Consanguinity and early mortality in the Muslim populations of India and Pakistan

Consanguineous Marriage and Early Pregnancy Loss in Rural to Peri-Urban India

Background

Consanguineous marriage (CM) has been linked to spontaneous abortion (SAB), although studies have largely been cross-sectional and likely underestimated early loss. We aimed to determine the relationships between CM and SAB in a prospective pregnancy cohort study in Telangana State, India.

Methods

Data from 661 participants aged 15-35 years in the Longitudinal Indian Family hEalth (LIFE) study actively followed for pregnancy and pregnancy loss were analyzed. SAB was classified as early (< 8) or late (8-22) weeks gestation. We used logistic regression to model the relationships between CM, defined by first-cousin marriage, and SAB, adjusted for maternal age.

Results

Women in CM were at a modestly increased risk of any (OR_adj 1.15, 95% CI 0.69, 1.91) and early (OR_adj 2.03, 95% CI 0.85, 4.83) SAB compared to women in non-CM, although results were not statistically significant. There was no relationship between CM and late SAB.

Conclusion

Among couples in southern India, there was a modest increase in early but not late SAB among CMs which may be explained by the expected influence of chromosomal abnormalities and lethal homozygous recessive disease on early loss. Pre- and Peri-marital Health Counseling that addresses this risk may be warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13224-021-01498-7.

Consanguinity and ocular disorders in India: Electronic medical records driven big data analytics

Purpose:

To describe the distribution of ocular disorders in patients with a family history of consanguinity presenting to a multi-tier ophthalmology hospital network in India.

Methods:

This cross-sectional hospital-based study included 2,805,267 new patients presenting between August 2010 and April 2021. Patients with a family history of consanguinity were included as cases. The sociodemographic and clinical data were collected using an electronic medical record system.

Results:

Overall, 20,445 (0.73%) new patients were documented to have a family history of consanguinity. The prevalence rates were 4.04% in children (age: <16 years) and 0.21% in adults. The mean age of the patients was 11.87 ± 11.06 years. The majority of the patients were males (56.48%) and students (54.43%) by profession. The majority (93.05%) of the patients were in the 0–30-years age bracket, with over half of them (53.71%) presenting in the first decade of life. A significant number of patients were from higher socioeconomic status (73.48%) and the rural region (47.62%). The most common degree of consanguinity documented was second degree (3.95%). The most common ocular disorders associated with a high proportion of consanguinity were congenital hereditary endothelial dystrophy (CHED) (100%), corneal macular dystrophy (83.78%), xeroderma pigmentosum (80.95%), and ocular albinism (73.59%). A tenth of the patients (9.8%) reported a similar history of ocular disorders among the family members and more commonly among the siblings (70.4%).

Conclusion:

Consanguineous marriages are not uncommon in India. They cause ocular disorders that cause visual impairment in a significant majority of those affected in their early decades of life. Genetic counseling plays a role in prevention.

Is diagnosing patients with Organic Acidurias and Aminoacidopathies enough? Conundrums of a low middle-income country

Objective:

This study was done to determine the factors responsible for non-treatment of inherited metabolic disorders (IMDs) requiring food for special medical purposes (FSMPs) in Pakistan.

Methods:

A descriptive cross-sectional study was conducted by Departments of Pediatrics & Child Health and Pathology & Laboratory Medicine, Aga Khan University. Patients diagnosed with IMDs from January 2013 to December 2016 requiring FSMPs were surveyed after a year of initial diagnosis to collect the details of treatment advised, mortality status, and reasons of non-treatment, including not prescribed by physician, non-acceptance by family, non-availability or non-affordability.

Results:

Over four years period, 311 patients were identified with IMDs; Median age of patients was 1.0 yrs (0.0.2-3.65) with 54% (n=168) being male. Of the total 38.2% (n=119) required FSMPs, 9% (n=28) patients were excluded due to unavailability of diagnostics information. Parents of 58 patients requiring FSMPs out of 119 participated in survey. The leading causes of non-treatment were, FSMPs not prescribed by physicians (n= 30, 51.7%) followed by non-affordability (n=23, 39.6%), families’ unacceptance in (n=9, 18%) patients, non-availability of FSMPs (n=2, 3.4%) and early death of patient (n=1, 1.7%).

Conclusion:

The main factors responsible for non-treatment of FSMPs requiring IMDs were non-prescription by physician and non-affordability.

Relationship between parental consanguinity and digit ratios (2D:4D) among Turkish newborns in Sivas

OBJECTIVES

The aim of this study was to investigate the effects of parental consanguinity on the 2D:4D digit ratio of newborn infants, whose parents were the first cousins.

METHODS

The study included healthy and full-term newborn infants, delivered in a hospital, at the gestational ages from 37 to 41 weeks. A total of 225 newborns and their parents were included in the study. Of these 225 newborns; 100 were inbred and 125 were outbred infants. We used a Vernier caliper to measure the length of the second and fourth digits of the newborns (accuracy: 0.01 mm).

