Intergenerational transmission of fertility in Spain among cohorts born during the first half of twentieth century.

It is known that historically fertility is correlated between generations of the same family. These links tend to be explained either in terms of the biogenetic determinants of reproduction or by the transmission of intra-familial values associated with reproduction and family life. Less is known about the micro-determinants of these links or about the extent to which the progressive modernization of reproductive outcomes over the past century has affected behavior. In this paper, we will address these issues for Spain with data from the Socio-Demographic Survey (SDS) carried out in 1991 and including data on cohorts born between 1900 and 1946. These data enable us to explore the micro determinants of fertility at different points of time during this period. Our results point to the existence of a significant correlation between intergenerational reproductive outcomes that persists and strengthens throughout this period of demographic change. Results confirm the importance of birth order in large family groups where firstborn offspring are more likely to have larger families than subsequent siblings. There is also evidence that the strength of these intergenerational ties increases with the onset of more modern demographic behavior characterized by sharply declining fertility. The results presented here promise to condition future debates on the subject.

Fertility and contraception: The experience of Spanish women born in the first half of the twentieth century.

New data based on retrospective interviews with older informants enable us to review the history of contraceptive use among Spanish women over much of the twentieth century. This source is unique because it includes cohorts of women whose reproductive lives took place before, during, and after the baby boom. Traditional contraceptive methods (withdrawal and periodic abstinence) were central to the experience of the first set of women, while the last set made full use of modern as well as some traditional methods. For the first cohorts, traditional methods spearheaded the historic decline in fertility, while among the last set of women modern methods led to a precipitous decline towards the below-replacement fertility that continues in Spain today. There is no evidence that the modest increases in fertility during the baby boom in Spain were the result of a decline in the use of contraception among married women.

Partnership and mortality in mid and late life: Protection or selection?

The main goal of this paper is to address how different partnership statuses impact the likelihood of death among mature adults and elderly persons in Spain circa 2012 using a massive new dataset of administrative registers linked to census data. First, gross and net effects of having a partner on mortality risks of partnered and non-partnered persons are evaluated; then the characteristics and the importance of selection and protection effects of marriage and partnership with regard to the likelihood of death are assessed. We make use of exact matching methods in order to avoid the selection bias associated with the non-random assignment of persons to different partnership statuses. Protection effects decline gradually with age, but always remain positive. Selection effects show a far more pronounced decline with age leading to a pattern in which selection is much stronger than protection during the mature adult ages, but then disappear entirely and even become negative as people age. While both sexes show similar patterns, the protection effect is slightly higher among men while the selection effect is much higher among women, especially before 65 years of age.

Revisiting mid-twentieth-century fertility shifts from a global perspective.

In the developed world, the historic process of fertility decline was interrupted by an unexpected period of increasing fertility called the baby boom. Recent studies suggest that a similar trend change in fertility may have occurred in many less developed nations at approximately the same time. Using cohort fertility data for 26 less developed countries from around the world taken from the Integrated Public Use Microdata Series, International (IPUMS-I), this paper aims to ascertain the extent to which these trend changes occurred in a large sample of countries around the world. It offers convincing proof of the existence of an upward shift in fertility among cohorts born during the 1930s, which was common to many countries in the less developed world. Despite many similarities with the baby boom, there are also differences stemming, mostly, from its timing with respect to the demographic transition.

Residential status and health in middle and late life: a population-based study with new data from Spain.

