In Japan, asthma mortality declined from 1950 to 2019, but halted in 1978 and continued to stall till 1996, plateauing at high levels. Notably, 1978 marked the onset of widespread pollen dispersal in Japan, suggesting increased pollen exposure may have influenced asthma severity, contributing to symptom changes, worsening, and exacerbations during this period nationwidely
Akira Awaya,
Yoshiyuki Kuroiwa,
Tatsuya Yamashita
Background: While examining a bar graph showing asthma deaths in Japan since 1950, the author
noticed that the steady downward trend had temporarily shifted to a sharp increase in 1995, and
suspected that this phenomenon might be an extremely useful clue in investigating the cause of death
from asthma. 1995 was the year that saw the largest amount of pollen ever recorded at that time. The
author found in 2003 the association between pollen dispersal levels and the onset of Kawasaki disease
(KD) during 1970 to 2003 and has reported on the phenomena in four papers by 2016. Subsequently,
the author analyzed the correlation between the dynamics of seasonal influenza cases and fluctuations in
pollen counts within Kanagawa Prefecture during the period from 1991 to 2002. As a result, the author
discovered that seasonal influenza outbreaks occur annually10 months after the peak pollen exposure
period, similar to KD.
Methods: The author then created a graph by merging a line graph showing the trend in asthma deaths
with a line graph analyzing the correlation between seasonal influenza patient numbers and pollen count
fluctuations within Tokyo and Kanagawa Prefectures.
Results: The declining trend in asthma deaths was interrupted in 1978, the year that marked the
beginning of massive pollen dispersal in Japan. During this period from 1978 to 1996, asthma deaths
fluctuated, but peaks in asthma-related deaths were observed three times around 1980, 1983, and 1985-
6.
Remarkably, three peaks in the number of KD cases occurred at almost the same time in 1979, 1982 and
1985-6, coinciding precisely with three peaks in pollen dispersal counts. An astonishing phenomenon
existed: three independent metrics—the number of asthma deaths, the number of KD patients, and
the number of hay fever sufferers—showed a perfect correlation, demonstrating three simultaneous
increases in peak numbers at precisely about the same time.
Peaks in pollen dispersal continued in 1988, 1990, and 1993. As a result of this sustained exposure to
pollen, a growing number of patients have developed severe chronic conditions, placing them at risk of
dying from asthma.
Conclusions: The author interpreted the reason for the transient surge in asthma deaths in 1995 as
follows: patients in this asthma death reserve group were exposed to the largest-ever mass pollen
exposure at the time, occurring in early spring 1995. This exposure caused them to die one after another
each month, as if clearing out a stockpile.
