—May 9th Every Year is 'Breathing Day'—Persistent Cough and Phlegm are Symptoms of Increasing 'Pulmonary NTM Disease' and 'Bronchiectasis' in Middle-Aged and Older Women, with 71.4% Believing 'It's Not Serious Enough to Go to the Hospital'

Insmade LLC (hereinafter 'Insmade', Headquarters: Chiyoda-ku, Tokyo) conducted an online questionnaire survey from December 9th (Tuesday) to December 11th (Thursday), 2025, targeting 1,030 men and women in their 30s to 70s who currently or previously experienced cough or phlegm symptoms. The purpose was to understand general awareness and behavior regarding infectious diseases and respiratory illnesses, including nontuberculous mycobacterial lung disease (hereinafter 'Pulmonary NTM disease'). This survey has been conducted annually since 2021, making this the fifth time. Pulmonary NTM disease and bronchiectasis are chronic respiratory diseases characterized by persistent cough and phlegm. In recent years, the number of patients and deaths from pulmonary NTM disease has been increasing in Japan, surpassing those of pulmonary tuberculosis (1,2). In this survey, while over 90% of respondents were aware of influenza and COVID-19, only 10.2% knew about pulmonary NTM disease and 19.8% about bronchiectasis. 46.6% of people with cough symptoms and 56.3% with phlegm symptoms had not visited a medical institution. The most prominent reason for not seeking medical attention was 'I don't think it's serious enough to go to the hospital' at 71.4%. Regarding the timing for considering a medical visit, over half of respondents cited severe symptoms such as 'when shortness of breath intensified' or 'when it became so painful at night that I couldn't sleep'. For the perception of persistent cough and phlegm, top responses included 'tends to persist due to seasonal or climatic influences' (62.6%) and 'likely to worsen due to allergies or constitution' (52.7%). Professor Koh Minamiya of the Department of Infectious Diseases, Keio University School of Medicine, who has long researched respiratory infections such as pulmonary NTM disease, provided the following message: 'The results of this survey show that many responses attributed the symptoms to 'seasonal or climatic influences' or 'constitution,' suggesting that even when symptoms persist, they are not perceived as potential diseases. Furthermore, awareness of pulmonary NTM disease and bronchiectasis remains low at about 10-20%, indicating that the diseases themselves are not well known, which is also a challenge. In this context, it is conceivable that cases arise where people with chronic symptoms consider them 'not serious enough to go to the hospital' and do not seek medical attention. When cough or phlegm persists for a long period, the possibility of a respiratory disease should be considered. If symptoms continue for three weeks or more, it is important to consider seeking medical attention as a guideline and to consult a doctor instead of self-diagnosing.' This survey clarified the status of medical consultations for chronic cough and phlegm, perceptions of the causes of symptoms, and the recognition status of diseases. When asked if they were aware of infectious and respiratory diseases, 93.2% responded 'yes' for 'influenza' and 93.6% for 'COVID-19'. In contrast, only 10.2% were aware of 'Pulmonary NTM disease' and 19.8% for bronchiectasis. Among those who were aware of cough or phlegm symptoms, 46.6% with cough and 56.3% with phlegm had not visited a medical institution. The most prominent reason for not seeking medical attention, significantly higher than other reasons, was 'I don't think it's serious enough to go to the hospital' at 71.4%, revealing the reality that many people with chronic symptoms observe their condition without seeing a doctor. While over half of the respondents cited severe symptoms such as 'when shortness of breath intensified' or 'when it became so painful at night that I couldn't sleep' as triggers for medical consultation, the results were low for 'when it continued for 2 weeks or more' at 26.6% and 'when it continued for 1 week' at 21.7%. When asked about the perception of persistent cough and phlegm, 'seasonal or climatic influences' and 'allergies or constitution' were frequently cited. Pulmonary NTM disease is an infectious disease caused by nontuberculous mycobacteria infecting the lungs (3). A survey conducted in Japan in 2017 showed that the incidence rate per 100,000 population increased by approximately 3.7 times compared to the national survey in 2007, and currently, the number of patients surpasses that of pulmonary tuberculosis (2,4). Furthermore, particularly in Asia, including Japan, the proportion of the population with pulmonary NTM disease is higher compared to the United States and Europe (5,6). Main symptoms of pulmonary NTM disease include cough, phlegm, hemoptysis (coughing up blood), fatigue, and weight loss, but the severity of symptoms and the course of the disease vary among patients. The Ministry of Health, Labour and Welfare's demographic survey (2024) reported that the annual number of deaths due to pulmonary NTM disease in Japan was 1,261.