SEARCH · PubMed Health

Results for “consanguinity”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1995

Consanguinity among the Saudi Arabian population.

This study was conducted on 3212 Saudi families to investigate the prevalence of consanguineous marriages. The families were interviewed and the information on the relationship between the husband and wife was obtained. The overall rate of consanguinity shows that 57.7% of the families screened were consanguineous. The most frequent were first cousin marriages (28.4%) followed by distant relative marriages (15.2%) and second cousin marriages (14.6%). The families were grouped according to the province of their origin and the consanguinity rates were calculated accordingly. There were slight differences in the consanguinity rates in the five provinces, which ranged from 52.1% to 67.7%. In each province first cousin marriages were the most frequently encountered pattern, ranging from 17.9% to 40.9%. The inbreeding coefficient (F) was calculated for each province and ranged from 0.020 to 0.030. Within each province, there were several significant differences among the populations in the different areas. The highest rate of consanguinity was 80.6% in Samtah and the lowest rate was around 34% in Abha in the South Western province. These results place Saudi Arabia among the countries of the world with a high rate of consanguinity. The possible consequences of increased consanguinity are presented and discussed.

Consanguinity↗

PubMed2004

Assessment of association between consanguinity and fertility in Asian populations.

Although a high proportion of marriages in Asia are consanguineous (i.e. contracted between close biological relatives), with some notable exceptions, there is a death of demographic and anthropological literature on the association between consanguinity and fertility. This paper presents an overview of the prevalence of consanguineous marriages in selected South and Southeast Asian countries, followed by an assessment of the association between consanguinity and fertility. The association between consanguinity and fertility was assessed reviewing published literature and analyzing demographic and health survey (DHS) data from Pakistan and India. Results of the review of published literature showed higher fertility among women in the first-cousin unions compared to those married to non-relatives. In the DHS analyses, consanguinity was found to be associated with a number of direct and indirect determinants of fertility, including lower maternal education, lower maternal age at marriage, lower contraceptive use, and rural residence. At the multivariate level, adjusted mean fertility was found to be lower among women in the first-cousin unions in the Pakistani DHS data, while for the Indian DHS, adjusted mean fertility levels were similar in the first-cousin and non-consanguineous marriages. The pathways through which consanguinity affects fertility in Asian populations are evaluated and discussed.

Adolescent↗

PubMed1995

An epidemiological study on consanguineous marriage among urban population in Alexandria.

The study was carried out using a cross-sectional approach, involving interviews with 500 households randomly selected from three urban areas in Alexandria (Bab Sharki, El Gomrok and Karmouz). A questionnaire interview was conducted with married females in these households to determine prevalence of consanguineous marriages and to study knowledge of married females about causes and effects of consanguineous marriages. Prevalence of consanguineous marriages among 500 married females was 22.8% with the highest frequency among marriage between first cousins (15.8%). Average inbreeding coefficient up to the marriage between second cousins equals to 0.01172. The linear trend of consanguineous marriages throughout the last 50 years was statistically significant. Age at marriage was younger in consanguineous marriages than non consanguineous marriages. Longstanding familiarity and sharing same traditions and customs with male relatives were the main causes of consanguineous marriages. The majority of the studied females (42.2%) reported that consanguineous marriage is harmful while 29.6% reported that it has no effect on offsprings.

Adult↗

PubMed1997

Genetic disorders among Palestinian Arabs: 1. Effects of consanguinity.

Among Palestinian Arabs the rate of consanguinity is very high and some 44.3% of the marriages are between relatives (22.6% of them between first cousins). In almost 2,000 files from Palestinian Arab families who attended the genetics clinic in the Hadassah Medical Center; we were able to study the effects of consanguinity on different disorders. The consanguinity rate in families with dominant or X-linked disorders and chromosome aberrations was similar to the one observed in the general population. We did not find any significant differences in the rate of consanguineous marriages between the parents and grandparents of children affected with trisomy 21 and the general population. Thus, we were not able to confirm the suggestion that there is an increase risk for trisomies in children/grandchildren of consanguineous parents. Among the parents of patients with rare autosomal recessive disorders the consanguinity rate was much higher than the one of the general population (92.5%). Among the autosomal recessive disorders, which were relatively frequent in the population, there were fewer marriages between relatives; but in most cases the difference from rare disorders is relatively small. The importance of genetic factors in various congenital malformations, such as neural tube defects and cleft lip/palate or in various forms of infertility, was confirmed by the observation of a significantly higher consanguinity rate in the parents of these patients than is observed in the general population.

