Objective: To estimate the genetic susceptibility and its relative risk (RR) in the first degree relatives of type 2 diabetes mellitus (DM) through family aggregation analysis.
Methods: A population-based case-control study including 654 pedigrees (363 index cases and 291 controls) was carried out.
Results: The prevalence rate in the first degree relatives of DM probands was 3.94%, significantly higher than that in the controls (1.09%), with a relative risk of 3.62 (chi(2) = 36.5, P < 0.001). The RRs in different consanguineal relatives were all higher than 3.0. The younger was the probands at diagnosis for DM, the higher its prevalence rates and RRs among their relatives was and the more likelihood that more than one case of DM occurred in them.
Conclusion: Significant family aggregation and higher genetic susceptibility were found in the first degree relatives of DM, on whom prevention and treatment for DM should be focused.