RESULTS

Controlling for education and number of pregnancies, male newborns had lower digit ratios than female newborns, for both left and right hands. There were, moreover, differences between inbred and outbred samples. We determined that inbreeding was related to a reduction in the digit ratios regardless of the side of the hand and the sex of the infant, showing a consistent tendency to appear more masculine. Interaction between marriage type*sex was highly significant.

CONCLUSIONS

Parental consanguinity appears to cause fetal masculinization of digit ratios by increasing fetal stress among Turkish newborns.

A Family Study of Consanguinity in Children with Intellectual Disabilities in Barwani, India

Background:

Intellectual disability (ID) can be inherited in families through consanguineous marriage. The ID in an individual can be associated with the ID, epilepsy, and mental illness in their parents. Such connections can be seen more closely among consanguineous marriages in tribal and nontribal population in India.

Objective:

This study shows a few common patterns of the consanguineous relationship in the parents of children with ID in India.

Materials and Methods:

This is a case series research design. Extreme or deviant case sampling was applied. Data were collected in homes, camps, and clinical settings in the Barwani district of Madhya Pradesh, India. The patterns of consanguineous marriages and the relationship between children with ID and their relatives with ID, epilepsy, and mental illness were analyzed and reported with pedigree charts.

Results:

Multiple patterns of consanguineous marriages in tribal and nontribal populations were observed. ID was found to be associated in children with their relatives of the first, second, and third generations.

Conclusion:

ID may inherit in individuals from their relatives of the first, second, and third generations who have ID, epilepsy, or mental illness and married in the relationship. Appropriate knowledge, guidance, and counseling may be provided to potential couples before planning a consanguineous marriage.

Early-life mortality clustering in families: A literature review

Research on early-life mortality in contemporary and historical populations has shown that infant and child mortality tend to cluster in a limited number of high-mortality families, a phenomenon known as 'mortality clustering'. This paper is the first to review the literature on the role of the family in early-life mortality. Contemporary results, methodological and theoretical shortfalls, recent developments, and opportunities for future research are all discussed in this review. Four methodological approaches are distinguished: those based on sibling deaths, mother heterogeneity, thresholds, and excess deaths in populations. It has become clear from research to date that the death of an older child harms the survival chances of younger children in that family, and that fertility behaviour, earlier stillbirths, remarriages, and socio-economic status all explain mortality clustering to some extent.

Obesity genetics: insights from the Pakistani population

The Pakistani population is extensively diverse, indicating a genetic admixture of European and Central/West Asian migrants with indigenous South Asian gene pools. Pakistanis are organized in different ethnicities/castes based on cultural, linguistic and geographical origin. While Pakistan is facing a rapid nutritional transition, the rising prevalence of obesity is driving a growing burden of health complications and mortality. This represents a unique opportunity for the research community to study the interplay between obesogenic environmental changes and obesity predisposing genes in the time frame of one generation. This review recapitulates the ancestral origins of Pakistani population, the societal determinants of the rise in obesity and its governmental management. We describe the contribution of syndromic, monogenic non-syndromic and polygenic obesity genes identified in the Pakistani population. We then discuss the utility of gene identification approaches based on large consanguineous families and original gene × environment interaction study designs in discovering new obesity genes and causal pathways. Elucidation of the genetic basis of obesity in the Pakistani population may result in improved methods of obesity prevention and treatment globally.

Prevalence and associated factors influencing stunting in children aged 2-5 years in the Gaza Strip-Palestine: a cross-sectional study

BACKGROUND

Stunting continues to be a major public health problem in developing countries. It is one of the most important risk factors for morbidity and mortality during childhood. In Palestine, it is another health problem, which adds to the catastrophic issues in the region. This study aimed to determine the prevalence of stunting and its associated factors among preschool children in the Gaza Strip.

METHODS

A cross-sectional study design was conducted in the Gaza Strip. A total of 357 children aged 2-5 years and their mothers aged 18-50 years were recruited. A multistage cluster sampling was used in the selection of the study participants from three geographical areas in the Gaza Strip: Jabalia refugee camp, El Remal urban area, and Al Qarara rural area. A structured questionnaire was used for face- to -face interviews with the respective child's mother to collect sociodemographic information and feeding practice. Anthropometric measurements for children were taken to classify height-for-age (HAZ), while maternal height was measured as well. Descriptive and binary logistic regression analyses were applied to determine the prevalence and associated factors with stunting.

RESULTS

The total prevalence of stunting in this study was 19.6%, with the highest prevalence being (22.6%) in Jabalia refugee camp. It turns out that shorter mothers had increased the odds of stunting in preschool children in the Gaza Strip. Children born to mothers whose height was 1.55-1.60 m or <1.55 m were more likely to be stunted (p = 0. 008), or (p < 0.001), respectively, than children born to mothers whose height was >1.60 m. Moreover, parental consanguinity increased the risk of stunted children (p = 0. 015).

