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\u2019s 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\u2019s brother\u2019s 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