Abortion, Habitual↗

PubMed1995

Pre-marital genetic counselling to consanguineous couples: attitudes, beliefs and decisions among counselled, noncounselled and unrelated couples in Israel.

Semi-structured interviews were conducted with 65 Israeli subjects who received genetic counselling while considering marriage to a close relative, 40 subjects married to a close relative who did not receive pre-marital genetic counselling, and 125 controls married to a nonrelative and never having considered marrying a relative. It was found that 72% of the consanguineous couples who received pre-marital genetic counselling proceeded with their plans and married their relative; 86% of them reported that the counselling influenced their final decision to some degree. Counsellees' appraisals of genetic counselling revealed unfulfilled expectations to obtain more definitive answers, and mixed reactions to the nondirective approach applied by the counsellors. Comparisons between consanguineous and control couples revealed different views about consanguinity in general, and genetic risks in particular. Consanguineous couples, unlike controls, perceived consanguinity as an ordinary form of marriage, and had more favorable attitudes towards it. Compared to the noncounselled consanguineous group, consanguineous couples who received pre-marital genetic counselling had fewer children, estimated their genetic risk as lower but its subjective significance as higher, and perceived genetic disorders as more severe. The implications of these results are discussed from both theoretical and practical standpoints.

Attitude to Health↗

PubMedDate not supplied

Consanguineous marriages in the province of Antalya, Turkey.

To assess the trends in the frequency and the medical effects of consanguinity in the south coast of Turkish population using local and national data in the last 11 years. This cross-sectional study was carried out in Manavgat province, which is a major tourism center on the Mediterranean coast of Turkey. The authors studied consanguineous marriages in rural and urban population in the Mediterranean coast, Manavgat province, Turkey, via a 1500 random survey sample of married couples. There has been a significant increase in the incidence of consanguineous marriages in rural areas (40.7%) since 1989 in the southern population of Turkey. The results showed that the most frequent type of marriage was between the first cousins. It is found that there is no statistically significant difference between the consanguineous and non-consanguineous marriages in the different age groups. The results were discussed on the basis of educational status, reasons for having consanguineous marriages and the general medical effects as well as with the relation of congenital malformations. The custom of consanguineous unions in the Mediterranean population of Turkey is still extremely high, and preventive measures should be done to decrease its frequency and associated complications.

Consanguinity↗

PubMed2004

Consanguineous marriage in the capital city Sana'a, Yemen.

Consanguineous marriage is traditionally common throughout the Eastern Mediterranean region, especially in the mainly Muslim countries. To date, there is little information on consanguinity in Yemen. The aim of this study was to ascertain the rate of consanguineous marriage and average coefficient of inbreeding in Sana'a City, Yemen. A population survey was conducted with the intention of covering married couples resident in Sana'a City by means of a multi-stage random sampling technique. A total of 1050 wives and husbands were interviewed on consanguinity in their households. The total incidence of consanguinity was 44-7% (95% CI 41.7-47.7%) with first-cousin marriages constituting 71.6% of the total consanguineous marriages and 32% of all marriages. Paternal parallel first cousins (Type I) accounted for 49% of first-cousin marriages. The average coefficient of inbreeding (F) was 0.02442. The incidence of consanguinity is relatively high in Yemen with predominantly first-cousin marriage. This might be related to the deeply rooted social and cultural beliefs in the country.

Adolescent↗

PubMed1997

Consanguineous marriages in the United Arab Emirates.

This study examines the frequency of consanguineous marriage and the coefficient of inbreeding in the United Arab Emirates (UAE). The study was conducted in Al Ain and Dubai cities between October 1994 and March 1995. A sample of 2033 married UAE females aged 15 years and over participated. The degree of consanguinity between each female and her spouse, and the degree of consanguinity between their parents were recorded. The rate of consanguinity in the present generation was high (50.5%) with a coefficient of inbreeding of 0.0222. The commonest type of consanguineous marriage was between first cousins (26.2%). Double first cousin marriages were common (3.5%) compared to other populations. The consanguinity rate in the UAE has increased from 39% to 50.5% in one generation. The level of consanguinity was higher in Al Ain (54.2%) than in Dubai (40%).

Adult↗

PubMed1999

Consanguineous marriage and differentials in age at marriage, contraceptive use and fertility in Pakistan.