CONCLUSIONS

This study showed the prevalence of stunting was of alarming magnitude in the Gaza Strip. Our results also demonstrated that parental consanguinity and short maternal stature were associated with stunting. Culturally appropriate interventions and appropriate strategies should be implemented to discourage these types of marriages. Policy makers must also raise awareness of the importance of the prevention and control of nutritional problems to combat stunting among children in the Gaza Strip.

Under-Five Child Mortality and Morbidity Associated with Consanguineous Child Marriage in Pakistan: Retrospective Analysis using Pakistan Demographic and Health Surveys, 1990-91, 2006-07, 2012-13

Objective To assess the combined effect of consanguineous and child marriages (CCM) on children health, which has not previously been explored, either globally or locally. Methods We analyzed secondary data from a series of cross-sectional, nationally representative Pakistan Demographic and Health Surveys 1990-91, 2006-07, and 2012-13. A total of 5406 mothers with 10,164 children were included in the analysis. Child health was assessed by variables such as history of diarrhea, acute respiratory infection (ARI), ARI with fever, Under-5 child mortality (U5CM) and small-size birth (SSB). Associations among variables were assessed by calculating unadjusted Odd Ratios (OR) and adjusted OR (AOR). Results A majority (n = 6,247, 61%) of the births were to mothers having CCM as compare to non-CCM (3917, 39%). There was a significant association between CCM and U5CM during 1990-91 (AOR 1.24, 95% CI 1.03-1.49) and 2006-07 (AOR 1.25, 95% CI 1.05-1.51), and infant mortality in 1990-91 (AOR 1.39, 95% CI 1.05-1.85) and 2006-07 (AOR 1.61, 95% CI 1.17-2.21). A significant association was also found between CCM and SSB infants in the period 2006-07 (AOR 1.19, 95% CI 1.01-1.42) and 2012-13 (AOR 1.22, 95% CI 1.02-1.46). We noted no effect of CCM on diarrhea, ARI, and ARI with fever. Conclusion CCM increases the likelihood of U5CM, infant mortality and SSB infants. Further quantitative and qualitative research should be conducted to assess the effects of environmental, congenital and genetic factors on the health of children born to mothers in CCM.

Attitudes towards non-invasive prenatal diagnosis among obstetricians in Pakistan, a developing, Islamic country

OBJECTIVES

Stakeholders' views are essential for informing implementation strategies for non-invasive prenatal testing (NIPT). Little is known about such views in developing countries. We explored attitudes towards NIPT among obstetricians in Pakistan, a developing, Islamic country.

METHODS

A 35-item questionnaire was distributed and collected at eight events (a national conference and seven workshops in five cities) for obstetric professionals on advances in fetal medicine.

RESULTS

Responses from 113 obstetrician show positive attitudes towards implementation of NIPT: 95% agreed prevention of genetic conditions was a necessity, and 97% agreed public hospitals should provide prenatal screening tests. However, participants also agreed the availability of NIPT would increase social pressure on women to have prenatal screening tests and to terminate an affected pregnancy (53% and 63%, respectively). Most participants would not offer NIPT for sex determination (55%), although 31% would. The most valued aspects of NIPT were its safety, followed by its utility and then accuracy.

CONCLUSION

Participants generally supported the implementation of NIPT but raised concerns about social implications. Therefore, national policy is needed to regulate the implementation of NIPT, and pretest information and post-test genetic counselling are needed to mitigate social pressure and support parents to make informed decisions. © 2017 John Wiley & Sons, Ltd.

Genetics of consanguinity and inbreeding in health and disease

CONTEXT

Inbreeding increases the level of homozygotes for autosomal recessive disorders and is the major objective in clinical studies. The prevalence of consanguinity and the degree of inbreeding vary from one population to another depending on ethnicity, religion, culture and geography. Global epidemiological studies have revealed that consanguineous unions have been significantly associated with increased susceptibility to various forms of inherited diseases.

OBJECTIVE

The study aimed to determine the role of consanguinity in human health and to highlight the associated risks for various diseases or disorders.

METHODS

PubMed and Google Scholar search engines were used to explore the published literature on consanguinity and its associated risks using the key words "consanguinity", "prevalence", "inbreeding depression", "coefficient of inbreeding", "child health", "mortality", "human health", "homozygosity" and "complex diseases" in different combinations. The studies were screened for eligibility on the basis of their epidemiological relevance.

RESULTS

This comprehensive assessment highlights the deleterious consequences in populations with a higher prevalence of consanguinity among different countries worldwide.

