How Does Parkinson’s Prevalence Differ in People With Diabetes, What Percentage Are Affected, and How Do Comorbid Risks Compare With Those Without Diabetes?
By mr.hotsia
This article is written by mr.hotsia, a long term traveler and storyteller who has spent years exploring Thailand, Laos, Vietnam, Cambodia, Myanmar, India and many other Asian countries. Along the way, he has seen how chronic conditions often travel in pairs. One diagnosis rarely walks alone for long. Parkinson’s disease and diabetes are a strong example of that pattern, and modern research increasingly suggests that the relationship between them is not accidental.
🌍 Why This Question Matters
For many years, Parkinson’s disease was treated mainly as a movement disorder and diabetes as a metabolic problem. That old separation is fading. Several recent reviews and meta-analyses suggest that people with diabetes, especially type 2 diabetes, are more likely to develop Parkinson’s disease than people without diabetes. On top of that, once Parkinson’s and diabetes occur together, the combined burden often looks heavier than Parkinson’s alone.
That does not mean most people with diabetes will develop Parkinson’s disease. They will not. The absolute percentage remains relatively low in broad population studies. But the difference is still clinically important because the relative risk is repeatedly higher, and the overlap seems to be linked with more difficult motor and cognitive outcomes.
📊 Does Parkinson’s Disease Occur More Often in People With Diabetes?
The shortest honest answer is yes. Most modern pooled analyses show that diabetes is associated with a modest but real increase in Parkinson’s risk.
A 2023 systematic review and meta-analysis of cohort studies reported that diabetes was associated with a 27% higher relative risk of developing Parkinson’s disease. Another 2023 meta-analysis found a pooled OR/RR of 1.23, while a 2021 meta-analysis found a pooled OR of 1.34 for Parkinson’s disease in people with diabetes versus those without diabetes. Put simply, many of the better-known pooled estimates cluster around a roughly 23% to 34% higher risk.
A 2024 systematic review and meta-analysis focused specifically on type 2 diabetes found an even stronger pooled estimate, reporting that type 2 diabetes increased the likelihood of Parkinson’s disease with an OR of 1.59. That same review also found that diabetes complications pushed the odds higher still. However, the authors also noted substantial heterogeneity and judged the certainty for some outcomes to be low, so that stronger figure should be read as important but not as a single final number for every population.
So if someone wants one plain-language takeaway, it is this: Parkinson’s disease appears more common in people with diabetes than in those without diabetes, but the increase is usually modest rather than dramatic.
🔢 What Percentage Are Affected?
This part needs careful wording, because researchers often report the relationship as risk or incidence rather than one universal prevalence percentage. There is no single global percentage that cleanly answers, “What percent of all people with diabetes have Parkinson’s?” Age, follow-up length, diabetes severity, and study design all change the number.
Still, there are a few useful percentage anchors.
In the 2024 type 2 diabetes meta-analysis, 48,609 of 32,551,133 participants, or about 0.15%, were reported as having both type 2 diabetes and Parkinson’s disease across the pooled datasets. That figure helps show that the absolute overlap is not huge in broad mixed populations, even though the relative risk is clearly elevated.
A large Taiwanese cohort study reported Parkinson’s incidence rates of 3.59 per 10,000 person-years in the diabetes group versus 2.15 per 10,000 person-years in the control group. In simpler terms, that is about 0.036% per year in the diabetes group compared with about 0.022% per year in the non-diabetes group in that study.
Looking from the other direction can also be useful. A 2021 systematic review found that the prevalence of diabetes among people who already have Parkinson’s disease was 10.02%. In the large Tracking Parkinson’s study, 8.7% of patients with Parkinson’s had type 2 diabetes. So while the absolute percentage of diabetic patients who later develop Parkinson’s remains fairly low, diabetes itself is not rare inside Parkinson’s cohorts.