Fertility rates in Pakistan have remained consistently high over the past three decades. While numerous studies have examined sociodemographic determinants, the role of biological factors, and particularly consanguinity, has received little attention, even though marriage between close biological relatives continues to be the norm in Pakistan. Reproductive behaviour among women in consanguineous (first cousin) and non-consanguineous unions was compared, using data from a 1995 study of multi-ethnic communities in Karachi and the 1990-91 Pakistan Demographic & Health Survey (PDHS). The results show that, although female age at first marriage has been gradually rising in both study samples, women in consanguineous unions married at younger ages and were less likely to use modern contraceptive methods. In the Karachi sample, women in first cousin unions experienced a higher mean number of pregnancies and also reported a higher mean number of children ever born (CEB). However, their mean number of surviving children did not differ from those born to women in non-consanguineous unions, implying higher prenatal and/or postnatal losses in couples related as first cousins. On the other hand, the PDHS showed both lower CEB values for women in consanguineous marriages and a lower number of surviving children. Given the continuing popularity of consanguineous marriage, these findings have important implications for future fertility reduction in Pakistan.

Adolescent↗

PubMed2001

Consanguinity and advanced maternal age as risk factors for reproductive losses in Alexandria, Egypt.

BACKGROUND: Consanguinity has been a long-standing social habit among Egyptians. Estimates of consanguinity ratios in different parts of Egypt ranged from 29 to 50%. This study aimed at delineating the role of consanguinity and advanced maternal age on reproductive losses in Alexandria, Egypt. METHODS: A case-control study, on 730 couples with history of reproductive losses and 2,081 normal couples, was done during the period October, 1998 until August, 2000. RESULTS: Of the 730 couples with reproductive losses, consanguinity frequency was 68.8% with 56.2% first cousins. Prenatal loss and infant deaths were highly encountered among consanguineous marriages (p < 0.0001). In a multivariate logistic regression analysis, consanguinity between couples increased the relative risk of repeated abortion (OR: 3.95; 95% CI: 3.04-5.14), stillbirths (OR: 10.6; 95% CI: 6.7-17.0), neonatal death (OR: 17.2; 95% CI: 10.8-27.3), post-neonatal death (OR: 14.5; 95% CI: 10.6-19.9) and total reproductive losses (OR: 8.3; 95% CI: 6.9-10.1). A positive association was found between advanced maternal age and repeated abortion (OR: 3.19; 95% CI: 2.04-4.97) as well as total reproductive losses (OR: 2.37; 95% CI: 1.74-3.2). CONCLUSION: This study, the largest-reported case-control study on reproductive losses in Alexandria, strongly suggests that consanguinity may play a major role in the high rates of prenatal and infant mortality while advanced maternal age has a significant role in the causation of repeated abortion, and they must be taken into account for genetic counseling in Egypt. Because of the possibility of controlling, the study gives clear indications for prevention.

Adult↗

PubMed2001

Genetic sperm defects and consanguinity.

BACKGROUND: The existence of a genetic component to human infertility has been suggested, although neither the specific abnormalities involved, nor their genetic mechanism of transmission, are currently defined. We have examined, by transmission electron microscopy (TEM), ejaculate from 1600 males with fertility problems. Among the subjects studied, we focused on a group of patients whose family histories revealed different degrees of consanguinity, in order to evaluate the relationship between consanguinity and particular sperm alterations. METHODS AND RESULTS: A total of 64 consanguineous individuals were identified. In this group, excluding two azoospermic patients, 17 patients (27%) were found to have well recognized genetic ultrastructural defects affecting their entire sperm population: eight subjects had spermatozoa with "stunted tails", four "detached tail" spermatozoa, two "Kartagener's syndrome", two "miniacrosome" and one "round headed" spermatozoa. Since these alterations affect the total sperm population and do not respond to medical treatment, they are suspected of having a genetic origin. The remaining group of 1506 non-consanguineous patients suffered from the same genetic defects in only 15 cases (<1%). CONCLUSIONS: From the data presented, it appears that some very peculiar and rare sperm defects may have a genetic basis since they occur more frequently in consanguineous patients, and are related to different degrees of consanguinity. Since the ejaculate of the remaining patients, both consanguineous and not, showed diverse types of ultrastructural sperm anomalies that did not affect the entire sperm population, they might represent pathologies lacking a genetic basis.

Acrosome↗

PubMed1993

Consanguinity as a determinant of reproductive behaviour and mortality in Pakistan.

