Ancestral kinship and cancer in Lastovo Island, Croatia.

The aim of this study was to compute the average kinship coefficient of cancer cases in an extreme isolate (Lastovo Island, Croatia) and to compare it to the corresponding value for the island's unaffected population. Kinship estimates were obtained by Wright's path method (phi) based on pedigree reconstruction and Lasker's coefficient of relationship by isonymy (Ri) based on surname distribution. A total of 76 cancer cases were recorded on the island between 1971 and 1995. The unaffected control population of 1144 persons was obtained from the population census in 1971. The data on five ancestral generations were collected from parish registries preserved in the local church, and included 5484 persons born on the island between 1750 and 1970. Both Wright's path method and Lasker's isonymy method indicated significantly greater kinship of female cancer cases than of the unaffected population. Cancer cases with increased values of Ri among them and Ri among their ancestors included cancers of the ovary, colon, brain, breast, and prostate and leukemias. This study confirms the role of heredity and common ancestry in the development of cancer, providing a rough insight into their relative importance for specific cancer sites.     

Fertility trends in Singapore

In 1966, the Singapore National Family Planning and Population Program established the goal of reaching replacement fertility by 1990 and zero population growth by the year 2030. To achieve this goal, the government relied on a series of incentives and disincentives to discourage births above the 3rd birth order, including tax relief for the 1st 3 children only, paid medical leave for women undergoing sterilization after the 3rd or subsequent birth, monetary stipends in some cases where the mother is sterilized after the 1st or 2nd birth, and increasing accouchement charges for increasing birth orders. Also important to demographic planning were liberalization of Singapore's abortion legislation and more aggressive promotion of contraception. As a result of these efforts, Singapore's crude birth rate has declined from 29.5/1000 population in 1965 to 16.6/1000 in 1985. Also observed have been dramatic declines in infant mortality in this same period, from 26.2/1000 live births to 9.3/1000, and in maternal mortality, from 52/100,000 live births to 10/100,000. In 1985, 42% of total births were to women in the 25-29-year age group. The numbers of 4th and later births fell by 90% between 1966 and 1985. The total fertility rate has declined from 4.6/woman in 1965 to 3.1 in 1970 to 1.6 in 1986. Below replacement level fertility was achieved in 1975, in part because of government policy but also as a result of cultural and socioeconomic factors such as increasing female labor force participation rates, a break-up of the extended family system, a rise in the age at 1st marriage, and rises in educational attainment. The drop in fertility was contributed mainly by the higher socioeconomic class, more affluent, and educated Singaporeans. Thus, in 1981, the government introduced certain pronatalist policies and incentives to encourage better educated women to produce more children, e.g., tax relief and the elimination of monetary incentives to sterilization acceptors above a median income level.     

Box-Jenkins modeling of chronological series of twin births and single births

A time-series analysis by Box-Jenkins modeling of the monthly observations of twin births and singleton births was attempted. The study is population based. The single-birth series has been matched to the twin-birth series for maternal birth cohort, parity of the twin birth, and residence of the parents. Three-hundred forty-one twin pairs and 340 singleton births were grouped into chronological series spanning 72 months of observation. Univariate and bivariate time-series analyses were used. Box-Jenkins modeling shows that both series share the same basic demographic and reproductive risk factors, such as ovulation and conception rates, abortions, sexual intercourse, and the less well-known random events that determine the time of delivery. These factors are randomly related to both birth processes but exert a more important influence on twin births. Beyond these crude features, twin- and single-birth series differ by the frequency of their seasonal cycle. Twin births show low-frequency variations because of a rather limited number of factors that impinge markedly on the twinning process. Single births are subjected to higher frequency variations that can be ascribed to a greater number of structuring factors, the action of which is less pervasive. Only the January peak is common to both types of births. Aside from the common features, the bivariate analysis shows that both series of births are independent, neither being related to the other. It is concluded that the subtle structuring of both processes is largely distinct. The large fraction of the unaccounted variation of each birth process (about 70%) suggests that most of the variation is due to as yet unidentified factors. The search for environmental and geocosmic factors at the origin of conception and confinement should be considered in future undertakings.     