OBJECTIVES: To address how different residential situations impact the likelihood of death among mature adults and elderly persons. DESIGN: Population-based study with administrative data linked to census data. SETTING: Spain. PARTICIPANTS: Spanish population alive on 1 January 2012, observed between 1 January 2012 and 31 December 2012. A 10% random sample of the Spanish population, including 2 054 427 person years and 28 736 deaths, is used. MAIN OUTCOME MEASURE: Registered deaths in the 2012 Spanish vital statistics. METHODS: Using a new data set based on linked administrative registers, we estimate unadjusted and adjusted mortality rates by coresidential situation. Differential mortality is measured by rate ratios (RR) estimated with Poisson regression. Cause of death data are used to explore the mechanisms involved in excess mortality by residential status. RESULTS: Compared with men 45-54 living with partners, the risk of death is much higher for those without partners living with others (RR 2.0, 95% CI 1.7 to 2.4) or for those living alone (RR 1.9, 95% CI 1.5 to 2.4). After 84, excess mortality among men living with others persists (RR 1.4, 95% CI 1.3 to 1.5), but disappears for those living alone (RR 1.0, 95% CI 0.9 to 1.1). Both among women 45-64 living with others but without partner (RR 1.8, 95% CI 1.5 to 2.3) and among those living alone (RR 2.2, 95% CI 1.5 to 3.1) the pattern is similar to men. At higher ages, however, excess mortality for women living alone decreases (RR 1.2, 95% CI 1.1 to 1.2), though it persists for women living with others (RR 1.9, 95% CI 1.7 to 2.0). CONCLUSIONS: These findings indicate direct effects of living arrangements on mortality and health-related selection effects influencing residential choices. These effects may be partially affected by age and prevailing societal and cultural contexts.

Childlessness in Twentieth-Century Spain: A Cohort Analysis for Women Born 1920-1969.

Studies of childlessness in the twentieth century in developed countries have underscored the existence of diverging trends with higher levels among cohorts born at the beginning of the twentieth century, lower ones among the baby boom cohorts and finally higher ones for cohorts born after the Second World War. Spain also shows these basic trends, but the fit is not identical to that of other countries, with differences affecting the timing of trend changes and also the levels of childlessness observed in the final part of the period. This paper focuses on Spanish women born 1920 and 1969 and explores the factors characterizing traditional/old childlessness and how these differ from those holding more recently. Using microdata from Spanish Census of 2011, our approach makes use of logistic regression and regression-based decomposition techniques. Change over time, as measured by inter-cohort variations, reveals strikingly different patterns of behaviour characterized by a reversal of the traditional association of childlessness with marital status and educational attainment that takes place in a period of intense and pervasive social change.

Immune Gene Diversity in Archaic and Present-day Humans.

Genome-wide analyses of two Neandertals and a Denisovan have shown that these archaic humans had lower genetic heterozygosity than present-day people. A similar reduction in genetic diversity of protein-coding genes (gene diversity) was found in exome sequences of three Neandertals. Reduced gene diversity, particularly in genes involved in immunity, may have important functional consequences. In fact, it has been suggested that reduced diversity in immune genes may have contributed to Neandertal extinction. We therefore explored gene diversity in different human groups, and at different time points on the Neandertal lineage, with a particular focus on the diversity of genes involved in innate immunity and genes of the Major Histocompatibility Complex (MHC).We find that the two Neandertals and a Denisovan have similar gene diversity, all significantly lower than any present-day human. This is true across gene categories, with no gene set showing an excess decrease in diversity compared with the genome-wide average. Innate immune-related genes show a similar reduction in diversity to other genes, both in present-day and archaic humans. There is also no observable decrease in gene diversity over time in Neandertals, suggesting that there may have been no ongoing reduction in gene diversity in later Neandertals, although this needs confirmation with a larger sample size. In both archaic and present-day humans, genes with the highest levels of diversity are enriched for MHC-related functions. In fact, in archaic humans the MHC genes show evidence of having retained more diversity than genes involved only in the innate immune system.

Seeding the gender revolution: Women's education and cohort fertility among the baby boom generations.

In Europe and the United States, women's educational attainment started to increase around the middle of the twentieth century. The expected implication was fertility decline and postponement, whereas in fact the opposite occurred. We analyse trends in the quantum of cohort fertility among the baby boom generations in 15 countries and how these relate to women's education. Over the 1901-45 cohorts, the proportion of parents with exactly two children rose steadily and homogeneity in family sizes increased. Progression to a third child and beyond declined in all the countries, continuing the ongoing trends of the fertility transition. In countries with a baby boom, and especially among women with post-primary education, this was compensated for by decreasing childlessness and increasing progression to a second child. These changes, linked to earlier stages of the fertility transition, laid the foundations for later fertility patterns associated with the gender revolution.