To determine the prevalence of consanguineous marriages and estimate the effects of consanguinity on reproductive behaviour and mortality, household and hospital-based surveys were conducted in 11 cities in the Pakistan province of Punjab between 1979 and 1985. The 9520 women interviewed reported 44,474 pregnancies, with data collected on maternal and paternal ages at marriage, abortions/miscarriages, stillbirths and deaths in the first month, at 2-12 months and 2-8/10 years. Six categories of consanguineous marriage were included: double first cousin, first cousin, first cousin once removed/double second cousin, second cousin, bradari (brotherhood) and non-consanguineous. Marriages contracted between spouses related as second cousins or closer accounted for 50.3% of the total, equivalent to an average coefficient of kinship (alpha = sigma piFi) of 0.0280. Unions between close biological relatives were characterized by younger maternal and paternal ages at marriage and reduced spousal age difference, but a longer time to first delivery. Overall, they exhibited greater fertility than non-consanguineous couples. Antenatal and postnatal mortality were assessed by consanguinity and age interval. Consanguinity-associated deaths were consistently higher in the neonatal, infant and childhood periods. The consequences of these outcomes on the health of the present and future generations is assessed.

Consanguinity↗

PubMed1998

Influence of consanguinity and maternal education on risk of stillbirth and infant death in Norway, 1967-1993.

To analyze the influence of consanguinity and maternal education on stillbirth and infant death for children born in Norway between 1967 and 1993, the authors studied 7,274 children of ethnic Pakistani origin and 1,431,055 children of Norwegian ethnic origin. Of these children, 31.0% of the Pakistani children and 0.1% of the Norwegian children had parents who were first cousins. Consanguinity increased the relative risk of stillbirth (odds ratio (OR) = 1.3, 95% confidence interval (CI) 1.0-1.6) and infant death (OR = 2.4, 95% CI 2.0-3.0), after adjustment for maternal education, maternal age, parity, and year of birth. In 1985-1993, 29% (95% CI 13-45) of stillbirths and infant deaths among the Pakistani group were attributable to consanguinity. In the Norwegian group, 17% (95% CI 13-21) of the deaths were attributable to factors associated with low maternal education, while in the Pakistani group, the corresponding estimate was nonsignificant. The risks of stillbirth and infant death were similar for children with non-consanguineous parents in both populations. This is an important observation considering the differences in socioeconomic status between the two groups. The authors conclude that consanguinity influenced stillbirth and infant death independent of maternal education, and that a large proportion of deaths could be attributed to consanguinity in the Pakistani group due to high frequencies of consanguinity.

Consanguinity↗

PubMedDate not supplied

Inconsistencies in genetic counseling and screening for consanguineous couples and their offspring: the need for practice guidelines.

PURPOSE: To determine current practices of genetic counseling and screening for consanguineous couples, their pregnancies and children, and to compare these practices to recommendations in the literature. METHODS: A questionnaire was mailed to 1,582 board certified genetic counselors and medical geneticists in the United States. RESULTS: The return rate was 20% (n = 309). There was wide variation in the risk figures quoted to consanguineous couples to have offspring with birth defects and mental retardation (1% to 75% for incest between first-degree relatives, and 0.25% to 20% for first cousin unions). Suggested screening practices differed for consanguineous unions before conception, during pregnancy, following birth, and for children placed for adoption. Most respondents recommended screening based on ethnicity, yet disagreed as to which genetic disorders to include. CONCLUSIONS: To standardize genetic services, guidelines for screening the offspring of consanguineous unions are needed. A consensus should be reached as to the empirical risks for genetic disorders, birth defects, and mental retardation that may impair the offspring of consanguineous unions, with definition as to what these disorders are, and if the data applies to global populations. Guidelines should consider costs, the sensitivity and specificity of DNA and biochemical testing, and current practices of prenatal and newborn screening. Consideration should be given to screening based on ethnicity, particularly in populations where consanguineous unions are common, while remaining sensitive to cultural belief systems. Recommendations for screening healthy children from consanguineous unions to be placed for adoption pose ethical challenges.

Child↗

PubMedDate not supplied

Consanguinity and associated socio-demographic factors in the United Arab Emirates.

The aim of this study was to explore the association between socio-demographic factors and consanguineous marriages in the United Arab Emirates (UAE). This was a cross-sectional population-based study conducted in the cities of Al Ain and Dubai between October 1994 and March 1995. A multi-stage sampling design was used and a representative total sample of 2,200 UAE females aged 15 years and above were included in this study. Data on 2,033 (85.8%) UAE national families who consented to participate in the study were obtained. The rate of consanguineous marriages in the sample was found to be 50.5% with 95% estimated population confidence limits 49.2-51.8%. The socio-demographic factors considered were: husband's age, wife's age, husband's and wife's educational levels, husband's occupation, wife's occupation, housing conditions, husband's parental kinship, wife's parental kinship, and kinship between the spouses. Consanguinity is more common among women with educated husbands (secondary or university/high) than among women with less educated husbands. The results indicate that the frequency of consanguineous marriages significantly increases when the husband's educational level is higher (p = 0.003). The distribution of relationship between spouses over the two generations of the study group and their parents is presented. The incidence of consanguineous marriages among the parents is 53% and 62% for the women and their husbands, respectively, and the overall incidence is 57%. The parallel patrilateral marriage is obviously the favoured practice when considering the parent's kinship distributions. The results of step-wise multiple logistic regression analysis for the occurrence of consanguineous marriages show that the husband's education and husband's parent's consanguinity status only are significantly associated variables.

