Incidence of diabetes after a partner's diagnosis.

People socially connected with each other often share health risks, possibly due to shared environments and behaviors. In a cohort study, we examined whether incidence of diabetes was different for individuals with recently diagnosed partners compared to individuals similar on other characteristics but whose partners were never diagnosed with diabetes. We analyzed 2007-11 data from Kaiser Permanente Northern California (KPNC), an integrated health system with >3.5 million members. We estimated annual diabetes incidence controlling for demographic, socio-economic, behavioral, and health characteristics. Using propensity score matching and multivariate logistic regression, we compared odds of incident diabetes among co-residing partners ages 18-89years of people who had been diagnosed with diabetes during the previous year (in robustness checks up to the previous three years) and people who had never been diagnosed but were similar on observed characteristics. Partners of newly-diagnosed people had annual diabetes incidence of 16.4/1000, equivalent to10.8 times higher (95%CI: 9.2-12.6) than people whose spouses had never been diagnosed (1.5/1000). Odds remained higher three years after a spouses' diagnosis (45.4 vs. 11.7/1000). Adjusting for other characteristics, odds of diabetes for those with a partner diagnosed in the previous year were 8.7 times higher (CI: 7.4-10.2) than among those whose partner had never been diagnosed. Also, partners of persons with recently-diagnosed diabetes developed diabetes at much higher rates than the general KPNC and U.S. POPULATIONS: Individuals with a recently diagnosed partner could be considered a high-risk population for screening and prevention.