The most accurate practical wording, then, is this: the absolute percentage of diabetic patients who have Parkinson’s is still relatively small in population datasets, but it is consistently higher than in comparable people without diabetes, and roughly one in ten Parkinson’s patients may also have diabetes.
⚠️ Does Severity of Diabetes Matter?
Yes, and this is one of the most important parts of the story.
A 2023 nationwide cohort study showed that Parkinson’s risk rose as diabetes severity increased. Compared with diabetic patients who had no diabetes-severity score parameters, the hazard ratios for Parkinson’s disease increased stepwise from 1.09 with one parameter to 2.78 with six parameters. The same study noted that people with a severity score of 4 or higher had more than double the risk of Parkinson’s compared with those with a score of 0.
That study also found that individual diabetes complications mattered. Chronic kidney disease was associated with an adjusted HR of 1.20, diabetic retinopathy with 1.35, and cardiovascular disease with 1.38 for Parkinson’s risk within the diabetic population. In other words, it is not just the presence of diabetes that matters. Longer duration, more complex treatment, and more complications seem to push Parkinson’s risk higher.
This is a very useful real-world clue. The label “diabetes” is only the first layer. The deeper issue is how long the diabetes has been present, how severe it is, and whether it has already left marks on blood vessels, kidneys, eyes, or cardiovascular health.
🧠 How Do Comorbid Risks Compare With Parkinson’s Patients Without Diabetes?
This is where the overlap stops looking like a small epidemiology footnote and starts looking like a real clinical burden.
The 2021 systematic review concluded that Parkinson’s patients with diabetes showed greater motor severity and faster progression than Parkinson’s patients without diabetes. Specifically, they had higher Hoehn and Yahr stage and higher UPDRS scores, which are standard measures of Parkinson’s severity. The same review also reported that several included studies linked diabetes with worse cognitive performance in Parkinson’s disease.
The 2023 meta-analysis added sharper numbers. It found that Parkinson’s patients with diabetes had faster motor progression than Parkinson’s patients without diabetes, with a pooled RR of 1.85, and faster cognitive decline, with a pooled OR/RR of 1.92. Those are not tiny differences. They suggest that diabetes may substantially worsen the trajectory once Parkinson’s is already present.
The 2024 systematic review focusing on type 2 diabetes reached a similar directional conclusion, reporting that type 2 diabetes was associated with more severe motor decline and that diabetes complications were linked to a higher likelihood of Parkinson’s disease. The authors were appropriately cautious because the certainty of several outcomes was low, but the overall signal still leaned toward a worse clinical burden in the comorbid group.
🚶 What Does This Look Like in Daily Life?
The Tracking Parkinson’s study helps make the issue more concrete.
In that study, 167 of 1,930 patients, or 8.7%, had both Parkinson’s disease and type 2 diabetes. Those patients had more severe motor symptoms at baseline and significantly faster motor symptom progression over time. They were also more likely to have depression, substantial gait impairment, and loss of independence than Parkinson’s patients without diabetes.
The same study reported that type 2 diabetes was independently associated with greater gait impairment with an OR of 2.91, depression with an OR of 1.62, and loss of independence with an OR of 2.08. Over time, it also predicted the development of substantial gait impairment with an HR of 1.55 and mild cognitive impairment with an HR of 1.70.
That translates into something patients and families can feel. The overlap may mean walking becomes harder earlier, balance becomes more fragile, thinking slows more quickly, mood symptoms become more common, and daily independence is easier to lose. It is not just “two diagnoses on the same chart.” It often looks like a steeper road.
🧩 Is This About Parkinson’s Starting, or Parkinson’s Progressing Worse?
The evidence suggests both.
First, diabetes is associated with a higher chance of later Parkinson’s disease compared with no diabetes. Second, once Parkinson’s disease is already present, diabetes appears to be associated with worse motor symptoms, faster progression, more gait problems, more depression, and more cognitive decline. That two-stage pattern is why so many newer reviews treat diabetes not as a side issue, but as a potentially important modifying factor in Parkinson’s disease.
