On the reliability of assessing consanguinity in a highly fertile population: a Kuwaiti example

ABSTRACT

Kuwait is considered to have the highest prevalence of consanguinity in the world. Since findings of consecutive surveys were not consistent, our objective was to explain the differences in assessing the extent of blood relationship among the Kuwaiti couples. A representative sample of 482 households from the most developed [the Capital] and the least developed [Jahra] of the five governorates in Kuwait was selected. Previously trained team members administered a structured questionnaire through a household face-to-face interview. The procedure was repeated after a year. There were 1407 ever married individuals who provided data on their parental blood relationship and their own marital consanguinity. Inter-observer variation was fairly satisfactory up to the level of second cousins, but appeared very poor when third cousins were taken into account. The large differences between the authors who assessed the prevalence of blood relationship in Kuwait were due to the methodological approach [operational definition of consanguinity, data collection, time frame, etc.] but the main reason appeared to be the recall bias resulting from a huge number of relatives. Consanguinity data obtained by interview are too 'soft' for studying a highly fertile population, like that of Kuwait. Meticulous data collection may provide reliable information up to the level of second cousins, but not beyond