Unrearable litters and prenatal reduction of litter size in the common marmoset (Callithrix jacchus).

It is widely believed that common marmosets (Callithrx jacchus) typically give birth to twins under natural conditions. In captivity, however, births of triplets or even larger litters are common, although parents rarely succeed in rearing more than two offspring. The traditional interpretation is that captive conditions, notably the ready availability of food, have led to increased reproductive output, perhaps involving a higher ovulation rate. The present paper provides evidence, combined from ultrasound examinations between ovulation and birth and hysterotomies conducted during the late embryonic and early fetal phase, that the litter size can be progressively reduced during pregnancy without spontaneous abortion. There is an unusually long lag phase prior to the onset of embryonic growth in common marmosets; the fetal stage does not begin until day 80 of the 144-day pregnancy. Reduction in litter size occurs during embryonic stages (up to day 80), and continues into the fetal stages. These results indicate that the common marmoset is adapted for flexible modification of litter size between ovulation and birth. The high incidence of triplet births in captive colonies may therefore be an expression of an adapted natural developmental process under artificial circumstances.     

Trivers-Willard at birth and one year: evidence from US natality data 1983-2001

Trivers & Willard (TW) hypothesized that evolution would favour deviations from the population sex ratio in response to parental condition: parents in good condition would have more sons and parents in poor condition would have more daughters. We analyse the universe of US linked births and infant deaths to white mothers 1983-2001, covering 48 million births and 310,000 deaths. We find that (i) married, better educated and younger mothers bore more sons and (ii) infant deaths were more male if the mother was unmarried and young. Our findings highlight the potential role of offspring sex ratio as an indicator of maternal status, and the role of infant mortality in shaping a TW pattern in the breeding population.     

DYS19 and DYS199 loci in a Chilean population of mixed ancestry

The current Chilean population originated from admixture between aboriginal populations (Amerindians) and Spanish conquerors of European origin. Consequently, the unions that gave rise to the Chilean population were chiefly between Spanish males and aboriginal females, and not the converse. To test the hypothesis that the Y chromosome of the Chilean population is mainly of Spanish origin, while the other chromosomes are from mixed (European and aboriginal) origin, we studied the DYS19 and DYS199 loci in two samples. One sample was obtained from a high socioeconomic stratum, while a second sample was from a low stratum. We studied male blood donors (N = 187) from Santiago, the capital of the country. Subjects were typed for the autosomal ABO and Rh (locus D) blood groups, and for the Y-linked DYS19 and the DYS199 loci, reported as Y-chromosome haplotypes. The aboriginal admixture was estimated for each genetic marker. The percentage of aboriginal admixture was 38.17% for the ABO system and 31.28% for the Rh system in the low socioeconomic stratum and 19.22% and 22.5%, respectively, in the high stratum. Y-chromosome haplotype frequencies constructed from the DYS19 and DYS199 loci demonstrated that the main haplotypes were DYS19*14/DYS199 C, as is often the case with many European populations, and DYS19*13/DYS199 C. The aboriginal admixture from Y-haplotype frequencies was estimated to be 15.83% in the low socioeconomic stratum and 6.91% in the high stratum. These values are lower than the values found using autosomal genetic markers, and are consistent with the historical background of the population studied. This study highlights the population genetic consequences of the asymmetric pattern of genome admixture between two ancestral populations (European and Amerindian).     