CONCLUSIONS

To avoid the inbreeding load there is the need to improve socioeconomic and educational status and to increase public awareness of reproductive health and anticipated deleterious effects. Pre-marital and pre-conception counselling of consanguineous populations should be an integral part of health policy to train people and make people aware of its harmful consequences. Furthermore, runs of homozygosity (ROH) and whole-exome sequencing (WES) are useful tools in exploring new genomic signatures for the cause of inbreeding depression.

Are hypertensive disorders in pregnancy associated with congenital malformations in offspring? Evidence from the WHO Multicountry cross sectional survey on maternal and newborn health

BACKGROUND

Annually, around 7.9 million children are born with birth defects and the contribution of congenital malformations to neonatal mortality is generally high. Congenital malformations in children born to mothers with hypertensive disorders during pregnancy has marginally been explored.

METHODS

Country incidence of congenital malformations was estimated using data on the 310 401 livebirths of the WHO Multicountry Survey which reported information from 359 facilities across 29 countries. A random-effect logistic regression model was utilized to explore the associations between six broad categories of congenital malformations and the four maternal hypertensive disorders "Chronic Hypertension", "Preeclampsia" and "Eclampsia" and "Chronic hypertension with superimposed preeclampsia".

RESULTS

The occupied territories of Palestine presented the highest rates in all groups of malformation except for the "Lip/Cleft/Palate" category. Newborns of women with chronic maternal hypertension were associated with a 3.7 (95 % CI 1.3-10.7), 3.9 (95 % CI 1.7-9.0) and 4.2 (95 % CI 1.5-11.6) times increase in odds of renal, limb and lip/cleft/palate malformations respectively. Chronic hypertension with superimposed preeclampsia was associated with a 4.3 (95 % CI 1.3-14.4), 8.7 (95 % CI 2.5-30.2), 7.1 (95 % CI 2.1-23.5) and 8.2 (95 % CI 2.0-34.3) times increase in odds of neural tube/central nervous system, renal, limb and Lip/Cleft/Palate malformations.

CONCLUSIONS

This study shows that chronic hypertension in the maternal period exposes newborns to a significant risk of developing renal, limb and lip/cleft/palate congenital malformations, and the risk is further exacerbate by superimposing eclampsia. Additional research is needed to identify shared pathways of maternal hypertensive disorders and congenital malformations.

THE CAUSAL RELATIONSHIP BETWEEN CONSANGUINEOUS MARRIAGES AND INFANT MORTALITY IN TURKEY

Turkey has high levels of infant mortality and consanguineous marriages. It has had a high level of infant mortality for its economic level for many years. Over recent decades, although adult mortality rates have not been very different from those of other countries with similar socioeconomic structures, its life expectancy at birth has remained low due to its high infant mortality rate. This has been called the Turkish Puzzle. According to the Turkey Family Structure and Population Issues Survey, 27% of women had a consanguineous marriage in 1968. Subsequent Turkish Demographic and Health Surveys (TDHSs) found the rate of consanguineous marriages to be stagnated at 22-24%, with a resistance to reduction. According to the TDHS-2008, 24% of women had a consanguineous marriage. Numerous studies in various countries of the world have indicated that consanguineous marriages, particularly of first-degree, have the effect of increasing infant mortality. The main aim of this study was to assess the causal impact of consanguineous, particularly first-degree consanguineous, marriages on infant mortality, controlling for individual, cultural, bio-demographic and environmental factors. Data were merged from four Turkish DHS data sets (1993, 1998, 2003 and 2008). Multivariate analysis revealed that first-degree consanguineous marriages have increased infant mortality by 45% in Turkey: 57% in urban areas and 39% in rural areas. The results indicate that there is a causal relationship between consanguineous marriages and infant mortality. This finding should be taken into account when planning policies to reduce infant mortality in Turkey, and in other countries with high rates of consanguineous marriage and infant mortality.

Attractiveness of Own-Race, Other-Race, and Mixed-Race Faces

Averaged face composites, which represent the central tendency of a familiar population of faces, are attractive. If this prototypicality contributes to their appeal, then averaged composites should be more attractive when their component faces come from a familiar, own-race population than when they come from a less familiar, other-race population. We compared the attractiveness of own-race composites, other-race composites, and mixed-race composites (where the component faces were from both races). In experiment 1, Caucasian participants rated own-race composites as more attractive than other-race composites, but only for male faces. However, mixed-race (Caucasian/Japanese) composites were significantly more attractive than own-race composites, particularly for the opposite sex. In experiment 2, Caucasian and Japanese participants living in Australia and Japan, respectively, selected the most attractive face from a continuum with exaggerated Caucasian characteristics at one end and exaggerated Japanese characteristics at the other, with intervening images including a Caucasian averaged composite, a mixed-race averaged composite, and a Japanese averaged composite. The most attractive face was, again, a mixed-race composite, for both Caucasian and Japanese participants. In experiment 3, Caucasian participants rated individual Eurasian faces as significantly more attractive than either Caucasian or Asian faces. Similar results were obtained with composites. Eurasian faces and composites were also rated as healthier than Caucasian or Asian faces and composites, respectively. These results suggest that signs of health may be more important than prototypicality in making average faces attractive.

