Qualitative Demography - Topic 1 - 3

Topic 1: Sociogenomics, Low Fertility, Second Demographic Transition; Topic 2: Demographic Transition Theory, Family Planning Programs, Global South; Topic 3 - Epidemiological Transition Theory, Health Disparities, Life Expectancy

J.C. Chenais, 1992 The Demographic Transition

The demographic transition consists of a logical succession of historical phases through which every population passes through on the movement towards modernity; attempts to validate the three central propositions: (1) the chronological sequence (e.g. mortality decline --> fertility decline), (2) the role of the reproductive transition in two phases (both the restriction of marriage and the limitation of births), (3) the influence on the context of modernization following fertility decline

Raymo et al., 2015

Declining marriage and fertility rates in East Asia are due to the conflict between socioeconomic change and traditional family roles; i.e. opportunity costs of marriage are high for well-educated women who are still expected to do housework; increase in divorce rates in China might be related to 2nd DTT

Environmental influences on fertility

The 'ecological context,' including the physical, cultural and social environment, e.g. social conventions, education, etc.

Mills and Tropf, 2015

15% of AFB (age at first birth) and 10% NEB (number of children ever born) variance is explained by common genetic variance

Billari, 2022, "Demography: Fast and Slow"

Extends the DTT to include mention of the speed of demographic change; suggests that transition between 'slow' to 'fast' demography is due to development and in particular migration; Found that population turnover (the speed of population change) is inversely related to population size; relevant to incorporation debates: rapid change in population composition can challenge host societies’ capacity to adapt.

Heritability

Ranges from 0 to 1; where at 1 all phenotypic variance is accounted for by genetic variance

Genetic Correlation

Ranges from 0 to 1; where at 1 all genetic variance is shared; compares one or more traits in one or more populations

Biodemography of Fertility

investigates human fertility and family formation by combining sociological/economic theories with approaches from behavioral genetics, molecular genetics, neuro-endocrinology; cross-species life history analysis, and evolutionary theory

Sociogenomics

Social genomics,' looking for the basis of social behaviors like fertility in the genome

Polygenic Risk Score

An index that linearly aggregates the estimated effects of individual single nucleotide polymorphisms on a trait of interest, using weights derived from GWAS

Genome-Wide Association Studies

take the genomes of a large population, and through statistical methods create a polygenic score, or a single quantitative variable that describes an individual’s predisposition for developing a particular trait

Gene x Environment Interaction

Metaphor of a horse race - the horse is genetics, the jockey is the environment → the phenotype (which horses win the race) is based on the interaction between both the jockey and the horse

Diathesis-Stress Model

Predisposition for a trait often lies dormant unless triggered by an environmental stressor, e.g. a high PGS for major depressive disorder only gets triggered after major life events (Mills and Tropf, 2020)

Bioecological (Social Compensation) Model

Genetic influences are maximized in stable, adaptive, and often high socioeconomic environments, e.g. higher heritability for IQ in higher income families from maximizing genetic potential (Mills and Tropf, 2020)

Differential Susceptibility Model

Argues that plasticity varies by individual, with some individuals more genetically susceptible (orchids) to both positive and negative environments; and others less so (dandelions) (Mills and Tropf, 2020)

Social control model

Genetic influences are filtered or buffered in particular environments due to cultural or structural restraints (Mills and Tropf, 2020)

Urdy, 1996

Proposed that there would be greater heritability of fertility behaviors in less socially restrictive contexts; example of social control model

Briley et al., 2016

Modern reproductive behavior in low fertility societies is subject to substantial sociocultural influences that may interact with genetic predispositions; some individuals may readily accept changing social norms and values for family formation, whereas others may respond more slowly

Kohler et al., 2002

For female Danish twin cohorts born between 1945 and 1952, shared environmental factors constitute the most important influence that leads to within-cohort variation on the level of early fertility; and heritable factors are virtually absent; this pattern REVERSES for cohorts born between 1961 and 1968: genetic effects are the most important, shared environment the least

Twin studies

Analyze monozygotic (MZ) and dizygotic (DZ) twin pairs to study heritability

Kohler and Rogers, 2003

Analyzed education and cohorts in a twin study; found that genetic influences on fertility tend to become stronger in twin pairs with higher levels of education and in later cohorts; evidence for the bioecological and social control models

Genetic correlation-by-environment (rGE)