Out of Arabia—The settlement of Island Soqotra as revealed by mitochondrial and Y chromosome genetic diversity

The Soqotra archipelago is one of the most isolated landmasses in the world, situated at the mouth of the Gulf of Aden between the Horn of Africa and southern Arabia. The main island of Soqotra lies not far from the proposed southern migration route of anatomically modern humans out of Africa ～60,000 years ago (kya), suggesting the island may harbor traces of that first dispersal. Nothing is known about the timing and origin of the first Soqotri settlers. The oldest historical visitors to the island in the 15th century reported only the presence of an ancient population. We collected samples throughout the island and analyzed mitochondrial DNA and Y‐chromosomal variation. We found little African influence among the indigenous people of the island. Although the island population likely experienced founder effects, links to the Arabian Peninsula or southwestern Asia can still be found. In comparison with datasets from neighboring regions, the Soqotri population shows evidence of long‐term isolation and autochthonous evolution of several mitochondrial haplogroups. Specifically, we identified two high‐frequency founder lineages that have not been detected in any other populations and classified them as a new R0a1a1 subclade. Recent expansion of the novel lineages is consistent with a Holocene settlement of the island ～6 kya. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Main results of recent Hungarian family planning studies.

The Hungarian Central Statistical Office has carried out five different sample surveys in the last fifteen years for investigating more closely questions of fertility, family planning and birth control. The study summarizes the main findings. Some of these surveys applied retrospective methods to investigate fertility, family planning and birth control bahaviour of females in the past. Surveys of another type tried to reveal in perspective manner, with longitudinal observation of the couples, changes which took place in family planning and birth control ideas and practice. The main purpose of recent population policy measures was to ensure simple reproduction of the population. As a result of the measures taken in 1974 to increase the number of births the birth-rate went up significantly. This increase (30% as compared to 1973) appeared primarily for the second birth which constitutes 62% of the increment in births in 1974, 31% is accounted for by an 11% increase in the first births. The number of third births rose by 13% and their relative share remained 10%. The number of fourthand further births did not increase and their relative share decreased by 1%. Fertility data of 1974 show that the birth-rate increase was not in line with the intended aim, i.e. it was not the number of third births that increased. The net reproduction coefficient showing long-range growth of the population calculated with birth-rate of 1974, has developed favourably, it was over unity for the first time since 1958 (it was about 1.05). The birth-rate increased in 1974 in every age-group of females. The largest increase (19%) occurred for females 25-34 years old. Though it was 16% also for females under 24. According to a sample survey investigating the number of intended children by married females under 35 it did not increase as compared to data of previous surveys of similiar character. The differences is that the proportion of those who wished to have two children increased, while of those who wished to have one or three and more children decreased. The study deals also with changes in the relative shares of intended children by females under 35 who are now to be married. In the concluding part of the study the femeles' attitude to birth control and changes in this field are discussed.     

Estimates of African, European and Native American ancestry in Afro-Caribbean men on the island of Tobago

BACKGROUND/AIMS: The Tobago Afro-Caribbean population is a valuable resource for studying the genetics of diseases that show significant differences in prevalence between populations of African descent and populations of other ancestries. Empirical confirmation of low European and Native American admixture may help in clarifying the ethnic variation in risk for such diseases. We hypothesize that the degree of European and Native American admixture in the Tobago population is low. METHODS: Admixture was estimated in a random sample of 220 men, from a population-based prostate cancer screening survey of 3,082 Tobago males, aged 40 to 79 years. We used a set of six autosomal markers with large allele frequency differences between the major ethnic populations involved in the admixture process, Europeans, Native Americans and West Africans. RESULTS: The ancestral proportions of Tobago population are estimated as 94.0+/-1.2% African, 4.6+/-3.4% European and 1.4+/-3.6% Native American. CONCLUSIONS: We conclude that Tobago Afro-Caribbean men are predominantly of West African ancestry, with minimal European and Native American admixture. The Tobago population, thus, may carry a higher burden of high-risk alleles of African origin for certain diseases than the more admixed African-American population. Conversely, this population may benefit from a higher prevalence of protective alleles of African origin.     

