Consanguinity and Prereproductive Mortality in the Utah Mormon Population
57
Citation
19
Reference
10
Related Paper
Citation Trend
Abstract:
To test the effects of parental consanguinity on mortality among offspring, inbreeding coefficients were estimated for 303,675 members of the Utah Mormon population who were born between 1847 and 1945. Although consanguinity has been relatively rare in this population, the large sample size permitted the identification of more than 3,500 inbred offspring. Among the offspring of unrelated parents, 13.2% died before the age of 16. Significant elevations in prereproductive mortality were seen among the offspring of first-cousin marriages (22%) and among the offspring of closer unions (32%). The cor- responding relative risks are 1.70 (95% confidence limits = 1.52, 1.91) and 2.41 (95% confidence limits = 1.59, 3.41), respectively. Other categories of relationship did not produce significant elevations in offspring mortality. Similar results were obtained when a case-control approach was used to remove the effects of socioeconomic variation. Consistent with many other studies of populations with low consanguinity rates, this population experienced a relatively high absolute increase in mortality among the offspring of first-cousin marriages (9%). Preliminary evidence is offered for the hypothesis that mortality differentials are larger in populations with low inbreeding and low mortality because nongenetic causes of death do not obscure the effects of consanguinity.Keywords:
Cousin
AN EPIDEMIOLOGIC APPROACH TO THE EVALUATION OF THE EFFECT OF INBREEDING ON PREREPRODUCTIVE MORTALITY
Although many studies report deleterious effects of inbreeding on prereproductive mortality (death before age 20 years), such effects are usually measured in terms of genetic load, a concept much debated in the literature. To evaluate the public health impact of inbreeding on prereproductive mortality in terms of relative and attributable risks, the authors reviewed 31 studies with 294 observations comparing various stages of infant and child mortality in offspring of unrelated parents with offspring of first cousin, first cousin once removed, and second cousin marriages, respectively. Compared with offspring of unrelated parents, offspring of first cousin marriages have a higher risk of prereproductive mortality (median relative risk (RR) = 1.41, signed-rank test, p <0.01). Offspring of first cousin once removed and second cousin marriages had median relative risks of 1.16 and 1.26, respectively. Countries with relatively higher rates of consanguineous marriages (>5%) had lower median relative risks than did countries with lower consanguinity rates. Also, the higher the mortality rate in the population, the lower the effect of consanguinity (median relative risk). Because of the rarity (<5%) and declining trends of consanguineous marriages in many places of the world, and because of their modest effect on prereproductive mortality (RR <2.0), it can be shown that the attributable risk of prereproductive mortality due to consanguineous marriages is less than 5%. Except for a few places with very high inbreeding levels, inbreeding has a minor impact on mortality in the prereproductive period.
Cousin
Cite
Citations (52)
To test the effects of parental consanguinity on mortality among offspring, inbreeding coefficients were estimated for 303,675 members of the Utah Mormon population who were born between 1847 and 1945. Although consanguinity has been relatively rare in this population, the large sample size permitted the identification of more than 3,500 inbred offspring. Among the offspring of unrelated parents, 13.2% died before the age of 16. Significant elevations in prereproductive mortality were seen among the offspring of first-cousin marriages (22%) and among the offspring of closer unions (32%). The cor- responding relative risks are 1.70 (95% confidence limits = 1.52, 1.91) and 2.41 (95% confidence limits = 1.59, 3.41), respectively. Other categories of relationship did not produce significant elevations in offspring mortality. Similar results were obtained when a case-control approach was used to remove the effects of socioeconomic variation. Consistent with many other studies of populations with low consanguinity rates, this population experienced a relatively high absolute increase in mortality among the offspring of first-cousin marriages (9%). Preliminary evidence is offered for the hypothesis that mortality differentials are larger in populations with low inbreeding and low mortality because nongenetic causes of death do not obscure the effects of consanguinity.
Cousin
Cite
Citations (57)
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.