A correlation of two factors, one genetic and one environmental; make it difficult to determine which one is involved in the development of the trait (e.g. depression)

Passive rGE

association between the genotype a child inherits from a parent and the environment in which they're raised

Evocative rGE

when a person's heritable traits evoke reactions from others in the environment

Assertive rGE

when individuals actively seek or create environments that are associated with their heritable traits (niche creation)

Chopstick effect

GWAS must account for populations or they can lead to overestimated SNP-based heritability; a GWAS for chopstick use would likely result in cases being drawn more often from an East Asian population rather than controls, SNPs identified may have nothing to do with chopsticks at all

Biological Proximity

Closeness' to DNA for particular traits, measures influence by environment; e.g. fertility is further from DNA, education is kilometers away

GWAS vs. Twin Studies

Twin studies heritability estimates are inflated; GWAS are slightly deflated; twin studies include rare variants whereas GWAS are common variants only

Genetic influences on Fertility

DIRECT - genetic disposition for physiological characteristics, e.g. fecundity

INDIRECT - genetic disposition for fertility-related decisions and behaviors, whether consciously or unconsciously

Both indirect and direct influences often require a polygenic configuration of alleles

Mills et al., 2023

Identification of 370 loci for age at onset of sexual and reproductive behavior, highlighting common causes with reproductive biology, externalizing behaviour and longevity

Akimova et al., 2021

Controlling for heritable covariates (like education or income) in models with polygenic scores can introduce collider bias, leading to spurious associations between genes and outcomes; the study warns that such bias can distort results in studies of mediation, confounding, and gene × environment interactions, and emphasizes the need for causal inference approaches.

Second Demographic Transition Theory (SDT) (van de Kaa, 1987)

Argues that sustained sub-replacement fertility, a multitude of living arrangements other than marriage, & the disconnection between marriage and procreation is driven by a cultural shift towards post-modern attitudes and norms (e.g. those stressing individuality and self-actualization)

Difference between first and second DTT

The transition was a switch from altruistic to individualistic norms; and led by factors such as greater female emanicipation and individual autonomy; first transition was motivated by economic change primarily, whereas the second transition was motivated by ideational change

Critiques of the second DTT

Failure to predict variation in declining fertility rates; for instance, Japan is leading the decline but it still lags in cohabitation rates; changing patterns in some Nordic countries towards an increase in fertility is yet explained

Esping-Andersen and Billari (2015)

Argues for an extension of the first demographic transition theory by two stages:

Stage IV: Very low fertility is due to unresolved work-family conflict for women; social norms and policies haven't caught up to women's new roles in the family and work

Stage V: The 'gender equity dividend;' fertility rates rebound (e.g. Sweden) when women have a better balance between work (maternity leave, childcare, etc.) and family life (more equal division of parenting and housework)

Strengths of the demographic transition model

General structure is followed by many European societies; most developed countries have low birth and death rates; 70% of all mortality declines in 28 cities from 1900-1936 were the direct result of water purification and increased caloric intake

Weaknesses of the demographic transition model

Ignores heterogeneity between/within populations (e.g. starting birth and death rates will be different); assumes no fertility control pre-transition (Hungarian villages and Cameroonian women); no mention of a pre decline rise; not all transitions are uniform (Spanish flu); ignores the potential for a migration transition; link between dependent variables (mortality and fertility) and independent variables (economics) is not very strong

Dependent variable problem

a critique of demographic models that overemphasize external drivers and treat populations as reactive rather than proactive in shaping their own demographic behaviors.

Revised Demographic Transition Theory

Should focus on both bottom-up (endogeneity) and top-down (exogeneity) approaches at meso-level, rather than national level, populations

Knodel and van de Walle, 1979 "Lessons from the Past: Policy Implications for Historical fertility declines"

Development' is the best contraceptive; Suggested that culture/language may play a role in fertility decline than just development; gives the example of French/Dutch speaking Belgium and suggests that birth control was just 'figured out' and spread;

England vs. France's fertility decline

In the England, the industrial revolution begins in the 18th century and the demographic transition in the 19th -- the opposite is true of France; France is influenced/interrupted by the decline of religious ideals because of the revolution, and the 'agrarian issue' (i.e. large population working in agriculture but a failure to improve food production)

A.J. Coale, 1986 The Decline of Fertility in Europe from the French Revolution to World War 2

