Consanguinity and its socio-biological parameters in Rahim Yar Khan District, Southern Punjab, Pakistan

Background: Rahim Yar Khan (RYK) District is a multi-ethnic assemblage of both ancient and migrated communities in Southern Punjab, Pakistan. There is a paucity of knowledge on the bio-demographic structure of this endogamous population.
Methods: We have carried out a cross-sectional epidemiological study in RYK District and recruited 2174 random Muslim married females. Detailed account of marital union types, level of consanguinity, and subject’s fertility, was taken.
Results: The analyses of these data revealed that consanguineous unions (CU) were 58.46 %, rendering an inbreeding coefficient (IC-F) = 0.0355. The CU were observed to be significantly higher in subjects originating from rural areas, speaking Saraiki language, illiterate or having a religious/Madarsa education only, and belonging to nuclear family type. The rate of consanguinity was also higher in subjects whose husbands were engaged in unskilled manual or skilled manual jobs, and had consanguinity in the parental generation. Multivariate logistic regression analyses revealed that variables like Saraiki language, illiteracy, reciprocal marriages, and parental consanguinity, were the significant predictors of CU in the subject. Among the first cousin unions (which constituted 52 % of all marriages), parallel-cousin and patrilineal unions were in the majority (54 and 57 %, respectively), and father’s brother’s daughter type had the highest representation (31 %). The analyses further demonstrated that fertility and mean live-births were significantly higher in women who had CU compared to the non-consanguineous (NCU) group (p < 0.006); and significantly higher number of sons per women were born to the mothers who had CU compared with the NCU sample (p = 0.0002). However, there were no differences in the CU and NCU samples with respect to pre- or post-natal mortalities and child morbidities.
Conclusions: The scientific findings in RYK District are distinct from the observations in other Pakistani populations and clue to a unique nature of this population. This study presents a comprehensive account of consanguinity and IC-F in RYK District and would be helpful in getting an insight into the structure of this population.

Keywords
Consanguinity; Inbreeding coefficient; Fertility; Sex ratio; Child mortality; Child morbidity; Genetic epidemiology; Rahim Yar Khan; Southern Punjab; Pakistan