Cousin
Cite
Citations (430)
Summary A high occurrence rate of consanguineous marriages may favour the onset and increased frequency of autosomal recessive diseases in a population. The population of Monte Santo, Bahia, Brazil, has a high frequency of rare genetic diseases such as mucopolysaccharidosis type VI, whose observed frequency in this population is 1:5000, while the incidence of this disease recorded in other regions of the world varies from 1:43,261 in Turkey to 1:1,505,160 in Switzerland. To verify the influence of consanguineous marriage on the increased frequency of observed genetic diseases in this population, the population structure and frequency of different types of marriage during different time periods were evaluated. A total of 9765 marriages were found in an analysis of parish marriage records from the city. Over three periods, 1860–1895, 1950–1961 and 1975–2010, the inbreeding rates were 37.1%, 13.2% and 4.2% respectively. Although there was a high rate of inbreeding, endogamic marriages were the dominant marriage type in all three periods. In the most recent period, there was an increase in the number of exogamous marriages and those among immigrants, but most of these occurred among individuals from cities that neighbour Monte Santo. The low rate of migration and high frequency of endogamic and consanguineous marriages show that growth of this population is predominantly internal and could explain the occurrence, and increase in frequency, of recessive genetic diseases in the city.
Consanguineous Marriage
Cite
Citations (18)
The study was performed in six mohallahs (colonies) of Aligarh City (North India). All six mohallahs are predominantly inhabited by Qureshi (meat sellers, a highly endogamous group) Muslims. A total of 1721 infants and children up to the age of 6 years were examined to determine the incidence of congenital heart diseases (CHD) in relation to the degree of consanguinity of the parents. Around 43% of the subjects were the offspring of consanguineous marriages including second‐cousin, first‐cousin‐once‐removed and first‐cousin. A higher percentage of CUD was found in the offspring of consanguineous marriages: about 3.37% out of 741 children as compared to 1.22% in 980 offspring of non‐consanguineous marriages, whereas in the first‐cousin offspring, the percentage of CHD rose to 4.41%. The differences were found to be statistically significant. The present study suggests a genetic influence and also casts doubt on the applicability of a polygenic threshold model to all forms of cardiac malformation.
Cousin
Consanguineous Marriage
Endogamy
Cite
Citations (56)
We conducted a population-based study of consanguineous marriages in Jordan. About two thousand households were interviewed. First cousin marriages were encountered in 32.03%, second cousin in 6.8%, distant relation in 10.5%, and no relation in 50% of all marriages, respectively. Inbreeding coefficients were compared with those of other countries. The most important variables affecting inbreeding were social tradition, religion, education, and place of residence--urban vs. rural. Secular trends appear rather stable since the early decades of the twentieth century, especially for first cousin marriages. Jordan society showed a deeply rooted traditional behavioral pattern when inbreeding is considered.Consanguineous marriage in Jordan is examined in a retrospective survey of 1995 households in 1980. The sample was stratified in 2 stages and self-weighing. The research objective was to determine the extent, patterns, characteristics, significant factors affecting inbreeding, and continuity over time. Interviewers collected data on dwelling, age, education, consanguinity, marriage arrangement, religion, number of pregnancies, place of residence, contraceptive use, and parent's marital patterns. The results were 51.25% of all marriages were consanguineous: 33% among first cousins, 6.8% among second cousins, 10.5% among distant relatives, and 49.7% no relation. The inbreeding in Jordan is compared with inbreeding incidence in Lebanon, Kuwait, Egypt, and Turkey; it appears that prevalence is associated with a Muslim affiliation. The rural population had a significantly higher proportion of first cousin consanguineous marriages. Urban and semi urban dwellers had similar second marriages. There were 29.82% first cousin marriages in urban areas, 30.99% in semi urban areas, and 37.91% in rural areas. Education (literate vs. illiterate) and consanguinity was negatively correlated for all unions and male unions, i.e., higher education levels had more unrelated unions. When educational level is differentiated, the university educated group behaves like the illiterate group. Life explanation is that the "best" males are pressured to remain within the family. Female university graduates showed greater freedom in selection of husbands. 66% were living in independent households, and the other 33% with the husband's family. 80% of marriages were arranged and educational level is an important determining factor. Consanguinity of marriage was significantly associated with parent's consanguinity. Comparison with trends in the 1920s indicates that first cousin marriages have remained stable.