Results from the Princeton Fertility Project concluded that the decline of fertility was due to the decline in mortality, the rising costs and diminished economic advantages of having children in industrial societies, higher status of women, religious changes and the development of a rational secular attitude

Santow, 1995

There are a lot of issues in the distinction between 'natural' fertility and 'parity-dependent' birth control (e.g. absitence and spacing are not considered birth control); evidence from pre-modern Hungary that a woman waited on average 40 months before her first child after marriage, likely due to the pull-out method (Coitus interruptus)

The demographic transition

First proposed by Notestein in 1945, the logical succession of populations from a state of high mortality and fertility to one of low mortality and fertility because of economic development

J.C. Chenais, 1992 The Demographic Transition

The demographic transition consists of a logical succession of historical phases through which every population passes through on the movement towards modernity; attempts to validate the three central propositions: (1) the chronological sequence (e.g. mortality decline --> fertility decline), (2) the role of the reproductive transition in two phases (both the restriction of marriage and the limitation of births), (3) the influence on the context of modernization following fertility decline

Cai, 2010

Suggested that even under China's One-Child Policy, regional variations to fertility were not significantly associated with enforcement or very strong policies, but rather Foreign Direct Investment (FDI), a proxy for economic development

Family Planning Programs (FPPs)

Public health initiatives aimed at both increasing access to contraceptives and decreasing desired family sizes

Lee et al, 1998

Cross-country comparison of several nations' FPPs, found that successful FPPs were guided by a strong national government effort; listing the formation of a strong coalition amongst policy elites, the spreading of policy risk, and institutional and financial stability

Pritchett, 1994

Argues that FPPs have no or limited effect, but rather changing fertility desires trump access to contraceptives (because coitus interruptus is always an option)

Population and Development 'P & D'

Based around the idea that the Western economy and society provided the only model for population change; widespread criticism that P & D worked strongly to sustain and increase inequalities of wealth, power, and well-being

Matlab Experiment

Family Planning and Health Services Project (PFHSP) Bangladesh experiment (1970s-1990s) -- provided half of the region with free contraceptives and biweekly visits to each married, fecund woman --> led to a drop in fertility rates in both the treatment and control groups

Ready, willing, and able' (Coale, 1973)

For fertility transition to occur: ‘Ready’ meaning that fertility is perceived as within the remit of conscious choice, ‘willing’ meaning that having fewer children is desirable, and ‘able’ meaning that there are known contraceptive methods

Dyson and Murphy, 1985 "The onset of the fertility transition"

Argues that the predecline rises should be considered an integral part of the fertility transition; attributes these to changes in breastfeeding, postpartum sexual abstinence, and disease-related sterility; coined 'widow effect'

Kreager and Bochow, 2017 Anthropological Perspectives on the Heterogeneity of Modern Fertility Declines

Emphasizes through a series of case studies that the modern fertility declines are due to a variety of cultural factors, e.g. Julia Pauli's Namibia data

Main Variations in Fertility Decline

Spatial: by province, district or community; temporal: simultaneity of mortality and fertility declines, "duration;" timing: the date of onset; tempo: variations in the rate at which declines proceed, and possible stalls; quantum: how big the whole population grows or declines

Type 3 Demographic Transition Countries

3 to 3.5% a year of 'natural increase' - less developed countries, characterized by a very high maximal growth and a very sudden onset of decline (between 40-80 years)

Malthus's 'Principle of Population'

It is a natural law that fertility increases exponentially if not checked but subsistence can only increase arithmetically; without 'moral restraints,' we will have cycles of misery in which there will be high mortality rates and starvation

First Demographic Dividend

As birth rates fall, there are fewer young mouths to feed and the labor force growths temporarily in proportion to those dependents; stimulating growth and freeing up resources for investment

Second Demographic Dividend

A larger population at working ages has a powerful incentive to accumulate assets, unless it is confident in a social security by the state; whether these additional assets are invested domestically or abroad, national production and incomes rise

Population Bomb

Written by Paul Ehrlich in 1968, argued that the world population would 'explode' over the world's capacity; like Malthus, assumed that technologies, cultures, and practices would not evolve over time

Tempo Effect

A distortion in Total Fertility Rate (TFR) caused by changes in the timing of births — e.g. rising maternal age — which can lead to underestimation or overestimation of actual fertility and affect population growth projections

Esping-Andersen and Billari (2015)

"Argues for an extension of the first demographic transition theory by two stages:

