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Trends in mortality from septicaemia and pneumonia with economic development: an age-period-cohort analysis.

Wong IO, Cowling BJ, Leung GM, Schooling CM - PLoS ONE (2012)

Bottom Line: The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women.Non-bacterial pneumonia-related deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s.The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men.

View Article: PubMed Central - PubMed

Affiliation: Lifestyle and Life Course Epidemiology Group, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.

ABSTRACT

Background: Hong Kong population has experienced drastic changes in its economic development in the 1940s. Taking advantage of Hong Kong's unique demographic and socioeconomic history, characterized by massive, punctuated migration waves from Southern China, and recent, rapid transition from a pre-industrialized society to the first ethnic Chinese community reaching "first world" status over the last 60 years (i.e., in two or three generations), we examined the longitudinal trends in infection related mortality including septicemia compared to trends in non-bacterial pneumonia to generate hypotheses for further testing in other recently transitioned economies and to provide generalized aetiological insights on how economic transition affects infection-related mortality.

Methods: We used deaths from septicemia and pneumonia not specified as bacterial, and population figures in Hong Kong from 1976-2005. We fitted age-period-cohort models to decompose septicemia and non-bacterial pneumonia mortality rates into age, period and cohort effects.

Results: Septicaemia-related deaths increased exponentially with age, with a downturn by period. The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women. Non-bacterial pneumonia-related deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s.

Conclusion: The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men. Given the interaction between the immune system and the gonadotropic axis, these observations are compatible with the hypothesis that upregulation of the gonadotropic axis underlies some of the changes in disease patterns with economic development.

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Related in: MedlinePlus

Age-standardized mortality rates due to pneumonia per 100,000 in Hong Kong, 1975–2005 for (a) female, (b) male populations.
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pone-0038988-g002: Age-standardized mortality rates due to pneumonia per 100,000 in Hong Kong, 1975–2005 for (a) female, (b) male populations.

Mentions: Figures 1 and 2 show the observed sex-specific age-standardized mortality rates for septicemia and pneumonia in Hong Kong from 1976–2005, respectively. Septicemia mortality rates showed an inverted U-shape, which peaked around 1985 to 1995 where female curve peaks later than male’s one (∼1995 vs ∼1985). Pneumonia death rates showed an overall downward trend but had upward short-term increases around 1998. Mortality rates were higher for men than women.


Trends in mortality from septicaemia and pneumonia with economic development: an age-period-cohort analysis.

Wong IO, Cowling BJ, Leung GM, Schooling CM - PLoS ONE (2012)

Age-standardized mortality rates due to pneumonia per 100,000 in Hong Kong, 1975–2005 for (a) female, (b) male populations.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375224&req=5

pone-0038988-g002: Age-standardized mortality rates due to pneumonia per 100,000 in Hong Kong, 1975–2005 for (a) female, (b) male populations.
Mentions: Figures 1 and 2 show the observed sex-specific age-standardized mortality rates for septicemia and pneumonia in Hong Kong from 1976–2005, respectively. Septicemia mortality rates showed an inverted U-shape, which peaked around 1985 to 1995 where female curve peaks later than male’s one (∼1995 vs ∼1985). Pneumonia death rates showed an overall downward trend but had upward short-term increases around 1998. Mortality rates were higher for men than women.

Bottom Line: The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women.Non-bacterial pneumonia-related deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s.The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men.

View Article: PubMed Central - PubMed

Affiliation: Lifestyle and Life Course Epidemiology Group, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.

ABSTRACT

Background: Hong Kong population has experienced drastic changes in its economic development in the 1940s. Taking advantage of Hong Kong's unique demographic and socioeconomic history, characterized by massive, punctuated migration waves from Southern China, and recent, rapid transition from a pre-industrialized society to the first ethnic Chinese community reaching "first world" status over the last 60 years (i.e., in two or three generations), we examined the longitudinal trends in infection related mortality including septicemia compared to trends in non-bacterial pneumonia to generate hypotheses for further testing in other recently transitioned economies and to provide generalized aetiological insights on how economic transition affects infection-related mortality.

Methods: We used deaths from septicemia and pneumonia not specified as bacterial, and population figures in Hong Kong from 1976-2005. We fitted age-period-cohort models to decompose septicemia and non-bacterial pneumonia mortality rates into age, period and cohort effects.

Results: Septicaemia-related deaths increased exponentially with age, with a downturn by period. The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women. Non-bacterial pneumonia-related deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s.

Conclusion: The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men. Given the interaction between the immune system and the gonadotropic axis, these observations are compatible with the hypothesis that upregulation of the gonadotropic axis underlies some of the changes in disease patterns with economic development.

Show MeSH
Related in: MedlinePlus