Latitudes mediate the association between influenza activity and meteorological factors : A nationwide modelling analysis in 45 Japanese prefectures from 2000 to 2018

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Ka Chun Chong
  • Katherine Min Jia
  • Nobumichi Kobayashi
  • Maggie Haitian Wang
  • Lai Wei
  • Steven Yuk Fai Lau
  • Ayako Sumi

Detail(s)

Original languageEnglish
Article number134727
Journal / PublicationScience of the Total Environment
Volume703
Online published31 Oct 2019
Publication statusPublished - 10 Feb 2020
Externally publishedYes

Abstract

Background: Cold and dry conditions were well-documented as a major determinant of influenza seasonality in temperate countries but the association may not be consistent when the climate in temperate areas is closer to that in sub-tropical areas. We hypothesized latitudes may mediate the association between influenza activity and meteorological factors in 45 Japanese prefectures.

Methods: We used the weekly incidence of influenza-like illness of 45 prefectures from 2000 to 2018 as a proxy for influenza activity in Japan, a temperate country lying off the east coast of Asia. A combination of generalized additive model and distributed lag nonlinear model was adopted to investigate the associations between meteorological factors (average temperature, relative humidity, total rainfall, and actual vapour pressure, a proxy for absolute humidity) and the influenza incidence. Kendall's tau b (τ) and Spearman correlation coefficient (rs) between latitude and the adjusted relative risk (ARR) of each meteorological factor were also assessed.

Results:  A higher vapour pressure was significantly associated with a lower influenza risk but the ARR strongly weakened along with a lower latitude (τ = -0.23, p-value = 0.02; rs= -0.33, p-value = 0.03). Lower temperature and lower relatively humidity were significantly associated with higher influenza risks in over 65% and around 40% of the prefectures respectively but the strength and significance of the correlations between their ARRs and latitude were weaker than that from vapour pressure.

Conclusion: Even though the range of latitudes in Japan is small (26°N-43°N), the relationships between meteorological factors and influenza activity were mediated by the latitude. Our study echoed absolute humidity played a more important role in relating influenza risk, but we on the other hand showed its effect on influenza activity could be hampered in a low-latitude temperate region, which have a warmer climate. These findings thus offer a high-resolution characterization of the role of meteorological factors on influenza seasonality.

Research Area(s)

  • Influenza, Temperature, Humidity, Latitude, Japan

Citation Format(s)

Latitudes mediate the association between influenza activity and meteorological factors: A nationwide modelling analysis in 45 Japanese prefectures from 2000 to 2018. / Chong, Ka Chun; Liang, Jingbo; Jia, Katherine Min et al.
In: Science of the Total Environment, Vol. 703, 134727, 10.02.2020.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review