Who and What Is a “Population”? Historical Debates,Current Controversies,and Implications for Understanding “Population Health” and Rectifying Health Inequities

Context: The idea of “population” is core to the population sciences but is rarely defined except in statistical terms. Yet who and what defines and makes a population has everything to do with whether population means are meaningful or meaningless, with profound implications for work on population health and health inequities. Methods: In this article, I review the current conventional definitions of, and historical debates over, the meaning(s) of “population,” trace back the contemporary emphasis on populations as statistical rather than substantive entities to Adolphe Quetelet's powerful astronomical metaphor, conceived in the 1830s, of l’homme moyen (the average man), and argue for an alternative definition of populations as relational beings. As informed by the ecosocial theory of disease distribution, I then analyze several case examples to explore the utility of critical population‐informed thinking for research, knowledge, and policy involving population health and health inequities. Findings: Four propositions emerge: (1) the meaningfulness of means depends on how meaningfully the populations are defined in relation to the inherent intrinsic and extrinsic dynamic generative relationships by which they are constituted; (2) structured chance drives population distributions of health and entails conceptualizing health and disease, including biomarkers, as embodied phenotype and health inequities as historically contingent; (3) persons included in population health research are study participants, and the casual equation of this term with “study population” should be avoided; and (4) the conventional cleavage of “internal validity” and “generalizability” is misleading, since a meaningful choice of study participants must be in relation to the range of exposures experienced (or not) in the real‐world societies, that is, meaningful populations, of which they are a part. Conclusions: To improve conceptual clarity, causal inference, and action to promote health equity, population sciences need to expand and deepen their theorizing about who and what makes populations and their means.     

The Trend of Hydatidosis in Kermanshah Province,Western Iran (1986–2008)

Background

Hydatidosis is the larval stage of the Echinococcus granulosus. This disease is endemic in Iran. There are many studies about hydatidosis in different regions of the country, but there is not any information about the disease in Kermanshah Province. This article will review all available data about hydatidosis in this province.

Methods

Using web based search engines and a survey on medical student''s theses, all the information about hydatid cysts in the province from 1986 -2008 was collected.

Results

During these twenty years, at least 482 proven cases of hydatid cyst have been identified in the province. Accordingly, the trend of hydatid cyst operation in the province has been growing and the average annual number of cases has reached 1.41/100,000. Frequency of disease in urban areas was slightly higher than rural areas and the rate of infection in housewives was more than others.

Conclusion

Because of the growing trend of hydatid cyst operation in Kermanshah Province, which may be due to many different reasons, this province should be considered as one of the important endemic regions of hydatidosis in Iran.     

Peer Reviewed: Mortality of Urban Aboriginal Adults in Canada, 1991–2001

Objective

To compare mortality patterns for urban Aboriginal adults with those of urban non-Aboriginal adults.

Methods

Using the 1991–2001 Canadian census mortality follow-up study, our study tracked mortality to December 31, 2001, among a 15% sample of adults, including 16 300 Aboriginal and 2 062 700 non-Aboriginal persons residing in urban areas on June 4, 1991. The Aboriginal population was defined by ethnic origin (ancestry), Registered Indian status and/or membership in an Indian band or First Nation, since the 1991 census did not collect information on Aboriginal identity.

Results

Compared to urban non-Aboriginal men and women, remaining life expectancy at age 25 years was 4.7 years and 6.5 years shorter for urban Aboriginal men and women, respectively. Mortality rate ratios for urban Aboriginal men and women were particularly elevated for alcohol-related deaths, motor vehicle accidents and infectious diseases, including HIV/AIDS. For most causes of death, urban Aboriginal adults had higher mortality rates compared to other urban residents. Socio-economic status played an important role in explaining these disparities.

Conclusion

Results from this study help fill a data gap on mortality information of urban Aboriginal people of Canada.

Keywords

Aboriginal people, First Nations, Métis, Inuit, North American Indians, age-standardized mortality rates, mortality rate, life expectancy     

Prevalence of Hepatitis E Virus Antibodies,Israel, 2009–2010

We investigated prevalence of hepatitis E virus in a sample of the population of Israel. The overall seroprevalence of antibodies to the virus was 10.6% (95% CI 8.4%–13.0%); age-adjusted prevalence was 7.6%. Seropositivity was associated with age, Arab ethnicity, low socioeconomic status, and birth in Africa, Asia, or the former Soviet Union.     