Characterisation of three novel CYP11B1 mutations in classic and non-classic 11β-hydroxylase deficiency

BACKGROUND

Congenital adrenal hyperplasia (CAH) is one of the most common autosomal recessive inherited endocrine diseases. Steroid 11β-hydroxylase (P450c11) deficiency (11OHD) is the second most common form of CAH.

AIM

The aim of the study was to study the functional consequences of three novel CYP11B1 gene mutations (p.His125Thrfs*8, p.Leu463_Leu464dup and p.Ser150Leu) detected in patients suffering from 11OHD and to correlate this data with the clinical phenotype.

METHODS

Functional analyses were done by using a HEK293 cell in vitro expression system comparing WT with mutant P450c11 activity. Mutant proteins were examined in silico to study their effect on the three-dimensional structure of the protein.

RESULTS

Two mutations (p.His125Thrfs*8 and p.Leu463_Leu464dup) detected in patients with classic 11OHD showed a complete loss of P450c11 activity. The mutation (p.Ser150Leu) detected in a patient with non-classic 11OHD showed partial functional impairment with 19% of WT activity.

CONCLUSION

Functional mutation analysis enables the correlation of novel CYP11B1 mutations to the classic and non-classic 11OHD phenotype respectively. Mutations causing a non-classic phenotype show typically partial impairment due to reduced maximum reaction velocity comparable with non-classic mutations in 21-hydroxylase deficiency. The increasing number of mutations associated with non-classic 11OHD illustrate that this disease should be considered as diagnosis in patients with otherwise unexplained hyperandrogenism.

Pre-pregnancy care for women with pre-gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Pre-gestational diabetes mellitus is associated with increased risk for maternal and fetal adverse outcomes. This systematic review was carried out to evaluate the effectiveness and safety of pre-pregnancy care in improving the rate of congenital malformations and perinatal mortality for women with pre-gestational diabetes mellitus.

METHODS

We searched the following databases, MEDLINE, EMBASE, WEB OF SCIENCE, Cochrane Library, including the CENTRAL register of controlled trials and CINHAL up to December 2011, without language restriction, for any pre-pregnancy care aiming at health promotion, glycemic control and screening and treatment of diabetes complications in women with type I or type II diabetes mellitus. Study design were trials (randomized and non-randomized), cohort and case-control studies.

RESULTS

Of the 2452 title scanned 54 full papers were retrieved of those 21 studies were included in this review. Twelve cohort studies at low and medium risk of bias, with 3088 women, were included in the meta-analysis. Meta-analysis suggested that pre-pregnancy care is effective in reducing congenital malformation, Risk Ratio (RR) 0.25 (95% CI 0.16-0.37), number needed to treat (NNT) 19 (95% CI 14-24), and perinatal mortality RR 0.34 (95% CI 0.15-0.75), NNT = 46 (95% CI 28-115). Pre-pregnancy care lowers glycosylated hemoglobin A1c (HbA1c) in the first trimester of pregnancy by an average of 1.92% (95% CI -2.05 to -1.79). However women who received pre-pregnancy care were at increased risk of hypoglycemia during the first trimester of pregnancy RR 1.51 (95% CI 1.15-1.99).

CONCLUSION

Pre-pregnancy care for women with pre-gestational type 1 or type 2 diabetes mellitus is effective in improving rates of congenital malformations, perinatal mortality and in reducing maternal HbA1C in the first trimester of pregnancy. Pre-pregnancy care might cause maternal hypoglycemia in the first trimester of pregnancy.

In-hospital neonatal mortality and the role of consanguinity

BACKGROUND

Consanguinity which increases the risk of genetic disorders has been implicated at times in infant mortality. The aim of this study was to determine the association between consanguinity and in-hospital mortality in newborns.

METHODS

Data was collected prospectively on all births from 26 hospitals in Lebanon from January 2004 to December 2008 and admitted to the National Collaborative Perinatal Neonatal Network. Secondary analysis was done on 65,402 singletons, after exclusion of stillbirths, infants of multiple gestation and infants of second cousin progeny.

RESULTS

In-hospital mortality was 6.7 per 1000 live births (439/65,402). The rate of first cousin marriage was 9.9%. Consanguinity was significantly associated with in-hospital mortality (odds ratio 2.4; 95% confidence interval (CI): 1.8, 3.1); consanguinity remained a significant predictor of mortality (odds ratio 1.8 [95% CI: 1.2, 2.9]) after adjusting for maternal age and education, crowding index, history of abortion, prenatal care, mode of delivery, gender, birthweight and apgar score at 5 minutes.