Reproductive seasonality in a free-ranging troop of stumptail macaques (Macaca arctoides): A five-year report

Seasonality in births and fertile matings are reported for a stumptail macaque group living on an island for a period of five years: 1975–1979. During this period 26 births occurred of which 24 represent infants conceived on the island. While births and fertile matings occurred throughout the year 21% of the births were concentrated in March, 34% in June and July and 17% in November. Additionally 63% of the births occurred during the rainy season. Of the 24 infants, 4 died during the first year of life thus yielding a reproductive success of 83%. The sex ratio at birth for the five years was 1:1 corrected to 1:1.2 with the four deaths. The mean interval between fertile matings for females was 19 months and 2 days and the mean age for first conception was 4 years and 5 months. The pattern of birth and breeding seasonality was markedly similar to that of the parent troop while in Puerto Rico.     

Effects on pregnancy outcome of changing partner between first two births: prospective population study

Objective To compare the effects on pregnancy outcomes of changing partner between the first two births with having the same partner for both births.Design Prospective population study.Setting Norway.Participants 31 683 women who changed partner between their first two births and 456 458 women with the same partner for both births.Results After adjustment for maternal age and education, interval between births, and decade of birth, the risk of adverse pregnancy outcomes for the second birth was higher for women who changed partner between the first two births compared with those who had the same partner for both births: preterm birth (< 37 weeks; relative risk 2.0, 95% confidence interval 1.9 to 2.1), low birth weight (< 2500 g; 2.5, 2.3 to 2.6), and infant mortality (1.8, 1.6 to 2.1). For the first birth, the risk of these adverse pregnancy outcomes was only slightly higher for mothers who subsequently had a second birth with another partner.Conclusion Women who change partner between their first two births are at an increased risk of delivering a preterm, low birthweight baby with an increased risk of infant mortality compared with women who have the same partner for both births.     

Changes in maternal risk factors and their association with changes in cesarean sections in Norway between 1999 and 2016: A descriptive population-based registry study

BackgroundIncreases in the proportion of the population with increased likelihood of cesarean section (CS) have been postulated as a driving force behind the rise in CS rates worldwide. The aim of the study was to assess if changes in selected maternal risk factors for CS are associated with changes in CS births from 1999 to 2016 in Norway.Methods and findingsThis national population-based registry study utilizes data from 1,055,006 births registered in the Norwegian Medical Birth Registry from 1999 to 2016. The following maternal risk factors for CS were included: nulliparous/≥35 years, multiparous/≥35 years, pregestational diabetes, gestational diabetes, hypertensive disorders, previous CS, assisted reproductive technology, and multiple births. The proportion of CS births in 1999 was used to predict the number of CS births in 2016. The observed and predicted numbers of CS births were compared to determine the number of excess CS births, before and after considering the selected risk factors, for all births, and for births stratified by 0, 1, or >1 of the selected risk factors. The proportion of CS births increased from 12.9% to 16.1% (+24.8%) during the study period. The proportion of births with 1 selected risk factor increased from 21.3% to 26.3% (+23.5%), while the proportion with >1 risk factor increased from 4.5% to 8.8% (+95.6%). Stratification by the presence of selected risk factors reduced the number of excess CS births observed in 2016 compared to 1999 by 67.9%. Study limitations include lack of access to other important maternal risk factors and only comparing the first and the last year of the study period.ConclusionsIn this study, we observed that after an initial increase, proportions of CS births remained stable from 2005 to 2016. Instead, both the size of the risk population and the mean number of risk factors per birth continued to increase. We observed a possible association between the increase in size of risk population and the additional CS births observed in 2016 compared to 1999. The increase in size of risk population and the stable CS rate from 2005 and onward may indicate consistent adherence to obstetric evidence-based practice in Norway.

In a population-based study, Ingvild Nedberg and colleagues investigate the relationship between maternal risk factors and changes in rates of cesarean section births in Norway.     

