Relationship Between Annual Airborne Pollen Levels and Occurrence of Parkinson Disease, Amyotrophic Lateral Sclerosis, Myasthenia Gravis, Multiple Sclerosis, Spinocerebellar Degeneration, Huntington’s Disease, Shy-Drager Syndrome, Moyamoya Disease and Creutzfeldt- Jakob Disease Based on the National Registry Database of Specific Intractable Disease in Japan, 1974-2014: A Retrospective Study
Akira Awaya and Yoshiyuki Kuroiwa
Background: In Japan, pollen counts increased between 1977 and 1987, including three peaks (1978-
1980, 1982, 1984-1986) coinciding with triphasic Kawasaki disease (KD) outbreaks. Epidemiological
findings have been then extensively accumulated that KD and related specific intractable diseases such as
systemic vasculitis, collagen diseases, inflammatory bowel diseases, idiopathic dilated cardiomyopathy
and further various cancers may be correlated to pollen exposure (PE).
Methods and results: To elucidate the effects of PE on outbreaks of neurological intractable diseases
(NIDs), we evaluated the annual occurrence of disorders in relation to pollen counts using data from a
national database. Specifically, we evaluated the occurrence of Parkinson disease (PD), amyotrophic
lateral sclerosis (ALS), Myasthenia Gravis (MG), multiple sclerosis (MS), spinocerebellar degeneration
(SCD), Huntington’s disease (HUNTG), Shy-Drager syndrome, moyamoya disease and CreutzfeldtJakob disease (CJD). During 1975–2014, the 1984-86 peak of pollen scatter was the earliest big peak
with which simultaneous increase in occurrence of PD, ALS, MG, MS, SCD and HUNTG coincided.
Furthermore, simultaneous outbreaks of each NID coincided with subsequent ten peaks of pollen
scatter till 2014. Our results showed statistically significant correlations for PD, ALS, MG, MS and
SCD between the annual number of newly registered patients (nRPs) in the patient-registry year and
annual pollen levels in the same patient-registry year. Significant correlations were also shown between
the number of nRPs in the patient-registry year and annual pollen levels measured 3 years (PD), 6 years
(PD, MG, MS, MMD), 9 years (PD, MS, MMD, CJD), 14 years (PD, CJD), and 16 years MG, MS,
HUNTG and MMD before the patient-registry year.
Conclusion: We assume that cumulative effects of PE during a decade or more before the diagnosis
of NIDs might possibly trigger onset of NIDs when cumulative effects of PE as environmental stress
overwhelmed immunoreactive threshold.