Stage IV: Very low fertility is due to unresolved work-family conflict for women; social norms and policies haven't caught up to women's new roles in the family and work

Stage V: The 'gender equity dividend;' fertility rates rebound (e.g. Sweden) when women have a better balance between work (maternity leave, childcare, etc.) and family life (more equal division of parenting and housework)"

Adhikari et al., 2024

Evidence from health surveys done on >1 million women in Sub-Saharan Africa suggest that education is a primary driver (both of the women themselves and the other women in their community) of declining fertility rates

Julia Pauli’s Namibian Data

South Africa divided Namibia into several 'homelands' each with a 'Big man;' the wives of Big men were seen as models and practiced 'stopping,' often having 4 or more children; these big men also had relations with other women from lower social classes who practiced 'spacing;' also an effect of sterilization programs by the South Africa gov't; post-colonial historical perspective on fertility decline; spread of fertility decline moved from the lower to upper classes

Fertility

Refers to the performance and bearing and timing of live births, both tempo (age at first birth) and quantum (number of children born)

Convergence Clubs

Proposed by Mayer-Foulkes in 2001, argued that countries can be grouped together based on economic and human development variables

Socioeconomic status (SES)

Usually defined by occupation or educational attainment; preference for educational attainment because it is finished in early adulthood and available for everyone

Chao et al., 2018

Data analysis from LMICs reveals that under-five deaths are disproportionately high across lower-income quintiles, and disproportionately low across higher-income quintiles

Torche and Nobles, 2022

COVID-19 Pandemic only exacerbated existing inequalities, not the 'great equalizer' (Madonna); but rather disproportionately affected mothers with low levels of schooling

Fundamental Cause Theory

Proposed by Link and Phelan (1995), founded on the assumption that some general mechanisms are responsible for social inequalities that regardless of what the diseases and risks are at any time, those who have greater access to social and economic resources will be less afflicted by disease; limitation as it is focused around human interventions around diseases, not exposure

Mackenbach, 2016

Synthesis of nine different theories to explain the paradox of healthcare coverage; suggested two hypotheses:

1. Lower social strata have been more exclusively composed of individuals with personal characteristics that increase ill-health, e.g. low cognitive ability and 'less favorable' personality profiles

(Critique of this would be that lower social stratas also have a failing education system in many cases, e.g. a crisis of confidence but not intelligence)

2. Advanced welfare states happen to be further along in epidemiological development in which health improvement is dependent on social behavior to change

Syndemic

When risk factors or comorbidities are intertwined, interactive, and cumulative, exacerbating the disease burden and its negative health effects; builds on top of existing health inequalities and chronic diseases

Social determinants of health

The conditions under which people 'live, work, grow, and age' including working conditions, unemployment, access to essential goods and services, housing and access to healthcare

Rapid epidemiological transition (Omran, 1998)

Exemplified by Singapore and Taiwan: rapid decline in infectious disease and strong family planning. Still experiences triple burden but achieved fast epidemiological transition.

Masterson, 2023

In the USA, over the longer term, it was clear that vaccination was not an issue of access but an issue of confidence

Pamuk, 1985

Education determines an individual's level of material well-being but also affects his or her attitude towards health and health care; Despite the introduction of the NHS in 1948; life expectancy continues to be stratified by socioeconomic class in the UK from 1921 to 1971

Omran, 1998

Revisited epidemiological transition for Low and Middle Income Countries, who went through the transition from 1930-1950:

1. Age of pestilence and famine

2. Age of receding pandemics

3. Age of the “Triple Health Burden”

Medium epidemiological transition (Omran, 1998)

Seen in countries like Mexico and India: moderate family planning success; continued issues with malnutrition and communicable disease. Slower, uneven progress

Western vs. Non-Western Epidemiological Transition

Timing of these transitions is crucial, as transitions around the mid 20th century were predominantly influenced by medical rather than social factors; aging was delayed and increased relatively fast; fertility decline was harder to initiate and 'required' organized family planning programs

Omran, 1971

Five proposed stages to the Western Demographic Transition:

1. Age of pestilence and famine

2. Age of receding pandemics

3. Age of degenerative, stress, and man-made diseases

4. Age of declining cardiovascular mortality, aging, lifestyle modification, and emergent and resurgent diseases

5. Age of aspired quality of life, with paradoxical longevity and persistent inequities (Futuristic stage)

Slow Transition Model (Omran, 1998)

Common in Sub-Saharan Africa: high fertility, weak health infrastructure, and persistent infectious disease. Represents the most delayed transition due to structural barriers.