Why Are Infant and Child Mortality Rates Lower in the MCH‐FP Area of Matlab,Bangladesh?

Infant and child mortality rates are significantly lower in the Maternal and Child Health-Family Planning (MCH-FP) area of Matlab, Bangladesh, than in a comparison area. The two areas are similar in terms of socioeconomic characteristics, but the MCH-FP area provides better maternal and child health and family planning services, resulting in different reproductive patterns, including lower fertility rates and longer intervals between pregnancies. We use data from the Matlab Demographic Surveillance System for nearly 126,000 singleton live births that occurred between 1982 and 2002 to investigate the extent to which the different reproductive patterns in the MCH-FP area explain why infant and child mortality rates are lower there. Differences in reproductive patterns account for a small portion (up to 20 percent) of the variation in these rates between the MCH-FP and comparison areas, suggesting that the majority of the difference is due to the quality of MCH services.     

入夏宝宝"降火"10则

夏天,宝宝很容易"上火",不是这儿冒出个疖子,就是那儿长了一堆痱子。妈妈们该如何担起灭火队长的重任,给宝宝"降降火"呢?学学我们的"降火"10则吧。     

Clinical,Environmental, and Serologic Surveillance Studies of Melioidosis in Gabon, 2012–2013

Burkholderia pseudomallei, an environmental gram-negative bacillus, is the causative agent of melioidosis and a bio-threat agent. Reports of B. pseudomallei isolation from soil and animals in East and West Africa suggest that melioidosis might be more widely distributed than previously thought. Because it has been found in equatorial areas with tropical climates, we hypothesized that B. pseudomallei could exist in Gabon. During 2012–2013, we conducted a seroprevalance study in which we set up microbiology facilities at a large clinical referral center and prospectively screened all febrile patients by conducting blood cultures and testing for B. pseudomallei and related species; we also determined whether B. pseudomallei could be isolated from soil. We discovered a novel B. pseudomallei sequence type that caused lethal septic shock and identified B. pseudomallei and B. thailandensis in the environment. Our data suggest that melioidosis is emerging in Central Africa but is unrecognized because of the lack of diagnostic microbiology facilities.     

Microevolution of Monophasic Salmonella Typhimurium during Epidemic,United Kingdom, 2005–2010

Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005–2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North America and Spain. The UK monophasic epidemic clones showed a novel genomic island encoding resistance to heavy metals and a composite transposon encoding antimicrobial drug resistance genes not present in other Salmonella Typhimurium isolates, which may have contributed to epidemiologic success. A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. This high level of microevolution may affect antigenicity, pathogenicity, and transmission.     

Ambient PM<Subscript>10</Subscript> impacts brought by the extreme flooding event of March 24–26, 2015, in Copiapó, Chile

On March 24–26, 2015, the Chilean city of Copiapó (27° 22′ S, 70° 20′ W), located in the hyperarid Atacama Desert, suffered an intense flooding brought by an extreme, unique rainfall event with a 35-year record of daily precipitation. A receptor model (positive matrix factorization, version 5) analysis, applied to ambient PM₁₀ chemical speciation from three short-term sampling campaigns, resolved four sources: crustal/road dust, sea salt, secondary sulfates, and emissions from Paipote copper smelter located 8 km east of Copiapó. Wind trajectories computed with US NOAA’s Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT) supported the above source identification and explained variability in source contributions. It was found that crustal/road dust increased 50 μg/m³, in April 8–10, 2015, as compared with values in November 2014 and October–November 2015, respectively. This was the dominant PM₁₀ source after the flooding and before debris were cleaned up, being on order of magnitude higher that the other source contributions. The Paipote copper smelter contributed with primary PM₁₀ emissions and secondary sulfates; this combined contribution averaged 11.8 μg/m³. Sea salt contributions contributed an average of 3.3 μg/m³. In normal conditions, crustal/road dust averaged 2.9 μg/m³, but the other resolved sources also contributed with crustal elements as their emissions are transported by winds to Copiapó. The positive matrix factorization solution included an unresolved concentration of 7.4 μg/m³. The small number of samples and the lack of measurements of nitrate, ammonia, and organic and elemental carbon may explain this result. Hence, sources such as secondary nitrates and combustion sources plus fugitive dust from sources surrounding Copiapó might be included in that unresolved concentration.     

