New Blood Biomarkers Identified for Headache Susceptibility: Findings Presented at the Japanese Society of Neurology Annual Meeting

New Blood Biomarkers Identified for Headache Susceptibility

Daiichi Sankyo Healthcare Co., Ltd. (Headquarters: Chuo-ku, Tokyo; President: Takahiro Uchida; hereafter "the Company") has revealed new findings regarding blood components (factors) common to people prone to headaches, through a joint analytical study utilizing health big data conducted with Hirosaki University and the University of Tokyo Institute of Medical Science.

The findings were presented at the 67th Annual Meeting of the Japanese Society of Neurology on May 21, 2026.

According to a survey conducted by the Company, approximately one in four Japanese people experience headaches at least once a week, making them a common and significant health concern. However, objective indicators (biomarkers) for evaluating headaches have not been sufficiently understood until now.

This study confirmed that specific blood factors tend to show lower levels in people prone to headaches, providing new scientific insights.

### 1. Research Background and Objectives While headaches are a common symptom experienced by many, they often go unaddressed or untreated at medical institutions, negatively impacting quality of life and daily activities such as work and housework. While constitutional factors, lifestyle habits, and nutritional status are believed to be involved, limited studies have examined the correlation between objective data, such as blood tests, and headaches in the general population.

In 2024, the Company established the "Health Life Science Research Course" with Hirosaki University, promoting research utilizing health big data collected for many years from annual health checkups of residents in the Iwaki district of Hirosaki City, as part of the "Iwaki Health Promotion Project." This big data covers approximately 30,000 people and includes about 3,000 items per person, such as blood tests, lifestyle habits, and sleep patterns.

This study aimed to: (1) understand the actual state of headaches, and (2) identify blood factors associated with headaches.

### 2. Research Overview and Results The study targeted 1,162 residents of the Iwaki district who underwent health checkups in fiscal 2024 as part of the "Iwaki Health Promotion Project." Participants were asked about the presence, frequency, symptoms, and coping methods for headaches over the past year, and their responses were analyzed in conjunction with blood test results.

#### <Results (1)> Understanding the Actual State of Headaches The prevalence of headaches in the past year was higher among women and younger generations. Among headache sufferers, less than 10% of both men and women had been diagnosed at a medical institution, confirming that many people manage them through self-judgment.

#### <Results (2)> Exploration of Blood Factors Associated with Headaches Comparing "people who experienced headaches in the past year" with "those who did not" in blood test results revealed differences in the blood concentration of the following factors:

- Nervonic acid (a type of ultra-long-chain fatty acid) - 25(OH)D3 (active vitamin D)

It was confirmed that these factors showed lower levels in headache sufferers regardless of age or gender. Furthermore, similar results were found in analyses considering the impact of other multiple blood factors simultaneously, suggesting these blood factors may be related to headache susceptibility.

(Note) Nervonic acid: A fatty acid known as a component of nerve cell membranes. Showing its association with headaches through this research is a new discovery.

### 3. Future Prospects This study has demonstrated a new link between physical condition and blood factors for headaches, a symptom difficult to evaluate objectively. With further detailed examination, these could become effective biomarkers for headache prediction and management.

While many people use over-the-counter headache medication, it is important to address headaches appropriately—including reviewing lifestyle habits or consulting medical institutions—if they persist or medication usage increases. These findings are expected to contribute to future self-care and health awareness, serving as a tool to help individuals understand their physical condition and manage headaches effectively.