# Findings on Age at Onset of Cancer in Diabetic and Non-diabetic Populations

## TL;DR

This study finds that people with diabetes tend to develop cancer about 7 years earlier than those without diabetes, suggesting a possible link between the two conditions.

## Contribution

The study reveals a significant age difference in cancer onset between diabetic and non-diabetic populations, highlighting new insights into their potential association.

## Key findings

- Diabetic patients developed cancer on average 7.4 years earlier than non-diabetic patients.
- 27 out of 28 cancer types showed differences in age at onset between diabetic and non-diabetic groups.
- BMI differences were statistically significant in breast, endometrial, head and neck, and thyroid cancers.

## Abstract

Background

Diabetes mellitus and cancer are two associated chronic diseases. Despite being a widely researched topic, the underlying mechanisms of this association remain unclear. One of the poorly explored topics regarding diabetes and cancer is the relation between the age of cancer onset and diabetes mellitus status; therefore, this research exposes the difference in the age of cancer diagnosis in both groups.

Methods

We conducted a retrospective study by reviewing the clinical files on a secondary care hospital's database. Files from first-time consultations of patients over 18 diagnosed using a histopathological report were included. The present study aimed to determine whether there is a difference in age at the onset of cancer in diabetic and non-diabetic individuals. Moreover, we calculated the average BMI at the onset for both populations.

Results

Our study included 8,741 patients; 1,551 (17.8%) were diabetic, and 7,190 (82.2%) were non-diabetic. From 28 types of cancer, 27 showed a difference in the age at the onset of cancer when diabetic and non-diabetic subjects were compared. This difference is significant as it suggests a potential link between diabetes and cancer, which could have implications for early detection and prevention strategies. Out of the 27 types, 17 showed statistical significance with p-values ranging from 0.048 to <0.0001 considering a 95% CI. Among those, the most significant types of cancer were breast, cervical, lung, ovarian, rectal, thyroid, and sarcoma, reporting p-values <0.0001. The mean age at onset of cancer in diabetic and non-diabetic populations was 62.7 years (SD ± 3.9) and 55.3 years (SD ± 7.9), respectively, showing a difference of 7.4 years in both groups. The BMI was statistically significant in patients with breast (p = 0.006), endometrial (p = 0.007), head and neck (p=0.014), and thyroid (p = 0.022) cancer types.

Conclusion

The data offer a critical view of the relationship between cancer and diabetes. Since virtually no one has produced a similar report, there is a broad field for researching the causal factors implicated in the pathway of diabetic and non-diabetic individuals who develop cancer. Research regarding metformin, diabetic neuropathy, and other possible causes must be addressed to determine whether they are involved in this process.