Cite
Citations (224)
Summary In genetics, a consanguineous marriage means union between couples who are related as second cousins or closer. The present cross-sectional study was carried out in order to illustrate the prevalence and types of consanguineous marriages in the Shi'a population living in widespread territories in Lebanon including the Bekaa Valley, the south of Lebanon and the southern suburb of Beirut. Data on types of marriages were collected using a simple questionnaire. The total number of couples in the study was 1203. Consanguineous marriage was classified by the degree of relationship between couples. The overall frequency of consanguinity was found to be 28.4%, with first cousin marriages (21.3%) being the most common type followed by first cousins once removed (5.5%), then double first cousins (0.8%). The frequencies of second cousin and beyond second cousin marriages were the same at 0.4% of all the marriages. The mean inbreeding coefficient ( α ) was estimated at about 0.0161 for the population. There were no significant differences between the three studied territories for frequencies of different types of marriages ( p >0.1), nor were there significant differences between the rural and urban areas ( p >0.1).
Consanguineous Marriage
Cousin
Cite
Citations (25)
Consanguinity, the marriage between relatives, has been associated with adverse child health outcomes. The objective of the present study was to assess the effect of consanguinity on offspring weight gain from birth to 12 months after birth. Data were collected on 250 consecutive live-born singleton newborns referred to a local health centre in Shiraz (Fars province, southern Iran). Collected data covered socio-demographic characteristics (such as parental age at delivery and parental education), sex, birth order, weights from birth to 12 months after birth and consanguinity of marriages of parents. Considering the low prevalence of double first cousin, first cousin once removed, second cousin, and beyond second cousin marriages, only first cousin and unrelated marriages were included in the study. The study population consisted of a total of 207 newborns (57 offspring of first cousins, 150 offspring of unrelated marriages). Based on the results of repeated measurements analysis of variance, weight gain was associated with type of marriage (p=0.018), sex of offspring (p=0.001) and paternal education (p<0.001). There was no interaction between type of marriage and sex (p=0.831). Birth weight was not affected by type of marriage (p=0.46). There was significant interaction between inbreeding and time (p=0.034). Offspring of consanguineous marriages showed lower weight gain in comparison with those of unrelated marriages during 3-12 months after birth.
Cite
Citations (11)
The objective of this study was to explore the secular trend in consanguinity in Jordan and the subtypes of consanguineous marriages that may be undergoing a change. A total of 1032 individuals attending a diabetic clinic in Amman were interviewed. The questionnaire provided information on consanguinity status and date of marriage among three generations: the persons interviewed, their parents, parents of their spouses and their offspring. Data on consanguinity status among 5401 marriages was obtained. Generations were named generation 1 for marriages contracted before 1950, generation 2 for marriages contracted between 1950 and 1979, and generation 3 for marriages contracted after 1980. For generations 1, 2, and 3, first-cousin marriages constituted 20.2, 28.5 and 19.5% of all marriages, respectively, while the subtype of paternal parallel first-cousin marriages constituted 75.6, 60.3 and 43.3% of all first-cousin marriages, respectively. The offspring of first-cousin parents were significantly more prone to marry their relatives than the offspring of non-consanguineous parents, with rates of first-cousin marriages among offspring of first-cousin parents and non-related parents constituting 25.3 and 17.1% of all marriages, respectively. For generations 1, 2 and 3, the average coefficient of inbreeding was 0.0135, 0.02 and 0.0142, respectively. In conclusion, first-cousin marriage rate among a representative population from Amman showed a significant decline among marriages contracted after 1980 compared to marriages contracted between 1950 and 1979, but not to marriages contracted before 1950. The proportion of paternal parallel first cousins among first-cousin marriages showed a steady decline from one generation to the next.
Cousin
Consanguineous Marriage
Cite
Citations (145)