Early detection can help prevent serious health problems.

The Research Details

This was a cross-sectional study, which means researchers looked at a group of people at one point in time rather than following them over months or years. Between January and June 2024, researchers recruited 200 adults aged 35-45 from outpatient clinics. Each participant had their height and weight measured to calculate body mass index (BMI), which is a measure of whether someone is at a healthy weight. Participants answered questionnaires about how much they exercise and what they eat, and reported whether they smoke. After fasting overnight (not eating or drinking), participants had blood tests to measure their fasting blood glucose and HbA1c levels—two tests that show if someone has diabetes.

This research approach is important because it shows a real-world picture of how many middle-aged adults have undiagnosed diabetes in typical doctor’s offices. By measuring actual blood sugar levels and asking about lifestyle habits, the researchers could identify which behaviors are most strongly connected to undiagnosed diabetes. This information helps doctors know who should be screened for diabetes and what warning signs to look for.

The study used standardized, validated questionnaires (International Physical Activity Questionnaire and Mediterranean Diet Adherence Screener) that are widely used in research. Blood tests followed official American Diabetes Association criteria, making the diabetes diagnosis reliable. The statistical analysis was appropriate for this type of study. However, because this was a snapshot in time at specific clinics, the results may not represent all middle-aged adults everywhere.

What the Results Show

Out of 200 middle-aged adults studied, 29 people (14.5%) had undiagnosed type 2 diabetes. This means that if you randomly selected 7 middle-aged adults from a doctor’s office, roughly 1 would have diabetes without knowing it. People with undiagnosed diabetes had a higher average body mass index (30.6 compared to 27.6 for those without diabetes), meaning they carried more weight relative to their height. They also reported exercising less and were more likely to be smokers. When researchers used statistical analysis to determine which factors were most important, three stood out: higher body weight, lower physical activity, and smoking. Each of these factors independently increased the chances of having undiagnosed diabetes.

The study’s statistical model was quite good at predicting who might have undiagnosed diabetes (with an area under the curve of 0.74, which is considered good discrimination). The model had a 93.3% negative predictive value, meaning if the model predicted someone didn’t have diabetes, there was a 93.3% chance that prediction was correct. This suggests these three factors—weight, exercise, and smoking—are reliable indicators for doctors to use when deciding who needs diabetes screening.

Previous research has shown that obesity, inactivity, poor diet, and smoking increase diabetes risk in general. This study confirms those findings specifically in middle-aged adults with undiagnosed diabetes, showing that these lifestyle factors are particularly important for identifying people who might have diabetes without knowing it. The finding that 14.5% of middle-aged adults in outpatient settings have undiagnosed diabetes is consistent with other studies showing that many people have diabetes without diagnosis.

This study looked at only 200 people from outpatient clinics during a 6-month period, so the results may not apply to all middle-aged adults everywhere. The study didn’t follow people over time, so we can’t say whether these lifestyle factors actually cause undiagnosed diabetes or just happen to occur together. The study didn’t measure diet quality directly, only diet adherence patterns. Additionally, the study was conducted at specific clinics, which may not represent the general population.

The Bottom Line

If you’re between 35-45 years old and have one or more of these characteristics—overweight or obese, physically inactive, or a current smoker—ask your doctor about getting your blood sugar tested. This is a simple blood test that can catch diabetes early. Even if you feel fine, early detection allows for treatment that can prevent serious complications like heart disease, kidney problems, and vision loss. (Confidence: Moderate—based on observational data)

This research is most relevant for middle-aged adults (35-45 years old), their doctors, and public health professionals designing screening programs. If you’re in this age group with risk factors (overweight, sedentary, or smoking), you should consider getting screened. This may be less directly applicable to younger adults or those already diagnosed with diabetes, though the lifestyle factors are important for everyone.

Getting screened takes just one blood test, which provides immediate results. If you’re diagnosed with diabetes, lifestyle changes like increasing physical activity and quitting smoking can show benefits within weeks to months. However, preventing diabetes complications is a long-term commitment, typically requiring ongoing lifestyle changes and medical monitoring over years.

Want to Apply This Research?

  • Track your weekly exercise minutes and smoking status. Set a goal of at least 150 minutes of moderate activity per week and monitor progress toward quitting smoking if applicable. Also track weight weekly to monitor BMI trends.
  • Use the app to set reminders for physical activity (aim for 30 minutes most days), log meals to ensure balanced nutrition, and track smoking reduction milestones if you smoke. Create alerts to remind you to schedule a diabetes screening if you haven’t had one recently.
  • Monthly check-ins on weight and exercise consistency. If you’ve been diagnosed with prediabetes or diabetes, use the app to track blood sugar readings if you have a home monitor, log medication adherence, and schedule regular follow-up appointments with your doctor. Set annual reminders for diabetes screening if you have risk factors.

This research describes associations between lifestyle factors and undiagnosed diabetes in a specific study population and should not be used for self-diagnosis. If you are concerned about diabetes risk or have symptoms such as increased thirst, frequent urination, or unexplained fatigue, consult with your healthcare provider for proper evaluation and testing. This information is educational and does not replace professional medical advice, diagnosis, or treatment. Always discuss screening recommendations and lifestyle changes with your doctor, especially if you have existing health conditions or take medications.