Risks of selected congenital malformations among offspring of mixed race-ethnicity

BACKGROUND: Little is known about the occurrence of specific congenital malformations among offspring of mixed race-ethnicity. METHODS: Using data from a population-based registry, we explored the occurrence of selected malformation phenotypes in offspring to parents who were of different race-ethnicity. Data were derived from the California Birth Defects Monitoring Program, a population-based active surveillance system for collecting information on infants and fetuses with congenital malformations using multiple source ascertainment. Approximately 2.6 million live births and stillbirths occurred during 1989-2000. Information on parental race-ethnicity (non-Hispanic white, Hispanic, black, and Asian) was obtained from birth certificates and fetal death files. Malformation phenotypes studied were spina bifida, anencephaly, cleft lip, cleft palate, tetralogy of Fallot, d-transposition of great arteries, hypospadias, small intestinal atresia, preaxial polydactyly, microtia, and hypertrophic pyloric stenosis. RESULTS: A total of 11.2% of births were to parents of mixed race-ethnicity. Compared to births of parents who were both white, moderately increased risks (risk ratio >/= 1.7) of anencephaly, polydactyly, and microtia, and decreased risks (risk ratio 相似文献   

Non-indigenous introgression into the Norwegian red deer population

Rates of introgression from non-indigenous into native populations are increasing worldwide, often as a result of anthropogenic translocation events. In ungulates translocations have been common, especially among deer. European red deer consists of two distinct lineages, one western and one eastern. These probably originate from different glacial refuges, but it is unknown to what extent they hold different adaptations. Here we address dispersal and introgression into the Norwegian mainland population from an introduced island stock consisting of an admixture of both European lineages. The last decade this stock has grown considerably in number and dispersal could be expected to have increased. We therefore used samples separated by a 5 year interval from Otterøya, adjacent mainland areas and a more distant sub-population. Bayesian assignment analysis verified the genetic structure and identified dispersal between the Otterøya stock and the adjacent mainland coastal areas. Three individuals (two newly sampled) with second or third generation non-indigenous origin were found among the adjacent mainland samples (5 and 3 %, respectively). Two individuals with first and second generation mainland-origin were found on Otterøya (old samples). This suggests some non-indigenous introgression from Otterøya into the mainland Norwegian population.     

Population surveillance of multimalformed infants--experience with the Swedish Registry of Congenital Malformations. First Part

The paper discusses the principles of an analysis of infants with multiple malformations, recorded in a birth defect registry. It is illustrated with 973 multimalformed infants recorded in the Swedish Registry of Congenital Malformations, 1965-1984. The detection and delineation of patterns of associated malformations is described and exemplified with the VATER association pattern. There is no time trend for the rate of infants with this association; they represent about 4% of all registered multimalformed infants; and their prevalence at birth is 2.7 per 100,000 births. The rate of infants probably representing unidentified trisomy 13 shows a decrease after 1977 indicating an increased access to cytogenetic services. A similar decrease is seen in infants probably representing unidentified Meckel's syndrome. Using 28 multimalformed infants registered in 1985, the technique for surveillance of multimalformed infants in a population is discussed.     

India’s Conditional Cash Transfer Programme (the JSY) to Promote Institutional Birth: Is There an Association between Institutional Birth Proportion and Maternal Mortality?

Background

India accounts for 19% of global maternal deaths, three-quarters of which come from nine states. In 2005, India launched a conditional cash transfer (CCT) programme, Janani Suraksha Yojana (JSY), to reduce maternal mortality ratio (MMR) through promotion of institutional births. JSY is the largest CCT in the world. In the nine states with relatively lower socioeconomic levels, JSY provides a cash incentive to all women on birthing in health institution. The cash incentive is intended to reduce financial barriers to accessing institutional care for delivery. Increased institutional births are expected to reduce MMR. Thus, JSY is expected to (a) increase institutional births and (b) reduce MMR in states with high proportions of institutional births. We examine the association between (a) service uptake, i.e., institutional birth proportions and (b) health outcome, i.e., MMR.

