Genetic association analysis of human longevity in cohort studies of elderly subjects

A system for sensing a characteristic of fluid flowing to or from the body of a human or animal comprising a conduit having a first end adapted to be outside the body, a second end adapted to be received within the body, and a flow passage through which fluid can flow between the first and second ends and a probe including a sensor for sensing a characteristic of the fluid. The probe is mounted on the conduit with the sensor in the flow passage. The sensor is isolated from the fluid flowing in the flow passage.