A high-coverage Neandertal genome from Vindija Cave in Croatia.

To date, the only Neandertal genome that has been sequenced to high quality is from an individual found in Southern Siberia. We sequenced the genome of a female Neandertal from ~50,000 years ago from Vindija Cave, Croatia, to ~30-fold genomic coverage. She carried 1.6 differences per 10,000 base pairs between the two copies of her genome, fewer than present-day humans, suggesting that Neandertal populations were of small size. Our analyses indicate that she was more closely related to the Neandertals that mixed with the ancestors of present-day humans living outside of sub-Saharan Africa than the previously sequenced Neandertal from Siberia, allowing 10 to 20% more Neandertal DNA to be identified in present-day humans, including variants involved in low-density lipoprotein cholesterol concentrations, schizophrenia, and other diseases.

Elderly women living alone in Spain: the importance of having children.

Our goal in this paper is to analyse the extent to which completed fertility, and in particular childlessness, is a valid predictor of living alone at advanced ages, an increasingly important residential option in advanced societies with crucial implications for social policy design and the organization of welfare services. Based on micro-data from the 2011 Spanish population census, logistic regression techniques are used to assess the impact of fertility on living alone among elderly women net the effect of age, marital status, educational attainment, and other standard population controls. Our results show a clear relationship between completed fertility and living alone. Childlessness is strongly associated with living alone, while having offspring acts as a powerful buffer against living alone, particularly in larger families. A relevant conclusion of this study is that a growing deficit of family resources available for the elderly women will take place in those societies where low fertility and high rates of childlessness have prevailed in recent decades, leading to substantial growth in the number of childless elderly women and in the incidence of living alone during later life.

Cell adhesion heterogeneity reinforces tumour cell dissemination: novel insights from a mathematical model.

BACKGROUND: Cancer cell invasion, dissemination, and metastasis have been linked to an epithelial-mesenchymal transition (EMT) of individual tumour cells. During EMT, adhesion molecules like E-cadherin are downregulated and the decrease of cell-cell adhesion allows tumour cells to dissociate from the primary tumour mass. This complex process depends on intracellular cues that are subject to genetic and epigenetic variability, as well as extrinsic cues from the local environment resulting in a spatial heterogeneity in the adhesive phenotype of individual tumour cells. Here, we use a novel mathematical model to study how adhesion heterogeneity, influenced by intrinsic and extrinsic factors, affects the dissemination of tumour cells from an epithelial cell population. The model is a multiscale cellular automaton that couples intracellular adhesion receptor regulation with cell-cell adhesion. RESULTS: Simulations of our mathematical model indicate profound effects of adhesion heterogeneity on tumour cell dissemination. In particular, we show that a large variation of intracellular adhesion receptor concentrations in a cell population reinforces cell dissemination, regardless of extrinsic cues mediated through the local cell density. However, additional control of adhesion receptor concentration through the local cell density, which can be assumed in healthy cells, weakens the effect. Furthermore, we provide evidence that adhesion heterogeneity can explain the remarkable differences in adhesion receptor concentrations of epithelial and mesenchymal phenotypes observed during EMT and might drive early dissemination of tumour cells. CONCLUSIONS: Our results suggest that adhesion heterogeneity may be a universal trigger to reinforce cell dissemination in epithelial cell populations. This effect can be at least partially compensated by a control of adhesion receptor regulation through neighbouring cells. Accordingly, our findings explain how both an increase in intra-tumour adhesion heterogeneity and the loss of control through the local environment can promote tumour cell dissemination. REVIEWERS: This article was reviewed by Hanspeter Herzel, Thomas Dandekar and Marek Kimmel.

