Sex and Age Differences in H1N1 Influenza Morbidity in Japan
Author Information
Author(s): Eshima Nobuoki, Tokumaru Osamu, Hara Shohei, Bacal Kira, Korematsu Seigo, Tabata Minoru, Karukaya Shigeru, Yasui Yoshinori, Okabe Nobuhiko, Matsuishi Toyojiro
Primary Institution: Oita University Faculty of Medicine
Hypothesis
Do morbidity rates of the 2009 pandemic influenza A H1N1 virus vary by age and/or sex?
Conclusion
Males under 20 years and over 80 years are more likely to suffer from pdmH1N1 influenza than females, while the trend reverses in adults aged 20 to 79 years.
Supporting Evidence
- M/F ratios for pdmH1N1 were >1 in age groups <20 years and ≥80 years.
- M/F ratios for pdmH1N1 were <1 in age groups 20–79 years.
- The study analyzed 2,024,367 cases of pdmH1N1.
- The M/F ratio for pdmH1N1 was higher in ages 3–29 years and lower in ages 40–79 years.
Takeaway
Boys and older men are more likely to get sick from a specific flu than girls and older women, but this changes when people are adults.
Methodology
Retrospective analysis of national surveillance data from influenza sentinel points in Japan.
Potential Biases
Possible underreporting of illness by adult males compared to females.
Limitations
The study could not estimate the morbidity rate for the entire Japanese population and may not capture asymptomatic or mild infections.
Participant Demographics
Data collected from various age groups, with a focus on differences between males and females.
Statistical Information
P-Value
<0.001
Confidence Interval
95% CI for M/F ratios varies by age group.
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
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