CONCLUSIONS

This association of consanguinity with in-hospital mortality points to potential genetic factors leading to this increased risk. Designing public health interventions, including raising the awareness and taking into consideration such risks in neonatal mortality studies are indicated.

Ethnic variations in mortality in pre-school children in Denmark, 1973-2004

The objective of the study was to describe ethnic differences in under-five-years mortality in Denmark according to maternal country of origin. We conducted a large registry-linkage study of all singleton live-born children from mothers born in Denmark and from the ten largest migrant groups (n = 1,841,450). Study outcomes were death before the age of 5 years from all causes combined and the most frequent death causes. Results showed that children of mothers of Turkish, Pakistani, Somali and Iraqi origin had an elevated risk of dying before the age of five compared to offspring of mothers born in Denmark, with hazards ratios and 95% confidence intervals of 1.48 (1.31-1.67), 1.97 (1.68-2.32), 1.70 (1.29-2.25), and 1.92 (1.41-2.62), respectively. Ethnic differences were also observed in the underlying causes of death. Children of mothers born in Former Yugoslavia, Lebanon, Norway, Sweden, Iran, and Afghanistan did not differ in under-five-years mortality from ethnic Danish children. Adjustments for household income did not attenuate the risk estimates. In conclusion, we found excess child mortality in some migrant groups, but not in all. The differences could not be explained by socioeconomic status.

Preconception care for diabetic women for improving maternal and fetal outcomes: a systematic review and meta-analysis

Background

Preexisting diabetes mellitus is associated with increased risk for maternal and fetal adverse outcomes. Despite improvement in the access and quality of antenatal care recent population based studies demonstrating increased congenital abnormalities and perinatal mortality in diabetic mothers as compared to the background population. This systematic review was carried out to evaluate the effectiveness and safety of preconception care in improving maternal and fetal outcomes for women with preexisting diabetes mellitus.

Methods

We searched the following databases, MEDLINE, EMBASE, WEB OF SCIENCE, Cochrane Library, including the CENTRAL register of controlled trials and CINHAL up to December 2009, without language restriction, for any preconception care aiming at health promotion, glycemic control and screening and treatment of diabetes complications in women of reproductive age group with type I or type II diabetes. Study design were trials (randomized and non-randomized), cohort and case-control studies. Of the 1612 title scanned 44 full papers were retrieved of those 24 were included in this review. Twelve cohort studies at low and medium risk of bias, with 2502 women, were included in the meta-analysis.

Results

Meta-analysis suggested that preconception care is effective in reducing congenital malformation, RR 0.25 (95% CI 0.15-0.42), NNT17 (95% CI 14-24), preterm delivery, RR 0.70 (95% CI 0.55-0.90), NNT = 8 (95% CI 5-23) and perinatal mortality RR 0.35 (95% CI 0.15-0.82), NNT = 32 (95% CI 19-109). Preconception care lowers HbA1c in the first trimester of pregnancy by an average of 2.43% (95% CI 2.27-2.58). Women who received preconception care booked earlier for antenatal care by an average of 1.32 weeks (95% CI 1.23-1.40).

Conclusion

Preconception care is effective in reducing diabetes related congenital malformations, preterm delivery and maternal hyperglycemia in the first trimester of pregnancy.

Consanguinity in Qatar: knowledge, attitude and practice in a population born between 1946 and 1991

From March 2007 to March 2008 a cross-sectional study was conducted in Qatar to estimate the prevalence of consanguinity among Qataris and to assess their knowledge of the risks and their attitudes towards the practice. A secondary objective was to test the acceptability of sixteen Likert-style questions within the Qatari population. Face-to-face interviews using a 70-item structured questionnaire were conducted by three native Arabic-speaking medical students with 362 Qatari employees. Where consanguinity existed between the employee's parents, a diagram of the consanguinal relationship (phylogram) was completed. The response rate was 93%. By phylogram, 22% of participants reported a cousin relationship between their parents (consanguinal relationship) and another 15% reported that their parents were from the same tribe (affinal relationship). With respect to their own marital decision, 68% of the respondents had been married at least once. By phylogram, 35% of these reported a consanguineous relationship (first marriage), 9% reported only an affinal relationship and 56% reported that they were not married to a blood relative. Results on the sixteen Likert-style attitude questions were stratified by consanguinity status of parents and of self. In the stratification by consanguinity status of parents the top five attitudes differed by group but there appeared to be more similarity between the consanguinal and only tribal groups. Attitudinal results were stratified by sex. Results showed that the males had a stronger belief in several of the attitudes than females with the exception of causation of genetic abnormalities and health problems. The phylogram was shown to collect more detailed and explicit data than hard-coding. With respect to knowledge, the results showed that knowledge was imperfect with high proportions of participants not knowing that consanguinity has been implicated in autosomal recessive diseases such as thalassaemia, inborn errors of metabolism, deafness, anomalies of the extremities and specific congenital heart defects. Additionally, a sizeable proportion of the participants did not know that a more distant cousin marriage (e.g. third cousin) theoretically could be a less genetically risky choice to potential offspring than a closer cousin marriage (half-first cousin). These results indicate that more effort needs to be made in developing public health strategies to improve the population's understanding of the cost-benefit analysis involved in contracting consanguineous marriages given the goal of healthy offspring.