Agency in Fertility Decisions in Western Europe During the Demographic Transition: A Comparative Perspective.

We use a set of linked reproductive histories taken from Sweden, the Netherlands, and Spain for the period 1871-1960 to address key issues regarding how reproductive change was linked specifically to mortality and survivorship and more generally to individual agency. Using event-history analysis, this study investigates how the propensity to have additional children was influenced by the number of surviving offspring when reproductive decisions were made. The results suggest that couples were continuously regulating their fertility to achieve reproductive goals. Families experiencing child fatalities show significant increases in the hazard of additional births. In addition, the sex composition of the surviving sibset also appears to have influenced reproductive decisions in a significant but changing way. The findings offer strong proof of active decision-making during the demographic transition and provide an important contribution to the literature on the role of mortality for reproductive change.

Baby booms, busts, and population ageing in the developed world.

The key challenge facing contemporary society is a process of population ageing rooted mainly in past fertility cycles. The goals of the study reported in this paper were (i) to analyse jointly the post-1930s baby boom and the baby bust that followed, (ii) to consider the specific ways this particular combination influenced the process of ageing in different societies, and (iii) to evaluate some possible implications for policy of different historical experiences. Demographic time series for 27 nations in the developed world were used. The main results confirm the importance of the boom and bust fertility cycle of the second half of the twentieth century for population ageing. Some countries will experience ageing processes driven mainly by the growth of elderly populations while others will age largely as a result of declines in working-age populations. These differences underscore the need to tailor policy priorities for specific patterns of ageing.

Cross cultural analysis of factors associated with age at natural menopause among Latin-American immigrants to Madrid and their Spanish neighbors.

OBJECTIVES: In this study, age at menopause was examined in relation to demographic and life style factors among Latin-American immigrants to Madrid and their Spanish counterparts. METHODS: Respondents were drawn from the Decisions at Menopause Study (2002-2003) and from a recent sample of Latin-American immigrants to Madrid (2010-2011). The final sample included 484 women after excluding women with induced menopause and use of HT. Probit analyses and Cox proportional hazard models were used to estimate median age at menopause and to identify factors associated with an early age at menopause. RESULTS: Median estimated age at natural menopause was 52.0 years (51.2-53.0) for Spanish women and 50.5 years (49.9-51.2) for Latin-American women. Immigrant women were more likely to reach menopause at an earlier age after controlling for confounding factors. Nulliparity and lower levels of education were associated with an earlier age at menopause. A higher body mass index was associated with a later age at menopause in the Spanish model. Among the Latin-American sample, women from the Dominican Republic and women who underwent menopause before migrating were more likely to reach menopause at an earlier age. CONCLUSIONS: The results reported here demonstrate that early life events, including place of birth, and later life events, such as timing of migration, were associated with age at menopause. This study highlights the importance of taking into account differences in the age of onset of menopause in the multicultural population of Madrid when considering the health of women at midlife and beyond.

Cross-cultural analysis of determinants of hot flashes and night sweats: Latin-American immigrants to Madrid and their Spanish neighbors.

OBJECTIVE: This study applies a biocultural perspective to better understand the determinants of hot flashes and night sweats within immigrant and local populations in Madrid, Spain. METHODS: A combined sample of 575 women from Madrid, aged 45 to 55 years, was drawn from two studies. The Spanish sample (n = 274) participated in The Decisions At Menopause Study in 2000-2002. The Latin-American sample (n = 301) was drawn from immigrants to Madrid in 2010-2011. χ(2) analyses and logistic regression models were carried out on the combined sample, controlling for origin of provenance. RESULTS: Forty-four percent of women reported hot flashes, 36% reported night sweats, and 26% reported both symptoms. Compared with Spanish women, Latin-American women were less likely to report hot flashes (odds ratio, 0.7; 95% CI, 0.4-0.9), after demographic variables and menopause status were controlled for. The same was not found for night sweats and for both symptoms combined. Determinants of hot flashes differed from determinants of night sweats. CONCLUSIONS: Because their determinants differ, hot flashes and night sweats should be queried and analyzed separately. Latin-American women are less likely to report hot flashes, but not night sweats or both symptoms combined. More research is needed to clarify the differences in reported hot flashes, as the lesser reporting among immigrants could have been a cultural phenomenon rather than a biological phenomenon.

