Biosocial perspective of consanguineous marriages in rural and urban Swat, Pakistan

Abstract

Consanguineous marriages in two population samples, one rural and one urban, from Swat (Pakistan) were studied. The frequency of consanguineous marriages was found to be 37.13% and 31.11%, and mean inbreeding coefficients were calculated as 0.0168 and 0.0162, for the rural and urban populations respectively. The most frequent type of marriage was between first cousins, in both samples. Among first cousin marriages, those with father's brother's daughter were predominant. Mean inbreeding coefficient was higher for higher socioeconomic groups in both samples. Differences by ethnic and educational groups were also found. Contrary to previous studies, a significant increase in the incidence of consanguineous marriages over the years has been observed. The incidence of premature mortality was significantly higher only in the offspring of first cousin marriages. Significantly higher incidence of morbidity in the offspring of consanguineous marriages was also observed.

PIP: Consanguineous marriages continue to be preferred in many major human populations. The subsequent inbreeding, however, leads to increased homozygosity which, in turn, leads to an increased risk of premature morbidity and mortality among offspring. The authors studied consanguineous marriages in one rural and one urban population in Swat, Pakistan, via a 1986 random survey sample of married couples. The proportion of sampled marriages to the total estimated marriages in the population is 0.062. There has been a significant increase in the incidence of consanguineous marriages over the years. 37.13% of marriages in the rural population and 31.11% in the urban population were consanguineous. Mean inbreeding coefficients were calculated to be 0.0168 and 0.0162, respectively. The most frequent type of marriage in both samples was between first cousins, predominated by those involving the father's brother's daughter. The mean inbreeding coefficient was higher for higher socioeconomic groups in both samples. Differences were also found by ethnic and educational group. A significantly higher incidence of morbidity was observed among the offspring of consanguineous marriages. The incidence of premature mortality was, however, significantly higher only in the offspring of first cousin marriages.