Adult↗

PubMed2001

Inbreeding in Gredos mountain range (Spain): contribution of multiple consanguinity and intervalley variation.

The present paper examines consanguineous marriages occurring between 1874 and 1975 in three valleys (Tormes, Alberche, and Tiétar) in the Sierra de Gredos mountain range, Avila province, Spain. Information was obtained from parish registers of 42 localities, corresponding to a total of 41,696 weddings. Consanguineous marriages were defined as those up to the third degree of consanguinity (second cousins). From 1874 to 1975 the percentage of related mates was 4.45% and the inbreeding coefficient was 0.0011868 (for 1874 to 1917 corresponding figures up to the fourth degree were 16.44% and 0.00 19085, respectively). In order to ascertain the characteristics and evolution of mating patterns in Gredos, the contribution of each degree of kinship was analyzed as a whole and then for each valley separately. Regarding total consanguineous marriages in Gredos, there is a low frequency of uncle-niece matings (0.21%) and a first-second cousin mating ratio (C22/C33) of 0.23 (up to the third degree of consanguinity). Before 1918 multiple matings (i.e., those involving more than a single relationship) accounted for 19.16% of consanguineous marriages (up to the fourth degree). The observed frequencies of multiple consanguineous marriages was, on average, about twice that expected at random, and the proportion of such marriages to total inbreeding was 34.65%. The temporal change of the Gredos inbreeding pattern was characterized by a recent decrease; the highest inbreeding levels correspond to the period from 1915 to 1944. Finally, intervalley differences (maximum inbreeding coefficient in the Tormes, minimum in the Tiétar) are interpreted considering the geography, population size, and population mobility for each valley

Consanguinity↗

PubMed2001

Local differences in the Archbishopric of Santiago de Compostela (Galicia, Spain) in relation to the consanguinity structure, 1900-1979.

The microgeographic variability of consanguinity in the Archbishopric of Santiago de Compostela (Galicia) between 1900 and 1979 was studied. This Archbishopric covers 106 local councils integrated by 964 parishes, of which 677 (70.23%) were analyzed. Of the 307,094 marriages counted within this period, 15,739 corresponded to weddings between biologically related couples. Within the Archbishopric, eight geographical regions were considered: six coastal regions (Golfo Artabro, Bergantiños, Fisterra, Xallas, Santiago Oeste, and Rías Baixas) and two inland regions (Santiago Este and Terra de Montes). In order to evaluate the differences and similarities among them, the frequencies of all types of marriages (consanguineous and nonconsanguineous) were considered. First, a hierarchical grouping of the regions based on their chi-squared distances was performed. Then, in order to analyze relationships that are exclusively due to the structure of consanguinity, a correspondence analysis was performed and only the frequency of the different types of consanguineous marriages was taken into account. The results from both statistical analyses indicate special features of the Xallas region, both in the level of inbreeding (8.75%, the highest in the Archbishopric) and in the structure of consanguinity, for which a high proportion of uncle-niece marriages was found (6.22% of all consanguineous marriages). In all cases the structure of consanguinity provides informative nuances on the differences and similarities among population groups.

Catholicism↗

PubMed1992

Health effects of consanguinity in Pondicherry.

Of 1000 pregnant women studied, consanguinity was observed in 30.8%, with a higher frequency among women from rural areas, and among Hindus. In the consanguineous group, first cousin marriages were present in 47.4%, and uncle niece marriages in 23.4% of women. Coefficient of inbreeding was highest in Harijans (0.0258), followed by non-Brahmins (0.0220) and Brahmins (0.0204). Fertility was not influenced by consanguinity. There was a significantly higher rate of still births and infant mortality in consanguineous matings as compared with non-consanguineous. Total morbidity was higher in the consanguineous group as compared with the non-consanguineous (p less than 0.01), especially that due to neonatal infections and jaundice. There was no significant difference in the prevalence of congenital malformations, chromosomal and genetic disorders between the two groups, although the number of abnormal births in this group was small.

Consanguinity↗