Estimated prevalence and incidence of hypersensitivity pneumonitis in Japan

Tsukasa Okamoto; Mariko Hanafusa; Taketomo Abe; Takashi Shimamura; Masaru Ito; Yoko Wakai; Torahiko Jinta; Katsuyuki Higa; Yasuhiro Kondoh; Yasumi Okouchi; Ryo Okuda; Masashi Bando; Takafumi Suda; Hiromi Tomioka; Takeo Fujiwara; Masato Takase; Shigemi Yoshihara; Hiroshi Odajima; Yasunari Miyazaki

doi:10.1016/j.alit.2024.06.002

Estimated prevalence and incidence of hypersensitivity pneumonitis in Japan

Allergol Int. 2025 Jan;74(1):66-71. doi: 10.1016/j.alit.2024.06.002. Epub 2024 Aug 19.

Authors

Tsukasa Okamoto¹, Mariko Hanafusa², Taketomo Abe³, Takashi Shimamura³, Masaru Ito³, Yoko Wakai⁴, Torahiko Jinta⁵, Katsuyuki Higa⁶, Yasuhiro Kondoh⁷, Yasumi Okouchi⁸, Ryo Okuda⁹, Masashi Bando¹⁰, Takafumi Suda¹¹, Hiromi Tomioka¹², Takeo Fujiwara¹³, Masato Takase¹⁴, Shigemi Yoshihara¹⁵, Hiroshi Odajima¹⁶, Yasunari Miyazaki¹⁷

Affiliations

¹ Department of Respiratory Medicine, Tokyo Medical and Dental University, Tokyo, Japan; Center for Personalized Medicine for Healthy Aging, Tokyo Medical and Dental University, Tokyo, Japan.
² Department of Tokyo Metropolitan Health Policy Advisement, Tokyo Medical and Dental University, Tokyo, Japan.
³ Department of Respiratory Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
⁴ Department of Respiratory Medicine, Tsuchiura Kyodo General Hospital, Ibaraki, Japan.
⁵ Department of Respiratory Medicine, St. Luke's International Hospital, Tokyo, Japan.
⁶ Department of Pulmonary Medicine, Nippon Medical School Hospital, Tokyo, Japan.
⁷ Department of Respiratory Medicine and Allergy, Tosei General Hospital, Aichi, Japan.
⁸ Department of Respiratory Medicine, Japan Community Health Organization, Tokyo Yamate Medical Center, Tokyo, Japan.
⁹ Department of Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center, Kanagawa, Japan.
¹⁰ Division of Pulmonary Medicine, Department of Medicine, Jichi Medical University, Tochigi, Japan.
¹¹ Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
¹² Department of Respiratory Medicine, Kobe City Medical Center West Hospital, Kobe, Japan.
¹³ Department of Global Health Promotion, Tokyo Medical and Dental University, Tokyo Japan.
¹⁴ Department of Pediatrics, Tokyo Teishin Hospital, Tokyo, Japan.
¹⁵ Department of Pediatrics, Dokkyo Medical University, Tochigi, Japan.
¹⁶ Department of Pediatrics, NHO Fukuoka National Hospital, Fukuoka, Japan.
¹⁷ Department of Respiratory Medicine, Tokyo Medical and Dental University, Tokyo, Japan. Electronic address: [email protected].

PMID: 39572336
DOI: 10.1016/j.alit.2024.06.002

Abstract

Background: The latest guidelines on hypersensitivity pneumonitis (HP) categorise the disease as either fibrotic or non-fibrotic because of the greater clinical utility of this stratification. However, the prevalence and incidence of fibrotic and non-fibrotic HP are unknown. This study assessed the exact prevalence and incidence of fibrotic and non-fibrotic HP in Japan in 2021.

Methods: For adults, the study hospitals were selected by stratified random sampling according to numbers of beds. The sampling rate was set at about 20%. The questionnaire survey was submitted to the target hospitals. For pediatric cases, a survey was distributed to all members of the Japanese Society of Pediatric Pulmonology and Japanese Society of Pediatric Allergy and Clinical Immunology.

Results: Regarding adult cases, in total, 575 facilities responded to the survey, resulting in a response rate of 36.4%. The estimated prevalence and incidence of fibrotic HP were 6.3 and 2.5 per 100,000 population, respectively, versus 3.6 and 2.0 per 100,000 population, respectively, for non-fibrotic HP. Both fibrotic and non-fibrotic HP were more prevalent in southern Japan (Kyushu) and less prevalent in northern Japan (Hokkaido). The incidence of non-fibrotic HP was significantly lower in December than in the other months (relative risk ratio = 0.36, p < 0.001). Three cases of fibrotic HP and five cases of non-fibrotic HP were identified in children.

Conclusions: This study determined the prevalence and incidence of fibrotic and non-fibrotic HP in Japan for the first time.

Keywords: Epidemiologic study; Fibrotic hypersensitivity pneumonitis; Incidence; Non-fibrotic hypersensitivity pneumonitis; Prevalence.

MeSH terms

Adolescent
Adult
Alveolitis, Extrinsic Allergic* / diagnosis
Alveolitis, Extrinsic Allergic* / epidemiology
Child
Child, Preschool
Female
Humans
Incidence
Japan / epidemiology
Male
Middle Aged
Prevalence
Surveys and Questionnaires