Method

Data from Sample Registration Survey of India were analysed to describe trends in proportion of institutional births before (2005) and during (2006–2010) the implementation of the JSY. Data from Annual Health Survey (2010–2011) for all 284 districts in above- mentioned nine states were analysed to assess relationship between MMR and institutional births.

Results

Proportion of institutional births increased from a pre-programme average of 20% to 49% in 5 years (p<0.05). In bivariate analysis, proportion of institutional births had a small negative correlation with district MMR (r = −0.11).The multivariate regression model did not establish significant association between institutional birth proportions and MMR [CI: −0.10, 0.68].

Conclusions

Our analysis confirmed that JSY succeeded in raising institutional births significantly. However, we were unable to detect a significant association between institutional birth proportion and MMR. This indicates that high institutional birth proportions that JSY has achieved are of themselves inadequate to reduce MMR. Other factors including improved quality of care at institutions are required for intended effect.     

Seasonality of births and conceptions in a pastoral community of the province of l'Aquila (Abruzzo,Italy), 1802-1965

Natality rates and seasonality of births and conceptions were analyzed from 6,116 birth records in the pastoral community of Roio (Abruzzo, Italy) from 1802 to 1965. Gross natality rates averaged 25.5 x 1000 in the past, lower than those reported for agricultural groups. Seasonality of births showed a marked pattern: 807-67% of births occurred in the first six months of the year. The monthly distribution of conceptions was compared to that of marriages. The results show a high correlation in the 19th century and a lower one in the 20th century. These findings suggest that pastoralism acted as a primary regulator of reproduction in this community.     

Low twinning rate and seasonal effects on twinning in a fertile population,the Hutterites

This paper analyzes from the mid 18th century to 1987 the birth records of the Dariusleut, one of the three subgroups of the Hutterite population. The aim of this study is to describe several aspects of the twinning rate in a fertile population. The overall rate of twinning was 0.90%:103 twins among all 11492 maternities. The rate peaked at the 7th birth order and at the maternal age of 40 years and over. Until the mid 19th century when the Hutterites lived in Russia, the twinning rate was higher (1.5%), and it decreased during the migration period in the second half of the 19th century (0.7%). After the group had settled in the USA and Canada, the population maintained a twinning rate of 1.0% until 1965. After 1965 the rate decreased to 0.7%, partly due to a decline in fertility among women aged 30 years and over. There was a significant seasonal variation: the twinning rate decreased to 0.5% in May–July compared to 1.2% for the other three seasons during the years up to 1965 (P<0.01), while more recent mothers did not show such a seasonal variation. The incidence of twin births in this population seems to have been influenced by environmental factors, which would change their effect seasonally and secularly.     

Segregation analysis of cleft lip with or without cleft palate in the First Nations (Amerindian) people of British Columbia and review of isolated cleft palate etiologies

BACKGROUND: The First Nations (Amerindian) population of British Columbia, Canada, has the highest reported birth prevalence in the world of cleft lip with or without cleft palate (CL/P) at nearly 3 per 1000 births. In addition, a substantial proportion of cleft palate only (CPO) cases in this population has been reported to be X‐linked. The aims of this study were to perform complex segregation analysis to investigate the mode of inheritance of CL/P in the First Nations people of British Columbia and to review the etiology of the CPO cases. METHODS: All First Nations children born in British Columbia between 1952 and 1971 with an orofacial cleft were included in the study. Multiple sources of ascertainment were used, so that nearly 100% of live births were identified and included during this time. No stillbirths were found but would likely have been ascertained. Extended pedigrees were constructed from these probands and examination of immediate family members, e.g., parents and siblings, was done wherever possible. Complex segregation analysis included all family members. In addition, a CPO case review was conducted. RESULTS: Complex segregation analysis supports the hypothesis that the most likely mode of inheritance of CL/P in this population is a mixed model; that is, an autosomal major gene with polygenic component. The review of 26 CPO cases showed that a substantial proportion are syndromic. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.