Staphylococcus aureus Infections in New Zealand, 2000–2011

The incidence rate for invasive and noninvasive Staphylococcus aureus infections in New Zealand is among the highest reported in the developed world. Using nationally collated hospital discharge data, we analyzed the epidemiology of serious S. aureus infections in New Zealand during 2000–2011. During this period, incidence of S. aureus skin and soft tissue infections increased significantly while incidence of staphylococcal sepsis and pneumonia remained stable. We observed marked ethnic and sociodemographic inequality across all S. aureus infections; incidence rates for all forms of S. aureus infections were highest among Māori and Pacific Peoples and among patients residing in areas of high socioeconomic deprivation. The increased incidence of S. aureus skin and soft tissue infections, coupled with the demographic disparities, is of considerable concern. Future work should aim to reduce this disturbing national trend.     

Hopanoid hydrocarbons in PM<Subscript>10</Subscript> from road tunnels in São Paulo,Brazil

The fleet of flexible fuel vehicles in Brazil is the largest in the world. To diagnose the contribution of vehicle emissions to atmospheric particulate matter, organic molecular markers, such as hopanes, can be used. However, nothing is known about the particulate matter mass fractions of these tracers in environments exclusively impacted by road emissions. In this study, the hopanoid composition of PM₁₀ inside two tunnels in the São Paulo metropolitan area with very distinct circulating fleets (Jânio Quadros (JQ) and Rodoanel (RA)) was obtained. Higher mean concentrations (82.4 ng m^?3) and PM₁₀ mass fractions (239 ng mg^?1) were obtained in RA, in which the fleet is composed of both light and heavy duty vehicles. The most abundant species were 17α(H),21β(H)-30-norhopane (27.9 ng mg^?1 in JQ, 47.9 ng mg^?1 in RA) and 17α(H),21β(H)-hopane (32.6 ng mg^?1 in JQ, 44.3 ng mg^?1 in RA). Diverse concentration ratios were calculated and compared with those of other sources. Overlapping values may preclude the use of these parameters as source assignment tools. Some compounds, such as 18α(H)-22,29,30-trisnorneohopane, 17α(H)-22,29,30-trisnorhopane, 17α(H),21β(H)-30-norhopane, 18α(H)-30-norneohopane, 17α(H),21β(H)-hopane, 17α(H),21β(H)-22S-homohopane and 17α(H),21β(H)-22R-homohopane, were found to be very good predictors of the total concentrations of hopanoids.     

再见,"鼻涕虫"

青少年正在长身体，又因上课、作业端坐时间过长，常有弯背现象。有一部分青少年，脊柱本身并没有伤病．但由于经常低头、窝胸．导致“曲线”变形而形成驼背。习惯性低头窝胸和韧带紧缩．后面的肌肉和韧带松弛．日久则形成脊柱韧带前紧后松。数年后，脊柱的前缘被压变窄，成为楔形，使驼背形成。这时再矫治就比较费事。驼背不仅影响形体美，又会挤压与脑、脊髓相关的脑神经、脊神经、内脏神经，造成神经障碍。导致青少年记忆力下降、反应迟钝、智商偏低。可以说驼背同近视一样，是危害青少年健康成长的一大公害。     

Acute Lower Respiratory Tract Infections in Soldiers,South Korea,April 2011–March 2012

During April 2011–March 2012, we retrospectively reviewed medical records for South Korea soldiers to assess the etiology and epidemiology of acute viral lower respiratory tract infections. Adenovirus was the most commonly identified virus (63.2%) and the most common cause of pneumonia (79.3%) and hospitalization (76.6%); 3 soldiers died of adenovirus-related illness.     

Invasive Salmonella enterica Serotype Typhimurium Infections,Democratic Republic of the Congo, 2007–2011

Infection with Salmonella enterica serotype Typhimurium sequence type (ST) 313 is associated with high rates of drug resistance, bloodstream infections, and death. To determine whether ST313 is dominant in the Democratic Republic of the Congo, we studied 180 isolates collected during 2007–2011; 96% belonged to CRISPOL type CT28, which is associated with ST313.