Gender of study partners and research participants associated with differences in study partner ratings of cognition and activity level.

OBJECTIVE: Studies of Alzheimer's disease (AD) typically include "study partners" (SPs) who report on participants' cognition and function. Prior studies show SP reports differ depending on the relationship between the SP and participant, that is, spouse or adult child. Adult children SPs are typically female. Could differing reports be due to gender? Knowing this may help explain variability in measurement.

METHODS: The Aging, Demographics and Memory Study (ADAMS) enrolled a subset of participants from the Health and Retirement Study (HRS). Each participant had a SP. Bivariate and multivariable regression models compared 718 SP-participant dyads.

RESULTS: In analyses of four groups defined by SP and participant gender, dyads composed of two women were less likely to identify as White (75.8%, 95%CI 70.4 to 80.5) than dyads composed of two men (93.3%, 95%CI 81.2 to 97.8). In analyses adjusted for severity of cognitive and functional impairment, women SPs rated women participants as more active than they rated men, mean 2.15 (95%CI, 2.07 to 2.22) versus mean 2.30 (95%CI, 2.24 to 2.37), respectively, on a 4-point scale. Similarly, men SPs rated women participants as more active than they rated men, mean 2.1 (95%CI, 2.0 to 2.2) and mean 2.4 (95%CI, 2.3 to 2.5), respectively. In an analysis of cognitively unimpaired participants, women SPs rated participants' memory worse than men SPs did (p<0.05).

DISCUSSION: SP and participant gender influence SPs' reports of another person's cognition and activity level. Our findings expand what is understood about how non-disease factors influence measures of disease severity.