The medical management of menopause: a four-country comparison care in urban areas.

OBJECTIVE: To compare the medical management of menopause across urban areas in four countries which differ by level of income and degree of medicalization. METHODS: Surveys of health providers who advise women on the menopausal transition were carried out in Beirut, Lebanon (n=100), Madrid, Spain (n=60), Worcester, MA, U.S. (n=59), and Rabat, Morocco (n=50) between 2002 and 2004. Physician characteristics, hormone therapy (HT) prescribing practices, and concerns about the management of menopause were compared across countries using chi(2) and logistic regression analyses. RESULTS: Across sites, physicians were generally well informed about HT and thought that symptom alleviation and disease prevention were equally important. They had concerns about risks associated with HT, particularly breast cancer, and in 3 sites where the survey was conducted after the WHI (Beirut, Rabat, and Madrid) physicians changed their practices to prescribe HT less frequently, for shorter durations, or shifted to other medications. There were significant differences across sites in the recommended duration of HT, time spent talking with patients, perceived benefits of HT, tests recommended before prescribing HT, and concern about the risks associated with HT. Physicians in Madrid and Massachusetts were more likely to report that decisions about the management of menopause were difficult, but in all sites the main reason for difficulties was concerns about risks. The results also suggest discrepancies between physicians' perceptions and women's reports about the reasons why women consult at menopause. CONCLUSIONS: Prescription patterns and perceived benefits of HT appear to reflect local medical culture rather than simply physician characteristics. The impact of the WHI study was seen in prescribing patterns and concerns about HT. Physicians in all four countries were generally well informed. Financial support: NIH 5 900 000196.

Intergenerational Transmission of Reproductive Traits in Spain during the Demographic Transition.

In this paper intergenerational dimensions of reproductive behavior are studied within the context of the experience of a mid-sized Spanish town just before and during the demographic transition. Different indicators of reproduction are used in bivariate and multivariate approaches. Fertility shows a small, often statistically significant intergenerational dimension, with stronger effects working through women and their mothers than those stemming from the families of their husbands. These effects are materialized mainly through duration-related fertility variables, are singularly absent for variables such as age at first birth or birth intervals, and are much stronger in the case of firstborn daughters than with later siblings. There is a substantial increase in the strength of intergenerational effects during the course of the demographic transition, most visible in age at last birth and duration of reproduction (between women and their mothers), as well as in the effects working through the families of their husbands. These results underscore the on-going importance of biological dimensions of reproduction as well as the way attitudes toward reproduction are taught within the family. The changes identified in this study suggest that the transmission of values and attitudes became more important for reproductive outcomes during this period of demographic modernization.

Factors related to inbreeding components from isonymy in an urban population: Aranjuez (Spain).

An isonymic analysis has been carried out using a sample of 1529 reconstituted families residing during 1870-1964 in Aranjuez, an urban area situated south of Madrid, Spain. The random, non-random and total-components inbreeding coefficients from isonymy were obtained and the various combinations of surnames compared in order to infer the patri- or matrilocal pattern of residence. Throughout the period studied the random component of inbreeding (F(r)) has not changed, in contrast to the non-random component (F(n)), thus suggesting the latter could be responsible for the reduction of total inbreeding. Using several methodological approaches (biplot analysis, alpha, nu and percentage of immigrants) the predominance of the immigration of grooms was interpreted in terms of Aranjuez as a matrilocal pattern of residence. From this study it can also be concluded that surnames provided by reconstituted families are good estimators of inbreeding and migration.