Consanguinity and adverse pregnancy outcomes: the north of Jordan experience

This cross-sectional study was carried out to assess the association between consanguineous marriages and adverse pregnancy outcome in the north of Jordan. Women delivered in four major hospitals in the north of Jordan between April 2007 and May 2007 were included in the study. Non-Jordanian women and women with multiple pregnancies were excluded. Mothers answered a pilot-tested structured questionnaire administered by trained personnel in the maternity ward. Data regarding pregnancy outcomes were obtained from the patients' individual records. A total of 3,269 women with a mean age of 27.2 (SD 6.6) years were included. About 49% of women had consanguineous marriages. Consanguineous marriages were significantly associated with low birth weight delivery (13.9% vs. 10.1%), preterm delivery (19.9% vs. 12.3%), and births with congenital anomalies (4.1% vs. 0.8%) compared with non-consanguineous marriages. In the multivariate analysis, consanguinity was significantly associated with preterm delivery (OR = 1.5, 95% CI 1.2, 1.9), and congenital malformations (OR = 6.5, 95% CI 2.8, 15.3). In conclusions, this study supports the association between consanguinity and some adverse pregnancy outcomes.

Consanguineous unions and child health in the State of Qatar

The aim of the study was to estimate the prevalence and sociodemographic predictors of consanguineous unions in the State of Qatar and to assess the association between consanguinity, fertility and child health. A representative sample of 1800 Qatari women aged > or =15 years was approached for the study. Of these, 1515 (84.2%) women agreed to participate. The consanguineous marriage rate was 54.0% with estimated population confidence limits of 52.3-55.7%. First cousin unions were the most common form of cousin marriage. The level of parental consanguinity (both in the respondent's parents and her parents-in-law) was quite high. In a multivariable analysis, both education of the respondent and her husband as well as parental consanguinity were found to be strong predictors of consanguineous unions in the index generation. Although fertility was high in both groups, the mean number of pregnancies was somewhat higher in respondents with first cousin unions. Concomitantly they also had a slighter higher rate of livebirths than women in non-consanguineous unions. The occurrence of asthma, mental retardation, epilepsy and diabetes was significantly more common in offspring of all consanguineous than non-consanguineous couples.

Infant mortality, ethnicity, and genetically determined disorders in The Netherlands

BACKGROUND

Infant mortality of ethnic minorities in The Netherlands (10% of the population) is twice as high as in the indigenous Dutch population. Causes of death are different for the diverse migrant groups.

METHODS

Hospital records of nearly 600 infants who died in the four major cities between 1995 and 1998 were analysed according to the cause of death, ethnicity, and possible heredity.

RESULTS

There was a four to five times higher proportion of hereditary causes of death in the Moroccan and Turkish population, compared with the Surinamese/Antillians and indigenous Dutch.

CONCLUSIONS

This might be explained by a high inbreeding coefficient as three-quarters of the marriage partners are recruited from the home villages and between a quarter and a third of these marriages are between first cousins. Health promotion activities in The Netherlands have not been successful so far. Preconception genetic counselling might help in reducing these differences.

Effects of consanguinity on pre-reproductive mortality: Does demographic transition matter?

The aim of this study was to investigate whether there is an increase on premature deaths due to genetically determined factors at the beginning of a demographic transition. We also analyzed the effects of parental consanguinity on offspring mortality from an epidemiological viewpoint, using parish records for family reconstitution in a Basque population (1800-1990). Among the offspring of unrelated parents, 13.1% died before their first year of life (infant mortality), and 22.8% died before the age of 16 (pre-reproductive mortality). Significant increases in both infant (23.6%) and pre-reproductive (38.5%) deaths were found among the progeny of first cousins or closer relatives, 1C (F > or = 0.0625). The corresponding relative risks of mortality were 1.79 (95% confidence limits: 1.37-2.28) and 1.68 (1.38-2.01), respectively. Estimates of the population attributable risks indicate that 4% of pre-reproductive mortality is ascribable to consanguineous unions, although kinships other than 1C produced only slight increases in offspring mortality. Evidence on the relationship between the demographic transition and the increase in premature deaths due to genetic factors was obtained through a principal component analysis (95.1% of variance accounted for). During the initial stages of the demographic transition, the population experienced substantial elevations in mean family size, natural increase of the population, frequency of close consanguineous matings (1C), and death rate due to congenital anomalies and perinatal diseases. These findings are of interest for the health services of many developing societies in Asia, Africa, and Latin America, which are nowadays immersed in the demographic transition process.

