The effect of unbalanced demographic structure on marriage and feritlity patterns in isolated populations: the case of Viking settlements in Greenland.

Can the decline of a small and isolated population occur as a consequence of a random imbalance in the sex ratio at birth and/or in the male/female mortality rates in subsequent age groups? We should stress here the use of the term “random”. Indeed, the imbalance we refer to is what occurs in a small population as the ultimate result of pure chance. This hypothesis (of the imbalance of the sex ratio) was studied in particular by the Italian statistician Corrado Gini (1957), although it had previously been put forward by other authors (Livi 1941, 1944). More specifically, Gini explained the extinction of the medieval settlements in Greenland using this hypothesis.The recent publication of Lynnerup’s book (1998) concerning the demography of these settlements, based on the archaeological evidence of skeletal remains, prompted us to re-evaluate Gini’s treatise. We wanted to give a statistical contribution – using a Bayesian inference – to evaluate Gini’s hypothesis of that extinction. The extinction of the settlements in Greenland is widely regarded as “almost an enigma hinting at some inexplicable and dramatic event veiled by the passage of time” (Lynnerup1998, p. 8).The aim of this paper is therefore to check Gini’s hypothesis from a Bayesian point of view. In this scheme, the prior distribution is the probability of an imbalance in the sex ratio occurring in the history of a small and closed population as a result of random and unfavourable alterations of the sex-ratio at birth and at death. In order to evaluate such a probability, a Monte Carlo technique that uses historical, demographic and biometric constants (Livi Bacci 1998) will be outlined. The posterior probability is then updated in the light of some archaeological data

Development of a clinical prediction model for the onset of functional decline in people aged 65-75 years: Pooled analysis of four European cohort studies

Background: Identifying those people at increased risk of early functional decline in activities of daily living (ADL) is essential for initiating preventive interventions. The aim of this study is to develop and validate a clinical prediction model for onset of functional decline in ADL in three years of follow-up in older people of 65-75 years old. Methods: Four population-based cohort studies were pooled for the analysis: ActiFE-ULM (Germany), ELSA (United Kingdom), InCHIANTI (Italy), LASA (Netherlands). Included participants were 65-75 years old at baseline and reported no limitations in functional ability in ADL at baseline. Functional decline was assessed with two items on basic ADL and three items on instrumental ADL. Participants who reported at least some limitations at three-year follow-up on any of the five items were classified as experiencing functional decline. Multiple logistic regression analysis was used to develop a prediction model, with subsequent bootstrapping for optimism-correction. We applied internal-external cross-validation by alternating the data from the four cohort studies to assess the discrimination and calibration across the cohorts. Results: Two thousand five hundred sixty community-dwelling people were included in the analyses (mean age 69.7 ± 3.0 years old, 47.4% female) of whom 572 (22.3%) reported functional decline at three-year follow-up. The final prediction model included 10 out of 22 predictors: age, handgrip strength, gait speed, five-repeated chair stands time (non-linear association), body mass index, cardiovascular disease, diabetes, chronic obstructive pulmonary disease, arthritis, and depressive symptoms. The optimism-corrected model showed good discrimination with a C statistic of 0.72. The calibration intercept was 0.06 and the calibration slope was 1.05. Internal-external cross-validation showed consistent performance of the model across the four cohorts. Conclusions: Based on pooled cohort data analyses we were able to show that the onset of functional decline in ADL in three years in older people aged 65-75 years can be predicted by specific physical performance measures, age, body mass index, presence of depressive symptoms, and chronic conditions. The prediction model showed good discrimination and calibration, which remained stable across the four cohorts, supporting external validity of our findings

Instability, investment, disasters, and demography: natural disasters and fertility in Italy (1820–1962) and Japan (1671–1965)

This article examines whether natural disasters affect fertility—a topic little explored but of policy importance given relevance to policies regarding disaster insurance, foreign aid, and the environment. The identification strategy uses historic regional data to exploit natural variation within each of two countries: one European country—Italy (1820–1962), and one Asian country—Japan (1671–1965). The choice of study settings allows consideration of Jones’ (The European miracle, Cambridge University Press, Cambridge, 1981) theory that preindustrial differences in income and population between Asia and Europe resulted from the fertility response to different environmental risk profiles. According to the results, short-run instability, particularly that arising from the natural environment, appears to be associated with a decrease in fertility—thereby suggesting that environmental shocks and economic volatility are associated with a decrease in investment in the population size of future generations. The results also show that, contrary to Jones’ (The European miracle, Cambridge University Press, Cambridge, 1981) theory, differences in fertility between Italy and Japan cannot be explained away by disaster proneness alone. Research on the effects of natural disasters may enable social scientists and environmentalists alike to better predict the potential effects of the increase in natural disasters that may result from global climate change