Epidemiological Transition

First proposed by Omran in 1971, encompasses several other transitions, including changing disease and health patterns (health transition), changing fertility and population age structure (parts of the demographic transition), changing lifestyles (lifestyle transition), changing healthcare patterns (health care transition), medical and technological evolutions (technologic transition), and environmental and ecological changes (ecological transition)

Critiques of Omran's revised model

Accused of overgeneralizing LMICs, ignoring local variation and colonial histories. Lacks nuance in socio-economic, political, and cultural factors across regions.

Mortality in Latin American and Caribbean Countries

Some nations making rapid progress while others stagnate or regress; men's mortality is notably dropping due to external mortalities like homicides and violence

Alvarez, Aburto and Canudas-Romo, 2019

There is both a shorter life expectancy in LAC countries today as well as more lifetime variability; as some countries make progress (e.g. Argentina) and other stagnate or slide backwards

García and Aburto, 2019

Next-door neighbors Colombia and Venezuela are moving in completely opposite directions for homicide deaths since the 1990s; men face higher external mortalities in Venezuela than women

Oppel and Vaupel (2023)

Female period life expectancy in best performing national populations has increased by a remarkable 3 months per year for the past 160 years

Clouston et al., 2016

Expanded FCT into four stages:

1. Natural mortality - no knowledge about risk factors, preventions or treatments for a disease in a population (e.g. MS)

2. Producing inequalities - characterized by an unequal diffusion of knowledge (e.g. Colon cancer)

3. Reducing inequalities - characterized by increasing access to health information (e.g. kidney infections)

4. Disease elimination - widely available prevention and treatment (e.g. smallpox)

Divergence-Convergence Hypothesis

Proposed by Antonovsky in 1967, suggested that there is variation over time in the relation between social class and mortality depending on changes in disease patterns and times

Three stages of Divergence-Convergence Hypothesis

First stage (until 1650) - showed no differences in life expectancy because many diseases were communicable and virulent with no treatment

Second stage (1650-1850) - showed increasing gap in life expectancy due to economic improvements of middle and upper strata and slow increase in position of lower strata (divergence); nutrition-dependent diseases become more important

Third stage (latter half of 19th century) - class gap begins to diminish and was very small before 1967 (convergence)

Limitation - recently, findings show an increase in social inequalities of mortality - so once again, divergence"

Overall Trend in Mortality (Worldwide)

Mortality is decreasing but there's a lot of heterogeneity across countries; at a stage where there has been some reversal but for the most part it looks like lifespans are continuing to grow

Triple Health Burden (Omran, 1998)

the intersection of three major health burdens imposing on one another: unfinished old health problems (e.g. communicable diseases, perinatal and maternal morbidity, malnutrition, etc.), rising new health problems (e.g. man-made diseases like heart disease and cancer), and ill-prepared health systems and medical training

Epidemiological Transition within a nation (Omran, 1971; Omran, 1998)

Suggests that the epidemiological transition begins at the higher classes, leading to disparities in health outcomes; although the other SES classes will eventually catch up

Santosa et al., 2014

Systematic review over the four decades since epidemiological transition theory has been proposed; found that ETT has largely neglected the role of social determinants; and while many countries have generally followed its path it lacks for within countries

Bengtsson, Dribe and Helgertz, 2020

Despite the introduction of universal healthcare to Sweden, disparities by SES persisted only since around 1950 (for women) and 1970 (for men); suggests that lifestyle factors and 'psycho-social' explanation

Clouston, Hanes and Link, 2023

In the early days of the COVID-19 pandemic, when access to vaccines were limited, they were disproportionally given out to higher SES classes in the USA, despite more 'frontline' workers being concentrated in the lower SES

Masterson, 2023

Suggests that the unequal rollout of COVID-19 vaccines in the US is not just a crisis of access (all vaccines were free!) but a crisis of 'confidence'

Scharff et al., 2010

Black Americans have grown a distrust of medical professionals because of histories of mistreatment

Mortality Transition

Describes the changes in death rates over time; focusing on how the decline in death rates (particularly infant and children mortality) leads to an increase in life expectancy

Meso level groups

Sub-population level groups, e.g. kin networks, social classes, ethnic groups, faiths, labor force sectors, etc.; formation of groups can be compared to population biology