The influence of consanguineous marriage on infant and child mortality among Palestinians in the West Bank and Gaza, Jordan, Lebanon and Syria

OBJECTIVES

The purpose of this paper is to explore the characteristics of mortality differences associated with consanguineous marriage among Palestinians in the Middle East.

METHODS

The data came from five surveys of Palestinians living in the West Bank and Gaza, Syria, Jordan and Lebanon, conducted during the period 1995-2000. Infant and child mortality was estimated for the offspring of consanguineous and non-consanguineous parents using the synthetic cohort method.

RESULTS

The data showed an increase in infant mortality of 15.0 additional deaths per 1,000 births among the offspring of first cousins, and a corresponding increase of 6.1 deaths per 1,000 for the progeny of parents from the same patrilineal clan.

CONCLUSION

In populations where marriage within kin groups is common, both first cousin marriage and intra-group marriage carries an added risk of infant and child mortality.

Risk factors for neonatal mortality in low-income population subgroups in Karachi, Pakistan

This paper assesses the risk factors for neonatal mortality (0-28 days of life) for full-term singleton live births. The study sample comprised 1,011 ever-married women who were residents of four multi-ethnic, multi-religious low-income areas of Karachi, Pakistan during 1995. The analysis sample was restricted to 4,488 live births to 912 women. Results showed that 4.8% (n = 217) of all births ended in death in the neonatal period, and 76% (n = 164) of these neonatal deaths occurred in the first week of life. While neonatal mortality rates had declined appreciably over time, a large proportion of neonatal deaths were clustered in a small group of women. The univariate analysis showed a statistically significant association between a number of maternal-level parameters (e.g., mother's age at birth, level of formal education, employment status, religious affiliation, and consanguinity) and child-level parameters (e.g., birth order, birth interval, survival status of the preceding child, sex of the neonate, year of death). At the multivariate level, consanguinity, birth order and year of death were found to be statistically significant risk factors for neonatal mortality analyses despite adjustment for death clustering. The study highlights the importance of inbreeding as a determinant of early offspring death, and points to the need for better understanding of why deaths are clustered in certain families. Given the widespread practice of close cousin marriages in Pakistan across all socio-economic groups, there is a need to validate the findings in less economically disadvantaged population subgroups within the country.

Endogamy, consanguinity and community genetics

The population of India is composed of many thousands of subpopulations, divided by geography, language, religion and caste or biraderi (patrilineage) boundaries, with endogamous marriage the norm. The net effect has been the creation of multiple genetic isolates with individual mutation profiles, but to date the clinical consequences of this highly complex differentiation have been largely ignored. In contrast, the topic of consanguinity continues to attract attention among medical and population geneticists, clinicians and social scientists. The significant progress made in India in improving childhood nutritional status and combating infectious disease means that genetic disorders have assumed ever-increasing importance. In populations where consanguineous marriage is widely practised, recessive genetic disorders will continue to gain greater prominence in the overall spectrum of ill health. At the same time this increase will in part be negated by urbanization and the move to smaller family sizes, which predictably will result in a decline in the prevalence of consanguineous unions. Developing an understanding of these changes will require a wide-ranging and multidisciplinary investigative approach for which community genetics is ideally suited.

Lay perceptions of genetic risks attributable to inbreeding in Pakistan

Pakistan along with many other West and South Asian countries has a very high prevalence of consanguineous, especially close cousin, marriages. Although there is substantial empirical information on offspring morbidity and mortality attributable to parental consanguinity, population-based information on how communities in general, and women in particular, perceive the health risks associated with consanguineous unions is limited. This paper considers community perceptions of health effects associated with consanguineous marriages using qualitative data from 15 focus group discussions and 294 in-depth interviews. The study was conducted in four low-income, multi-ethnic, and multi-religious communities in Karachi, the principal commercial center of Pakistan. The results show a general lack of awareness of the possible adverse health effects of consanguineous marriage. In cases where a link between consanguinity and ill health was acknowledged, it often centered on the familial origins of non-communicable disorders such as diabetes and hypertension or infectious diseases such as tuberculosis. Belief in fate and the "evil eye" was widespread across all ethnic and religious groups. Many respondents did not agree with medical explanations of a genetic mode of disease inheritance, even in cases where there was an affected child in the family. The absence of a uniform manifestation of disease among all children of a couple who were identified as carriers of a specific mutation added to the confusion among participants. The study highlights the need for further quantification of risks associated with consanguinity and a need for provision of appropriate information to primary-care clinicians and also to communities. The likely impact of increasing morbidity attributable to inbreeding on the health care system in resource poor settings is also discussed.