La vicenda delle colonie lorenesi in Maremma (XVIII secolo) come esempio di studio di demografia differenziale

Si analizza, prevalentemente sulla base di fonti parrocchiali, il tentativo di ripopolamento della Maremma effettuato attorno alla met\ue0 del XVIII secolo tramite l'insediamento a Massa Marittima di alcune centinaia di famiglie proveniente dalla Lorena. Sulla base di una ricostruzione delle vicende familiari e dei percorsi individuali di vita si evidenzia la rapida e quasi totale estinzione di questo gruppo di immigrati, soprattutto a causa dell'elevatissima mortalit\ue0 provocata dalla malaria

Tendenze della statura e della struttura per cognomi desunte dai dati delle leve militari in cinque comuni della provincia di Bologna a cavallo tra XIX e XX secolo: primi risultati

I dati desunti dai registri delle leve militari di cinque comuni della provincia di Bologna sono stati utilizzati per delineare differenze geografiche e modificazioni nel tempo (tra fine XIX e inizio XX secolo) dei caratteri antropometrici dei coscritti, e per ricavare indicazioni sul livello di isolamento delle comunit\ue0, desumibili dalle strutture per cognomi. In questo lavoro sono presentati i primi risultati dell\u2019analisi dei dati di coscritti delle classi 1887, 1897, 1907 e 1920, iscritti nelle liste di leva di cinque comuni situati in provincia di Bologna, in aree di montagna (Lizzano in Belvedere e Porretta Terme), di collina (Pianoro e Sasso Marconi) e di pianura (Medicina). Obiettivo di questa fase dello studio era delineare e confrontare l\u2019evoluzione delle caratteristiche socio-demografiche, antropometriche e della struttura per cognomi a cavallo tra XIX e XX secolo. L\u2019analisi demografica, attraverso il calcolo dei tassi di accrescimento, natalit\ue0, mortalit\ue0 e dei saldi migratori, evidenzia nel periodo una crescita di tutti i comuni, determinata prevalentemente dalla componente naturale, e una accentuata emigrazione per i comuni di montagna. Le stature medie dei coscritti tendono ad aumentare in tutti i comuni nelle classi di nascita successive alla classe 1897. L\u2019isonimia random e l\u2019indice di diversit\ue0 in cognomi di Shannon, pur differenziandosi nei valori assoluti nelle aree di montagna rispetto alla collina e pianura, restano ovunque relativamente stabili. Non si osserva evoluzione temporale delle relazioni isonimiche tra i comuni. Questi risultati suggeriscono che all\u2019aumento della statura dei nati nel primo ventennio del XX secolo non abbiano contribuito in modo apprezzabile fattori genetici legati alla diminuzione dell\u2019isolamento riproduttivo

L'evoluzione demografica (secoli XIV-XX)

Nel contributo si delineano, sulla base delle documentazioni disponibili per i vari periodi esaminati, le tendenze del popolamento dell'area esaminata. Per gli ultimi due secoli si ricostruiscono inoltre i principali caratteri del regime demografico naturale (fecondità e mortalità), e si mette in evidenza il contributo dei movimenti migratori interni all'area e tra l'area medesima e le aree limitrofe, nel determinare tendenze differenziali di crescita dei vari centri oggetto di studio

Athos Bellettini, demografo storico, pubblico amministratore e primo presidente della SIDES

In occasione del trentennale dalla fondazione della SIDES, gli autori hanno ricordato il primo presidente della SIDES tracciandone un profilo umano, scientifico e di pubblico amministratore

Elderly mortality in italian regions at the beginning of the health transition (1881-1921)

The paper aims to highlight and analyze possible regional patterns of mortality at advanced age (70-90 years) in Italy at the turn of the nineteenth century. The available data are referred to four distinct occasions, namely 1881-82, 1900-01, 1911-12 and 1921-22. After focusing attention on several elderly mortality indicators, we propose to analyze the resulting three-way array (with modes regions x indicators x occasions) using the STATIS method. As a critical preliminary step, new regional life tables for 1881-82 are constructed in order to reduce the possible bias due to the inaccuracy of the age distribution of the population and of the deaths in 1881. The resulting life tables are compared with Gini and Galvani\u2019s ones and those available in the Human Mortality Database