Limits...
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.

Show MeSH

Related in: MedlinePlus

Parameter estimates of age, period and cohort effects from the age-period-cohort model (DIC=1486.8) with sex-age, sex-cohort and sex-period interactions (solid circle points for male and triangle points for females).Left hand panel: Estimated age-specific annual female mortality rates due to pneumonia (ICD9=485–486; ICD10= J12 to J18) in 5-year age groups in Hong Kong with 95% credible intervals. Right hand panel: Estimated relative risks for 10-year birth cohorts (nineteen birth cohorts beginning in the calendar year 1986 for each sex) and 5-year calendar periods with 95% credible intervals (six periods beginning from 1976 for each sex).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3375224&req=5

pone-0038988-g004: Parameter estimates of age, period and cohort effects from the age-period-cohort model (DIC=1486.8) with sex-age, sex-cohort and sex-period interactions (solid circle points for male and triangle points for females).Left hand panel: Estimated age-specific annual female mortality rates due to pneumonia (ICD9=485–486; ICD10= J12 to J18) in 5-year age groups in Hong Kong with 95% credible intervals. Right hand panel: Estimated relative risks for 10-year birth cohorts (nineteen birth cohorts beginning in the calendar year 1986 for each sex) and 5-year calendar periods with 95% credible intervals (six periods beginning from 1976 for each sex).

Mentions: We fitted age, period and cohort effects sequentially and compared different models in terms of DICs. Age, period and cohort all contributed to both septicemia and pneumonia mortality rates, and varied with sex, as assessed from the DIC (Table S1). The two full APC models with sex interactions provided the best fit with the smallest values of DICs compared to the other partial models (Table S1). There was also a downturn for the cohort effect for both septicemia and pneumonia in about 1910 (Figure 3, Figure 4). It coincided with the collapse of the Qing dynasty (ending centuries of successive dynastic rule in 1911) and a subsequent fall in living standards, due to the ensuing instability from civil strife. This is most likely a systematic effect due to the population history, whereby any pre-1911 birth cohorts among the mid 20th century migrants had already exceeded life expectancy in China, and were with age increasingly strongly selected healthy migrants [17], [18].


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)

Parameter estimates of age, period and cohort effects from the age-period-cohort model (DIC=1486.8) with sex-age, sex-cohort and sex-period interactions (solid circle points for male and triangle points for females).Left hand panel: Estimated age-specific annual female mortality rates due to pneumonia (ICD9=485–486; ICD10= J12 to J18) in 5-year age groups in Hong Kong with 95% credible intervals. Right hand panel: Estimated relative risks for 10-year birth cohorts (nineteen birth cohorts beginning in the calendar year 1986 for each sex) and 5-year calendar periods with 95% credible intervals (six periods beginning from 1976 for each sex).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0038988-g004: Parameter estimates of age, period and cohort effects from the age-period-cohort model (DIC=1486.8) with sex-age, sex-cohort and sex-period interactions (solid circle points for male and triangle points for females).Left hand panel: Estimated age-specific annual female mortality rates due to pneumonia (ICD9=485–486; ICD10= J12 to J18) in 5-year age groups in Hong Kong with 95% credible intervals. Right hand panel: Estimated relative risks for 10-year birth cohorts (nineteen birth cohorts beginning in the calendar year 1986 for each sex) and 5-year calendar periods with 95% credible intervals (six periods beginning from 1976 for each sex).
Mentions: We fitted age, period and cohort effects sequentially and compared different models in terms of DICs. Age, period and cohort all contributed to both septicemia and pneumonia mortality rates, and varied with sex, as assessed from the DIC (Table S1). The two full APC models with sex interactions provided the best fit with the smallest values of DICs compared to the other partial models (Table S1). There was also a downturn for the cohort effect for both septicemia and pneumonia in about 1910 (Figure 3, Figure 4). It coincided with the collapse of the Qing dynasty (ending centuries of successive dynastic rule in 1911) and a subsequent fall in living standards, due to the ensuing instability from civil strife. This is most likely a systematic effect due to the population history, whereby any pre-1911 birth cohorts among the mid 20th century migrants had already exceeded life expectancy in China, and were with age increasingly strongly selected healthy migrants [17], [18].

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