This does not prove that diabetes directly causes every case of Parkinson’s disease. But from a practical standpoint, it means metabolic health may matter more in Parkinson’s than people once assumed. It also explains why researchers are interested in whether better diabetes management, or even diabetes-targeted medications, could influence Parkinson’s outcomes in the future.
🌿 What Should Patients and Families Take From This?
First, most people with diabetes will not develop Parkinson’s disease. The absolute numbers remain low in the general population. Second, the association still matters because diabetic individuals, on average, appear to have a higher relative risk of Parkinson’s disease than people without diabetes. Third, if a patient already has Parkinson’s disease, coexisting diabetes may be a clue to monitor more carefully for gait decline, mood symptoms, cognitive change, and loss of independence.
In everyday terms, this means glucose control, cardiovascular risk management, exercise, fall prevention, and attention to cognition may carry extra importance in this group. The evidence does not say that every problem can be prevented, but it clearly says that Parkinson’s plus diabetes is usually a less friendly combination than Parkinson’s without diabetes.
✅ The Bottom Line
People with diabetes appear to have a higher risk of Parkinson’s disease than people without diabetes. Across major pooled analyses, the excess risk usually falls in the range of roughly 23% to 34%, although some type 2 diabetes analyses report even stronger associations.
There is no perfect single universal percentage for “how many diabetics get Parkinson’s,” but broad datasets suggest the absolute overlap is still relatively low, with one large meta-analysis reporting 0.15% of participants diagnosed with both conditions and one cohort showing 3.59 versus 2.15 per 10,000 person-years in diabetes versus non-diabetes groups.
When both conditions occur together, the clinical picture is usually worse than Parkinson’s alone. Compared with Parkinson’s patients without diabetes, those with diabetes tend to show more severe motor symptoms, faster motor progression, faster cognitive decline, more gait impairment, more depression, and greater loss of independence.
That is the real headline. Diabetes does not simply sit beside Parkinson’s disease. In many patients, it seems to make the journey harder.
❓ FAQs
1. Do people with diabetes have a higher chance of Parkinson’s disease?
Yes. Most pooled analyses report a modest but real increase in risk compared with people without diabetes.
2. Does that mean most people with diabetes will get Parkinson’s?
No. The absolute percentage remains low in broad population studies, even though the relative risk is higher.
3. What is the best simple number to remember?
A fair summary is that diabetes is associated with roughly one-quarter to one-third higher relative risk of Parkinson’s disease in many pooled analyses.
4. What percentage of Parkinson’s patients also have diabetes?
A 2021 systematic review estimated that 10.02% of Parkinson’s patients had diabetes, and the Tracking Parkinson’s cohort found 8.7% with type 2 diabetes.
5. Is severity of diabetes important?
Yes. More severe diabetes, longer duration, and more complications are linked with higher Parkinson’s risk.
6. Which diabetes complications seem especially relevant?
Chronic kidney disease, diabetic retinopathy, and cardiovascular disease were each linked with higher Parkinson’s risk in a large cohort study.
7. Do Parkinson’s patients with diabetes usually have worse movement symptoms?
Yes. Studies and meta-analyses suggest worse motor severity and faster motor progression than in Parkinson’s patients without diabetes.
8. What about memory and thinking?
Comorbid diabetes has been linked with faster cognitive decline and a higher risk of mild cognitive impairment in Parkinson’s disease.
9. Does diabetes affect gait and independence in Parkinson’s disease?
Yes. In the Tracking Parkinson’s study, type 2 diabetes was linked with more gait impairment and greater loss of independence.
10. What is the main practical takeaway?
The overlap between Parkinson’s and diabetes deserves extra attention because it appears to increase both the chance of Parkinson’s and the chance of a more difficult disease course once Parkinson’s is present.
I’m Mr.Hotsia, sharing 30 years of travel experiences with readers worldwide. This review is based on my personal journey and what I’ve learned along the way. Learn more |